HomeMy WebLinkAbout3.1Attachment 11 ATTACHMENT 11A
INTRODUCTION
This document responds to issues raised by Sarah H. Sigman of the law firm of Shute, Mihaly&
Weinberger LLP, in a letter to the Town of Los Altos Hills dated January 20, 2016 regarding the
"Stirling Subdivision Mitigated Negative Declaration" ("Shute Letter"). The Shute Letter was
submitted on behalf of the Friends of Upper Matadero Creek whose members are not identified in
the letter. The environmental document to which the Shute Letter refers is the Initial
Study/Mitigated Negative Declaration for the Stirling Subdivision (EMC Planning Group,
September 2015) ("IS/MND" or "IS"), which was prepared for the Town of Los Altos Hills as
the lead agency. The responses included in this letter are organized and numbered to correspond
to those included in the Shute Letter.
This document also responds to issues raised by Sue Welch, whose comments are included in a
letter dated January 22,2016 regarding 28030 Natoma Road("Welch Letter")
Both letters were submitted after the close of the 30-day public review period for the IS/MND.
The letters are included as Attachments A and B,respectively.
This document contains information that supplements and refines analysis and mitigation
measures already included in the IS/MND pursuant to issues raised in the above-referenced
comment letters.
ILA Footbridge Description
The commenter states that the IS/MND's description of the footbridge across the Matadero Creek
is not described with sufficient detail toallow an.informed analysis of its impacts under CEQA.
CEQA Guidelines Section 15146, Degree of Specificity, notes that the degree of specificity
required in an Environmental Impact Report ("EIR") will correspond to the degree of specificity
involved in the underlying activity which is described in the EIR. CEQA Guidelines Section
15071, Contents, states that a Negative Declaration shall include a brief description of the
project. At the time the IS/MND was prepared, detailed information about the pedestrian
footbridge design was not available. Consequently, information included in the project
description about the footbridge was brief, but sufficient to allow an informed analysis of its
potential impacts. Sheet.3 of the Tentative;Map included in Attachment C of the IS/MND
identified the approximate location of the proposed footbridge. Furthermore, as part of the
project description, the planned footbridge is shown across Matadero Creek (p. 14). Since
publication of the IS/MND, additional detail has been provided about the footbridge (described
below), however this supplemental information does not change the analysis, mitigations, or
conclusions in the IS/MND.The potential impacts of constructing the footbridge are identified
throughout the IS/MND, including potential impacts on biological resources and water quality as
described below. Thus, there is no basis for the commenter to conclude that the analysis of the
footbridge's impacts is inadequate under CEQA.
Level of Detail. CEQA requires an MND to include the location of the project,preferably shown
on a map, the proposed findings, a copy of the ISIMND documenting the reasons supporting the
findings, and mitigation measures, if any, included in the project to avoid potentially significant
effects. The location of the proposed footbridge and its approximate size are identified and
disclosed to the public in the IS/MND. Furthermore, the potential impacts of constructing the
STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE:LETTERS
footbridge over Matadero Creek to riparian habitat and wildlife are adequately anticipated and
described in the IS/MND. Construction and operational impacts on Matadero Creek (a
jurisdictional waterway) and on riparian habitat were conservatively assumed to be-potentially
significant as described in the IS/MND (p. 51). Mitigation measure BIO-7 is included in order to
mitigate the potential impacts to less than significant.Mitigation measure BIO-7 describes bridge
design conditions that would trigger significant impacts and includes specific performance
standards that must be met to reduce the impacts to less than significant. The IS/MND thus
adequately describes the size and location of the footbridge and proposes mitigation to avoid any
potentially significant impacts.
Water Quality Impacts. Water quality in Matadero Creek could be adversely affected by
footbridge construction activities if erosion control and other water quality protection measures
are not taken. As described in the IS/MND (pp. 68-70), all construction activities within the site
would be regulated through-the National Pollutant Discharge Elimination System ("NPDES")
requirements of the California Water Quality Control Board. Best management practices (which
could include timing of construction, erosion protection and sediment control, solid waste
management, etc.)must be employed during bridge construction to protect water quality, and will
be defined in a Storm Water Pollution Prevention Plan ("SWPPP"). The,adequacy of the Storm
Water Pollution Prevention Plan will be evaluated by the Town Engineer subject to consistency
with defined regulatory performance standards. This issue is discussed in more detail in the
discussion of water quality issues in Section IV.C.2 below. Best management practices to protect
water quality during construction of the footbridge, as well as the entire project, must be
employed regardless of the detailed bridge design.
Wildlife Impacts. The IS/MND also discloses the effects of the proposed project on special-
status wildlife (pp. 41-50). As stated at the bottom of page 41, "If present within proposed
impact areas on the site (including the pedestrian bridge and recreational trail within the wooded
open space easement area), development may impact the above species." Mitigation measures
BIO-2, BIO-3, BIO-4, BIO-5, BIO-6, and BIO-7 proceed to address potential impacts of
constructing the proposed project, including the footbridge, on the nine special-status wildlife
species with potential to occur within the site, including Matadero Creek and its associated
riparian habitat.. 'The mitigation measures contain performance standards that must be met
regardless of the final detailed bridge design,which is all that CEQA requires.
Additional analysis of the potential impacts of the footbridge on wildlife movement and wildlife
has been conducted by Live Oak Associates in a letter dated April 21, 2016, and in a letter
prepared by H.T.Harvey&Associates dated April 28, 2016. The letters were prepared to clarify
and refine analyses in the IS/MND. The letters are included as Attachments D and E. Live Oak
Associates concludes thatthe proposed trail along the northern boundary of the site and the
bridge design (perpendicular crossing of creeks with a free-span bridge is preferred by resource
agencies) will not substantially impede movement patterns of any wildlife. Live Oak also notes
that during construction of the trail and bridge, daytime wildlife movements may be temporarily
altered, but movements during dawn and twilight (crepuscular movements), and nighttime
movements will not be appreciably affected. Once the 4 to 12 week construction period for these
improvements ends, regional movement patterns are expected to return to pre-construction
conditions. Live Oak Associates concludes that the temporary effects on daytime movements
would be less than significant(Live Oak Associates 2016,p. 3).
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H.T. Harvey draws conclusions that are similar to Live Oak Associates. H.T. Harvey does not
expect the construction of a footpath-on the northern portion of the project site or a.footbridge
across Matadero: Creek to substantially interfere with wildlife movement along the Matadero
Creekcorridor. H.T. Harvey observed numerous trails paralleling the creek within the future
open space area such that animals will not be restricted to moving through the open space area at
any one location(e.g., the location of the proposed footbridge). Neither the path nor bridge will
include features such as tall, impassable fencing that would preclude the ability of a variety of
animals to simply walk across the path or under or around the bridge. Furthermore, because
many of the reptiles, amphibians, and mammals that may move within or through the project site
along the Matadero Creek corridor are active at night when little or no human use of the path or
bridge is expected, human activity along the path and bridge will not substantially interfere with
the ability of wildlife to cross the trail(H.T.Harvey&Associates2016,p. 3).No evidence,much
less substantial evidence,has been provided to support a fair argument that the proposed pathway
and footbridge, as mitigated,would have a significant impact on the environment.
Additional Footbridge Description Information. Prior availability of a refined footbridge
design or construction plan would not have materially affected the conclusions in the IS/MND
regarding its potential impacts. Regardless, the applicant has now provided supplemental design
and construction methodology details for informational purposes.
The location of the footbridge is now defined. Its location has been established based on the
results of a Creek and Riparian Jurisdictional Assessment conducted by WRA in April 2016.The
jurisdictional assessment is included as Attachment F. The field surveys consisted of multiple
site visits to determine the location of the Ordinary High Water and the California Department of
Fish and Wildlife ("CDFW')jurisdictions of the creek as required in mitigation measure BIO-7
in the IS/MND. The purpose was threefold: 1) to locate the bridge outside of any portion of the
creek that could be considered jurisdictional by the United'States Army Corps of Engineers
(USACE); 2) to avoid removal of riparian vegetation; and 3) to identify the narrowest reach of
the creek in the immediate vicinity of the preliminary bridge location shown on the Tentative
Map at which the bridge abutments can be installed above the bed or bank of the creek. For the
proposed location, an approximately 35-foot long bridge measured as the distance between the
bridge abutments would be required. The bridge would be approximately five feet wide.
Regarding construction, exact scheduling and details will be determined with a qualified
contractor when the contractor is retained. However, the preliminary construction and materials
approach can be summarized as follows:
■ Light weight construction materials will be selected during the detailed design phase. There
is an abundance of light-weight material choices for the footbridge. The footbridge
abutments will be constructed using concrete and backbone support will consist of three steel
beams.
■ There will be two construction access points, one from the project site and one from the
opposite side of the creek. From the project site, construction materials will be hand carried
down the hill from the upland portion of the project site where subdivision improvements are
proposed. From across the creek, access will be via Edgerton Road, using the paved Fire
District access road, which is also a Pathway Easement. This access road connects to the
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Stegner Trail within approximately 150 feet of the intersection of the Stegner Trail and the
new trail planned as part of the proposed project.
■ To adjust for the narrow and sensitive access routes to the footbridge site, equipment for
constructing the footbridge will largely be limited to hand tools, small trucks, and simple
excavation equipment such as backhoes and Bobcat loaders. Any vehicles and light
equipment will utilize the Fire District access road.
■ The abutment excavations will most likely be dug with hand tools. Concrete for the
abutments will be mixed at the abutment sites to avoid the need for large concrete transport
vehicles to access the footbridge location. Approximately 250 gallons of water are needed to
mix the concrete. This volume can be accommodated with a tank on a one-ton pickup truck.
■ A temporary cable pulley system will be constructed between the two bridge abutments so
that the bridge beams and other materials can be transported across the creek. This is a
commonly used bridge construction mechanism that is used to limit the need to cross the
creek and minimize the construction zone footprint.
ILB Additional Activities within Open Space Easement
The commenter also states that the IS/MND does not adequately describe information about
additional project activities occurring within the proposed Open Space Easement.The analysis in
the IS/MND explains that regulatory standards and mitigations identified in the IS/MND would
ensure that potential impacts from construction/operation of these features on special-status
species plant and wildlife, water quality, and cultural resources will be less than significant.
Nonetheless, a more detailed overview of these improvements is provided below in order to
amplify and clarify the IS/MND's discussion.
Stormwater Drainage Pipe and Energy Dissipator. As described in the IS/MND (pp. 68-70),
the proposed project is subject to C.3 stormwater control requirements. Stormwater control
measures must be included in the proposed project to ensure its consistency with Santa Clara
County's broader NPDES Permit No. CAS029718. Sheet 7 of the Tentative Map included in
Appendix A of the IS/MND show stormwater control and stormwater quality design features
included in the project.
As required by current storm water regulations, the storm water runoff from the subdivision will
be treated to maintain water quality using multiple features, including a bio-filtration pond. After
treatment (natural filtering), the runoff will be conveyed through an underground detention tank
designed to limit the rate of peak runoff from the site to the pre-development peak rate. These
features are shown on the Tentative Map and are located above the boundary of the open space
easement.
Two additional storm drainage improvements that are part of the proposed project were
inadvertently omitted from the project description. These include a storm drainage conveyance
pipe and a storm water energy dissipator. The flow from the detention tank will be conveyed
downhill through the open space easement in a 15-inch diameter pipe. The pipe will be installed
underground within a trench from the detention tank location to the uphill (eastern) boundary of
the open space easement. To minimize the disturbance of tree roots the pipe will "daylight" out
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of the ground at the easterly edge of the open space easement. The segment within the open
space easement will be only partially buried. The pipe will be staked to the ground surface using
a standard pipe installation technique for a "downdrain pipe". A semicircular gro"ove will be
excavated in the slope using hand tools to embed the lower half of the pipe into the soil, leaving
approximately eight to nine inches of pipe above ground. This technique will minimize trenching
and disturbance to tree roots, while reducing the profile height of the pipe to allow wildlife
movement over the pipe. The hand excavated soil will be compacted as a wedge on each side of
the pipe to further assist small animals to cross over the pipe. The drainage pipe will terminate at
an energy dissipator.
An energy dissipator will be used to dramatically reduce the velocity of stormwater traveling
through the pipe so that its potential to cause soil erosion at the drainage discharge point is
negligible. After the Tentative Map was prepared, the Town provided input to the applicant
regarding limits on improvements that can be made within property line setbacks. In response,
the location of the discharge outfall/energy dissipator on Matadero Creek as shown on the
Tentative Map has been moved about 30 feet uphill from the subdivision boundary (and creek)
The dissipator will consist of a pipe"T"with perforated extensions of pipe that will dissipate the
water at a very low flow rate.
Construction methods to install the drainage pipe and energy dissipator would be similar to those
for other proposed utility improvements. Construction for the drainage pipe would involve
excavating a narrow trench. Construction activities would result in removal of vegetation within
the footprint of the 15-inch pipe and the energy dissipator pipe. Like all other construction
activities associated with the proposed project, vegetation could also be damaged by movement
of construction workers and equipment.
Like other aspects of the proposed project, regulatory standards and mitigations identified in the
IS/MND would ensure that potential impacts from construction/operation of these features on
special-status species plant and wildlife, water quality, and cultural resources will be less than
significant. For special status species, representative regulations include the federal and state
endangered species acts, California Fish and Game Code, federal Migratory Bird Act, and U.S.
Army Corps of Engineers and State Water Quality Control Board Regulations promulgated under
the federal Clean Water Act. The applicable mitigation measures include mitigation measures
include BIO-1 through BIO-8. For water quality, representative regulations include NPDES
requirements promulgated under the Clean Water Act and implemented locally as "C.3"
requirements, and the Porter-Cologne Water Quality Control Act. Cultural resources analysis
and impact determination requirements are defined in CEQA Guidelines Sections 15064.5 and
15126.4. Mitigation measures CR-1 and CR-2 address potential impacts on cultural resources.
Like the proposed footbridge discussed in Section ILA above, the drainage pipe and dissipator
would be constructed within the open space easement area. Potential biological resource and
water quality impacts, regulatory requirements, and mitigation measures associated with
construction in this area are described in Section ILA above. Construction and operation of the
drainage pipe and dissipator would not have new or more intensified biological resource or water
quality impacts than are identified for the footbridge for other components of the proposed
project described in the IS/MND. Implementation of the proposed project consistent with
regulatory requirements and mitigation measures identified in the IS/MND for biological
resource and water quality impacts would ensure that related impacts would be less than
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significant. Similarly, implementation of the proposed project consistent with the cultural
resources mitigation measures included in the IS/MND would reduce potential impacts on
cultural resources to less than significant.
Supplementary analysis of the potential effects of constructing the storm water improvements
within the open space easement is addressed in Live Oak Associates letter in Attachment D. Live
Oak Associates states that the technique planned for partially burying the storm drainage pipe
will minimize trenching and disturbance to tree roots while allowing the free movement of
wildlife through the open space; consequently, the storm water improvements will have a less-
than-significant impact regarding regional wildlife movement (Live Oak Associates 2016,pp. 3-
4).
Construction of Subdrains on Lots 5 and 6. Installation of subdrains on Lots 5 and 6 is
recommended by the project geologist and by the Town's consulting geologist (see Appendix B
of the IS/MND) to enhance the stability of a past landslide that traverses both lots. The drains
would function solely to redirect existing subsurface flow through and around the unstable area.
Like installation of stormwater collection piping and other wet and dry utilities proposed as part
of the project, installation of subdrains would involve excavating a narrow trench, placing gravel
and four-inch drain pipes in the trench and backfilling the trench.
The subdrains will consist of four-inch perforated PVC pipes installed within the old landslide
area as directed by the geotechnical engineer. The trenches will be approximately one foot wide.
Oak trees are located within the footprint of the slide. The trenches for segments of pipe to be
placed under the drip lines of the oak trees will be initially dug with hand tools to locate roots.
Major roots of two inches or greater in diameter will be preserved. Trenches located outside of
the drip line or previously exposed by hand digging that are clear of roots may be excavated with
a small backhoe.
The subdrains will be connected to solid (non-perforated) four-inch PVC piping to convey the
seepage to a point below the mapped landslide area as shown on the Tentative Map. These
trenches will be approximately four inches wide and will be dug where theycross into the open
space easement boundary. The trenches will be located to minimize impacts to tree roots. A"T"
will be installed at the outfall of these pipes with perforated pipes extending a few feet in each
direction to dissipate and spread the flows. Similar to the energy dissipator noted above for the
storm water pipe, the rate of flow from the subdrains will be managed by the energy dissipator
resulting in minimal flows that will not have any significant impact.
As with the storm water discharge pipe and related energy dissipator described previously,
construction of the subdrains would not result in potentially significant biological resource or
water quality impacts that are not already identified for constructionand operation of other
components of the proposed project. Those effects are mitigated to less than significant through
conformance with regulations and mitigation measures included in the IS/MND that apply to all
project construction and operational activities. This is also the case for potential impacts on
cultural resources.
Demolition of Existing Structures. Demolition of single-family structures typically involve the
use of standard construction equipment such as a small bulldozer and hand held power tools.
Demolition of an existing structure is subject to regulatory requirements related to handling and
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disposal of hazardous materials, including asbestos and lead based paint. Mitigation measure
HAZ-1 in the IS/MND (pp. 65-66) identifies applicable regulatory requirements and the related
performance standards that must be followed to assure that related impacts would be reduced to
less than significant. If such materials are found, the regulations identify how such materials are
removed,transported, and disposed to ensure public health and safety is maintained.
III.A Lack of Special-Status Species Information
The commenter asserts that there is insufficient information regarding the potential presence of
special status species at the Project site. However, the methodology used in the IS/MND for
evaluating special-status plant species impacts is standard professional practice in preparing
CEQA documentation. Please refer to the IS/MND (pp. 39-41). The initial field reconnaissance
is intended to record observable plant species and habitats and to determine the potential for
presence of plant species that,cannot be reliably observed during the reconnaissance given peak
blooming seasons that occur outside.the reconnaissance date. Where any potential exists for
special-status plant species to be present based on field conditions (e.g. presence of suitable
habitat) and review of records of occurrence in the project site vicinity, mitigations are included
in CEQA documentation. Based on this methodology, the IS/MND (pp. 39-41) identifies that
there is low potential for five special-status plant species to occur on the project site due to the
presence of marginally suitable habitat. A brief description of each species is included.
Mitigation typically requires that focused surveys for such species be conducted during their
respective peak blooming seasons to determine their presence or absence. Mitigation measure
BIO-1 in the IS/MND (pp. 40-41) is proposed precisely for this purpose. It requires focused
plant surveys for the five special-status plant species prior to construction and sets forth the steps
to be undertaken in the event any such species are discovered, to reduce impacts to less than
significant.
CEQA does not require focused plant surveys to be conducted prior to a lead -agency's
determination to approve or deny a project. CEQA Guidelines Section 15126.4(a)(1)(B)permits
a.lead agency to include measures that specify performance standards to mitigate a significant
effect of a project that can be accomplished in more than one specified way. Mitigation measure
BIO-1 identifies the specific performance standards that must be met in conducting focused
surveys. It further identifies specific actions that must be taken to reduce impacts to less than
significant if such species are observed during the focused surveys in areas where they could be
impacted by construction or operation of a project. In this regard, mitigation measure BIO-1
does not constitute deferral of mitigation.
To proactively advance the implementation of mitigation measure BIO-1, the applicant retained
WRA, a qualified biological consulting firm, to conduct focused surveys for the four species
whose peak blooming season occurs before or within the spring. The results of the surveys are
included in Attachment G.None of the four species were observed. The focused surveys covered
all areas that could be affected by construction and operation of subdivision improvements, areas
within the open space easement where the footbridge, trail pathway, landslide subdrain system,
and storm drainage pipeline/energy dissipator improvements are planned. A focused survey for
Congdon's tarplant will be conducted in the fall during its peak blooming season, with a
complete report on all focused surveys and results delivered at that time, before any construction
occurs.
STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LETTERS
III.B Asbestos and Lead-Based Paint
The commenter states that the IS/MND does not adequately disclose the existence of hazardous
materials in existing structures on-site that will be demolished as part of the Project. That is not
the case. The IS/MND follows standard professional practice in preparing CEQA documentation
for analysis of these impacts. The IS/MND includes discussion of potential impacts on public
health and safety from demolishing existing structures. Impacts could occur if the structures
contain asbestos or lead-based paint. The state regulates asbestos and lead-based paint
containing materials, including where such materials may be present and released to the
environment through demolition of existing structures. The related regulatory requirements are
described in mitigation measure HAZ-1 in the IS/MND (p. 65)._
There is no requirement in CEQA or elsewherethat a determination of the presence of these
materials in a building proposed for demolition must occur prior to a lead agency's consideration
to approve a project that proposes such demolition. Nor does the commenter cite any authority to
the contrary. Mitigation measure HAZ-1 contains reference .to the performance standards
(regulatory requirements)that must be met prior to,during, and after demolition. As described in
CEQA Guidelines Section 15126.4(a)(1)(B), "Formulation of mitigation measures should not be
deferred until some future time. However, measures may specify performance standards which
would mitigate the significant effect of the project and which may be accomplished in more than
one specified way." Implementation of the mitigation measure does not, therefore, constitute
deferred mitigation and would reduce potential public health and safety impacts to less than
significant.
IV.A Low Threshold for Requiring an EIR
An agency must prepare an EIR whenever it is presented with substantial evidence of a fair
argument that a project may have a significant effect on the environment, even if there is also
substantial evidence to indicate that the impact is not significant. CEQA expressly defines
"substantial evidence" as "fact, a reasonable assumption predicated on fact, or expert opinion
supported by fact." Public Res. Code Section 21080(e)(1). While the commenter provides
extensive comments on the content of the IS/MND, which are addressed below, the commenter
does not provide substantial evidence that that the IS/MND fails to disclose one or more
significant impacts of the proposed project.
IV.B Heritage Oaks
The commenter states that the IS/MIND's analysis of potential impacts on Heritage Oaks is
uncertain, and does not specify adequate mitigation measures. HortScience provided a
supplemental evaluation of the project's impacts to Heritage Oaks in a Revised Arborist Report
dated April 2016. The Revised Arborist Report is included as.Attachment H. In that report,
HortScience clarifies the number of Heritage Oaks to be removed as part of the proposed project
due to refinement of the development plans. Nine oaks are to be removed within the proposed
road alignment, six oaks are to be removed that are adjacent to the new road, and nine oaks are to
be removed within the slide repair. Of these 24 trees, 19 are Heritage Oaks. An additional five
trees, all Heritage Oaks, will be removed to allow construction of the access road. Of the 24
Heritage Oaks to be removed, five have low suitability for preservation. HortScience also
identifies three Heritage Oaks along the access road previously listed for removal that will be
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preserved. In sum, in the area where development will occur a total of 129 trees will be
preserved, including 108 Heritage Oaks. In addition, there are 285 additional Heritage Oaks in
the open space easement area, all of which will be preserved, and which will not be significantly
impacted by the very limited.construction activities in the easement area. These clarifications do
not affect the adequacy of the ISJMI'4D's analysis, nor its conclusion that impacts on Heritage
Oaks would be less than significant.
All revised arborist reports from 2014 to the present include a description of the impacts to trees
on the development site from grading of the road, drainage,potential driveways, access roads and
the pedestrian path. HortScience identifies 23 trees as being close to the road and access road
improvements. HortScience concludes that the 23 trees will tolerate the impacts from the
proposed improvements because of necessary precautions that will be required during demolition
and construction(see mitigation measure BIO-8).
The IS/MND and the HortScience Revised Arborist Report consider impacts to trees from the
proposed subdivision improvements (road,pathway etc.). The exact location of future residential
structures is not known at this time. The Tentative Map and the November 2014 HortScience
report include information known at this time regarding Heritage Oaks that may require removal
due to construction of subdivision improvements. The only proposed project subdivision
improvements planned within the open space easement include the footbridge, meandering path,
landslide subdrain system,.and storm water drainage pipeline/dissipator system. HortScience
concludes that the future construction of any houses within the envelopes shown in the May 22,
2015 Proposed Tentative Map will not result in any more tree loss because of the Tree Protection
Guidelines required under mitigation measure BIO-8.
Tree Protection Zone Information. HortScience also prepared a supplemental Response Letter,
dated April 20, 2016, clarifying previous recommendations for Tree Protection Zones that
appeared inconsistent. The Response Letter is included as Attachment I. The alleged
discrepancies identified in public comments regarding inconsistent protection zones are in fact
different recommendations for different phases of the project. Table 5 in the Response Letter
provides HortScience's recommended protection zones for 42 trees within the building envelopes
or other easements and made binding through mitigation measure BIO-8. Table 5 further
describes the ideal recommended protection zones guiding the design and construction of
improvements adjacent to trees on individual lots. Any intrusion into the protection zones must
receive prior approval of and be monitored by the Project Arborist(see mitigation measure BIO-
8).
IV.B.1 Heritage Oak Preservation Mitigation
Heritage Oak Tree Mitigation. Mitigation measure BIO-8 can be refined to provide more
specific guidance for Heritage Oak replacement and preservation and to clarify the link between
the HortScience report and recommendations for protecting trees to be preserved. For this
purpose,the following revisions to mitigation measure BIO-8 are recommended(deletions shown
in strikethrough text/additions shown as underlined text):
BIO-8. The project applicant shall prepare and implement a tree replacement plan pursuant to
municipal code Title 12, Article 3 for all Heritage Oaks to be removed as a result of project
implementation. The plan shall be subject to review and approval of the Town, and shall be
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implemented as a subdivision improvement. The tree replacement plan shall specify the
following:
■ A final tree survey showing all Heritage Oaks within all subdivision improvement impact
areas that require removal;
• Heritage Oaks to be removed shall be replaced at a minimum ratio of three new replacement
trees for every one tree removed. Replacement trees shall be of the same species that will be
removed;
• All replacement trees must be grown in deep five-gallon containers and the trees shall not
have been in the containers for more than two years;
• Replacement trees must be spaced such that they do not compete with one another and do not
compete with established vegetation. Trees shall be planted a sufficient distance (as
determined by a certified arborist) away from planned subdivision improvements or
improvements on individual lots (if known) to avoid damage to improvements or trees.
Replacement trees should be planted as near to the location of removed trees as possible
subject to the above specifications. A tree planting plan shall be prepared which shows the
proposed tree planting locations subject to these specifications; and
■ The viability of the replacement trees shall be monitored by the applicant for two years from
the date they are planted. Failed trees shall be replaced no later than 2.5 years after their
initial planting.
For all Heritage Oaks to be retained the project applicant shall fully implement the protection tree
preservation methodology guidelines for tree preservation contained in the HortScience 2014
revised project arborist report fpp. 13-15). The tree protection zones referenced in the
recommendations are defined in the Specific Tree Protection Zones table found in the
HortScience report (p. 14) and the tree numbers refer to those included in the HortScience report
and reflected on Sheets 3 and 4 of the proposed Tentative Map. The recommendations are as
follows:
Design Recommendations
1. All plans affecting trees shall be reviewed by the Consulting Arborist with regard to tree
impacts. These include, but are not limited to, demolition plans, grading and utility
plans, landscape and irrigation plans.
2. Evaluate the design of the path to minimize grading and provide as much room from trees
#109, 110, 112, 113, 115, 116118, 121 and 122 as possible. By placing the path on
grade, or as close to existing grade as possible, and providing as much room from trees as
possible,root loss will be minimized.
3. To the extent feasible, Uunderground services including utilities, sub-drains, water or
sewer shall be routed around the tree protection zone. Where encroachment cannot be
avoided, special construction\techniques such as hand digging or tunneling under roots
shall be employed where necessary to minimize root injury.
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4. A tree protection zone must be established for trees to be preserved, in which no
disturbance is permitted without the prior review by and approval of the Consulting
Arborist. Tree protection zones for trees identified for preservation are identified in the
following table adjacent to the subdivision improvements are identified in the Revised
Arborist Report. No grading, excavation, construction or storage of materials shall occur
within a Tree Protection Zone. Trees not given specific Tree Protection Zones and not
designated for removal shall be fenced at the dripline in all directions.
5. As trees withdraw water from the soil, expansive soils may shrink within the root area.
Therefore, foundations, footings and pavements on expansive soils near trees should be
designed to withstand differential displacement.
Underground services including utilities, sub-drains, water or sewer shall be plac-ed
designed to avoid tree protection zones, where possible. Where not possible, special
construction techniques, such as boring or hand trenching and threading of utilities
beneath roots 2 inches in diameter and larger must be employed.
6. Tree Preservation Notes, prepared by the Consulting Arborist, should be included on all
plans.
7. Do not lime within 50 feet of any tree. Lime is toxic to tree roots.
8. Any herbicides placed under paving materials must be safe for use around trees and
labeled for that use.
9. Irrigation systems must be designed so that no trenching will occur within any tree
protection zone.
Pre-Construction Treatments and Recommendations
1. The construction superintendent shall meet with the Consulting Arborist before beginning
work to discuss work procedures and tree protection.
2. Fence all trees to be retained to completely enclose all tree protection zones prior to
demolition, grubbing or grading. Fences shall be six (6) foot high chain link or
equivalent as approved by the Consulting Arborist. Fences are to remain until all grading
and construction is completed.
3. Pruning trees to provide construction and access clearance will be required. Trees#3, 4,
7, 23, 25, 27, 28, 33, 66, 95, 101, 121, 122 and 125 have been preliminarily identified for
pruning to provide construction and road clearance. Additional trees may require pruning
for pedestrian clearance over the path.
4. Prune trees to be preserved to clean the crown and to provide clearance. All pruning
shall be done by a State of California Licensed Tree Contractor (C61/D49). All pruning
shall be done by Certified Arborist or Certified Tree Worker in accordance with the Best
Management Practices for Pruning (International Society of Arboriculture, 2002) and
adhere to the most recent editions of the American National Standard for Tree Care
Operations(Z133.1)and Pruning(A300).
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE1ThRS
5. All tree work shall comply with the Migratory Bird Treaty Act as well as California Fish
and Wildlife Code Sections 25003-3513 to not disturb nesting birds. To the extent
feasible tree pruning and removal should be scheduled outside of the breeding season.
Breeding bird surveys should be conducted prior to tree work. Qualified biologists shall
be involved in establishing work buffers for active nests.
6. Have brush from the pruning and removal operations chipped and spread beneath the
trees within the tree protection zone. Mulch shall be 2 to 4 inches in depth and kept a
minimum of 3 feet from the base of the trees.
Recommendations for Tree Protection during Construction
1. Prior to beginning work, the contractors working in the vicinity of trees to be preserved
are required to meet with the Consulting Arborist at the site to review all work
procedures, access routes,storage areas and tree protection measures.
2. Except as absolutely necessary,Nno grading,construction,demolition or other work shall
occur within any tree protection zone. Any exceptions must be approved and monitored
by the Consulting Arborist to ensure that trees are protected.
3. Fences have been erected to protect trees to be preserved. Fences define a specific tree
protection zone for each tree or group of trees. Fences are to,remain until all site work
has been completed. Fences may not be relocated or removed without permission of the
Consulting Arborist.
4. Construction trailers, traffic and storage areas must remain outside fenced areas at all
times.
5. Prior to grading, pad preparation, excavation for foundations/footings/walls, trenching,
trees may require root pruning outside the tree protection zone. Any root pruning
required for construction purposes shall receive the prior approval of, and be supervised
by,the Consulting Arborist.
6. If accidental injury should occur to any tree during construction, it shall be evaluated as
soon as possible by the Consulting Arborist so that appropriate treatments can be applied.
7. No excess soil, chemicals, debris, equipment or other materials shall be dumped or stored
within the tree protection zone.
8. Any additional tree pruning needed for clearance during construction must be performed
by a Certified Arborist and not by construction personnel.
IV.B.2 Replacement of Certain Trees Other Than Heritage Oaks.
Project compliance with Town municipal code requirements, including Municipal Code Section
9-1.607, is sufficient to reduce any impacts to non-heritage oak trees from the proposed project to
less than significant. Municipal Code Section 9-1.607 includes development regulations for
replacement of trees that are larger than 20 inches in circumference measured at a point four feet
from the ground. No such trees are to be removed unless they must be removed to facilitate the
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE 111:RS
locating of public and/or private roadways, the placement of structures within the proposed
rights-of-way, or for the rough grading of driveways and/or parking areas. Trees removed for this
purpose must be replaced at a ratio of two new trees for every one removed. Diseased or dead
trees removed for this purpose need not be replaced subject to evidence verifying the condition of
the trees. Project compliance with these requirements is mandatory and the applicant has
incorporated this mandatory compliance into the project plans (Attachment J). To ensure such
tree replacement is completed by the applicant consistent with the municipal code requirement,
the Town will also condition approval of the project on the applicant's preparation of a non-
heritage oak tree replacement plan. The plan will be subject to review and approval of the Town,
and shall be implemented as a subdivision improvement. The tree replacement plan for non-
heritage trees more than 20 inches in circumference shall specify the following:
• Trees to be removed shall be replaced at a minimum ratio of two new replacement trees for
every one tree removed, excluding trees that are determined to be diseased or dead.
Replacement trees shall be of the same species as the tree removed;
• All replacement oak trees must be grown in deep five-gallon containers and the trees shall
not have been in the containers for more than two years;
• Replacement trees must be spaced such that they do not compete with one another and do not
compete with established vegetation. Trees shall be planted within sufficient distance from
planned subdivision improvements (as determined by a certified arborist) as to avoid damage
to improvements or trees or within a sufficient distance from anticipated improvements on
individual lots if known. Replacement trees should be planted as near to the location of
removed trees as possible subject to the above specifications. A tree planting plan shall be
prepared which shows the proposed tree planting locations subject to these specifications;
and
• The viability of the replacement trees shall be monitored for two years from the date they are
planted. Failed trees shall be replaced no later than 2.5 years after their initial planting.
The commenter claims that the IS/MND fails to address how 'oaks will be affected by the
construction of new homes and driveways. Potential effects from construction of new homes and
driveways on additional oaks is speculative and premature at this time, since the proposed project
only involves a subdivision and associated subdivision improvements and not any particular
residential development. The proposed Tentative Map identifies for each lot a potential building
envelope and driveway which could be constructed without the removal of any Heritage Oaks.
While these driveway and house configurations are not binding on a future home builder, they
are evidence that the lots can be developed without additional Heritage Oak removal. While it is
conceivable that an owner proposing to develop a lot could propose a house design outside these
envelopes that could cause removal of or impact on additional Heritage Oaks,whether this would
happen is entirely speculative at this stage. In addition, the Town's tree protection ordinance
restricts the removal of Heritage Oaks and other trees with a circumference of 20 inches or more,
and subjects any proposed 'removals to replacement ratios. Further analysis at this time of
potential impacts from future housing designs would therefore be premature and speculative.
Finally, any future proposal to remove additional Heritage Oaks or other trees with a
circumference of 20 inches or more in connection with a home development will be subject to
Town review and approval, and likely trigger a requirement that replacement trees be provided.
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STIRLING SUBDIVISION—SHUTE/WELCH RESPONSE LE 1"11sRS
IV.C.1 Existing Hydrological Setting
Existing stormwater infrastructure and storm water conditions are briefly described in the
IS/MND (pp. 1-2, p. 69). There currently is no organized storm water control system on the site.
Rainfall from existing undisturbed surfaces and from impermeable surfaces (e.g. roofs and paved
areas associated with the two existing residences) infiltrates into the soil and may move by
overland sheet flow downslope to Matadero Creek.
As described in the IS/MND, the proposed project would alter existing hydrological conditions.
This will occurprimarily through introducing new impervious surfaces such as the extension of
Charles Avenue and widening of the existing segment of the road, sidewalks, driveways, and
roofs that result in modification of the volume and rate of storm water that flows from the site
under existing/natural condition. Storm water runoff from these surfaces will be managed using
the planned storm water control system. Details of the system are included on sheet 7 of the
Tentative Map included in Appendix A of the IS/MND. By regulatory requirement, the storm
water management system is designed to pre-treat storm water to protect the quality of
downstream receiving waters,promote percolation/recharge, limit the rate of runoff from the site
to pre-project conditions, and dispose of storm water in a manner that does not cause soil erosion
and water quality impacts on Matadero Creek.
Thereare no standing surface water bodies within the boundary of the project site. Matadero
Creek, which flows intermittently at its reach adjacent to the site, traverses the western and
southern boundary of the site. Based on the California Water Quality Control Board's Clean
Water Act Section 303(d) listing protocol, water quality in Matadero Creek has been
compromised by trash and by the pesticide diazinon. The sources of the pollutants include illegal
dumping (trash) urban runoff, and storm sewers
(http://www.swrcb.ca.gov/waterissues/pro grams/tmdl/2010state it reports/00685.shtml).
Diazinon is a pesticide most commonly used in agricultural applications to kill insects and mites
that damage crops; domestic uses include cockroach,ant,and beetles control.
IV.C.2 Project Effect on Water Quality
If not properly managed and pre-treated, storm water runoff from impervious surfaces of the
project site could contain urban pollutants such as oil, grease, sediment, and household fertilizers
and pesticides at levels that could contribute to Matadero Creek water quality impacts.
Project compliance with regulatory requirements, including C.3 requirements (and preparation of
a storm water control plan ["SWCP"]) and General Construction Permit (and preparation of a
SWPPP) is sufficient to reduce water quality impacts of the proposed project to less than
significant. Compliance with these requirements is mandatory for qualifying projects. Given its
characteristics, the proposed project is a qualifying project and is subject to the requirements.
These regulations include specific performance standards that must be met to achieve their
respective goals of reducing water quality impacts as described below.
The C.3 requirements are promulgated by the Town to ensure compliance with the Town's
NPDES Permit as referenced in the IS/MND (p. 68). The C.3 standards require site designs for
new,developments and redevelopments to minimize the area of new roofs and paving. Where
feasible, pervious surfaces should be used instead of paving so that runoff can infiltrate to the
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE ITERS
underlying soil. Remaining runoff from impervious areas must be captured and used or pre-
treated using bioretention or other measures to filter out urban pollutants prior to its discharge.
Increased runoff flow rate must be managed so that post-project runoff rates do not exceed
estimated pre-project rates. This is necessary where increased flow is otherwise likely to cause
increased potential for erosion ("hydromodification") of receiving waters, including creek beds
and banks, silt pollution, or other adverse impacts on beneficial uses of receiving waters due to
increased erosive force.
To demonstrate compliance with C.3 requirements, a SWCP must be prepared according to
rigorous standards contained in the requirements. The SWCP must, among other specifications,
identify site design measures, source control measures, and treatment methods that will be used
to control and treat storm water prior to its discharge. A conceptual SWCP was prepared by the
applicant and is shown on sheet 7 of the Tentative Map in Appendix A of the IS/MND.
Preparation of a conceptual SWCP is the first step in the process of demonstrating C.3
compliance. The SWCP includes a number of stormwater control features including, but not
limited to: pervious pavement, self-retaining areas,preserved open space, a bioretention area, and
storm water detention. Additional measures such as storm drain labeling and beneficial
landscaping (to minimize irrigation runoff, pesticides, fertilizers, and to promote treatment) are
also included.
The applicant's SWCP and related C.3 compliance input worksheets were reviewed by an
independent consulting environmental engineer retained by the Town. The purpose was to
determine whether the conceptual SWCP complies with C.3 regulations, which is required prior
to the Town's consideration of the proposed project for approval. In a memorandum dated June
25, 2015, the consulting environmental engineer concluded that the SWCP is conceptually
acceptable and that the Town may approve the conceptual SWCP subject to conditions. The
conditions generally address the need for additional details for some aspects of the SWCP (Letter
from Jill Bicknell, P.E., Eisenberg, Olivieri & Associates June 25, 2015). The additional detail
will be incorporated into a final SWCP whose implementation will be required as a condition of
approval and whose implementation will be monitored by the Town consistent with C.3
regulations. Approval of the final SWCP is not required prior to the Town's consideration of the
proposed project. The final SWCP will be prepared as part of the final improvement plan process
and prior to the Town's approval of a final subdivision map.
Given the purpose of the C.3 regulations, and the confirmed compliance of the project with those
regulations, the proposed project's operational impacts on water quality from urban pollutants
and erosion/hydromodification of Matadero Creek would be less than significant as described in
the IS/MND.
Construction Phase Water Quality Effects. The C.3 requirements described above are
separate from, and in addition to,requirements for erosion and sediment control and for pollution
prevention measures during construction. These latter requirements are also a component of the
Town's required compliance with Clean Water Act legislation as promulgated by the California
Water Quality Control Board through its NPDES General Permit for Storm Water Discharges
Associated with Construction Activity. An overview of the NPDES program is provided in the
IS/MND (pp. 68-69). To demonstrate that a new project which disturbs one or more acres of
land will minimize potential effects on water quality during the construction phase, a SWPPP
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE 1"1 ERS
must be prepared by the project applicant. The measures in the SWPPP must meet precise
performance standards.
A SWPPP must identify all construction activities with potential to enable storm water to come
into contact with potential sources of water pollution. "Construction"refers to actions that result
in land disturbance, including clearing, grading, excavating, and other similar activities.
Stockpiles, borrow areas, concrete truck washouts, fueling areas, material storage areas and
equipment storage areas are also considered to be areas of land disturbance. During construction,
the primary concern is exposure of soils to the erosive effects of rainfall and concentrated storm
water runoff. If sediment and erosion controls and good housekeeping practices are not
followed, construction activity can result in soil erosion and the discharge of significant amounts
of sediment and other pollutants to receiving waters.
A SWPPP is a written, enforceable document that describes the pollution prevention practices
and activities that will be implemented on the site. It includes identification of potential pollutant
sources, description of controls to reduce pollutants, and control maintenance/inspection
procedures. It also would include descriptions of the site and of each major phase of the planned
activity, the roles and responsibilities of contractors and subcontractors, and the inspection
schedules and logs. Construction of infrastructure, including storm drainage systems, is a phase
of the project that would be described in the SWPPP. For this reason, the SWPPP would
describe pollution prevention practices that would be employed to minimize erosion of all
exposed soil surfaces, including those associated with construction of the proposed footbridge,
storm drainage discharge pipe, and storm water dissipator improvements as described in Section
II.B above. There is no evidence that SWPPP pollution prevention measures cannot be
effectively employed on slopes. Slope inclination and length instead affects the selection and
placement of appropriate best management practices, which routinely occurs throughout
California in steeply sloped areas. Representative Best Management Practices (BMPs) for soil
erosion control on slopes are identified in the 2009 California Stormwater BMP Handbook for
Construction Activities prepared by the California Stormwater Quality Association.
A SWPPP must be approved by the Town prior to initiation of any ground disturbing activity at
the site and implementation of control measures must be monitored and reported. Hence,
implementation of the SWPPP will reduce potential impacts on water quality during the
construction phase to less than significant.
As described above and consistent with IS/MND conclusions, required compliance with
regulatory requirements will ensure that water quality impacts from project-related activities
during construction and during operations would be reduced to less than significant. No
mitigation measures are required.
IV.C.3 Flooding and Erosion Effects
The commenter expresses concern that the IS/MND does not adequately analyze potential
impacts affecting downstream erosion. By way of background, bank erosion occurring
downstream of the project site on Matadero Creek has apparently been exacerbated by a number
of human causes and natural causes. Those causes are unrelated to the rate or volume of storm
water runoff from the project site in Matadero Creek that occurs under existing conditions. If the
rate of storm water runoff from the site discharged to the creek were to increase under post-
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE 1"1'hRS
project conditions, the erosive effects of flow in the creek could incrementally increase. This
change would have potential to cause hydromodification and decreased water quality from
increased sedimentation and turbidity.
As described above in Section IV.C.2, the applicant's SWCP has been reviewed by the Town's
independent consulting environmental engineer for consistency with C.3 requirements. The
proposed project qualifies as one for which the rate of storm water discharge from the site under
post-project conditions is not permitted to exceed pre-project conditions. The SWCP preparation
and approval process includes a requirement to model pre-project storm water conditions and
compare them to post-project conditions (with implementation of SWCP control measures) to
assure that this requirement is met. The modeling conducted for this purpose was reviewed by
the Town's independent consultant and found to be acceptable. Therefore, there is no evidence
that the proposed project would exacerbate existing downstream erosion of the bed or banks of
Matadero Creek.
The detention basin is a control measure included in the SWCP. Its operation is one component
of the overall SWCP control measure system. As noted above, the SWCP system has been
reviewed to verify that the post-project storm water runoff rate to Matadero Creek will not
exceed pre-project rates.
IV.D Aesthetic Effects
Concern was raised by the commenter regarding the project's impacts on private views and
nearby trails.The only potential visual impacts from the proposed project are on the views of and
through the project site from a small number of adjacent private properties. There are four to five
private residential properties adjacent to proposed lots 1 and 4 that have some limited views into
the project site. These private residential properties adjacent to lots 1 and 4 could experience a
change to their views, including a potential loss to some distant views across the project site
toward the west. Notably,the existing views across the site from these adjacent residents toward
the west are already constrained by existing tress. While a few adjacent neighbors may presently
enjoy limited private views across the project site which could be obstructed,the obstruction of a
few private views is not a significant impact under CEQA. (Bowman v. City of Berkeley, (2004)
122 Cal.App.4th 572, 586, the "obstruction of a few private views in a project's immediate
vicinity is not generally regarded as a significant environmental impact.")
CEQA distinguishes whether a project will adversely affect the views of particular persons (not a
significant impact) and whether a project will adversely affect the environment of persons in
general (potentially a significant impact). (§ 21083, subd. (c).) In Assn. for Protection of
Environmental Values in Ukiah v. City of Ukiah (1991) 2 Cal.App.4th 720, 720, the court held
that the proposed project did not create a potentially significant aesthetic impact because the
"height, view and privacy objections... [that affect] only a few of the neighbors... did not affect
the environment of persons generally." (Id. at 734.) No authority is presented in the public
comments to support the argument that CEQA is intended to afford private view rights to a few
neighbors adjacent to a proposed project. In Ocean View Estates Homeowners Association, Inc.
v. Montecito Water District (2004) 116 Cal.App.4th-396, the determining factor in the court's
analysis was the photographic evidence showing a fair argument that a portion of the reservoir
was visible from public trails.
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE1 i'bRS
As noted in the IS/MND for this project,there are no Town-identified scenic vistas in or near the
project site, and the site is not within the view shed of a scenic.highway. There are no public
paths or trails in:the vicinity of the project site with views that could potentially be affected by
the project. Sheet 6 of the Tentative Map Appendix A of the IS/MND shows a pathway
easement ending at the northeastern corner of the project site, but this easement dead-ends at the
project's boundary and does not appear to be active. The view from the "Scenic Stegner Path"
that runs just west of the property's western boundary is obscured from the project site due to
thick wooded overgrowth and will be protected by an open space easement. Moreover, there are
no'existing public pathwayson the project site or any public park adjacent to or nearby from
which the project would block public views. Photographs taken from the Stegner Path and from
Edgerton Road provide substantial evidence that public trails in the vicinity of the project site
will not be substantially affected by the proposed project. These photographs are included as
Attachment K.
The City has not adopted a view protection ordinance. The Town Municipal Code Sections 10-
2.701 and 10-2.702 provide guidelines, not mandatory regulations barring any impairment of
private views, that the Town shall consider when approving the construction of new homes.
However, none of the listed guidelines under these sections directly address impacts on private
views. Any future construction of new homes shall comply with Municipal Code Sections 10-
2.701 and 10-2.702, but these potential effects are speculative and premature to analyze at this
stage. The proposed project only involves a subdivision and associated subdivision
improvements and not any particular residential development. The only proposed project
subdivision improvements include the footbridge, meandering path, landslide subdrain system,
and storm water drainage pipeline/dissipator system, all of which are not reasonably likely to
obstruct off-site views.
As the IS/MND demonstrates, the proposed project would not affect any recognized scenic
vistas, or any views from public parks and trails. Even to the extent that impacts on private
views are relevant to a CEQA analysis, the fact that the project would impact only a few private
views supports the conclusion that the visual impact in this case would not be significant.
Substantial evidence supports the conclusion that the project would not result in significant
aesthetic impacts.
IV.E Wildlife Effects
Open space easement improvements/wildlife movement. Concern has been expressed that
construction of improvements within the proposed 7.22-acre open space easement area along
Matadero Creek could result in significant impacts on wildlife movement. The open space
easement area represents approximately 40 percent of the total area of the 18.18-acre site. As
described in Sections ILA and lI.B above, the proposed project does include very limited
improvements within the open space easement area. These include a pathway, the pedestrian
footbridge over Matadero Creek, a storm drainage pipe and associated storm water energy
dissipator, and a subsurface landslide stabilization subdrain system. The types and intensity of
improvements proposed are described in the aforementioned sections.
The pathway and footbridge are the only improvements of note that are planned in the open space
easement area. The footbridge would span Matadero Creek without affecting the creek bed or
banks. 'The area of the bridge footprint constitutes approximately .0004 percent of the total open
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LETTERS
space easement area. The storm drainage pipe/dissipator system and the landslide subdrain
system improvements would have minimal surface expression. The storm drainage pipe would
be a maximum of 15 inches in diameter. It would be partially buried in the ground suchthat its
vertical surface expression would be minimal. The pathway would run near the north edge of the
open space easement area and connect to the bridge.
As described in Sections lI.A and II.B above, Live Oak Associates and H.T. Harvey &
Associates provided supplemental information regarding the potential effects of the
trail/footbridge and storm drainage improvement on wildlife movement. Both concluded that
construction phase effects would be less than significant. Both also concluded that the
improvements would have a less-than-significant impact on the ability of wildlife to move
through the open space corridor.
Wildlife Movement and Subdivision Improvements/Fencing. Concern has been expressed
that construction and use of the subdivision improvements (e.g. roads, homes, fencing, etc.)
would degrade the quality of the site as a wildlife corridor. Fencing and its effect on the
movement of wildlife through the site is of special concern. Both Live Oak Associates and H.T.
Harvey & Associates provided supplemental evaluations of the potential effects of these
subdivision improvements, with a focus on fencing. The evaluations are included in their letters
previously discussed and included as Attachments D and E, respectively. Live Oak Associates
states that from a regional wildlife movement/habitat perspective,the site as a whole represents a
relatively small landscape for regional wildlife, representing about five percent of an average
deer home range and less than one percent of a bobcat or coyote home range. Live Oak
Associates concludes that despite the small groups of deer that have been seen on the site from
time to time, the site from a pure habitat perspective is insignificant for the local deer population.
It is further stated that even assuming the entire forage capacity of the site was removed, the
impact on the regional population would be too small to measure (Live Oak Associates 2016,pp.
2-3).
Live Oak Associates also clarifies information it provided for the IS/MND regarding fencing and
its impact on movement of wildlife within the open space easement. In its letter of November 11,
2014 that was referenced in the IS/MND, Live Oak Associates concluded that deer will continue
to access the site with regularity assuming that the individual lots are not surrounded by
impermeable fencing. Live Oak Associates clarifies that this conclusion was based on the
assumption that any fencing placed in the open space easement area between lots 5-9 and along
the western boundaries of lots 5-9 would be wildlife friendly fencing. This assumption is
verified by the fact that the Town will require wildlife friendly fencing in these locations as a
design feature to be included as a condition of approval.
H.T. Harvey & Associates' letter includes extensive discussion about important wildlife
movement corridors in the CEQA context and about the portions of the site that serve this
function. H.T. Harvey & Associates states that the CEQA Guidelines related to wildlife
movement require an assessment of whether a project would "interfere substantially with the
movement of any native resident or migratory species or with established-native resident or
migratory wildlife corridors." H.T Harvey&Associates' historical practice has been to interpret
"substantial interference"as pertaining to movement that has biologically important implications
—that is, movement necessary to help sustain populations (e.g., by allowing immigration of new
individuals) and maintain genetic diversity within populations. Such interpretation takes into
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE11B.RS
account regional wildlife movements, and movement between populations,rather than movement
by animals at a scale as small as an 18-acre project site, or between such a small site and adjacent
areas. As a result, H.T. Harvey & Associates states that the appropriate assessment of the
proposed project's impacts on wildlife movement focus on whether the project would
substantially interfere with the ability of animals to move between large off-site habitat areas
(such as between large habitat patches near Altamont and Moody Roads to the south and
Arastradero Preserve to the northwest), not on whether animals can move as freely within the site
as they currently do, whether animals have access to particular areas on the site, or whether
animals can move on and off this particular site via less important pathways (H.T. Harvey &
Associates 2016,pp. 1-2).
Based on its review of the Live Oak Associates 2006 wildlife corridor study that was referenced
in the IS/MND and in the Shute Letter comments, and based on review of conditions in the field,
H.T. Harvey&Associates concludes that the Matadero Creek corridor provides opportunities for
larger and/or more mobile species to move long distances using this corridor(e.g., between large
habitat patches near Altamont and Moody Roads to the south and Arastradero Preserve to the
northwest). In addition, the resources provided by the well-vegetated drainages in the Matadero
Creek watershed, as well as native vegetation present within the low-density residential areas
throughout the watershed,provide habitat that supports many of these animals within their home
ranges. The biological importance of the Matadero Creek corridor for wildlife movement
includes both long-distance dispersal movements (e.g., by a mule deer, coyote, or mountain lion
dispersing several miles in a night) and short-distance movements and genetic exchange among
individuals that make small portions of the corridor part of their home range. The observation of
numerous game trails within the proposed Matadero Creek open space easement indicate that the
easement area is connected to similarly suitable areas for wildlife movement both upstream and
downstream of the project site(H.T.Harvey&Associates 2016,p.2).
For the reasons noted above, H.T. Harvey & Associates concludes that it does not expect that
future construction on the land upslope from the proposed Matadero Creek open space easement
corridor to result in a substantial reduction in the use of the creek corridor for wildlife movement.
H.T. Harvey & Associates also states that species such as mule deer and coyotes that currently
occur on the site have to be sufficiently habituated to, or tolerant of,residential land uses on other
immediately adjacent parcels to be moving through the site to begin with, given that the project
site is embedded within a fairly extensive matrix of low-density residential development.
Furthermore, the dense vegetation present in much of the on-site portion of the Matadero Creek
corridor, coupled with the width of the open space easement area, would allow animals to move
through this corridor relatively unaffected by activities on residential land uses upslope (H.T.
Harvey&Associates 2016,pp. 2-3).
Regarding the wildlife corridor value of the site outside the open space easement area, H.T.
Harvey & Associates evaluated potential wildlife movement corridors represented in the 2006
Live Oak Associates study and further considered movement potential in light of existing fencing
constraints and post-project fencing conditions. H.T.Harvey validated that the corridor along the
northern boundary of the site is valuable for wildlife movement. If the proposed project includes
wildlife friendly fencing along the northern and eastern borders of the site, it would improve
potential wildlife movement through this portion of the site, as compared to the existing non
wildlife friendly fencing on those boundaries. However, even if the fencing isn't wildlife
friendly, H.T. Harvey concludes that wildlife movement through the corridor to the
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LETTERS
North/Northeast will be at least as good as under current conditions (H.T. Harvey & Associates
2016,p. 3).
H.T. Harvey & Associates also discusses at length the potential project effects on smaller
movement pathways, such as those identified in the 2006 Live Oak Associates study as extending
from the east side of the site to Natoma Road (H.T. Harvey & Associates 2016, p. 4). In short,
H.T. Harvey&Associates concludes that the proposed project may inhibit or preclude the use of
these much smaller-scale movement pathways, but that these impacts would not be significant.
This conclusion is based on the determination that the movement that occurs along these smaller
pathways does not contribute substantially to regional movements or exchange of individuals or
genes among populations. A conclusion is also drawn that movement from the site to Natoma
Road and beyond (e.g. Poor Clare's orchard) will likely continue to be possible via Charles
Avenue,as wildlife often move along minimally traveled roads.
In summary, H.T. Harvey & Associates finds that the proposed project will have a less-than-
significant impact on wildlife movement corridors because the two most important corridors —
Matadero Creek and the corridor to the north/northeast will continue to be available after the
project is constructed (H.T. Harvey & Associates 2016, p. 3). The proposed project will not
result in substantial interference with established or biologically important movement pathways
and animals will still be able to access and use the biologically important movement pathways
identified in the 2006 Live Oak Associates wildlife corridor study (H.T. Harvey & Associates
2016,p.4). These findings provide additional support for the conclusions in the IS/MND.
V. Cumulative Impacts
Cumulative Impact Scenario and Cumulative Impacts. CEQA Guidelines Section
15130(b)(1)(a) identifies options for formulating a cumulative impact scenario against which the
contribution of a proposed project's effects can be assessed for cumulative significance. One
such scenario is to compare the contribution of a proposed project to the cumulative impacts of
projects contained in a list of past, present, and probable future projects that would produce
related cumulative impacts.
The Matadero Creek Restoration and Bank Stabilization Project("restoration project")is the only
project represented by commenters on the IS/MND to be relevant to a discussion of the proposed
project's cumulative impacts. As confirmed by the Town, the restoration project is the only
current, known probable future project within the vicinity of the project site with potential to
contribute to related cumulative impacts. It is located approximately 0.9 miles downstream on a
350-foot segment of Matadero Creek. The restoration project involves removal of a portion of a
concrete creek culvert and creation of a longer rock rip-rap chute structure. The restoration
project is designed to reduce erosional processes at the existing culvert that have caused stream
bank erosion and bank failure at that site.
As generally reported in the Draft Initial Study for the Matadero Creek Restoration and Bank
Stabilization Project (WRA 2015), the primary effects of the restoration project would occur
during its short-term construction phase. Construction phase effects of small projects like the
restoration activity are generally limited to the immediate vicinity of the activity. The short-term
construction impacts of the restoration project as identified in the IS/MND for the restoration
project include temporary impacts to views to the restoration site from a local road; generation of
21
STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE1 lhRS
air quality emissions; impacts on biological resources including special-status/protected species,
sensitive habitat (wetlands and waterways), and tree removal; potential disturbance of unknown
cultural resources; soil erosion and related water quality degradation; construction equipment
noise; and slight delays on roadways due to construction traffic (no level of service performance
standards would be exceeded). All of the potential construction impacts are mitigated to less
than significant. The cumulative analysis in the IS/MND notes that "due to thelimited scope of
direct physical impacts to the environment associated with construction, the project's impacts are
project-specific in nature[...]. Consequently,the project along with other cumulative projects will
create a less than significant cumulative impact with respect to all environmental issues." (WRA
2015,p. 66). The referenced cumulative projects are not identified.
Because the .restoration project impacts are limited to its construction phase, only the
construction phase effects of the proposed project have potential to combine with the restoration
project effects to create cumulatively considerable impacts during the construction phase.
Further, such effects are only possible if the construction periods for both projects overlap. The
IS/MND states that the restoration project would take about two months to construct and that
pending permitting clearances, construction is tentatively planned for July to August of 2016. A
tentative August start date has been confirmed by the Town. A specific construction start date
for the proposed project has not yet been identified. Prior to initiating construction, a number of
actions must be taken. The proposed project must first be approved by the Town. Final
development plans would then need to be prepared and approved. In addition, a range of project
conditions and mitigations would need to be met and-implemented. Given these factors, it is
highly unlikely that construction would begin any time before late spring/early summer of 2017.
Hence, it is also highly unlikely that the construction periods for the two projects would overlap,
in which case the proposed project would have no potential to result in construction phase
cumulative impacts.
Construction phase impacts of the proposed project are identified in the IS/MND and are similar
to those identified in the restoration project IS/MND. Like construction effects described for the
restoration project, the construction effects of the proposed project would largely be limited to
the project site and its immediate surroundings. Its construction impacts are reduced to less than
through compliance with regulatory standards and mitigation measures described in the IS/MND.
Consequently, the proposed project effects would be less than cumulatively considerable even if
construction of the two projects were to overlap.
Because construction impacts are localized, even if the two projects were under construction at
the same time, it is highly unlikely that effects of the proposed project would combine with those
of the restoration project to create a cumulatively considerable impact.
Fencing and Wildlife. Regarding existing property line fencing and the potential for the
proposed project to result in cumulatively considerable impacts on wildlife movement, please
refer to the discussion in Sections II.A, II.B, and IV.E above. The proposed project will not have
a cumulatively considerable impact on wildlife movement because the two most important
wildlife corridors on the site will be maintained. The proposed project will be conditioned to
require that all new fencing in the open space easement area between lots 5-9 and along the
western boundary of lots 5-9 is wildlife friendly.
DISCUSSION OF ISSUES RAISED IN THE WELCH LETTER
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STIRLING SUBDIVISION-SHUTE/WELCH RESPONSE LE I'I bRS
Consistent with CEQA Guidelines Section 15063(d), the IS/MND adequately identifies the
environmental setting, including a description of the Matadero Creek. The IS/MND describes the
Matadero Creek as originating upstream of the project site, draining to the Mayfield Slough and
ultimately into the San Francisco Bay, with slopes of 30 percent or more in some areas. Figure 2
in the IS/MND is an aerial photograph showing existing conditions on and adjacent to the project
site. Figure 3A and 3B show representative conditions within the site. Further details are
described above in Sections IV.C.1, IV.C.2 and IV.C.3. There is no evidence that the proposed
project would exacerbate existing downstream erosion of the bed or banks of Matadero Creek.
The applicant's SWCP has been reviewed by the Town's independent consulting environmental
engineer for consistency with C.3 requirements. The proposed project qualifies as one for which
the rate of storm water discharge from the site under post-project conditions is not permitted to
exceed pre-project conditions. The SWCP preparation and approval process includes a
requirement to model pre-project storm water conditions and compare them to post-project
conditions (with implementation of SWCP control measures) to assure that this requirement is
met. The modeling conducted for this purpose was reviewed by the Town's independent
consultant and found to be acceptable. The detention basin is a control measure included in the
SWCP. Its operation is one component of the overall SWCP control measure system. As noted
above, the SWCP system has been reviewed to verify that the post-project storm water runoff
rate to Matadero Creek will not exceed pre-project rates. The on-site Matadero Creek tributary
will be preserved as part of the open space easement. Accordingly, Matadero Creek would not
be altered as part of the project and no impact on flood conditions from alteration of the stream or
water course would occur.
Chapter 12 of the IS/MND describes the existing noise environment and the temporary noise
increase that would accompany construction of the Project. The IS/MND finds impacts from
project noise to be less than significant because residential use activities will not result in a
significant increase in ambient noise levels relative to existing conditions in the project area. On-
site residential use activities are not typical sources of permanent increases in ambient noise
levels. Project compliance with regulatory requirements, including the Town's applicable
allowable noise standards set forth in the Town's municipal code, is sufficient to reduce any
temporary construction noise to less than significant. Although compliance with these Town
municipal code requirements is mandatory by law and the applicant has stated in the record that
the project has always assumed full compliance with the Town's code, the Town will condition
approval of the project on the applicant's compliance with the limitations provided in the Town's
noise standards, as referenced in the IS/MND (Attachment J). By ensuring full compliance with
the Town's allowable noise standards, any temporary noise from construction activities of the
proposed project will be minimized to less than significant levels.
2698414.1
23
ATTACHMENT 11B
ii.,
ii
LIVE OAK ASSOCIATES, IC.N
,, i A an Ecological Consulting Firm
April 21, 2016
Jeff Peterson, P.E.
Principal
3130 La Selva Street,Suite 100
San Mateo, CA 94403
RE: Response to the Shute Mihaly&Weinberger Comment Letter for the Stirling Subdivision
Project being considered by the Town of.Los Altos Kills,California (PN 1898-01).
Dear Mr. Peterson:
Live Oak Associates, Inc. (LOA) has reviewed the comments by Shute Mihaly&Weinberger as it
relates to impacts on wildlife movement corridors from the proposed 9-lot subdivision.Their
comments focused on my assessment dated November 11, 2014, and they note one aspect of
my letter, namely:
"I would suggest this change is not significant under CEQA as based On my experience
and evidenced by the regional distribution and abundance of deer, deer will continue to
access this site with regularity assuming that the individual lots are not surrounded by
impermeable fencing."
Their assertion is that this statement is inconsistent with the findings of the Initial Study, as the
plans do not provide sufficient evidence that impermeablefencing will not be placed around
each parcel, which would be allowed by the Town's fencing ordinance.
As noted in my letter,(November 11, 2014),over 7 acres, consisting of the lower third to half of
lots 5-9 are being preserved via an open space easementprotecting the steeper sloped wooded
areas of the site that also includes Matadero Creek. It is standard practice not to enclose areas
being preserved for open space and wildlife with impermeable fencing, as it defeats the
purpose of encouraging wildlife use and movement through an area. Thus, my evaluation was
predicated on this standard principle that any fencing in the easement area between lots 5-9
and along the western boundaries of lots 5-9 would in fact consist of wildlife friendly fencing.
The review of the project plans (Tentative Map 5/22/15)finds them consistent with this
assumption.
As for wildlife friendly fencing, a number of wildlife agencies across the west provide
recommendations for their construction. Even though these recommendations are usually
San Jose:6840 Via del Oro,Suite 220•San.Jose,CA 95119.Phone:(408)224-8300.Fax:(408)224=1411
Oakhurst:P.O..Box 2697 39930 Sierra Way,Suite B.Oakhurst,CA 93644.Phone (559)642-4880.Fax:(559)642-4883
Bakersfield:"8200 Stockdale Highway,M10-293•Bakersfield,CA 93311
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associated with fencing large landscapes for livestock,while retaining movements patterns for
several large ungulates species, some useful principles can be adopted or this project. If a
wired fence is to be installed, I would recommend it be 4-wire and at least,the top and bottom
wire be barbless; if at all possible all 4 wires should remain barbless where feasible.There
should be 20" between the ground and the first wire, as this permits easy passage for deer,
particularly fawns. Wood constructed fences or even wired mesh fences can be used, if there is
a 20"gap at the bottom.
Riparian areas such as occurring along Matadero Creek are known to disproportionately
facilitate regional movement of wildlife. This is currently the case on this site and will remain so
after project buildout, due in large part to the preservation of approximately 7 acres of open
space along Matadero Creek.The Open Space Easement with the integration of wildlife friendly
fencing ensures that the important regional movements of wildlife, primarily along the creek,
will not be appreciably impeded by buildout of the project. In addition to the natural
movement of wildlife along Matadero Creek,the northern boundary of the site also supports a
trail easement that also facilitates regional wildlife movements.
In order to evaluate the effect that the proposed project might have on regional movement
patterns, I reviewed the various project components considered including the construction of
the: 1) access road; 2) nine houses and associated infrastructure related to these homes; 3)
east-west trail along the northern boundary and footbridge spanning Matadero Creek; and 4)
storm drain, energy dissipater and subdrains that are designed to maintain water quality of the
runoff from the project on the lower portion of lot#7 above the open space easement. Also
explicit in the project is the 7-acre Open Space Easement along Matadero Creek.
Therefore, even if lots 1-4 included impermeable fencing that prevented wildlife movement to
and along the eastern boundary fence,the project's overall effect on wildlife movement is
expected to result in a less than significant impact on regional wildlife movement, due in large
part,to the preservation the existing important regional pathways such as along Matadero
Creek and along the trail easement on the northern border of the site. Additional detailed
discussion on various project elements are discussed in more detail below.
Context for Regional Wildlife
The following discussion provides context for understanding the impact assessment from
buildout of the site. For medium to large mammals, this 18-acre site while appearing large by
our standards, represents a relative small landscape for regional wildlife;for example, it is
about 5%the size of an average deer home range, and less than one percent the size of a
bobcat or coyote home range. The average deer density for these urban/rural areas is
approximately 25-30 deer/mi2,thus the site from a population perceptive supports less than
one deer.This seems confusing and conflicting for some, because at any one time, several deer
may forage or move through the site.The answer lies in the fact that animals are not
distributed evenly across the landscape, and so deer can and are both spatially and temporally
clustered, but when an average density is estimated at a suitable spatial scale for deer(e.g.,the
entire eastern slope of the Santa Cruz Range), it averages 25-30 deer/mi2.Therefore, despite
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the groups of deer that may be seen from time to time, the site from pure habitat perspective
is insignificant for the local deer population. For example, hypothetically, if we removed the
entire forage capacity of this 18-acre site, its impact on the regional population would be too
small to measure.
But, as with real estate, location is important. Topographic features (e.g., ridge tops, creek
systems) and/or suitable large habitat patches disproportionately facilitate wildlife movement.
It is these very factors that contributed to the conclusion that I reached in my original letter
(November 11, 2014),the proposed open space easement with the wildlife friendly fencing
area along Matadero Creek preserved the most important wildlife pathway on the site for
regional wildlife.
Trail and Bridge Crossing.
Shute Mihaly&Weinberger, also believe the IS did not adequately discuss potential impacts
associated with the proposed trail along the project's northern boundary nor evaluate the
bridge crossing on Matadero Creek. Non-paved trails are a regular feature of open space areas
throughout the Bay Area and California. In fact,trails are an integral feature that is explicitly
integrated into projects within the Town of Los Altos Hills.The trail proposed for this project,
follows the northern boundary within a contained space, and crosses perpendicularly over the
creek with a free span bridge. These design elements minimize any impact on the landscape
and movements of wildlife species. Human trails use in these urban/rural settings are biased to
daylight hours.The trail alignment, along with the bridge design (perpendicular crossing with
free-span bridge is preferred by the resource agencies) will not substantially impede movement
patterns of any regional wildlife. During construction of the trail and bridge, daytime wildlife
movements may be altered temporarily;but crepuscular and nighttime movements will not be
appreciably affected. The construction window for the trail and bridge are expected to extend
between 4 to 12 weeks. Once construction is completed, regional movement patterns are
expected to return to pre-construction conditions. This temporary affect on daytime
movements is considered a less than significant impact as wildlife will temporarily shift the
activity time.
Water Quality Features
The project will incorporate water quality features into the project to comply with storm water
regulations by treating storm water runoff in such a manner as to maintain water quality.
These features include a bio-infiltration pond on the lower portion of lot#7, but above the
Open Space Easement. After treatment the runoff will be conveyed through an underground
detention tank and drained down the hill via a 15" pipe to the creek. The pipe is to be installed
underground within a trench from the detention tank to the boundary of the Open Space
Easement. Within the Open Space Easement, the 15" pipe will be partially buried with
approximately 8 to 9" of the pipe above ground. The excavated soil will be compacted as a
wedge on each side of the pipe so as to minimize its above ground profile. This technique will
minimize trenching and disturbance to tree roots, while allowing the free movement of wildlife
through the open space area.
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L
The temporary impacts from the construction of these features, contained within lot#7 and the
Open Space Easement will have at most some potential influence on daytime movement
patterns of locally occurring wildlife.These temporary effects are considered a less than
significant impact to regional wildlife movement.The partially buried pipe within the open
space has been designed specifically so that it will notsubstantially impedemovement of
wildlife. Once built,the water quality features including the partially buried pipe in the Open
Space Easement will not significantly impede movement of wildlife regionally, as regional
wildlife will be able to relatively easily maneuver over the exposed pipe.Therefore,these
features will result in a less than significant impact to regional wildlife movement.
Summary .
Buildout of the project will preserve the most important areas for regional wildlife movement,
namely along Matadero Creek.The trail easement on the northern boundary also contributes
to regional wildlife movement.This area is already a human dominated landscape, and
individual deer, bobcat and coyote for example, have adapted to regular human use of the
landscape. The bridge design proposed for the project is precisely the style of bridge that
should be integrated over a creek as it has a relatively small footprint, and allows the creek to
flow unimpeded. Smaller, aquatic species will easily move along the creek, as will small rodents
and all medium to large mammals. Bird use of the riparian area along the creek would not be
expected to be substantially altered. The water quality features being integrated into the
above the open space easement in the lower portion of lot 7 may temporarily alter movements
during daylight hours, with movements returning to normal post-construction.The extension of
the partially buried pipe within the Open Space Easement will not impede movement of
wildlife.Therefore, due to the placement of the homes and access road,the specific design of
the trail, bridge and the temporary affects from the water quality features, and the 7-acre Open
Space Easement along a wildlife movement pathway(i.e., Matadero Creek), it is my
professional opinion that these components considered in total,would result in a less than
significant impact to loss of habitat for wildlife and to impacts to regional wildlife movement.
If you have any questions regarding this analysis please feel free to contact me at 408-281-5885
or via email at rhopkins@loainc.com.
Sincerely,
Rick A. Hopkins, Ph.D.,
Principal and Senior Conservation Biologist
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r _ ATTACHMENT 11C
H.T. HARVEY & ASSOCIATES
Ecological Consultants
Privileged and Confidential Work Product
DRAFT MEMORANDUM
•
PROJECT #3863-01
DATE: . April 28,2016 .
TO: Steve Atkinson,Arent Fox LLP
.. .-.
FROM: Steve Rottenborn
SUBJECT: Stirling Subdivision—Wildlife Movement Impact Assessment
This memorandum summaries H. T. Harvey & Associates' opinions regarding the potential impacts of the
proposed Stirling Subdivision project on wildlife movement. It is our understanding that the project entails the
subdivision of an existing 18.18-acre site in Los Altos Hills, California, into nine lots. The project proponent
has requested our opinions related to comments on the project's September 14, 2015 Initial Study/Mitigated
Negative..Declaration (IS/MND; EMC Planning Group 2015) related to potential impacts on wildlife
movement. This memo provides our opinions pertaining to potential project impacts on wildlife movement,
particularly regarding the adequacy of the California Environmental Quality Act(CEQA) analysis of impacts.
Project Impacts on Wildlife Movement
The IS/MND assessed impactsof the subdivision on wildlife movement;concluding that "even though this
project will lead to.changes in spatial use patterns of local common species of wildlife,this would not constitute
a significant CEQA impact because the project will preserve approximately 40 percent of the project site in an
open space easement along the tributary to Matadero Creek, and this area is the highest qualitycorridor for
wildlife movement."We agree with the conclusion that wildlife movement impacts will be less than significant.
We base our opinion on the proposed subdivision plan, the current movement pathways of biological
importance to wildlife in the site vicinity, and our expectations regarding the ability of wildlife to continue to
access and use these biologically important movement pathways after project implementation.
CEQA guidelines related to wildlife movement require an assessment of whether a project would "interfere •
substantially with the movement of any native resident or migratory species or with established native resident
or migratory wildlife corridors". In our decades of experience assessing impacts of projects on wildlife
movement, we have interpreted "substantial interference" as pertaining to movement that has biologically
important implications-that is,movement necessary tohelp sustain populations (e.g.,by allowing immigration
983 University Avenue,Building D•Los Gatos,CA 95032•Ph:408.458.3200 •F:408.458.3210
of new individuals) and maintain genetic diversity within populations. Such interpretation takes into account
regional wildlife movements, and movement between populations, rather than movement by animals at a scale
as small as an 18-acre project site, or between such a small site and adjacent areas. As a result, the appropriate
assessment of the Stirling Subdivision's impacts on wildlife movement focuses on whether the project would
substantially interfere with the ability of animals to move between large off-site habitat areas (such as between
large habitat patches near Altamont and Moody Roads to the south and Arastradero Preserve to the northwest),
not on whether animals can move as freely within the site as they currently do,whether animals have access to
particular areas on the site, or whether animals can move on and off this particular site via less important
pathways.
Live Oak Associates (2006) prepared a draft wildlife corridor study for the Town of Los Altos Hills that
identified the potential pathways by which wildlife might move within and through the Town. This study
determined that wildlife could move through or around the Stirling Subdivision site in several locations; these
locations included pathways along Matadero Creek (and a tributary to the creek) to the northwest, southwest,
and southeast of the site; pathways involving other parcels to the north and northeast; and two narrow
pathways through residential lands to the east(Figure 1). Of these potential movement locations,the movement
pathway along Matadero Creek and the pathway leading to the northeast were the ones that were part of larger-
scale movement corridors (Figure 1).The first pathway included areas along Matadero Creek and its tributaries,
which allow for wildlife movement among a number of habitat areas in the Town of Los Altos Hills and more
widely. Given the presence of ample cover in the form of tree, shrub, and ground-layer vegetation, the
Matadero Creek corridor provides cover and refugia for a variety of reptiles, amphibians, small mammals, and
birds, while also being open enough to support movement by larger animals such as mule deer (Odocoileus
hemionus), bobcats (Lynx rufus), coyotes (Canis latrans), and even mountain lions (Puma concolor). Movement
pathways along Matadero Creek thus provide opportunities for larger and/or more mobile species to move
long distances using this corridor (e.g., between large habitat patches near Altamont and Moody Roads to the
south and Arastradero Preserve to the northwest). In addition, the resources provided by the well-vegetated
drainages in the Matadero Creek watershed, as well as native vegetation present within the low-density
residential areas throughout the watershed, provide habitat that supports many of these animals within their
home ranges:In other words, the biological importance of the Matadero Creek corridor for wildlife movement
includes both long-distance dispersal movements (e.g., by a mule deer, coyote, or mountain lion dispersing
several miles in a night) and short-distance movements and genetic exchange among individuals that make small
portions of the corridor part of their home range.
During a site visit on March 31, 2016, I observed numerous "game trails", established primarily by mule deer
but undoubtedly used by numerous other species, following the contours of the slope within the proposed
Matadero Creek open space area (which follows Matadero Creek and one of its tributaries) on the Stirling
Subdivision site.The well-established nature of these trails,which connect to similarly suitable areas for wildlife
movement both upstream and downstream from the project site, indicates the importance of this proposed
open space area for wildlife movement. We do not expect future construction on the land upslope from the
Matadero Creek corridor to result in a substantial reduction in use of the creek corridor for wildlife movement.
Species such as mule deer and coyotes that currently occur on the site have to be sufficiently habituated to, or
2
tolerant of, residential land uses on other immediately adjacent parcels to be moving through the site to begin
with, given that the project site is embedded within a fairly extensive matrix of low-density residential
development. Furthermore,the dense vegetation present in much of the on-site portion of the Matadero Creek
corridor, coupled with the width of the open space easement area,would allow animals to move through this
corridor relatively unaffected by activities on residential land uses upslope.
We also do not expect the construction of a footpath on the northern portion of the project site, or a
footbridge across Matadero Creek, to substantially interfere with wildlife movement along the Matadero Creek
corridor.We observed numerous trails paralleling the creek within the future open space area,and thus,animals
will not be restricted to moving through Matadero Creek at any one location(e.g.,the location of the proposed
footbridge). Granted, they will need to cross the path, but there is no expectation that the path or bridge will
include features such as tall,impassable fencing that would preclude the ability of a variety of animals to simply
walk across the path. Furthermore, because many of the reptiles, amphibians, and mammals that may move
within or through the project site along the Matadero Creek corridor are active at night, when little or no
human use of the trail is expected, human activity along the trail will not substantially interfere with the ability
of wildlife to cross the trail.
The second major movement pathway identified by Live Oak Associates'wildlife corridor study, and involving
the Stirling Subdivision site,involves parcels to the north and northeast of the site (Figure 1).Animals on these
parcels could move northeast,through low-density residential areas,toward movement pathways along the west
side of Interstate 280. Currently, animals from the Stirling Subdivision site can access this pathway in the
northwestern part of the Stirling site, where there is no fence to constrain movement of animals to and from
the parcels north of the site. The tall fence along the eastern portion of the northern boundary of the Stirling
site, as well as along the northern portion of the eastern site boundary,inhibits such movement under existing
conditions. This was demonstrated during a March 31, 2016 site visit,when I observed eight mule deer in the
northeastern corner of the site,unable to cross over the fence in that location.
The proposed project may continue to include fencing along the northern and eastern boundaries where such
fencing is currently proposed.However,this fencing may be designed to be permeable to wildlife,in which case
it would allow movement through the northern and eastern site boundaries even more freely than currently
occurs. In addition,regardless of the permeability of the future fencing along the eastern boundary and most of
the northern boundary, no fencing is proposed along the northern boundary where the open space easement is
located.As a result,after project implementation and residential development on the site,animals that currently
have access to the movement pathway to the north and northeast will continue to have access to that pathway
that is at least as good as,if not better than(with wildlife-permeable fencing),existing conditions.
Therefore,the two most important wildlife corridors involving the Stirling Subdivision site,the Matadero Creek
corridor and the corridor to the north/northeast,will continue to be available after project implementation and
subsequent construction on the residential lots,and the project will have little effect on the ability of animals to
use either corridor. For this reason, the biologically important wildlife movement that currently involves use of
the project site will continue to occur relatively unaffected, and the project will not substantially interfere with
such movement.
3
The project may inhibit or preclude the use of much smaller-scale movement pathways, but these impacts are
, less than significant under CEQA because the movement that occurs along these pathways does not contribute
substantially to regional movements or exchange of individuals or genes among populations. For example,Live
Oak Associates'wildlife corridor study identified two very narrow, short wildlife movement pathways between
the eastern side of the Stirling Subdivision site and Natoma Road, through the residential areas to the east
(Figure 1). It is our understanding that small gaps in the eastern fence allow animals to move along those
pathways. However, those pathways lead primarily to the Poor Clare Nuns' relatively small orchard east of
Natoma Road; that orchard.is so small that it alone does not provide habitat to,support large numbers of
individuals of any species.From that orchard,animals can only use very narrow corridors to reach broader ones
such as the larger corridor north/northeast of the project site. In other words,the two narrow corridors leading
to and from the eastern side of the site provide only for local, small-scale movement of wildlife and contribute
little to more biologically important population-level or regional movements. In that respect, they are not
typical of the broader, better-connected movement pathways that are usually identified as "corridors", and I
was actually surprised to see those two pathways included in Live Oak Associates'study as corridors.
Under current conditions, wildlife can move relatively freely throughout the portion of the site where future
residential development would occur,and they can move through the eastern fenceline in the two narrow,short
movement pathways discussed above. Residential development would curtail or preclude free movement
throughout the entire site, as homes and other features,which may include fences or hedgerows that may not
allow easy movement in certain areas,will be constructed in certain areas.This development may also reduce or
preclude movement through those two narrow eastern pathways. However, these developed features will not
result in substantial interference with established or biologically important movement pathways —animals will
still be able to access and use the biologically important movement pathways identified in Live Oak Associates'
wildlife corridor study.
In addition, to the extent that animal movement between the project site and Natoma Road to the east is
important even locally,animals will be able to continue to make such movements along Charles Avenue (Figure
1). I am surprised that Live Oak Associates' wildlife corridor study identified such narrow,,short movement
pathways east of the Stirling Subdivision site as "corridors"in the first place,and that,given that such pathways
were included, Charles Avenue was not also included as a movement pathway. Wildlife often move along the
path of least resistance, even in developed areas, and as a result, deer, bobcats, gray foxes (Uro fyon
cinereoargenteus), striped skunks (Mephitis mephitis), and a variety of other animals often move along roads that
have little traffic. After the project is implemented and residential development occurs, animals will be able to
access Charles Road (both from the residential lots and from the open space area along Matadero Creek), and
such animals will be able to move along Charles Road to reach the Poor Clare Nuns' small orchard and any
other movement pathways that may currently be accessed via the two narrow pathways east of the site that
were identified in Live Oak Associates'study.As a result,the limited/local east-west movement by wildlife that
currently occurs will still be able to occur following project implementation.
4
Literature Cited
EMC Planning Group Inc. 2015. Initial Study/Mitigated Negative Declaration. Stirling Subdivision. Prepared
for Town of Los Altos Hills.September 14,2015.
Live Oak Associates.2006.The Town of Los Altos Hills draft wildlife corridor study.December 2006.
•
5
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Figure 1: Wildlife Movement Pathways
, H.T. HARVEY & ASSOCIATES Stirling Subdivision
ti."--Th Ecological Consultants 3863-01
April 2016
ATTACHMENT 11D
Owra •
ENVIRONMENTAL CONSULTANTS
April 1, 2016
Rosy Ko
425.West 53rd St
New York, NY 10019
RE: Ko Subdivision Project, Creek and Riparian Jurisdictional Assessment
Dear Ms. Ko,
The purpose of this letter is to describe the methods and results of a creek and riparian
jurisdictional assessment performed on November 11, 2015 at the site of the Ko Subdivision
Project(Project) at 28030 Natoma Road, Los Altos Hills, California (Project;Area),
Per Mitigation Measure #8 of the Mitigated Negative Declaration (MND) and attached Mitigation
Monitoring Program (MMP), if the bed or banks of the creek or riparian'trees/habitats will be
impacted by installation of the pedestrian footbridge, the applicant shall retain a qualified
biologist/wetland regulatory specialist to evaluate the impacts of this project feature. This
consultant shall prepare a preliminary jurisdictional assessment to document proposed impacts
to the waterway and riparian habitat that are potentially under the jurisdiction of the U.S. Army
Corps of Engineers (Corps), California Department of Fish and Wildlife (CDFW), Regional
Water Quality Control Board (RWQCB), and/or Santa Clara Valley Water District (SCVWD). If
the drainage feature is not determined to be jurisdictional by'any of the agencies, no further
action is necessary.
WRA, Inc. (WRA) conducted a preliminary jurisdictional assessment of the creek and
associated riparian habitat in the area of the planned footbridge installation to identify the limit
and extent of areas potentially under the jurisdiction of federal, state and local regulatory
agencies including the Corps, CDFW, RWQCB, and/or SCVWD within the Project Area.
Project Description
The proposed Project is a tentative map to subdivide an 18.18 acre (gross) project site into nine
lots. Two existing residential structures on the site would likely be demolished and up to nine
new homes could be constructed. Access into the site would be via Natoma Road and an
extension of existing Charles Avenue.
The proposed Project includes an open space easement along an intermittent creek/tributary to
Mataderol Creek, a United States Geological Survey (USGS) "blue-line" stream. The open
space easement is located in the western portion of the Project Area. A pedestrian footbridge is
proposed across the creek for public trail access.
During a previous site assessment, it was determined that the only portionof the Project that
has potential to impact jurisdictional features is the planned footbridge over the creek and
2169-G East Francisco Blvd., San Rafael, CA 94901 (415) 454'-8868 tel (415) 454-0129 fax info@wra-ca.com www.wra-ca.cam
therefore for the purposes of this jurisdictional study, only the upper end of the creek within the
Project Area was assessed. This area is referred to here as the Footbridge Study Area.
Federal, State, and Local Regulatory Jurisdictions
U.S.Army Corps of Engineers
The U.S.. Army Corps of Engineers (Corps) is responsible for regulating the discharge of fill
material into waters of the United States under Section 404 of the Clean Water Act (CWA). The
extent of the Corps jurisdiction includes areas below the ordinary high water and adjacent
wetlands. For freshwater non-tidal creeks, Corps jurisdiction extends to the ordinary high water
mark(OHWM). A jurisdictional determination is used to define the extent of Corps jurisdiction. .
Corps jurisdiction include lakes, rivers and streams (including intermittent streams) in addition to
all areas below the HTL in areas subject to tidal influence. Jurisdiction in non-tidal areas
extends to the ordinary high water mark defined as:
"...that line on the shore established by the fluctuations of water and indicated by
physical characteristics such as clear, natural line impresses on the bank,
shelving, changes in the characteristics of the soil, destruction of terrestrial
vegetation, the presence of litter and debris, or other appropriate means that
consider the characteristics of the surrounding areas."
Federal Register Vol. 51, No. 219,
Part 328.3 (e). November 13, 1986
Regional Water Quality Control Board
The Regional Water Quality Control Boards (RWQCB) have been delegated responsibility under
Section 401 of the CWA for certifying water quality of projects requiring CWA Section 404
approval. The RWQCB also regulates projects that may impact waters of the State under.the
Porter-Cologne Water Quality Control Act. RWQCB is generally consulted on projects that
require a Corps permit as described above or for projects that would impact Waters of the State.
Although jurisdiction not specifically defined geographically, the RWQCB generally takes
jurisdiction to the top of bank of a stream or river or outer edge of riparian vegetation, whichever
is greater.
California Department of Fish and Wildlife
The California Fish and Game Code (CFGC) section 1602 requires an entity to notify CDFW
prior to commencing any activity that may do one or more of the following:
• Substantially divert or obstruct the natural flow of any river, stream or lake;
• Substantially change or use any material from the bed, channel or bankof any river,
stream, or lake; or
• Deposit debris, waste or other materials that could pass into any river, stream or lake.
CDFW has jurisdiction over the bed and bank of streams, rivers and open water of lakes and
ponds. Their jurisdiction extends to the top of bank of a stream or river or outer edge of riparian
vegetation, whichever is greater. The top of bank designates a stream boundary where a
majority of normal discharges and channel forming activities takes place. The top of bank
boundary will contain the active channel, active floodplain, and their associated banks. CDFW
generally requires a Streambed Alteration Agreement Application for structures placed over or
under a stream.
Santa Clara Valley Water District
The Santa Clara Valley Water Resources Protection Collaborative Guidelines and Standards for
Land Use Near Streams(2006) provides a set of guidelines and restrictions to apply to land use
activities near streams to protect streams and streamside resources within Santa Clara County.
The Town of Los Altos Hills adopted these guidelines by Resolution No. 26-07 in 2007. Prior to
2007, applicants were required to get permits from both the SCVWD and the local jurisdiction
(city or county, if unincorporated) for construction activities near streams in addition to permits
required by the Corps, RWQCB, and CDFW. With the adoption of the guidelines in 2007, the
Town of Los Altos Hills has permitting authority for streamside activities within incorporated
town limits, unless the activity is on land either owned by, or under easement to, SCVWD, in
which case an encroachment permit must be obtained.
Methods
On November 11, 2015, WRA biologists Sean Avent and Scott Yarger, traversed the Footbridge
Study Area on foot to determine the limit and extent of any areas that would be subject to
USACE, CDFW, RWQCB, and/or SCVWD jurisdiction, including creeks, wetlands, and riparian
habitat. Prior to the site visit, background resources were reviewed including the ISMND for the
proposed Project (EMC Planning Group 2015), U.S. Fish and Wildlife Service (USFWS)
National Wetland Inventory (NWI) data (USFWS 2015), aerial photography (Google Earth
2015), and the Mindego Hill USGS 7.5 minute topographical map (USGS 2015).
The Footbridge Study Area was examined for indicators of wetlands, creeks, and riparian
features, including the extent of riparian vegetation, the top of bank, and the ordinary high water
mark. Potentially jurisdictional features were delineated in the field with a GPS unit with sub-
meter accuracy.
Identification of the OHWM followed the Corps Regulatory Guidance Letter No. 05-05, Ordinary
High Water Mark Identification (Corps 2005). The OHWM was delineated in the field using a
GPS unit with sub-meter accuracy. Sections of the creek were impassable due thick vegetation
or downed woody debris. In areas where access was not feasible, the centerline of the creek
was delineated using GPS or topographic data available in ArcGIS1, and an appropriate
distance as visually estimated by the biologist in the field off of the centerline was applied.
ArcGIS topographic data was verified by comparison of sample segments of the creek that were
accessible and measured by GIS.
The top of bank of Matedero Creek was delineated where a clear change in slope was evident
and above the OHWM. The top of bank was also visually confirmed to be outside the majority
of normal discharges and channel forming activities asobserved by wrack lines and erosional
features. The top of bank was also confirmed to be located outside the active channel, active
floodplain, and associated banks as marked by the clear delineation in slope.
ArcGIS is an industry standard geographic information system (GIS) for managing geographic
information and creation of professional maps.
Results
An intermittent tributary to Matadero Creek traversesthe northwestern corner of the larger
Project Area where the open space easement and pedestrian footbridge is proposed. Coast
live oak (Quercus agrifolia) woodlands intergrade with poison oak (Toxicodendron diversilobum)
scrub, and California bay (Umbellularia californica) woodland, in the Footbridge Study Area. A
small patch of red willow (Salix laevigata) riparian scrub is present within the creek channel in
the Footbridge Study Area. The majority of the larger Project Area outside of the Footbridge
Study Area is characterized by non-native grassland and oak woodland habitats. The Project
Area is situated atop a hill, and generally slopes downward from the northeast to the western
and southern boundaries of the Project Area. The limit and extent of Corps, CDFW, and
RWQCB jurisdiction within the Footbridge Study Area are described below, and shown in
Appendix A.
The proposed footbridge crossing is shown in Appendix A. The location of the proposed bridge
was chosen to use the shortest span of the bridge possible while providing the maximum
avoidance of riparian habitat possible. This location also allows for the footbridge to be installed
on a flat grade. The proposed footbridge footings are located above the top of bank of the creek
and also outside the riparian vegetation, and with Best Management Practices (BMPs) for
construction, will avoid any impacts to Matedero Creek. The proposed footbridge construction
location avoids Corps and RWQCB jurisdiction and minimizes impacts within CDFW jurisdiction
as described below.
Corps Jurisdiction
Corps jurisdiction within the Footbridge Study Area is limited to the OHWM of the intermittent
creek and is shown in Appendix A. Standing water in isolated pools was observed within the
creek during the site visit. Other observed indicators of OHWM included scour, bed and bank,
sediment sorting and wrack lines. The OHWM varies from approximately 4 to 8 feet in width
along the length of the creek.
RWQCB Jurisdiction
RWQCB jurisdiction within the Footbridge Study Area matches CDFW jurisdiction as described
below and shown in Appendix A. But because no actions or foreseeable impacts will occur the
creek or banks and Corps permits will not be required within their jurisdiction (at or below the
OHWM of the intermittent creek), authorization from the RWQCB would not be required.
CDFW Jurisdiction
CDFW jurisdiction within the Footbridge Study Area is shown in Appendix A, and is limited to
the top of bank of the intermittent creek or the outer extent of riparian vegetation, whichever is
greater. As discussed above, top of bank is used as the extent of CDFW jurisdiction in the
absence of riparian vegetation. The intermittent creek within the Footbridge Study Area is a
relatively incised channel with steep banks on both sides of the creek. Top of bank was
delineated where a clear change in slope was evident, and this was generally located
approximately 10 to 12 feet above the OHWM. In areas where hydrophytic vegetation including
willows (Salix sp.) and California bay was present at or below top of bank, the outer edge of the
riparian vegetation canopy was delineated as the extent of CDFW jurisdiction. In areas where
the vegetation above top of bank was dominated by upland vegetation, including coyote brush
(Baccharis pilularis), and poison oak, this vegetation was excluded from riparian CDFW
jurisdiction.
•
•
1
CDFW jurisdiction as shown in Appendix A depicts top of bank or the outer extent of riparian
vegetation, including willow and bay trees located either below or directly above the top of bank
of the creek.
Santa Clara Valley Water District
The Project Area is located within a Streamside Review Area as defined in the Guidelines and
Standards for Land Use Near Streams (SCVWRPC 2006) because the parcel abuts "or is in
proximity of a stream including all properties located within 50 feet from the top of stream bank."
The Project Area lies outside any SCVWD jurisdiction as determined by the Town of Los Altos
Hills. The riparian area will be within a dedicated open space easement and does not need a
separate creek setback(Avila 2016).
If you have any questions or comments, please do not hesitate to contact me..
Sincerely,
Sean Avent
Associate Biologist
References
Avila, Suzanne. 2016. Email communication between Suzanne Avila (Towm of Los Altos Hills
Planning and Building Department) and Sean Avent (WRA, Inc.) regarding SCVWD
jurisdiction within the Project Area. April 1.
EMC Planning Group, Inc. 2015. Stirling [Ko] Subdivision Mitigated Negative Declaration.
Prepared for Town of Los Altos Hills, 26379 Fremont Road, Los Altos Hills, CA 94022.
September 14.
Google Earth: 2015. Aerial Photographs: 1948-2015.
Santa Clara Valley Water Resources Protection Collaborative (SCVWRPC). 2006. Guidelines
and Standards for Land 'Use Near Streams - A Manual of Tools, Standards and
Procedures to Protect Streams and Streamside Resources in Santa Clara County.
August, 2005. Revised July, 2006.
Town of Los Altos Hills. 2007. A Resolution of the City Council of the Town of Los Altos Hills
Adopting the Santa Clara Valley Water Resources Protection Collaborative Guidelines
and Standards for Land Use Near Streams. Resolution No. 26-07. Adopted May 27.
[USFWS] U.S. Fish and Wildlife Service. National Wetlands Inventory,(NWI). 2015. National
Wetlands Inventory website. U.S. Department of the Interior, USFWS, Washington D.C.
Available at: http://www.fws.gov/nwi/. Accessed November 2015.
APPENDIX A
JURISDICTIONAL ASSESSMENT MAP
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‘ , 1 . ir, . •,„,Parcel Boundary - •c'
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Top of Bank or Outer Edge of ,, -, "'1r `-
Q Riparian Vegetation(CDFW and ti."
RWQCB Jurisdiction)
n OHWM(Corps Jurisdiction) '}' t
Stream Centerline :rt; - •++:,
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03
Figure 1. Matedero Creek Jurisdictional Assessment
+,,,WE
ENVIRONMENTAL CONSULTANTS
Ko Subdivision
Los Altos Hills 0 25 50 100 Map Prepared Date 3242016
Map Prepared By:Fhourigan
Santa Clara County, California Feet Base Source:EsriStreaming-NAIP2914
Data Source(s):WRA
Path.L:\Aced 2000 Files\25000\25302\GIS\ArcMap\Figurel_PreliminaryJurisdictionalAssessment.mxd
ATTACHMENT 11E
•wra
ENVIRONMENTAL CONSULTANTS
April 6, 2016
Rosy Ko
425 West 53rd St
New York, NY 10019
Rosy,
The following summarizes WRA's findings from the site visit conducted March 24, 2016 at the
site of the Ko Subdivision Project (Project) at 28030 Natoma Road, Los Altos Hills, California
(Project Area). No special-status plant species, including Franciscan onion, western
leatherwood, white-flowered rein orchid, and woodland woolythreads, were observed within the
Study Area.
Per Mitigation Measure #2 of the Initial Study and.Mitigated Negative Declaration (IS/MND).for
the Sterling Subdivision and attached Mitigation Monitoring Program (MMP):dated September
14, 2015, the presence/absence of the following plant species shall be determined prior to
initiation of construction activities:
• Franciscan onion,Allium peninsulare Lemmon var. franciscanum, blooming April- June
• western leatherwood, Dirca occidentalis, blooming January-April
• white-flowered rein orchid, Piperia candida, blooming March -September
• woodland woolythreads, Monolopia gracilens, blooming February—July
• Congdon's tarplant, Centromadia parryi ssp. congdonii, blooming May—November
On March 24, 2016 botanists, Scott Yarger and Erich Schickenberg visited the Project Area, to
perform a targeted rare plant survey for the early-season blooming plants Franciscan onion,
western leatherwood, white-flowered rein orchid, and woodland woolythreads. Mr. Yarger and
Mr. Schickenberg have extensive experience with the flora, vegetation types, and wetland
habitats of Santa Clara County.: The entire Project Area was traversed on foot. No special-
status plant species, including the four early-season blooming rare plants identified abovewere
observed within the Study Area.
An additional targeted survey for Congdon's tarplant will be conducted later in the year, after
which, a complete report including these results will be presented.
Should you have any questions or concerns, please feel free to contact me.
Sincerely,
Sean Avent
Associate Biologist •
avent@wra-ca.com
2169-G East Francisco Blvd., San Rafael, CA 94901 (415) 454-8868 tel (415) 454-0129 fax info@wraLca.com. wtvw.wra-ca.com
ATTACHMENT 11F
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"' Revised Arborist Report
28030 Natoma Road
i Los Altos Hills, CA
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Prepared for:
Top Elegant Investment LLC.
H 425 West 53rd St., #411
New York, NY 10019
7 '3 -
!; Prepared by:
HortScience, Inc.
325 Ray Street
/ Pleasanton CA 94566
•',
- ',
April 2016
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HORT SCIENCE.
.
Revised Arborist Report
28030 Natoma Road, Los Altos Hills CA
Table of Contents
Page
Introduction and Overview 1
Assessment Methods 1
Description of Trees 2
Oak-Bay Woodland Census 4
Suitability for Preservation 4
Evaluation of Impacts and Recommendations for Preservation 6
Sudden Oak Death 12
Tree Preservation Guidelines 13
List of Tables
Table 1. Condition ratings and frequency of occurrence for trees 2
Table 2. Oak-Bay Woodland Census 3
Table 3. Tree suitability for preservation 5
Table 3. Trees recommended for removal 7
Table 4. Recommended Tree Protection Zones for future lot develop. 11
Attachments
Tree Assessment Form
Tree Assessment Plan
Revised Arborist Report,Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 1
Introduction and Overview
Top Elegant Investment LLC is proposing to subdivide the property at 28030 Natoma Rd., in
Los Altos Hills, California. The project includes subdivision of the property, construction of a
new road, improvement of the access road leading to the property and installation of utilities
to service the new lots. HortScience, Inc.was asked to prepare an Arborist Report for the
project for review by the Town of Los altos Hills.
This report provides the following information:
1. An assessment of the health and structural condition of those trees identified by the
project's Civil Engineer, Wilsey Ham.
2. Identification of Heritage trees as defined by the Town of Los Altos Hills Ordinance
#12-2.
3. An assessment of the impacts of constructing the proposed project on,the trees.
4. A discussion of sudden oak death, its presence in the area and potential impacts to
the site.
5. Guidelines for tree preservation during the design, construction and maintenance
phases of development.
Assessment Methods
Trees were assessed on November 8, 2012 and April 15, 2014. The assessment included
trees 6"and greater in diameter(19" in circumference). The survey procedure consisted of
the following steps:
1. Identifying the tree as to species;
2. Measuring the trunk diameter at a point 48"above grade;
3. Evaluating the health and structural condition using a scale of 1 —5:
5-A healthy, vigorous tree, reasonably free of signs and symptoms of disease,
with good structure and form typical of the species.
4-Tree with slight decline in vigor, small amount of twig dieback, minor
structural defects that could be corrected.
3-Tree with moderate vigor, moderate twig and small branch dieback, thinning
of crown, poor leaf color, moderate structural defects that might be
mitigated with regular care.
2-Tree in decline, epicormic growth, extensive dieback of medium to large
branches, significant structural defects that cannot be abated.
1-Tree in severe decline, dieback of scaffold branches and/or trunk; most of
foliage from epicormics; extensive structural defects that cannot be abated.
5. Rating the suitability for preservation as"high", "moderate"or"low". Suitability
for preservation considers the health, age and structural condition of the tree,
and its potential to remain an asset to the site for years to come.
High: Trees with good health and structural stability that have the
potential for longevity at the site.
Moderate: Trees with somewhat declining health and/or structural defects
than can be abated with treatment. The tree will require more
intense management and monitoring, and may have shorter life
span than those in 'high'category.
Low: Trees in poor health or with significant structural defects that
cannot be mitigated. Tree is expected to continue to decline,
regardless of treatment. The species or individual may have
characteristics that areundesirable for landscapes, and
generally are unsuited for use areas.
Revised Arborist Report, Top Elegant Investment LLC HortScience,.Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 2
Description of Trees on the Development Site &Access Road
One-hundred and fifty-eight(158)trees were assessed, including 135 trees on the
development site and 23 along the access road connecting the site to Natoma Road.
Descriptions of each tree are found in the Tree Assessment Forms, and locations are
shown on the Tree Assessment Plan(see attachments). Walnut and eucalyptus trees were
not included in the assessment.
The site sits at the edge of the oak-bay woodlands that extend down the east side of the
coastal mountain range in this area. A closed canopy forest of coast live oak exists along the
western edge of the property,with a small finger extending east and south to the driveway
entrance(Photo 1,following page). The northeastern half of the site was an open oak
woodland, dotted with open-grown valley oaks (Photo 2, following page).
Three(3)species of oaks were assessed at the site(Table 1). The most frequently occurring
species was coast live oak(116 trees, or 73% of the population). Valley oak,with 41 trees
(26%),was the second most frequent species assessed. One blue oak(#157)was also.
assessed. Tree size ranged from 6"to 46"in diameter. Forty-one(41)trees had multiple
trunks arising below 48".
Table 1: Condition ratings and frequency of occurrence of trees.
28030 Natoma Rd., Los Altos Hills
Common Name Scientific Name Condition Rating . No.of
Poor Fair Good Trees
(1-2) (3) (4-5)
Coast live oak Quercus agrifolia 6 51 59 116
Blue oak Quercus douglasii - - 1 1
Valley oak Quercus lobata 2 22 17 41
Total 8 73. 77 158
5% 46% 49% 100%
Coast live oaks were growing in groups, or stands,where one or two trees were dominant
and the rest were subordinate. Dominant trees tended to be mature to over-mature, with
diameters from 24"to 46", and in good to excellent condition. Subordinate trees were
typically young to semi-mature(<24" in diameter)and growing at the edge of the group or
beneath their larger neighbors. The competition for light and resources among this group
often produced trees in fair condition, that leaned or had asymmetric or one sided crowns.
Fifty-nine(59)of the coast live oaks were in good or excellent condition, 51 were in fair and
six(6)were in poor(Table 1).
Mature valley oaks dominated the northeast half of the site,with young to semi-mature trees
located in the grove between Lots 1 and 2. Theremaining seven (7)valley oaks were along
the access road. Condition of the valley oaks was fair(22 trees)to good (17 trees). Two(2)
of the valley oaks were in poor condition. There were fewer young valley oaks than coast live
oaks(22 valley oaks with diameters <24"vs. 85 coast live oaks with diameters <24"),
indicating that the valley oaks are not regenerating naturally and may slowly disappear from
the landscape.
Overall, tree condition was good (77 trees or 49%)to fair(73 trees or 46%). Eight(8)trees
(5%of the population),were in poor condition, including tree#51, a 42" diameter coast live
oak with a several cavities and extensive trunk decay.
The Town of Los Altos Hills defines all oaks with a diameter of 12" (circumference of 36")as
Heritage Oaks. Based on this definition, 132 of the 158 trees qualified as Heritage Oaks.
Heritage Oaks are identified in the Tree Assessment Forms(see attachments).
Revised Arborist Report, Top Elegant Investment LLC HortScience,.Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 3
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Revised Arborist Report;Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 4
Oak-Bay Woodland Census Outside of development Area
For the remainder of the site,we performed a census of all trees 6"and greater in diameter.
The census procedure consisted of the following steps:
1. Identifying the tree as to species;
2. Counting the number of trees of each species in the following diameter classes:
6-11", 12-17", 18-23", 24-32", and. 32".
The remainder of the site was a west-facing slope with a dense cover of oak-bay woodland.
The property boundary was defined by the creek running along the southern and western
boundaries, except in the northwestern corner where the boundary extended over the creek
(see attached Tree Assessment Map). Table 2 provides a summary of the census data by
species and diameter class.
The majority of trees were coast live oaks (316 trees, or 63% of the census trees) and
California bays (106 trees or 21%). Two-hundred and eighty-five(285) of the trees in this
area qualified as Heritage Oaks, including 253 coast live oaks, 23 valley oaks and 9 blue
oaks.
Table 2: Oak-Bay Woodland Census.
28030 Natoma Rd., Los Altos Hills
Common name Scientific name Diameter Classes Total
6-11 12-17 18-23 24-31 >_32
Calif. buckeye Aesculus californica 11 14 - 2 1 _ 28
Toyon Heteromeles arbutifolia - - 1 - - 1
Coast live oak Quercus agrifolia 63 94 63 52 4 4 316
Valley oak . Quercus lobata 9 10 7 2 4 32
Common elderberry Sambucus nigra 2 5 - - - 7
Calif. Bay Umbellularia californica 80 19 5 1 1 106
Blue oak Quercus douglasii 2 4 - 4 1 11
Total 167 146 76 61 51 501
Suitability for Preservation
Before evaluating the impacts that will occur during development, it is important to consider
the quality of the tree resource itself, and the potential for individual trees to function well over
an extended length of time. Trees that are preserved on development sites must be carefully
selected to make sure that they may survive development impacts, adapt to a new
environment and perform well in the landscape.
Our goal is to identify trees that have the potential for long-term health, structural stability and
longevity. For trees growing in open fields or creek channels, away from areas where people
and property are present, structural defects and/or poor health presents a low risk of damage
or injury if they fail. However,we must be concerned about safety in use areas. Therefore,
where development encroaches into existing plantings,we must consider their structural
stability as well as their potential to grow and thrive in a new environment. Where
development will not occur, the normal life cycles of decline, structural failure and death
should be allowed to continue.
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 5
Evaluation of suitability for preservation considers several factors:
• Tree health
Healthy, vigorous trees are better able to tolerate impacts such as root injury,
demolition of existing structures, changes in soil grade and moisture, and soil
compaction than are non-vigorous trees.
• Structural integrity
Trees with significant amounts of wood decay and other structural defects that cannot
be corrected are likely to fail. Such trees should not be preserved in areas where
damage to people or property is likely. Coast live oak#51 is an example of such a
tree.
• Species response
There is a wide variation in the response of individual species to construction impacts
and changes in the environment. In our experience,for example, valley oak is
moderately sensitive to site disturbance, while coast live oak is more tolerant of root
loss.
• Tree age and longevity
Old trees,while having significant emotional and aesthetic appeal, have limited
physiological capacity to adjust to an altered environment. Young trees are better
able to generate new tissue and respond to change.
• Species invasiveness
Species which spread across a site and displace desired vegetation are not always
appropriate for retention. This is particularly true when indigenous species are
displaced. None of the species surveyed at the Natoma Rd. property are considered
invasive.
Each tree was rated for suitability for preservation based upon its age, health, structural
condition and ability to safely coexist within a development environment. Table 3 provides a
summary of the suitability ratings. Suitability ratings for individual trees are included in the
Tree Assessment Form(see attachments).
Table 3: Tree Suitability for Preservation
28030 Natoma Rd., Los Altos Hills
High These are trees with good health and structural stability that have the
potential for longevity at the site. Thirty-five(35)trees were highly
suitable for preservation; including 25 coast live oaks and 10 valley oaks.
Moderate Trees in this category have fair health and/or structural defects that may
be abated with treatment. Trees in this category require more intense
management and monitoring, and may have shorter life-spans than
those in the"high"category. Ninety(90)trees were of moderate
suitability for preservation, including 68 coast live oaks, 21 valley oaks
and one(1) blue oak.
- Low Trees in this category are in poor health or have significant defects in
structure that cannot be abated with treatment. These trees can be
expected to decline regardless of management. The species or
individual tree may possess either characteristics that are undesirable in
landscape settings or be unsuited for use areas. Thirty-three(33)trees
were of low suitability for preservation, including 23 coast live oaks and
10 valley oaks.
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 6
Evaluation of Impacts and Recommendations
Appropriate tree retention develops a practical match between the location and intensity of
construction activities and the quality and health of trees. The Tree Assessment Form was
the reference point for tree condition and quality. Potential impacts from construction were
evaluated using the Proposed Subdivision Map (dated May 22, 2015) and Access Road
Improvement Plan (dated January 13, 2016), prepared Wilsey Ham.
The plan proposes to subdivide the property into 9 lots, with the existing house possibly to
remain on Lot 9. Building envelopes and potential building and driveway locations were
shown on the plans.
The existing dirt driveway will be improved and extended to the north. The new road would
be 22'wide,with a 3'curb and gutter and a 5'wide pathway installed along the eastern edge.
Utilities are shown on the plan and will be located within the new road. Accurate tree trunks
were shown on the plans for most, but not all, of the trees.
In addition, the access road from Natoma Rd.to the development site will be widened to 20',
with a 2' gutter and a 5'wide pathway installed along the northern edge. The path is
proposed to be constructed of decomposed granite and will be designed to meander through
the trees.
Potential impacts from construction of the new road, driveways, drainage and landslide repair
on Lot 7 were estimated for each tree. Impacts from the development of individual lots were
not assessed, as no development plans exist for each lot. The most significant impacts to the
trees would occur as a result of the road grading, access road widening, curb and gutter
installation and slide repair on Lot 7.
For the Development Site:
Based on my evaluation of the plans and associated impacts on the trees, I recommend
preservation for 111 trees, including 92 Heritage Oaks. Preservation is predicated on
establishing a Tree Protection Zone and other recommendations listed in the Tree
Preservation Guidelines(page 13).
Removal is recommended for 24 trees, including 9 that fall within the proposed road
alignment, 6 that were adjacent to the new road but which would be impacted beyond their
tolerance and 9 within the slide repair. Of the 24 trees recommended for removal, five (5)
had low suitability for preservation and 19 qualified as Heritage Oaks. Table 4(following
page) provides the recommended action for each tree, along with their Heritage Oak status
and a description of impacts.
Twenty-one(21) of the trees identified for preservation had low suitability for preservation.
Most of these were suppressed trees with poor structure; however, some were structurally
unstable including#11, 50, 51 and 64. I do not believe it is appropriate to recommend these
for removal before we have an understanding of where they would be located relative to the
individual lot developments. Although all of these trees had some amount of decay and had
experienced limb or stem failures, they continue to provide environmental and.aesthetic
benefits as they decline and fail. I am recommending these trees be fenced at the dripline
during construction of the subdivision improvements to protect construction personnel should
they want to park and/or linger under the trees. However,trees#11, 50, 51 and 64 may have
to be removed with the development of individual lots.
For the 49 trees identified for preservation adjacent to the subdivision improvements, I have
provided specific Tree Protection Zones based on their proximity to the work(see Tree
Preservation Guidelines(page 13). Trees not given a specific Tree Protection Zones shall
be fenced at the dripline in all directions.
Revised Arborist Report,Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 7
For the 42 trees within the buildable area of each lot or other easements and which were
appropriate for retention (high or moderate suitability for preservation) but far enough from
the subdivision improvements to not be impacted at this time, I have provided what I consider
the ideal Tree Protection Zone that would limit root loss and associated impacts (Table 5,
page 11). This information is provided to help with the deign of improvements on individual
lots and distances provided represent radii in all directions. These distances are an ideal and
some amount of encroachment may be acceptable based on the size, location and nature of
the disturbance and construction techniques employed.
Thirteen (13)of the trees recommended for preservation will be in close proximity to the new
road alignment and are expected to require canopy and root pruning for construction of the
road and vehicle clearance. These are trees#1, 3,4, 7, 23, 25-27, 28, 33, 66, 95 and 101.
Pruning recommendations are provided in the Tree Preservation Guidelines(page 13).
For the Access Road:
Based on my evaluation of the plans and associated impacts on the trees, I recommend
preservation for 18 of the 23 trees along the access road, including 16 Heritage Oaks.
Preservation is predicated on establishing a Tree Protection Zone and other
recommendations listed in the Tree Preservation Guidelines(page 13).
Removal is recommended for 5 trees, all of which qualified as Heritage Oaks. Table 4
provides the recommended action for each tree, along with their Heritage status and a
description of impacts. Impacts were as follows:
• Tree#107 had failed at the base and will need to be removed to construct the path.
• Tree#108 fell within the proposed access road alignment, requiring removal.
• Trees#111, 118 and 119 were adjacent to the new access road but would be
impacted beyond their tolerance.
Ten (10) of the trees recommended for preservation will be in close proximity to the new
access road alignment, including trees#105, 106, 109, 110, 115-117, 120-122, and 125. For
most of these trees, the new road alignment will match the existing alignment, however, root
loss associated with construction of the access road may lead to decline, such as dieback of
twigs and branches,for some trees. This is especially true for trees#106, 120-122 and 125,
which are large-diameter trees in very close proximity to construction. In addition, these trees
may require pruning for construction and vehicle clearance.
In summary, a total of 129 trees can be preserved (111 on the subdivision site and 18 along
the access road), including 108 which qualified as Heritage Oaks. Twenty-nine (29)trees will
require removal (24 on the subdivision site and 5 along the access road), 24 of which
qualified as Heritage Oaks.
Table 4: Recommendations for action
28030 Natoma Rd., Los Altos Hills
Tree# Species Trunk Heritage Impact
Diameter Oak?
(in.)
1 Coast live oak 14,9,9,6 Yes Preserve,8' N. of 5'new rd.
2 Coast live oak 13 Yes Remove, impacted by new rd. alignment
3 Coast live oak 13 Yes Preserve, 6'N. of 5'path.
4 Coast live oak 11 No Preserve, 6'N. of 5'path.
5 Coast live oak 12,10,10,9,8 Yes Preserve, 18'N. of 5'path.
6 Coast live oak 8 No Preserve,20'N. of 5'path.
7 Coast live oak 17 Yes Preserve,6'N.of 5'path.
8 Coast live oak 8 No Preserve,20'N. of 5'path.
9 Coast live oak 13 Yes Preserve,20'N. of 5'path.
10 Coast live oak 17 Yes Preserve, outside impacts
(Continued,following page)
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 8
Table 4: Recommendations for action,continued
28030 Natoma Rd., Los Altos Hills
Tree# Species Trunk Heritage Impact
Diameter Oak?
(in.)
11 Valley oak 32 Yes Preserve,outside impacts
12 Coast live oak 12,10 Yes Preserve,outside impacts
13 Coast live oak 7 No Preserve,outside impacts
14 Coast live oak 17,9 Yes Preserve,outside impacts
15 Valley oak 17,17 Yes Preserve,outside impacts
16 Coast live oak 35 Yes Preserve,within Lot 1 bldg.envelope
17 Coast live oak 25,22,18 Yes Preserve,within Lot 1 bldg.envelope
18 Coast live oak 10 No Preserve,within Lot 1 bldg.envelope
19 Valley oak 10 No Preserve,within Lot 1 bldg.envelope
20 .Valley oak 17,8 Yes Preserve,within Lot 1 bldg.envelope
21 Coast live oak 28 Yes Preserve,within Lot 1 bldg.envelope
22 Coast live oak 21,18 Yes" Remove,within new rd. alignment
23 Coast live oak 12,10 Yes Preserve,6'W.of new rd.
24 Coast live oak 18 Yes Preserve,20'W.of new rd.
25 Coast live oak 18,16 Yes Preserve, 18'W.of new rd.; 12'N.of Lot 8 dr.
26 Coast live oak 20 Yes Preserve, 8'W. of new rd.
27 Coast live oak 16,12,11 Yes Preserve, 15'W. of new rd.
28 Coast live oak 20 Yes Preserve, 10'W. of new rd.
29 Coast live oak 18,17 Yes Preserve, outside impacts
30 Coast live oak 29 Yes Preserve, outside impacts
31 Coast live oak 40 Yes Preserve,outside impacts
32 Coast live oak 46 Yes Preserve,outside impacts
33 Coast live oak 8 No Preserve, 8'W.of new rd.
34 Valley oak 16 Yes Remove, impacted by new rd. alignment
35 Coast live oak 12 Yes Remove,within new rd. alignment
36 Coast live oak 11,10 Yes Remove,within new rd.alignment
37 Coast live oak 8,8 Yes Remove,within new rd. alignment
38 Valley oak 14 Yes Remove,within new rd. alignment
39 Coast live oak 12 Yes Preserve, outside impacts
40 Coast live oak 8 No Preserve, outside impacts
41 Coast live oak 20 Yes Preserve,25'W.of new rd.
42 Coast live oak 9 No Preserve, outside impacts
43 Coast live oak 14 Yes Preserve, outside impacts
44 Coast live oak 8,8 , Yes Preserve, outside impacts
45 Coast live oak 17 Yes Preserve,25'W.of new rd.
46 Coast live oak 20 Yes Preserve,20'S. of Lot 7 drive
47 Coast live oak 18 Yes Preserve,within Lot 7 bldg. envelope
48 Coast live oak 25 Yes Preserve,within Lot 7 bldg.envelope
49 Coast live oak 42 Yes Preserve,within Lot 7 bldg.envelope
50 Valley oak 32 Yes Preserve,within Lot 8 bldg.envelope
51 Coast live oak 42 Yes Preserve,declining and high risk
52 Coast live oak 29 Yes Preserve,within Lot 8 bldg.envelope '
53 Valley oak 28 Yes Preserve,within Lot 8 bldg. envelope
54 Coast live oak 28 Yes Preserve, outside impacts
55 Valley oak 20 Yes Preserve, outside impacts
56 Valley oak 30 Yes Preserve,outside impacts
57 Valley oak 28 Yes Preserve,outside impacts
58 Valley oak 23 Yes Preserve,outside impacts
59 Valley oak 16 Yes Preserve,outside impacts
60 Valley oak 23 Yes Preserve,within Lot 4 bldg.envelope
(Continued,following page)
Revised Arborist Report,Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 9
Table 4: Recommendations for action,continued
28030 Natoma Rd., Los Altos Hills
Tree# Species Trunk Heritage Impact
Diameter Oak?
(in.)
61 Valley oak 38 Yes Preserve,within Lot 4 bldg.envelope
62 Valley oak 26 Yes Preserve,35'SE. of Lot 4 drive
63 Valley oak 28 Yes Preserve,35'SE.of Lot 4 drive
64 Valley oak 44 Yes Preserve,35' NW. of Lot 4 drive
65 Valley oak 44 Yes Preserve,20'W. of Lot 4 drive
66 Valley oak 36 Yes Preserve, 15'NE. of rd., 15'S. of Lot 4 drive
67 Coast live oak 20,18,18 Yes Preserve,within Lot 6 bldg.envelope
68 Coast live oak 40 Yes Preserve,within Lot 6 bldg.envelope
69 Coast live oak 19,19 Yes Preserve, outside impacts
70 Coast live oak 7,5 Yes Preserve, outside impacts
71 Coast live oak 8 No Preserve, outside impacts
72 Coast live oak 9 No Preserve, outside impacts
73 Coast live oak 35 Yes Preserve, outside impacts
74 Coast live oak 18,18,15 Yes Preserve,outside impacts
75 Coast live oak 16 Yes Preserve,outside impacts
76 Coast live oak 10,10 Yes Preserve,outside impacts
77 Coast live oak 14 Yes Preserve,outside impacts
78 Coast live oak 17 Yes Preserve,outside impacts
•
79 Coast live oak 8 No Remove,within slide repair
80 Coast live oak 9 No Remove, within slide repair
81 Coast live oak 12 Yes • Remove, within slide repair
82 Coast live oak 20 Yes Remove, within slide repair
83 Coast live oak 20 Yes Remove, within slide repair
84 Coast live oak 14 Yes Remove, within slide repair
85 Coast live oak 26 Yes Remove, within slide repair
86 Coast live oak 6 No Remove, within slide repair
87 Coast live oak 32 Yes Preserve, 15'S. of Lot 7 drive,10' E. of slide rpr.
88 Coast live oak 17 Yes Preserve, 8' E. of slide repair
89 Coast live oak 11 No Preserve, 5' E. of slide repair
90 Coast live oak 9 No Preserve, outside impacts
91 Coast live oak 14 Yes Preserve, outside impacts
92 Coast live oak 9 No Remove, within slide repair
93 Coast live oak 9,4,4 Yes Preserve, 5' E. of slide repair
94 Valley oak 17 Yes Remove, impacted by new rd. alignment
95 Coast live oak 33 Yes Preserve, 15' E. of new rd., 10'E'of path
96 Coast live oak 10 No Remove,within new rd. alignment
97 Coast live oak 13,11 Yes Remove,within new rd.alignment
98 Coast live oak 16 Yes Remove, impacted by new rd. alignment
99 Coast live oak 14,10 Yes Remove,within new rd.alignment
100 Coast live oak 18 Yes Remove, impacted by new rd. alignment
101 Coast live oak 22,21 Yes Preserve, 15' E.of new rd., 10'E'of path
102 Coast live oak 21,20 Yes Remove, impacted by new rd. alignment
• • 103 Valley oak 9 No Preserve, outside impacts
104 Coast live oak 15 Yes Remove,within new rd. alignment
105 Coast live oak 27 Yes Preserve,6'S.of access rd. alignment
106 Coast live oak 25,24,22,19,17, Yes Preserve, at edge of access rd.alignment
12,6
107 Coast live oak 17,14,12,6 Yes Remove,tree failed at base.
108 Coast live oak 21,19 Yes Remove,within access rd.alignment
(Continued,following page)
Revised Arborist Report, Top Elegant Investment LLC - ` HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 10
Table 4: Recommendations for action, continued
28030 Natoma Rd., Los Altos Hills
Tree# Species Trunk , Heritage Impact
Diameter Oak?
(in.)
109 Coast live oak 33,8 Yes Preserve,6' N. of access rd.,5'S. of path
110 Coast live oak 25 Yes Preserve,7' N. of access rd., at edge of path N.
111 Coast live oak 22 Yes Remove, impacted by new access rd. alignment
112 Coast live oak 21,20 Yes Preserve, 10' N. of access rd.,2'N. of path
113 Coast live oak 33,13 Yes Preserve, 12' N. of access rd.,2'N. of path
114 Valley oak 10,6 Yes Preserve, 13'N. of access rd., 3. N'of path
115 Coast live oak 23,22,13,12,9 Yes Preserve,6'N. of access rd.,2'S. of path
116 Coast live oak 12 Yes Preserve,3'N. of access rd., 5'S. of path
117 Valley oak 11 No Preserve,3'N. of access rd., 5'S. of path
118 Valley oak 16,9 Yes Remove, impacted by new access rd..alignment
119 Coast live oak 29 Yes Remove, impacted by new access rd. alignment
120 Valley oak 25 Yes Preserve,3'S.of access rd.alignment
121 Coast live oak 19 Yes Preserve,4' N. of access rd., 5'S. of path
122 Valley oak 35 Yes Preserve, at edge of access rd., 5'S.of path
123 Coast live oak 6 No Preserve, 13'N. of access rd., path at base S.
124 Coast live oak 18 Yes Preserve, 10' N. of access rd.,2' N. of path
125 Valley oak 28 Yes Preserve,3'S. of access rd.
126 Coast live oak 15,14,8 Yes Preserve, 10'S. of access rd.
127 Valley oak 14 Yes Preserve, 12' N. of access rd.,5' N. of path
128 Coast live oak 22,14,10 Yes Preserve,outside impacts
129 Coast live oak 35,19 Yes Preserve,outside impacts
130 Valley oak 18 Yes Preserve,outside impacts
131 Valley oak 14 Yes Preserve,outside impacts
132 Coast live oak 18 Yes Preserve,within Lot 1 bldg. envelope
133 Coast live oak 28,10 Yes Preserve,within Lot 1 bldg.envelope
134 Coast live oak 30 Yes Preserve,within Lot 1 bldg.envelope
135 'Coast live oak 29 Yes Preserve, outside impacts
136 Valley oak 8,4 Yes Preserve, outside impacts
137 Valley oak 11 No Preserve,outside impacts
138 Valley oak 9 No Preserve,outside impacts
139 Valley oak 12 Yes Preserve,outside impacts
140 Coast live oak 19 Yes Preserve,outside impacts
141 Coast live oak 12 Yes Preserve, outside impacts
142 Valley oak 29 Yes Preserve, outside impacts
143 Valley oak 21 Yes Preserve, outside impacts
144 Coast live oak 9 No Preserve, outside impacts
145 Coast live,oak 22 Yes Preserve,outside impacts
146 Coast live oak 26 Yes Preserve,,within Lot 1 bldg.envelope
147 Valley oak 8 No Preserve,within Lot 1 bldg.envelope
148 Valley oak 15 Yes Preserve,within Lot 1 bldg.envelope
149 Coast live oak 10,9,8 Yes Preserve,within Lot 1 bldg.envelope
150 Coast live oak 17 Yes Preserve,outside impacts
151 Coast live oak 20 Yes Preserve,outside impacts
152 Coast live oak 29,23,19,10 Yes Preserve,outside impacts
153 Coast live oak 23 Yes Preserve, outside impacts
154 Coast live oak 16,11 Yes Preserve, outside impacts
155 Valley oak 18 Yes Preserve, outside impacts
156 Coast live oak 22 Yes Preserve, outside impacts
157 Blue oak 9 No Preserve,outside impacts
158 Valley oak 16 Yes Preserve, 15'E. of new rd.
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 11
Table 5: Ideal Tree Protection Zones for future lot development
28030 Natoma Rd., Los Altos Hills
Tree# Species Trunk Heritage Ideal Tree
Diameter Oak? Protection Zones
(in.)
12 Coast live oak 12,10 Yes 10' in all directions
13 Coast live oak 7 No 10' in all directions
14 Coast live oak 17,9 Yes 12' in all directions
15_ Valley oak 17,17 Yes 12' in all directions
16 Coast live oak 35 Yes 20'in all directions
17 Coast live oak 25,22,18 Yes 20'in all directions
18 Coast live oak 10 No 8' in all directions
19 Valley oak 10 No 10' in all directions
20 Valley oak 17,8 Yes 15' in all directions
21 Coast live oak 28 Yes 15' in all directions
46 Coast live oak 20 Yes 15' in all directions
47 Coast live oak 18 Yes 12' in all directions
48 Coast live oak 25 Yes 18' in all directions
49 Coast live oak 42 Yes 20' in all directions
52 Coast live oak 29 Yes 20'in all directions
53 Valley oak 28 Yes 20' in all directions
54 Coast live oak 28 Yes 15'in all directions
55 Valley oak 20 Yes 15' in all directions
56 Valley oak 30 Yes 25'in all directions
57 Valley oak 28 Yes 25'in all directions
58 Valley oak 23 Yes 20'in all directions
59 Valley oak 16 Yes 15' in all directions
60 Valley oak 23 Yes 20' in all directions
61 Valley oak 38 Yes 25' in all directions
62 Valley oak 26 Yes 20' in all directions
63 Valley oak 28 Yes 20' in all directions
67 Coast live oak 20,18,18 Yes 15' in all directions
68 Coast live oak 40 Yes 20' in all directions
69 Coast live oak 19,19 Yes 15' in all directions
70 Coast live oak 7,5 Yes DL in all directions
71 Coast live oak 8 No DL in all directions
72 Coast live oak 9 No DL in all directions
73 Coast live oak 35 Yes 20' in all directions
74 Coast live oak 18,18,15 Yes 15' in all directions
75 Coast live oak 16 Yes 10' in all directions
78 Coast live oak 17 Yes 10' in all directions
90 Coast live oak 9 No 8' in all directions
132 Coast live oak 18 Yes DL in all directions
133 Coast live oak 28,10 Yes 18 in all other directions
134 Coast live oak 30 Yes 20'all other directions
146 Coast live oak 26 Yes DL in all directions
149 Coast live oak 10,9,8 Yes DL in all directions
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 12
SuddenOakDeath
I was asked to provide some information on the current state of the disease, its presence in
the region and the potential for it to affect trees at the 28030 Natoma Rd. site. Sudden Oak
Death (SOD) is caused by Phytophthora ramorum, a fungal pathogen (actually a water mold)
affecting oaks in the red oak group, including coast live oak. Valley oak, in the white oak
group, is not affected.
The disease was first recognized in Santa Cruz and Marin counties in the mid 1990's.
Research indicates it was likely introduced through the nursery industry and may have been
in the environment for many years before it'escaped' into the forest.
The disease requires water to grow and spread, and has many host species that are not
affected by the disease but play a critical role in its spread. The disease has been shown to
move from plant to plant via wind-driven rain,water, plant material, and human activities.
The disease typically lands on the foliage of a susceptible plant and migrates with water
movement onto the trunk. Trunk lesions and foliar dieback ensue, eventually girdling the
trunk, but the tree may remain green for several months or even years before it suddenly
turns brown (hence the name). Bleeding cankers and dieback are not sufficient to make a
positive SOD identification. Lab analysis of plant material is required before the suspected
case can be confirmed.
In general, SOD is a forest disease and has had limited impact in the urban-wildland
interface. However, there are thousands of confirmed cases of SOD in Santa Clara County
(mostly in the forested areas), but there are dozens within the immediate area around the
28030 Natoma Rd. site. We did not see any indications of SOD during our November field
work, however, several precautions are recommended to help limit the possibility of infection.
A detailed list of susceptible and host species, management and monitoring guidelines and
prophylactic treatments are provided on the California Oak Mortality Task Force website(link
provided below).
The greatest potential for the disease to move onto the site will be during the development
process, including the road construction and development of the lots. Current research
indicates that the wet months (typically Novemebr through March)are when the disease is
most active,with the highest probability of infection occurring in March. The same research
has revealed that the presence of Calif. bay laurel (Umbellularia californica)within 20 meters
of a susceptible oak species is the best indicator of a high probability for infection.
Should the disease become established at the 28030 Natoma Rd. site, all coast live oaks
would be at risk, representing approximately 2/3 of the tree population. Although not included
in the current assessment, other species, such as black oak,tan oak and madrone are also
at risk for infection and death. Several species such as Calif. bay laurel are host species and
do not decline as a result of the infection, but are important vectors in the movement of the
disease.
Following is a brief list of the most important steps to take to limit the chances of SOD
becoming established. I have also included the Best Management Practices for minimizing
the chances of infection on individual trees and the movement of infected material, provided
by the California Oak Mortality Task Force (see attachments).
• Monitor the coast live oaks and other susceptible species for indicators of the
disease.
• If susceptible species are showing SOD indicators, have the presence of the disease
confirmed through a recognized laboratory. Contact the Project Arborist or the
County Agriculture Commissioner for assistance with sampling of oaks.
• Avoid the purchase and movement of host plants, including several ornamental
plants commonly available in the nursery trade.
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 13
• Avoid construction activities and major tree removal during the wet months(typically
Novemebr through March).
• Make sure arborist performing tree work are aware of and follow all sanitation
guidelines for personnel and equipment during the course of their work.
• The movement of infested soiland plant material is regulated by the state and federal
government. Avoid movement of plant material,including dead and downed woody
debris. Debris from tree removal,whether confirmed to have SOD or not, should be
left on site. It can be chipped and spread as mulch but cannot bemoved off site
without contacting your County Agricultural Commissioner.
• Certain phosphate containing compounds have been registered for use as
prophylactics against infection from SOD. These compounds are not a cure but can
be used on individual, high-value trees as a preventative against infection. Where
appropriate, consider the use of these compounds to help protect trees.
Current information on susceptible species can be found at the US Dept. of Food and
Agriculture website: http://www.aphis.usda.qov/plant health/plant pest info/pram/index.shtml
Information on the current research can be found at the California Oak Mortality Task Force
website: http://www.suddenoakdeath.org/
Information on the local presence of the disease can be found at the Oak Mapper website:
http://oakmapper.orq/
Tree Preservation Guidelines
The goal of tree preservation is not merely tree survival during development but maintenance
of tree health and beauty for many years. Trees retained on sites that are either subject to
extensive injury during construction or are inadequately maintained become a liability rather
than an asset. -The response of individual trees will depend on the amount of excavation and
grading,the care with which construction is undertaken, and the construction methods.
Coordinating any construction activity inside the Tree Protection Zone can minimize these
impacts.
The following recommendations will help reduce impacts to trees from development and
maintain and improve their health and vitality through the clearing;grading and construction
phases.
Design recommendations
1. All plans affecting trees shall be reviewed by the Consulting arborist with regard to tree _
impacts; These include, but are not limited to, demolition plans, grading and utility plans, •
landscape and irrigation plans. - -
2. Evaluate the design of the path to minimize grading and provide as much room from
trees#109, 110, 112, 113, 115, 116, 121 and 122 as possible. By placing the path on
grade, oras close to existing grade as possible, and providing as much room from trees
as possible, root loss will be minimized.
3. To the extent feasible, underground services including utilities, sub-drains, water or
sewer shall be routed around the TREE PROTECTION ZONE. Where encroachment cannot
be avoided, special construction techniques such as hand digging or tunneling under
roots shall be employed where necessary to minimize root injury.
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 14
4. A TREE PROTECTION ZONE must be established for trees to be preserved, in which no
disturbance is permitted without the prior review by and approval of the Consulting
;Arborist. TREE PROTECTION ZONES for trees identified for preservation adjacent to the
subdivision improvements are identified in the following table. No grading, excavation,
construction or storage of materials shall occur within that zone. Trees not given a
specific Tree Protection Zones shall be fenced at the dripline in all directions.
Specific Tree Protection Zones
Tree No. TPZ
#120 and 125 3' N. DL in all other directions
#116 and 117 3'S., 5' N. DL in all other directions
#121 4'S., 5' N., DL in all other directions
#122 5' N., DL E. &W.
#109 5' S., 5' N., DL in all other directions
- #89 and 93 5'W., DL in all other directions
#1, 3,4 and 7 6' S. and DL in all other directions.
#23 6' E. and DL in all other directions.
#105 6' N., DL in all other directions
#115 6'S., 2'N., DL in all other directions
#26, 33 7' E. and DL in all other directions.
#110 7'S., 2' N. DL in all other directions
#88 8'W., DL in all other directions
#6, 8, 112, 124 and 127 10'S. and DL in all other directions.
#106 DL S., E. &W.
#126 10' N. DL in all other directions
#9 and 113 12'S., DL in all other directions
#114 and 123 13' S. and DL in all other directions.
#87 15' N., 10'W., DL in all other directions
#5 and 10 15' S. and DL in all other directions.
#66 15' SW. DL in all other directions
#24 and 27 15' E. and DL in all other directions.
#25 15' E., 12'S. & DL N. &W.
#95, 101 and 158 15'W. DL in all other directions
#115 13' S., 2' N. DL in all other directions
#41 and 45 20' E. DL in all other directions
#46 20' N. DL in all other directions
#65 20' S. DL in all other directions
#62 and 63 35' NW. DL in all other directions
64 35' SE. DL in all other directions
5. As trees withdraw water from the soil, expansive soils may shrink within the root area.
Therefore, foundations, footings and pavements on expansive soils near trees should be
designed to withstand differential displacement.
6. Underground services including utilities, sub-drains,water or sewer shall be designed to
' avoid the TREE PROTECTION ZONE.Where possible. Where not possible, special
construction techniques, such as boring or hand trenching and threading of utilities
beneath roots 2" in diameter and larger must be employed.
7. ' Tree Preservation Notes, prepared by the Consulting Arborist, should be included on all
plans.
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 15
8. Do not lime within 50' of any tree. Lime is toxic to tree roots.
9. Any herbicides placed under paving materials must be safe for use around trees and
labeled for that use.
10. Irrigation systems must be designed so that no trenching will occur within the TREE
PROTECTION ZONE.
Pre-construction treatments and recommendations
1. The construction superintendent shall meet with the Consulting Arborist before beginning
work to discuss work procedures and tree protection.
2. Fence all trees to be retained to completely enclose the TREE PROTECTION ZONE prior to
demolition, grubbing or grading. Fences shall be 6 ft. chain link or equivalent as
approved by Consulting Arborist. Fences are to remain until all grading and construction
is completed.
3. Pruning trees to provide construction and access clearance will be required. Trees#3, 4,
7, 23, 25, 27, 28, 33, 66, 95, 101, 121, 122 and 125 have been preliminarily identified for
pruning to provide construction and road clearance. Additional trees may require pruning
for pedestrian clearance over the path.
4. Prune trees to be preserved to clean the crown and to provide clearance. All pruning
shall be done by a State of California Licensed Tree Contractor(C61/D49). All pruning
shall be done by Certified Arborist or Certified Tree Worker in accordance with the Best
Management Practices for Pruning.(International Society of Arboriculture, 2002) and
adhere to the most recent editions of the American National Standard for Tree Care
Operations(Z133.1)and Pruning (A300).
5. All tree work shall comply with the Migratory Bird Treaty Act as well as California Fish
and Wildlife code 3503-3513 to not disturb nesting birds. To the extent feasible tree
pruning and removal should be scheduled outside of the breeding season. Breeding bird
surveys should be conducted prior to tree work. Qualified biologists should be involved in
establishing work buffers for active nests.
6. Have brush from the pruning and removal operations chipped and spread beneath the
trees within the TREE PROTECTION ZONE. Mulch shall be 2"to 4" in depth and kept a
minimum of 3'from the base of the trees.
Recommendations for tree protection during construction
1. Prior to beginning work,the contractors working in the vicinity of trees to be preserved
are required to meet with the Consulting Arborist at the site to review all work procedures,
access routes, storage areas and tree protection measures.
2. Except as absolutely necessary, no grading, construction, demolition or other work shall
occur within the TREE PROTECTION ZONE. Any modifications must be approved and
monitored by the Consulting Arborist.
3. Fences have been erected to protect trees to be preserved. Fences define a specific
TREE PROTECTION ZONE for each tree or group of trees. Fences are to remain until all site
work has been completed. Fences may not be relocated or removed without permission
of the Consulting Arborist.
4. Construction trailers, traffic and storage areas must remain outside fenced areas at all
times.
Revised Arborist Report, Top Elegant Investment LLC HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page 16
5. Prior to grading, pad preparation, excavation for foundations/footings/walls, trenching,
trees may require root pruning outside the TREE PROTECTION ZONE. Any root pruning
required for construction purposes shall receive the prior approval of, and be supervised
by,the Consulting Arborist.
6. If injury should occur to any tree during construction, it should be evaluated as soon as
possible by the Consulting Arborist so that appropriate treatments can be applied.
7. No excess soil, chemicals, debris, equipment or other materials shall be dumped or
stored within the TREE PROTECTION ZONE.
8. Any additional tree pruning needed for clearance during construction must be performed
by a Certified Arborist and not by construction personnel.
Maintenance of impacted trees
Preserved trees will experience a physical environment different from that pre-development.
As a result, tree health and structural stability should be monitored. Occasional pruning,
fertilization, mulch, pest management, replanting and irrigation may be required. In addition,
provisions for monitoring both tree health and structural stability following construction must
be made a priority. As trees age,the likelihood of failure of branches or entire trees
increases. Therefore, annual inspection for hazard potential is recommended.
HortScience,Inc.
61-•
144
J .
John Leffingwell
Board Certified Master Arborist WE-3966B
Registered Consulting Arborist#442
Attached: . Tree Assessment Form
Tree Assessment Plan
l
Tree Assessment 28030 Natoma Rd. C '
Los Altos,California
November 2012 and April 2014
HORT SCIENCE
TREE SPECIES SIZE HERITAGE? CONDITION SUITABILITY COMMENTS
No. DIAMETER 1=POOR FOR
(in inches) 5=EXCELLENT PRESERVATION
l
1 Coast live oak 14,9,9,6 Yes 3 Poor Multiple attachments at base;topped for overhead
utilities.
2 Coast live oak 13 Yes 3 Poor Topped for overhead utilities; poor form.
3 Coast live oak 13 Yes 4 Moderate Side pruned for overhead utilities;fair structure.
4 Coast live oak 11 No 3 Poor Topped for overhead utilities; one sided.south.
5 Coast live oak 12,10,10,9,8 Yes • 3 Poor Multiple attachments at base; all but one stem
topped for overhead utilities.
6 Coast live oak 8 No 3 Moderate Suppressed; crown bowed east.
7 Coast live oak 17 Yes 3 Moderate Side pruned for overhead utilities; one sided S.
8 Coast live oak 8 No 3 Poor Topped for overhead utilities; lateral south.
9 Coast live oak i 13 Yes 3 Poor Topped for overhead utilities;poor form.
10 Coast live oak 17 Yes 3 Poor Topped for overhead utilities; poor form.
11 Valley oak 32 Yes 3 Poor Codominant trunks at 6'; N. stem failed at 10'; S.
stem with trunk wound &decay.
12 Coast live oak 12,10 Yes 4 Moderate Codominant trunks at 3'; multiple girdling ropes on
13 Coast live oak 7 No 3 Moderate Suppressed form; small crown.
14 Coast live oak 17,9 Yes 3 Moderate Side pruned for overhead utilities;fair structure.
15 Valley oak 17,17 Yes 4 Moderate Codominant trunks at 3'; N. stem upright; S. stem
,topped for overhead utilities.
16 Coast live oak 35 Yes 5 Good Codominant trunks at 6'; one sided S.; branches to
the ground S. &W.
17 Coast live oak 25,22,18 Yes 4 Good Multiple attachments at 2'; included bark&narrow
attachments.
18 Coast live oak 10 No 5 Good Good young tree; upright form.
19 Valley oak 10 No 3 Moderate Suppressed form; epicormic shoots; dieback.
20 Valley oak 17,8 Yes 3 Moderate 17"stem upright; epicormic shoots; dieback.
21 Coast live oak 28 Yes 4 Moderate Multiple attachments at 6'; included bark; twig
dieback in upper canopy.
P 1
Page
28030 Natoma Rd.
Tree Assessment Los Altos,Califomia
November 2012 and April 2014
HORT SCIENCE
i
TREE SPECIES SIZE HERITAGE? CONDITION SUITABILITY COMMENTS
No. DIAMETER 1=POOR FOR
(in inches) 5=EXCELLENT PRESERVATION
22 Coast live oak 21,18 Yes 4 Good Codominant trunks at 2'; included bark; one sided E.
23 Coast live oak 12,10 Yes 3 Moderate Codominant trunks at 2'; basal wound with decay;
asymmetric crown.
24 Coast live oak 18 Yes 3 Moderate Codominant trunks at 6'; lateral N.;fair structure.
25 Coast live oak 18,16 Yes 4 Moderate Codominant trunks at 2'; very one sided S.
26 Coast live oak 20 Yes 3 Moderate Lateral W. at 6'; one sided S.; thin canopy.
27 Coast live oak 16,12,11 Yes 4 Moderate Multiple attachments at 3'; seam in attachment;thin
canopy.
28 Coast live oak 20 Yes 4 Good Codominant trunks at 12'; upright form.
29 Coast live oak 18,17 Yes 4 Moderate Codominant trunks at 4'; one stem upright; one stem
extends SW.; dieback.
30 Coast live oak 29 Yes 4 Moderate Codominant trunks at 6'; good form and structure;
thin canopy.
31 Coast live oak 40 Yes 4 Moderate Multiple attachments at 12'; leans SE.; thin canopy;
cabled.
32 Coast live oak 46 Yes 4 Moderate Multiple attachments at 7'; crown one sided SW.;
thin canopy; adding wood on large branches.
33 Coast live oak .8 No 4 Good Good young tree; slight lean W.
34 Valley oak 16 . Yes 5 . Good Upright form.
35 Coast live oak 12 Yes 4 Moderate Leans E.; small crown.
36 Coast live oak 11,10 Yes 4 Moderate Codominant trunks at 2'; stems kiss at 6'; one stem
upright.
37 Coast live oak 8,8 Yes 3 Moderate .Codominanttrunks at 2'; suppressed; one sided NE.
38 Valley oak 14 Yes 5 Good Upright form.
39 Coast live oak 12 Yes 5 Good Good young tree.
40 Coast live oak 8 No 4 Moderate Slight crook at base;crowded &one sided N.
Page 2
•
•
Tree Assessment 28030 Natoma Rd.
Los Altos,California
November 2012 and April 2014
HORT. SCIENCE
•
•
TREE SPECIES SIZE HERITAGE? CONDITION SUITABILITY COMMENTS
No. DIAMETER 1=POOR FOR •
(in inches) 5=EXCELLENT PRESERVATION
41 Coast live oak 20 Yes 4 Good Trunk sweeps at 3-4'; one sided S.
•
42 Coast live oak 9 No •• 3 Poor Suppressed form; Leans S.;small crown.
43 Coast live oak 14 Yes 4 Moderate One sided & leaning E.
44 Coast live oak 8,8 Yes 3 Poor Codominant trunks at 4'; suppressed; leans W.;
small crown.
45 Coast live oak 17 • •Yes 4 Good Upright form; a little thin in upper canopy.
46' Coast live oak 20 Yes 3 Moderate Leans E.; twig dieback.
47 Coast live oak 18 Yes 4 Moderate One sided N.; twig dieback.
48 Coast live oak 25 Yes 4 Moderate Codominant trunks at 5'; included bark; rodent
damage.
49 Coast live oak. 42 Yes 4 Moderate Multiple.attachments at 18'; basal cavity W.;twig
dieback.
50 Valley oak 32 Yes 3 Poor Codominant trunks at 10'; E. stem with trunk wound
&decay; lateral S. ,
51 Coast live oak .. 42 ' Yes 2 Poor Hollow with extensive trunk decay; lost several main
leaders.
52 Coast live oak 29 Yes 3 Moderate Very one sided S.; long laterals S.to the ground.
53 Valley oak 28 Yes 4 Good Multiple attachments at 10';fair branch structure;
twig dieback.
54 Coast live oak • 28 • ' Yes 4 Good Multiple.attachments at 5'; spreading form; heavy
lateral limbs.
55 Valley oak 20 Yes 4 Moderate Multiple attachments at 7'; twig and branch dieback.
56 Valley oak 30. Yes 5 • Good Upright; good form an structure; lateral S.; engulfed
in poison.oak. •
57 Valley oak 28 Yes 4 Moderate One sided S.; lost upright limb; engulfed in poison
oak.
58 Valley oak 23 Yes 5 Good Multiple attachments.at 12'; good form and
• structure. •
• • Page 3
•
Tree Assessment 28030 Natoma Rd.
Los Altos,California
November 2012 and April 2014 •
HORT : ,SCIENCE
TREE SPECIES SIZE HERITAGE? CONDITION SUITABILITY COMMENTS
No. DIAMETER 1=POOR FOR '
' • (in inches) 5=EXCELLENT PRESERVATION
59 Valley oak 16 Yes 5 Good Multiple attachments at 7'; good form and structure;
laterals.
60 Valley oak 23 Yes 5 Good Multiple attachments at 7'; good form and structure;
branches to the ground.
61 Valley oak 38 Yes 4 Moderate Multiple attachments at.12; narrow attachments;
. • one sided with branches to the ground S.
62 Valley oak 26 Yes 4 Moderate Codominant trunks at 8'; one stem upright; one stem•
bowed W. to horizontal.
63 Valley oak 28 Yes 3 Moderate Codominant trunks at 8'; suppressed; crown bowed
W.to horizontal.
• 64 Valley oak .. 44 • Yes 3 • Poor Codominant trunks at 7'; large trunk wound/cavity
N.; lost limb W.
65 Valley oak • 44 Yes 4 Good Codominant trunks at 6'; spreading form; branches
to ground S.
66 Valley.oak . . ' 36 Yes 4 Moderate . History of branch failure; lateral N.;.engulfed in
poison oak.
67 Coast live oak 20,18,18 Yes 5 Good Multiple attachments at 4'; good form; included bark.
68 Coast live oak 40 Yes 4 Moderate Multiple attachments at 10'; narrow attachments;fair
structure; engulfed in poison oak.
69 Coast live oak 19,19 Yes 4 Good Codominant trunks at 3'; seam in attachment.
70 Coast live oak 7,5 Yes 5 Good Codominant trunks at 3'; good young tree. .
71 Coast live oak 8 No 4 Moderate Crowded; fair structure.
72 Coast live oak 9 No . 5 Good Crowded; one sided W.
73 Coast live oak 35 Yes 4 Good . Multiple attachments at 20'; lateral W.to ground; . .
thin canopy/oak moth damage.
74 Coast live oak 18,18,15 Yes 5 Good Multiple attachments at 3'; good form; included
bark/seam.
75 Coast live oak - 16 Yes 3 Moderate .. One sided W.; poison oak.
Page 4
TreeTree28030 Natoma Rd.
Assessment Los Altos,California
November 2012 and April 2014
IIORT SCIENCE
TREE SPECIES SIZE HERITAGE? CONDITION SUITABILITY COMMENTS
No. DIAMETER 1=POOR FOR . •
, (in inches) 5=EXCELLENT PRESERVATION
76 Coast live oak 10,10 Yes 2 Low Suppressed; crown bowed W. to horizontal.
77 ' Coast live oak. • 14 Yes 3 Low Suppressed; one sided SE.
78 Coast live oak 17 Yes 3 Moderate Sparse canopy; one sided E.
79 Coast live oak 8 No 5 High Slight lean N.; good young tree.
80. Coast live oak 9 No 5 High Good young tree.
81 Coast live oak 12 ' Yes 3 Low Trunk sweeps S.; crook at 3'; poor form and
structure.
82 Coast live oak 20 Yes 4 Moderate Multiple attachments at 7'; crowded &one sided N.
83 Coast live oak 20 Yes 4 Moderate Crowded; high crown; lateral S.
84 Coast live oak 14 Yes 3 Moderate Trunk leans NW:; one sided W. ..
85. Coast live oak 26 Yes 4 Moderate Crowded &one sided S.; fair branch structure.
86 Coast live oak 6 No 3 Moderate Suppressed;branch wounds.
87 Coast live oak 32 Yes 4 High Slight lean N.;.good form and structure; dead wood.
88 •Coast live oak 17 . Yes 3 Low Leans W.;trunk wound at 15'.
89 Coast live oak 11 No 3 Moderate Suppressed; crown bowed E.
90 Coast live oak 9 No 3 Moderate , Leans W.; small crown.
91 Coast live oak 14 Yes 3 Low Leans S.; embedded barbed wire.
92 Coast live oak 9 No 5 High Good young tree.
93 Coast live oak 9,4,4 Yes 5 High Good young tree:
94 Valley oak 17 • Yes 3 Low Codominant trunks at 6'; narrow crown; dieback.
95 Coast live oak 33 Yes 4 Moderate Multiple attachments at 5'; one sided E.; laterals&
dead wood.
96' Coast live oak 10 No 3 Low Suppressed; small, high crown.
97 Coast live oak 13,11 Yes 3 Moderate Codominant trunks at 3'; high crown.
98 Coast live oak 16 Yes 3 Moderate Codominant trunks at 10'; leaning &one sided S.;
cavity E.
Page 5
•
Tree Assessment 28030 Natoma Rd.
Los Altos,California
November 2012 and April 2014
• .HORT SCIENCE
TREE SPECIES SIZE HERITAGE? CONDITION SUITABILITY COMMENTS
•
• No. • DIAMETER 1=POOR FOR
•
• (in inches) 5=EXCELLENT PRESERVATION •
99 Coast live oak 1.4,10 • Yes 3 Low Codominant trunks at 1'; crown bowed S.to •
horizontal.
100 Coast live oak 18 Yes 3 Moderate Codominant trunks at 10';fair structure; high crown.
101 Coast live oak 22,21 Yes 4 Moderate Codominant trunks at 3'; one sided E.; laterals&
/
dead wood. .
102 Coast live oak 21,20 Yes 4 Moderate Codominant trunks at 3'; good form; large pruning
wounds.
103 Valley oak 9 No 3 Low Codominant trunks at 5';.suppressed; crown bowed
E.to horizontal.
104 Coast live oak 15 Yes 3 Moderate High crown; sunscald S.
105 Coast live oak.. 27 Yes 4 Moderate . Crowded; crown bowed W.
106 Coast live oak 1,24,22,19,17,12 Yes 2 s Low Multiple attachments at 3; history of stem failure E.;
ganoderma at base W.
107 Coast live oak 17,14 ,12,6 Yes 2 .Low Failed at base; laying on ground. •
108 Coast live oak . 21,19 Yes 3 Moderate Overtopped;crown bowed W.
109 Coast live oak 33,8 Yes 3 Moderate Codominant trunks at 10'; overtopped; crown bowed
W.
110 Coast live oak 25 Yes 3 Moderate Overtopped; crown bowed W.to horizontal.
_ 111 Coast live oak 22 Yes 3 Low - Crowded; one sided S.
112 Coast live oak 21,20 Yes .. 3. Moderate . Codominant trunks at 3'; W. stems bowed W.
113 Coast live oak 33,13 Yes 4 Moderate One sided N.; dominant tree.
114 Valley oak 10,6 Yes 3 Low Codominant trunks at 2'; suppressed; poor form.
115 Coast live oak 23,22,13,12,9 Yes 3 Moderate Multiple attachments at 3'; some stems upright;
some stems bowed N. .
,116 Coast live oak 12 Yes 2 Low Small crown; dieback. •
117 Valley oak 11 No 3 Low Codominant at base w/#116; high crown; dieback.
118 Valley oak 16,9 Yes 3 Moderate Codominant at 2'; high crown; deadwood •
Page 6
/
Tree Assessment 28030 Natoma Rd.
Los Altos,California
November 2012 and April 2014
HORT SCIENCE
TREE SPECIES SIZE HERITAGE? CONDITION SUITABILITY COMMENTS
No: DIAMETER 1=POOR FOR
(in inches) 5=EXCELLENT PRESERVATION
119 Coast live oak 29 Yes 3 Moderate Leans E. to horizontal
120 Valley oak 25 Yes 4 Moderate High crown; one sided S.
121 Coast live oak 19 Yes 2 Low Leans E.to horizontal; bark checking;trunk wounds.
122 Valley oak 35 Yes 3 Moderate Multiple attachments at 6'; sparse crown; spreading
form.
123 Coast live oak . 6 No 5 High Good young tree.
124 Coast live oak 18 Yes 4 High Multiple attachments at 8'; good form and structure.
125 ,Valley oak 28 Yes 4 High Multiple attachments at 10'; good form; recently
pruned.
126 Coast live oak 15,14,8 Yes 3 Moderate Suppressed; one sided SE.
127 Valley oak .-14 Yes 3 Moderate Pruned N.; one sided S.
128 Coast live oak 22,14,10 Yes 4 Moderate Multiple attachments at 3'; one sided S.
129 Coast live oak 35,19 Yes 4 Moderate Multiple attachments at 5';wide attachment; 19"
stem is low lateral W.
130 Valley oak 18 . Yes 3 Moderate Upright form; dieback; powdery mildew.
131 Valley oak 14 Yes 3 Low Leans N.; asymmetric crown; embedded barbed
wire; dieback to 4".
132 Coast live oak 18 Yes 4 Moderate Codominant trunks at 6'; included bark; sap flow at
attachment.
133 Coast live oak. 28,10 Yes 4 Moderate Multipleattachments at 8'; beetleactivity along.
trunk; 10"stem is low lateral.
134 Coast live oak 30 Yes 4 Moderate Multiple attachments at 5'; heavy lateral E.
135 Coast live oak 29 Yes 4 Moderate Multiple attachments at 8'; low lateral S.
136 Valley oak . . 8,4 Yes 3 Moderate One sided E.;twig dieback.
137 Valley oak 11 No 3 Moderate Crowded; crown bowed NW.
138 Valley oak 9 No 3 Moderate Crowded; slight lean W.
139 Valley oak 12 Yes 3 Moderate Crowded; leans N. to horizontal then turns upright.
Page 7
28030 Natoma Rd.
Tree Assessment Los Altos,California 40
November 2012 and April 2014
H O R T SCIENCE
TREE SPECIES SIZE HERITAGE? CONDITION SUITABILITY ' COMMENTS
No. DIAMETER 1=POOR FOR
(in inches) 5=EXCELLENT PRESERVATION
140 Coast live oak 19 Yes 3 Moderate Crowded; reaching through the canopy of#142.
141 Coast live oak 12 Yes 3 Low Crowded; leans E.to horizontal over fence.
142 Valley oak 29 Yes 4 High Multiple attachments at 10'; dominant tree; laterals
W.
143 Valley oak 21 Yes 3 Moderate Codominant trunks at 5'; asymmetric crown.
144 Coast live oak 9 No 3 Moderate Crowded; growing through canopy of#142.
145 Coast live oak 22 Yes 4 High Upright form; high canopy.
146 Coast live oak 26 Yes 3 Moderate Codominant trunks at 4'; one sided S.
147 Valley oak 8 No 2 Low Suppressed; crown formed by epicormics.
148 Valley oak 15 Yes 2 Low - One sided S.; dieback; crown formed by epicormics.
149 Coast live oak . 10,9,8 Yes 4 Moderate Multipleattachments at 2'; narrow.attachments.
150 Coast live oak 17 Yes 3 Moderate Crowded; high crown bowed SW.
151 Coast live oak 20 Yes 3 Moderate Crowded; asymmetric crown.
152 Coast live oak . 29,23,19,10 Yes 4 High Multiple attachments at 3'; dominant tree; beetle
activity at base.
153 Coast live oak 23 Yes 4 Moderate Codominant trunks at 15'; upright; one sided W.
154 Coast live oak 16,11 Yes 3 Moderate Codominant trunks at 3'; wide attachment; crown
bowed S.
155 Valley oak • 18 Yes 3 Moderate Multiple attachments at 10'; good form; thin canopy.
156 Coast live oak 22 Yes 3 , Moderate Codominant trunks at 5'; asymmetric crown.
157 Blue oak 9 No 4 Moderate Good young tree; lower branches covers in lichen.
158 Valley oak 16Yes 3 Moderate One sided S.; twig dieback;wires attached to trunk
at 10'.
Page 8
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Tree Assessment Plan
11
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HORTICULTURE I ARBORICULTURE I URBAN FORESTRY -
ATTACHMENT 11G
April 20, 2016
Top Elegant Investment LLC H O R T SCIENCE
Attention: Rosy Ko
425 West 53rd St.,#411
New York, NY 10019
Subject: Response to Shute, Mihaly&Weinberger, LLP
28030 Natoma Rd., Los Altos Hills
Dear Mrs. Ko:
Top Elegant Investment, LLC is proposing to subdivide the subject site, in Los Altos Hills.
HortScience, Inc. has been involved with the project since 2012 and most recently
prepared a Revised Arborist Report for the site based on the most recent development
plans. Top Elegant Investment, LLC asked HortScience, Inc. to respond to the tree
related claims presented by Shute, Mihaly&Weinberger, LLP. This letter responds to
that request.
Background
HortScience, Inc. has been involved with the proposed development of the 28030
Natoma Rd. since 2012 as follows: A
• November 2012:Working for Los Altos Property, LP,we performed an
assessment of 74 trees (measuring>_6" in diameter) identified by the project
engineer(Clements and Associates)and prepared a DRAFT Arborist.Report,
dated December 2012.
• September 2013: Prepared a Revised Arborist Report, dated September 2013.
Revisions were based on the August 15, 2013 Improvement Plan, prepared by
Wilsey Ham Engineers.
• October 2013: Performed an assessment ofadditional trees on the development
site and along the access road identified by the new project engineer(Wilsey
Ham Engineers). Prepared a Revised Arborist Report, dated October 2013
based on the October 10,2013 Subdivision and Access Road Improvement Plan,
prepared by Wilsey Ham Engineers.
• April 2014: Performed a census of trees on the remainder of the property.
Prepared a Revised Arborist Report, dated April 2014, including census
information, based on the October 10, 2013 Subdivision and Access Road
Improvement Plan, prepared by Wilsey Ham Engineers.
• November 2014:Prepared a Revised Arborist Report, dated November 2014,
including census information, based on the July 17, 2014 Subdivision and
Access Road Improvement Plan; prepared by Wilsey Ham Engineers.
• December 2015: Met with members of the Pathway Committee,the
Environmental Design and Open Space Committee, Town of Los Altos Hills
Planning Department and.Wilsey Ham Engineers to review the site,proposed
project and the potential to preserve additional trees.
• April 2016: Prepared a'Revised Arborist Report, dated April 2016 based on the
• January 13, 2016 Access Road.Improvement Plan and the May 22, 2015
Proposed Tentative Map, prepared by Wilsey Ham Engineers.
HortScience,Inc. I 325 Ray St. I Pleasanton,CA 94566
phone 925.484.0211 I fax 925:484.5096 I www.hortscience.com
Response to Shute, Mihaly&Weinberger, LLP HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page. 2
Responses to tree-related comments
Community members have hired the law firm, Shute, Mihaly&Weinberger,to comment
onthe environmental initial study and negative declaration. Following are my responses
to the specific tree-related comments provided in the January 20, 2016 letter to Suzanne
Avila, City of Los Altos Hills Planning Director, regarding the Sterling Subdivision
Mitigated Negative Declaration.
Section IV, B-1 (page 9):
Based on the latest plans provided to me and as described in the April 2016 Revised
Arborist Report, 24 Heritage oak trees will be removed. Changes in the number of
Heritage oaks identified for preservation/removal reflect the ongoing revisions to and
refinement of the development plans.
Section IV, B-2 (page 10):
All of the Arborist Reports prepared by HortScience, Inc.for this project and listed
above, included a description of impacts to all trees based on the plans available at the
time. The November 2012 and September 2013 Arborist Reports included impacts to
trees on the development site but not along the access road. The remaining Arborist
Reports included a description of impacts to trees on the development site from grading
for road, drainage and potential driveways, as well as the access road and pedestrian
path.
The 20 trees identified in the April 2016 Revised Arborist Report as being close to road
and access road improvements will require special attention and care during the
demolition and construction process and may show some amount of decline, such and
twig dieback, as a result of the root loss. I expect all 20 of these trees to tolerate the
impacts from the proposed improvements or I would not have recommended them for
preservation.
None of the previous Arborist Reports include an assessment of impacts to trees from
the development of individual lots, as development plans for individual lots have not been
n
prepared. I understand that through the geotechnical review of the project, slope
stabilization grading has been proposed since the time of the November 2015 Arborist
Report. This grading will result in the removal of 9 additional oak trees. This additional
tree removal is incorporated into the April 2016 Revised Arborist:Report. If the houses
are built within the envelopes shown on the May 22, 2015 Proposed Tentative Map for
the remaining lots and the Tree Protection Guidelines are implemented, I would not
anticipate that development of the individual lots would necessarily result in more tree
loss.
Table 5 (page 11 of the April 2016 Revised Arborist Report) provides the ideal
recommended protection zones for the 42 trees within the building envelopes or other
easements and which were appropriate for retention (high or moderate suitability for
preservation) but far enough from the subdivision improvements to not be impacted at
this time. This is provided as a guideline only, as some encroachment into the ideal
recommended protection zones may be acceptable depending on the nature and location
of the proposed improvement.
Tree Protection Guidelines provided in the April 2016 Revised Arborist Report(page
13)are designed to help minimize damage to trees. These guidelines are only
recommendations unless made binding by the Mitigated Negative Declaration or the
Town.
HortScience,Inc. I 325 Ray St. I Pleasanton,CA 94566
phone 925.484.0211 I fax 925.484.5096 I www.hortscience.com
Response to Shute, Mihaly&Weinberger, LLP HortScience, Inc.
28030 Natoma Rd., Los Altos Hills,April 2016 Page. 3
Again,Table 5 describes the ideal recommended protection zones to help guide the
design and construction of improvements adjacent to trees on individual lots. Where
improvements were shown on the plans adjacent to trees identified for preservation, I
prepared specific Tree Protection Zones for each tree(page 13 of the April 2016
Revised Arborist Report). Specific Tree Protection Zones may vary from those listed in
Table 5 as additional space may be available around specific trees that can be protected
(i.e. trees 46, 62-64 and 66).
The'discrepancies' identified by Shute, Mihaly&Weinberger in the Tree Protection
Guidelines are in fact different recommendations for the various phases of the process.
For example, in the design phase, I recommend establishing a protection zone around
each tree in which no encroachment is allowed. However, once the project moves into
the pre-construction and/or construction phases, the reality is that encroachment into the
recommended protection zones may be required for a variety of reasons. This is why in
the pre-construction and construction phases, I recommend that any intrusion into
protection zones receive the prior approval of and be monitored by the Project Arborist.
Finally, I have been provided a description of and locations for the footbridge, pathways,
subdrains and storm drain outfalls. Based on the descriptions of the materials and
construction techniques for each of the proposed improvements, I believe the bridge,
storm drain, energy dissipater and subdrains can be constructed with minimal impacts to
trees. Minimizing impacts to trees will depend on strategically locating improvements
such as the biofiltration pond,the 15"storm drain pipe and the subdrain system on Lots 5
and 6 to avoid Tree Protection Zones where possible and/or the use of specific
construction techniques, such as hand excavation and boring of drain lines rather than
trenching,to minimize root loss.
If you have any questions regarding my responses, please feel free to contact me. I look
forward to hearing from you.
Sincerely,
•
4fAt(.4
John Leffingwell
Board Certified Master Arborist#3966B
Registered Consulting Arborist#442
HortScience,Inc. I 325 Ray St. I Pleasanton,CA 94566
phone 925.484.0211 I fax 925.484.5096 I www.hortscience.com
ATTACHMENT 11H
June 1,201.6
Suzanne Avila
Planning Director
Town of Los Altos Hills
26379 Fremont Road
Los Altos Hills,CA 94022
Re: Subdivision,28030 Natoma Road
Dear Suzanne:
We understandthat a question has arisen regarding the standards that would apply
regarding construction noise with respect to the planned subdivision improvements at the 28030
Natoma site. Therefore,we wish to confirm that as the owners of the site,we have always
intended and expected that any construction activities at the site Would be subject to compliance
- with Los Altos Hills Municipal Code 5-6:02.
In addition,we wish to confirm that as the owners of the site,we have been aware of,and
have always intended and expected to comply with,the provisions of Municipal Code 9-1:607
regarding mitigation for removal of certain trees..
'Please'contact me if you have any questions about this.
.-• • Best regards,
Rosy Ko
Top :j—
Elegant. 6` 20(b
AFDOCS/13368324.1,