HomeMy WebLinkAboutItem 3.23.�Z_
TOWN OF LOS ALTOS HILLS February 24, 2005
Staff Report to the Planning Commission
RE: SITE DEVELOPMENT PERMIT AND REVIEW OF INITIAL STUDY AND
NEGATIVE DECLARATION FOR THE LA CRESTA SEWER MAIN
EXTENSION, MAINTENANCE ACCESS ROAD AND BRIDGE PROJECT;
LANDS OF MAD MANOR II, LLC (RUTH B. MORRISON), 27641 PURISSIMA
ROAD, FILE #95-03-ZP-SD-GD-IS-ND
FROM: Leslie Hopper, Project Planner ; _ 4
APPROVED BY: Carl Cahill, Planning Director C,C,
That the Planning Commission
1. Review and forward a recommendation that, based on the attached Initial Study, the
City Council adopt the Mitigated Negative Declaration and Mitigation Monitoring
Program in Attachment 9 for extension of the La Cresta sanitary sewer main and
construction of an associated maintenance access road, a 100 -foot -long bridge for the
road and sewer line to span Deer Creek, and a sediment detention basin; and
2. Review and forward a recommendation that the City Council approve the requested
Site Development Permit, subject to the conditions of approval in Attachment 1.
BACKGROUND
Project Site
The subject property is a 10.82 -acre parcel located at the intersection of Purissima Road
and Elena Road. Deer Creek runs through the center of the project site and flows north,
joining Matadero Creek and eventually emptying into San Francisco Bay. Existing
development on the project site includes a single-family residence, swimming pool, tennis
court, volleyball court, guest house, barn and stable. Access from Purissima Road to the
residence and accessory structures is provided by an existing driveway and bridge over
Deer Creek, north of the proposed location of the new sewer line, maintenance road and
bridge. Surrounding uses consist mainly of large -lot single-family residences.
Proiect Description
The proposed sewer line will connect to an existing sewer manhole located at the
intersection of Elena Road and Purissima Road, run through APN parcel 175-73-035,
over Deer Creek and across the adjacent hillside for hookup to residences west of La
Cresta Drive that currently rely on septic systems and leach fields. Owners of 11
properties on La Cresta and Canario Way have expressed their support of the project and
their desire to be future users of the La Cresta sewer line (see Attachment 4). The
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 2 of 13
proposed line will be a gravity flow line extending approximately 1200 linear feet and
generally located about 5 feet below the roadway surface; however, the trench excavation
at some points may reach as much as 12 to 14 feet below the existing ground surface.
This proposed maintenance access road will be asphalt paved from Purissima Road to
above the bridge crossing. From there, the access road will consist of a 14 -foot wide
gravel surface leading up over the property to the eastern boundary of the site. The
grading for the roadway will include both cuts and fills of 2 to 4 feet in height. The access
road will be used for maintenance of the proposed gravity flow sewer line located under
the road as well as the parallel sewer force main located along the southern boundary of
the site. The parallel main currently ties into the sewer manhole and pump station located
at the intersection of Purissima Road and Elena Road.
The proposed 14 -foot -wide bridge will cross Deer Creek. The bridge structure will be
based on a modified railroad flat car that will span the creek, extending 95 feet from end
to end. The roadway approach to the abutment on the west side of the creek will be
graded with up to about 10 feet of fill, while the eastern abutment will support roughly 5
feet of fill adjacent to cuts of similar depth. The bridge will be sloped down from east to
west at an approximately 16 percent grade.
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 3 of 13
The project also includes construction of a sediment detention basin located upslope on
the east bank. The basin will include metered outlet structures leading to energy
dissipaters that discharge into Deer Creek.
Once completed, the new sewer line extension will be maintained by the Town because it
will be part of the public sewer system. However, the bridge structure, roadway and
detention basin will remain in private ownership and maintenance will be the
responsibility of the property owner.
CRITERIA FOR PROJECT REVIEW
In order to recommend approval of the application, the Planning Commission must
determine that the project is consistent with the General Plan and complies with the
Zoning and Site Development Ordinances, as well the California Environmental Quality
Act (CEQA). Comments on the application have been received from the Town
Geotechnical Consultant, the Town Engineer, Santa Clara County Fire Department, Santa
Clara Valley Water District, and the Environmental Design Committee, and are attached
for the Planning Commission's review. In addition, the Town has retained the services of
MHA Environmental Consulting, Inc., to assess the potential environmental impacts of
the project in compliance with CEQA. Their findings and recommendations are
summarized in the following discussion of environmental review. Neighboring residents
and property owners within 500 feet of the site have been notified of the public hearing.
GENERAL PLAN POLICIES
Public utilities policies in the Land Use Element generally encourage the conversion of
residences from septic tanks to sanitary sewers, and emphasize the need to protect the
natural environment while installing utilities. As stated in General Plan Section 154:
To preserve the natural environment and rural atmosphere desired by the
residents of Los Altos Hills, it is important that the installation and/or
extension of utilities be conditioned by concerns for preventing damage to the
natural beauty of the area. Standards for the extension of utilities, sewers in
particular, should be based on health and safety considerations.
To ensure that the proposed project does not damage or negatively impact Deer Creek and
the natural resources on the property, the Town retained the services of MHA
Environmental Consulting, Inc., to analyze the potential impacts of the project and
recommend measures to mitigate them. The applicant will be required to comply with the
mitigation measures and conditions of approval. In addition, the applicant will be
required to obtain permits from the California Department of Fish and Game and the
Santa Clara Valley Water District, which will further ensure protection of the creek and
riparian habitat.
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 4 of 13
Existing Structures
Some existing accessory structures appear to have been constructed without permits. Any
structure constructed without proper permits would be required to be removed prior to
subdivision or new development. (Condition 2)
Road Standards
Ordinarily staff would not recommend the construction of a road through residential
property; however, the proposed maintenance road is not serving as a driveway for any
residential properties at this time but will only provide access for maintenance of the new
sewer line. If subdivision of the property is proposed in the future and the maintenance
road is to be used as a means of access to the new parcels, the maintenance road and
bridge probably will need to be widened to at least 20 feet in width if serving 3 lots or
more. Condition 3 provides that the bridge shall be no wider than 14 feet at this time.
Condition 4 requires the service road beyond the bridge to remain unpaved. Condition 5
provides that at such time as the property is proposed for subdivision, or at any time that
the bridge is proposed to he widened in excess of 14 feet, the applicant shall be required
to remove the existing north driveway bridge over Deer Creek and restore the natural
terrain and vegetation in the affected area.
Conservation Easement
Portions of the property contain steep slopes or are located within an Open Space
Conservation Area as designated on the General Plan Land Use Diagram. A conservation
easement will be required prior to any new development or subdivision. (Condition 6)
Creek Protection
Section 10-2.702 of the Site Development Ordinance sets out the following requirements
to ensure creek protection:
Structures shall be set back a minimum of 25 feet from the top of bank of all
creeks. Greater setbacks may be required along major creeks in the Town;
however, lesser setbacks may be allowed where approved by the Planning
Commission. Improvements required to all creeks shall be accomplished to
appear natural and to maintain the natural meandering course of the existing
creek. Creeks and banks shall be protected so as to remain in their natural state
as much as possible. They should not be disturbed by the building or grading
process. No grading shall be allowed in creeks or within the required setbacks
from top of bank. Siting of structures shall be done with safety as a primary
concern. Safety concerns and preservation of riparian habitat are required to be
simultaneously addressed when designing development and required
improvements to creeks.
Although the eastern abutment of the bridge is outside the required 25 -foot setback from
the top of bank, the western abutment is located right at the top of the west bank of Deer
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 5 of 13
Creek. To determine whether the lesser setback is justifiable and the creek will be
protected in accordance with the above requirements, the Town retained a consultant to
conduct environmental review of the project. As described below, MHA Environmental
Consulting, Inc. has identified the potential impacts of the project and recommended
measures to mitigate them.
ENVIRONMENTAL REVIEW
The attached Initial Study, Negative Declaration and Mitigation Monitoring Program
have been prepared to assess the potential environmental impacts of the project in
compliance with the California Environmental Quality Act (CEQA). The Town's
consultant, MHA Environmental Consulting, Inc., identified several potentially
significant environmental effects of the project and recommended 19 mitigation measures
to reduce the impacts to a less than significant level. Major environmental issues include
trees and vegetation, water quality, wildlife protection, grading, and drainage as
summarized below.
Trees and Vegetation
The project will involve removal of approximately eight trees, some of which qualify as
Heritage Oaks and are protected under the Town's Tree Ordinance. Mitigation Measure
1-2 requires replacement of the protected trees at a ratio of 3:1 (15 -gallon size) and of the
same species as removed trees, unless otherwise approved by the Planning Director. A
maintenance deposit will be required to ensure the planted trees are maintained and cared
for. Mitigation Measure 1-1 requires submittal of a landscape and revegetation plan prior
to issuance of grading permit, and Mitigation Measure 4-2 requires that all disturbed
areas shall be revegetated with drought tolerant and native species to prevent erosion.
Water Ouality
Deer Creek water quality could be impacted by project construction and post -construction
operation, which could cause soil erosion and sedimentation. Mitigation Measure 4-1
requires the applicant to develop an erosion control plan that includes the placement of
silt fences, hay bales or other control measures to ensure that sediments from grading,
digging, and placement of the central bridge pile do not erode into the creek. The
applicant will also be required to revegetate disturbed areas and to meet State Water
Quality Control Board Stormwater Permit requirements.
Wildlife Protection
The project should have no adverse effect on any potentially occurring sensitive species
except the California red -legged frog and the western pond turtle. California red -legged
frogs may be found along the riparian corridor or could migrate through upland areas.
Western pond turtles may also occur along the stream bank or the upland area. Both
species could be negatively impacted by sedimentation or degradation of water quality
resulting from erosion at the project site or injured by construction activities. Mitigation
Measures 4-4 through 4-7 will ensure protection of these sensitive species through
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 6 of 13
education of construction personnel, avoiding construction during the rainy season,
performing pre -construction surveys to determine whether California red -legged frogs are
present, and monitoring of all work by a qualified biologist.
Grading
Estimated earthwork quantities for the project are 1425 c.y. of cut and 1425 c.y. of fill.
Of that total, grading for the bridge will entail 575 c.y. of cut and an equivalent amount of
fill. Grading for the roadway will include both cuts and fills of 2 to 4 feet in height for an
estimated total of 850 c.y. of cut and 850 c.y. of fill. The gravity sewer main will
generally be about 5 feet below the roadway surface; however, the trench excavation at
some points may reach 12 to 14 feet below the existing ground surface. Mitigation
Measure 6-3 requires that, prior to issuance of a grading permit, the applicant shall have a
qualified geotechnical engineer evaluate whether cut slopes proposed for the roadway
may destabilize adjacent slopes.
As noted by Cotton, Shires and Associates, the placement and location of the detention
basin may have negative slope stability impacts. Mitigation Measure 6-4 requires that,
prior to issuance of a grading permit, the potential for the proposed detention basin to
result in negative slope stability impacts shall be evaluated and addressed.
Drainage
The drainage pattern of the site generally would not be impacted by the project. As
originally designed, the proposed sediment detention basin and drainage system would
have allowed over -bank drainage into Deer Creek, which could have resulted in
sedimentation and water quality impacts in the creek. The Santa Clara Water Valley
District recommended using existing on-site storm drain systems to reduce potential
impacts to the creek. In response, the Town Engineer worked with the applicant to
redesign the proposed drainage system so that over -bank drainage into Deer Creek is
minimized as per Mitigation Measure 8-1.
Noticing
In accordance with Section 15072(a) of the CEQA Guidelines, the Town provided notice
of intent to adopt a Mitigated Negative Declaration no later than no later than 20 days
before the public hearing. A public notice was published in the Los Altos Town Crier on
February 2, 2005 for a Planning Commission public hearing on February 24, 2005 and a
City Council public hearing on March 17, 2005. Notices were also posted in the Town's
established posting places.
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 7 of 13
CONCLUSION
Based on the Initial Study, staff has concluded that the proposed project, as mitigated,
will not have a significant effect on the environment. The Negative Declaration identifies
specific mitigation measures and establishes a Mitigation Monitoring Program to ensure
that any potential significant environmental impacts identified in the Initial Study are
mitigated.
The proposed project, as mitigated, is consistent with the General Plan and Zoning and
Site Development Ordinances.
Therefore, the Planning Commission should recommend that the City Council, based on
the Initial Study, should adopt the Negative Declaration and Mitigation Monitoring
Program and approve the Site Development Permit.
ATTACHMENTS
1. Recommended Conditions of Approval
2. Site Map
3. Diagram of Proposed Bridge and Maintenance Access Road
4. List of Future Users of La Cresta Sewer Line, dated December 12, 2003
5. Comments from Santa Clara County Fire Department, dated June 16, 2003
6. Comments from Santa Clara Valley Water District, dated July 2, 2003
7. Comments from Cotton, Shires and Associates, dated July 27, 2004
8. Comments from Environmental Design & Protection Committee evaluations,
received June 13, 2003
9. Initial Study/Negative Declaration/Mitigation Monitoring Program, dated January
2005
10. Development plans
Staff Report to the Planning Commission ATTACHMENT I
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 8 of 13
RECOMMENDED CONDITIONS FOR SITE DEVELOPMENT PERMIT
FOR THE LA CRESTA SEWER MAIN EXTENSION, ACCESS ROAD
AND BRIDGE PROJECT
LANDS OF MAD MANOR II, LLC (RUTH B. MORRISON)
27641 PURISSIMA ROAD
FILE #95-03-ZP-SD-GD-IS-ND
This project is also subject to the Mitigation Measures prepared by MHA Environmental
Consulting, Inc., and presented in the La Cresta Sewer and Access Road Initial
Study/Mitigated Negative Declaration dated January 2005
A. PLANNING DEPARTMENT
1. No other modifications to the approved plans are allowed except as
otherwise first reviewed and approved by the Planning Director or the
Planning Commission, depending on the scope of the changes.
2. This Site Development Permit does not confer approval for any other
structure on the property. Any existing structure constructed without
proper permits may be subject to removal prior to new development or
subdivision.
3. The bridge shall have a maximum width of 14 feet.
4. The service road (leading to the rear of the property toward La Cresta)
shall not be paved.
5. At such time as the property is proposed for subdivision, or at any time
that the bridge is proposed to be widened in excess of 14 feet, the
applicant shall be required to remove the existing north driveway bridge
over Deer Creek and restore the natural terrain and vegetation in the
affected area. The Town may retain the services of a habitat restoration
ecologist, at the applicant's expense, to ensure that appropriate native
riparian plants are selected.
6. At such time as the property is proposed for subdivision, the applicant
shall be required to grant a conservation easement on undeveloped areas
with slopes of 30% or more and that portion of the property designated as
Open Space Conservation Area on the General Plan Land Use Diagram.
7. Prior to beginning any grading operation, all significant trees are to be
fenced at the drip line. Town staff must inspect the fencing and the trees
to be fenced prior to commencement of grading. The property owner shall
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 9 of 13
call for said inspection at least three days in advance of the inspection. The
fencing must remain throughout the course of construction.
Tree fencing requirements:
a. Fencing shall be located at the drip line of the tree or trees.
b. All trees to be preserved shall be protected with chain link fences
with a minimum height of five feet (5') above grade.
C. Fences are to be mounted on two-inch diameter galvanized iron
posts, driven into the ground to a depth of at least two feet (2') at
no more than 10 -foot spacing.
d. Fencing shall be rigidly supported and maintained during all
construction periods.
e. No storage of equipment, vehicles or debris shall be allowed within
the drip lines of these trees at any time.
f. No trenching shall occur beneath the drip line of any trees to be
saved.
Prior to issuance of grading and building permits, a landscape and
revegetation plan shall be submitted for review and approval. The
landscape plan shall provide for landscape screening with a mixture of
native shrubs and trees, particularly along the upper road section, around
the detention basin, and in other disturbed areas. The plan shall also
indicate the trees to be removed, the number and size of replacement trees,
replacement tree locations, and irrigation for all vegetation until it is
established. All landscaping required for screening purposes or for erosion
control (as determined by the City Engineer) must be installed prior to
final inspection of the project.
9. A landscape maintenance deposit of $20,000.00 (cashiers check) shall be
posted prior to final inspection. An inspection of the landscape to ensure
adequate establishment and maintenance shall be made two (2) years after
installation. The deposit will be released after two (2) years if the
plantings remain viable.
10. No new outdoor lighting is approved. Any proposed outdoor lighting shall
be reviewed with the landscape plan. Lighting fixtures shall generally be
shielded downlights. No lighting may be placed within setbacks except
for two driveway or entry lights.
11. No new fencing or gates are approved. Any proposed fencing or gates
shall require review and approval by the Planning Department prior to
installation.
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 10 of 13
12. If a demolition permit is required, clearance from the Bay Area Air Quality
Management District shall be obtained prior to issuance of the demolition
permit.
B. ENGINEERING DEPARTMENT:
12. As recommended by Cotton, Shires & Associates in their report dated July
27, 2004, the applicant shall comply with Mitigation Measures 6-3 and 6-
4. In addition, the applicant shall be responsible for the following:
a. The applicant shall have a qualified geotechnical consultant review and
approve all geotechnical aspects of the project building and grading plans
(i.e., site preparation and grading, site drainage improvements and design
parameters for bridge foundations, retaining walls and adjoining
roadways) to ensure that their recommendations have been properly
incorporated. In addition, the consultant shall address the following:
• Confirm that the wing wall design, including backdrains, is satisfactorily
detailed on plans.
• Verify that appropriate geotechnical design parameters have been utilized
in bridge structural calculations.
• Confirm that appropriate placement of recommended clay plugs along the
sewer alignment are detailed on project plans.
The results of the plan review shall be summarized by the geotechnical
consultant in a letter and submitted to the Town Engineer for review along
with other documents prior to acceptance of plans for building plancheck.
b. The geotechnical consultant shall inspect, test (as needed), and approve all
geotechnical aspects of the project construction. The inspections should
include, but not necessarily be limited to: site preparation and grading, site
surface and subsurface drainage improvements, and excavations for bridge
foundations and retaining walls prior to the placement of steel and concrete.
The results of these inspections and the as -built conditions of the project
shall be described by the geotechnical consultant in a letter and submitted to
the Town Engineer for review prior to final (as built) project approval.
For further details on the above requirements, please refer to the letter from
Cotton, Shires & Associates dated July 27, 2004.
13. Any, and all, changes to the approved Sanitary Sewer Gravity Main and
Maintenance Road Plan shall be submitted as revisions from the project
engineer and shall first be approved by the Town Engineering Department.
No grading shall take place during the grading moratorium (November I
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 1 l of 13
to April 1) except with prior approval from the City Engineer. No grading
shall take place within ten feet of any property line.
14. Two copies of an erosion and sediment control plan shall be submitted for
review and approval by the Engineering Department prior to issuance of
building permit. The contractor and the property owner shall comply with
all appropriate requirements of the Town's NPDES permit relative to
grading and erosion/sediment control. The first 100 feet of the
maintenance road shall be rocked during construction and all cut and fill
slopes shall be protected from erosion. All areas on the site that have the
native soil disturbed shall be protected for erosion control during the rainy
season and shall be replanted prior to final project approval.
15. Two copies of a grading and construction operation plan shall be
submitted by the property owner for review and approval by the City
Engineer and Planning Director prior to issuance of building permit. The
grading/construction operation plan shall address truck traffic issues
regarding dust, noise, and vehicular and pedestrian traffic safety on
Purissima Road and surrounding roadways, storage of construction
materials, placement of sanitary facilities, parking for construction
vehicles, clean-up area, and parking for construction personnel. A debris
box (trash dumpster) shall be placed on site for collection of construction
debris. Arrangements must be made with the Los Altos Garbage Company
for the debris box, since they have a franchise with the Town and no other
hauler is allowed within the Town limits.
16. The property owner shall inform the Town of any damage and shall repair
any damage caused by the construction of the project to pathways, private
driveways, and public and private roadways, prior final project approval
and shall provide the Town with photographs of the existing conditions of
the roadways and pathways prior to issuance of building permit.
17. An as -built mylar sewer plan shall be submitted to the Town prior to final
project approval.
18. An encroachment permit shall be required by the Town's Public Works
Department for all work proposed within the public right-of-way prior to
start of work.
19. The property owner shall provide the Town a copy of permits from the
Department of Fish and Game and Santa Clara Valley Water District prior
to issuance of building permit.
20. The property owner shall dedicate a 14 -foot -wide sanitary sewer easement
to the Town over the maintenance access road and bridge. The property
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 12 of 13
owner shall provide legal description and plat exhibits that are prepared by
a registered civil engineer or a licensed land surveyor, and the Town shall
prepare the dedication document. The dedication document, including the
approved exhibits, shall be signed and notarized by the property owner and
returned to the Town prior to issuance of building permit.
C. FIRE DEPARTMENT:
21. The bridge structure shall have a load bearing capacity of 40,000 pounds.
The load limit as engineered shall be posted at the entry point to the
bridge.
22. The maintenance road shall comply with Standard, Detail and
Specification D-1 of this department (for driveways serving up to two
single-family homes). At such time as the maintenance road is proposed
to serve more than two home sites, the roadway shall comply with
Standard, Detail and Specification A-1 of this department.
23. The fire department turnaround shall not be located on side hill slope
exceeding 5%.
Throughout the construction, a Site and Grading inspection and a Pre -Rough inspection
shall be required to be set with the Planning and Engineering Departments.
Upon completion of construction, a final inspection shall be required to be set with the
Planning and Engineering Departments two weeks prior to final building inspection
approval.
CONDITION 12a SHALL BE COMPLETED AND SIGNED OFF BY THE
ENGINEERING DEPARTMENT PRIOR TO ACCEPTANCE OF
CONSTRUCTION PLANS FOR PLAN CHECK BY THE BUILDING
DEPARTMENT.
CONDITIONS 7, 14, 15, 16, 19 AND 20 AND MITIGATION MEASURES 1-1, 1.2,
3.1, 4-1, 4-5, 4-6, 6-1, 6.2, 6.3, 6.4, 7-1 AND 8.1 SHALL BE COMPLETED AND
SIGNED OFF BY THE PLANNING AND ENGINEERING DEPARTMENTS
PRIOR TO ISSUANCE OF GRADING AND BUILDING PERMITS.
CONDITIONS 8,126, 14,16 AND 17 AND MITIGATION MEASURE 4-2 SHALL
BE COMPLETED AND SIGNED OFF BY THE PLANNING AND
ENGINEERING DEPARTMENTS PRIOR TO FINAL INSPECTION OF THE
NEW RESIDENCE.
The Site Development permit is valid for one year from the approval date (until March
17, 2006). All required building permits must be obtained within that year and work on
Staff Report to the Planning Commission
La Cresta Sewer Line, Access Road and Bridge
February 24, 2005
Page 13 of 13
items not requiring a building permit shall be commenced within one year and completed
within two years.
CONDITIONS OF APPROVAL ACCEPTANCE:
I hereby accept the above conditions of approval.
Property Owner Signature (#95-03-ZP-SD-GD-IS-ND) Date
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ATTACHMENT
SITE MAP
Lands of Mad Manor II, LLC (MORRISION)
27641 Purissima Road
#95-03-Z P -S D -G D -I S -N D
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Attachment 3
ATTACHMENT q
PURISSIMA/ LA CRESTA SANITARY SEWER
FUTURE USERS
December 12, 2003
I I Proper-ieiy
Address
APN
12805
La Cresta
175-44-073
12813
La Cresta
17544-072
12827
La Cresta
17544-029
12841
La Cresta
17544-028
12857
La Cresta
17544-027
13005
La Cresta
17544-025
12824
Canario Way
17543-016
12849
Canario Way
17543-016
12797
La Cresta
175-44-074
12785
La Cresta
17544-033
12869
La Cresta
17544-026
I I Proper-ieiy
2.2.5
2.2
.2.2.4
FIRE DEP ARTMEN7
SANTA CLARA COUNTY
14700 Winchester Blvd., Los Gatos, CA 95032-1818
(408) 3784010 , (408) 378-9342 (fax) • wu accfd.org
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DEVELOPMENT REVIEW COMMENTS
of a proposed new railcar bridge and driveway.
structure shall reflect load bearing capacity of 40,000 pounds. The load limit as
ineered shall be posted at the entry point to the bridge.
access driveway shall comply with Standard, Detail and Specification D-1 of
department (for driveways serving up to two single family home sites). The
icant shall indicate the purpose of the roadway/driveway and if serving more
. two home sites, the roadway shall comply with Standard, Detail and
ification A-1 of this department.
fire department turnaround shall not be located on side hill slope exceeding
dry PLORB sref3 REW IYOL AS
UCIANKY
WR .TYPE
APPEoIeWIM
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CLIFFORD BECIML &
6/16/2003
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Residential Development
Holcarvson, Wayne
J.& OF PROJECT
LOa4l 1
LANDS OF MAD MANOR II
27641 Purissima Rd
Organized as the Santa Clara County Central Fire Protection District
Serving Santa Clam County and the aammunitias of Campbell, Cupertino, l.os Altos,
Cos Altos Hill, Los Gatos, Monte Sereno, Ma,9.n Hill, and Samtoga
YI,)L v 8 2003
July 2, 2003
File: 26140
Deer Creek
Ms. Angelica Herrera
Associate Planner
Town of Los Altos Hiils
26379 Fremont Road
Los Altos Hills, CA 94022
Subject: 27641 Purissima Road—Town of Los Altos Hills File 95-03-ZP-SD-GD-IS/ND
Dear Ms. Herrera:
The Santa Clara Valley Water District (District) has reviewed the proposed improvement plans
to install a bridge overcrossing Deer Creek at the subject site, received on June 16, 2003.
The plans show two proposed outfalls into Deer Creek from the proposed bridge and road.
These outfalls should be removed from the plans, and all drainage should be directed to the
existing on-site storm drain system. There should be no overbank drainage into Deer Creek
from the improved areas of the site. All disturbed areas should be vegetated with drought
tolerant natives to prevent erosion of the slopes and the introduction of sediments into Deer
Creek. All other comments remain the same as in our letter to Mr. Bruce Asked dated March 3,
2003 (copy enclosed).
Please reference District File No. 26140 on future correspondence regarding this project. I may
be reached at (408) 265-2607, extension 2319, 'If you have any questions.
Sincerely,
Yvnne Arroyo
Assistant Engineer
Community Projects Review Unit
Enclosure: Letter Dated March 3, 2003
cc: Mr. Bruce Asked, Purissima Lift Project LLC; California State Department of Fish and
Game
S. Tippets, N. Ali-Adeeb, Y. Arroyo, K. Turner, Jennie Micko, File (2)
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0702b-pl.doc
The mission of the Sant Clara Valley Water District is a heahhy, safe and enhanced quality of living in Same Clara County through watershed rq
stewardship and comprehensive management of watem
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SAN JOSE, CA 95118 614
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ENCLOSURE
File: 26140
Deer Creek
March 3, 2003
Mr. Bruce Asked
Pudssima Lift Project LLC
452 East EI Camino Real
Sunnyvale, CA 94087
Subject: Proposed Bridge Over Deer Creek for Access to Existing Sewer Line at
27641 Pudssima Road, Los Altos Hills
Dear Mr. Askad:
The Santa Clara Valley Water District (District) has reviewed the proposed plans for the subject
20 -foot wide bridge overcrossing Deer Creek, received on January 21, 2003.
The District reviewed the bridge with respect to its hydraulic aspects only. The proposed bridge
abutments are located outside the 100 -year flow conveyance area. However, the bridge
appears to be in an area which may impact the riparian corridor, including the removal of trees
and other habitat. The plans do not show how much vegetation will be removed as a result of
the project. The District would like verification that the Town of Los Altos Hills and the California
State Department of Fish and Game has reviewed and approved the proposed bridge
installation particularly with regards to any adverse impacts to the riparian corridor and possible
mitigation for any impacts.
Please forward copies of these approvals along with two sets of final plans, if changes are made
subsequent to this set of plans, for our review and issuance of a permit prior to start of
construction. Please reference District File No. 26140 on future correspondence regarding this
project. I maybe reached at (408) 265-2607, extension 2319, if you have any questions.
Sincerely,
YvohAe Arroyo
Assistant Engineer
Community Projects Review Unit
cc: Planning Department/Public Works Department, Town of Los Altos Hills
California State Department of Fish and Game, Yountville, CA
S. Tippets, N. Ali-Adeeb, Y. Arroyo, K. Turner, Jennie Micko, File (2)
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RECEIVED
26 COTTON, SHIRES &ASSOCIATES, INC. ATTACHMEf�I� 2 8 2004
CONSULTING ENGINEERS AND GEOLOGISTS Tnwm nF 1 ne m me un 1 e _
July 27, 2004
L0093A
TO: Angelica Herrera
Assistant Planner
TOWN OF LOS ALTOS HILLS
26379 Fremont Road
Los Altos Hills, California 94022
SUBJECT: Geotechnical Review
RE: Askari (Mad Manor II) Bridge, Sewer and Maintenance Road
N95-03-ZP-SD-GD-IS-ND
27641 Purissima Road
At your request, we have completed a geotechnical review of permit applications
for the subject project using:
Report Addendum, Geotechnical Engineering Investigation
(report), prepared by Bay Area Geotechnical Group, dated May
19, 2004;
Plans for the Improvement of Sanitary Sewer Gravity Line and
Maintenance Road (4 sheets, various scales), prepared by
Advanced Development, dated February 25,2004; and
Plans for Road Bridge (5 sheets, 4 -scale), prepared by Roseville
Design Group, dated May, 2004.
In addition, we have reviewed pertinent maps and reports from our office files
and completed a recent site inspection.
DISCUSSION
The applicant proposes to construct a new bridge and associated connecting
maintenance road, and sanitary sewer across Deer Creek to undeveloped hill slopes
located east of the creek. The referenced plans are now updated and include a roadway
that extends to the east end of the property (beyond the originally prouosed fire -truck
turnaround). A detention basin is proposed to collect runoff from the unpaved roadway
above the east bridge abutment. The gradient of the bridge has been increased to 16
percent, and changes have been made to the supporting foundation system. Portions of
the proposed maintenance roadway reach grades of 16 to 18 percent. Multiple
documents prepared by the Project Geotechnical Consultant (BAGG) have indicated that
the sewer, roadway and bridge are to service future lots above the east end of the bridge.
If this intended use of the property is correct, then if would be appropriate for a
Tentative Map to be prepared so that roadway alignments and bridge design could be
considered with respect to lot boundaries. At this point, we understand that the current
application is to be evaluated only for purposes of the sewer line and maintenance road.
Project grading will likely include significant cut and fill quantities for the
establishment of the proposed detention basin, roadway and bridge abutments.
Northern California Office
www.cottonshires.com
Southern Calitorma uttrce
Angelica Herrera July 27, 2004
Page 2 L0093A
Grading volume estimates of the cubic yards of cut and fill are not indicated on the
referenced plans.
In our previous review letter (dated June 10, 2003), we recommended that a
Supplemental Geotechnical Evaluation and Plan Review be completed by the Project
Geotechnical Consultant (BAGG). The recommended supplemental evaluation and
review was primarily intended to address the adequacy of supporting elements of the
proposed bridge prior to issuance of building permits. The depth of bridge supporting
piers has been increased in the currently proposed bridge design. Our present
geotechnical review work has been focused on the updated plans, which include a
proposed new maintenance road east of the bridge. We understand that determination
of Deer Creek flood elevations are to be completed to the satisfaction of the Town
Engineer.
SITE CONDITIONS
The site is generally characterized as moderately steep to precipitous (15 to 100
percent inclinations), northwest -facing hillside topography east of Deer Creek. The face
of a southwest -trending spur ridge occupies the central portion of the property and is
flanked by a moderately steep hillside to the south, and a steep colluvial swale to the
north. An intervening gently sloping saddle occupies the ridgeline approximately half-
way down to Deer Creek from the eastern property line. Drainage is characterized as
partially -controlled sheetflow to the northwest which is intercepted by a southwest -
trending swale, and by sheetflow to the southwest intercepted by the channel of Deer
Creek
The Los Altos Hills Geotechnical Hazards Map indicates that slopes east of Deer
Creek are mantled by colluvium and are underlain by conglomerate and sandstone
bedrock materials of the Santa Clara Formation, and the Unnamed Sandstone. Boring
logs in the submitted geotechnical reports indicate that the hillsides are underlain by
between 2 and 5.5 feet of native soil materials that overly bedrock of the Santa Clara
Formation.
CONCLUSIONS AND RECOMMENDED ACTION
Proposed project construction is potentially constrained by thick colluvium,
possible liquefaction along the creek corridor, potential sloughing of creek banks,
ongoing fluvial erosion, expansive soil conditions and anticipated seismic ground
shaking. The referenced report addendum by BAGG provides recommendations for
construction of the proposed roadway east of the bridge. Recommendations include
excavation and recompaction of soils beneath the proposed roadway to a depth of at
least 2 feet, and keying and benching of new fill into firm soil and/or bedrock. BAGG
evaluations do not address the proposed detention basin that is missing provisions for
an overflow drainage outlet structure. In general, we do not have significant
geotechnical feasibility objections to the layout of proposed site improvements.
However, the location of the detention basin should be evaluated by the Project
Geotechnical Consultant with respect to potential negative slope stability impacts. In
addition, the merits of placing impermeable trench plugs periodically along the sewer
trench alignment and periodic water bars along the maintenance road should be
addressed by BAGG.
COTTON, SHIRES & ASSOCIATES, INC.
Angelica Herrera
Page 3
July 27, 7004
L0093A
Prior to issuance of construction permits, or acceptance of documents for
building permit plan -check, we recommend that the following items be satisfactorily
addressed.
1. Supplemental Geotechnical Evaluations — The Project Geotechnical
Consultant should address the following issues regarding proposed
project plans:
• The potential for the proposed detention basin to result in
negative slope stability impacts should be evaluated. The
geotechnical consultant- should address the feasibility of the
proposed detention basin and provide appropriate design
recommendations (including consideration of an outlet structure
and potential liner).
During our recent field review, we noted several small areas of
shallow instability along the west -facing slope near the ridgeline
in the eastern part of the property. The consultant should
evaluate whether cut slopes proposed for the roadway may
destabilize adjacent slopes mantled with colluvium and
recommend any appropriate mitigation measures.
• The consultant should consider recommending keying and
benching fill for the roadway into bedrock beneath potentially
unstable colluvium deposits.
• The consultant should address the potential merits of placing
water bars along the maintenance road to help control erosion of
unpaved road surfaces.
Appropriate documentation to address the above items should be
submitted to the Town, for review by the Town Engineer and Town
Geotechnical Consultant, prior to submittal of final site improvement
plans.
2. Geotechnical Plan Review — The applicant's geotechnical consultant
should review and approve all geotechnical aspects of the project
building and grading plans (i.e., site preparation and grading, site
drainage improvements and design parameters for bridge
foundations, retaining walls and adjoining roadways) to ensure that
their recommendations have been properly incorporated. In addition,
the consultant should address the following:
• Confirm that the wing wall design, including backdrains, is
satisfactorily detailed on plans.
• Verify that appropriate geotechnical design parameters have been
utilized in bridge structural calculations.
• Confirm that appropriate placement of recommended clay plugs
along the sewer alignment are detailed on project plans.
COTTON, SHIRES & ASSOCIATES, INC.
Angelica Herrera
Page 4
July 27, 2004
L0093A
The results of the plan review should be summarized by the
geotechnical consultant in a letter and submitted to the Town
Engineer for review along with other documents for building permit
plan -check
3. Geotechnical Field Inspection — The geotechnical consultant should
inspect, test (as needed), and approve all geotechnical aspects of the
project construction. The inspections should include, but not
necessarily be limited to: site preparation and grading, site surface
and subsurface drainage improvements, and excavations for bridge
foundations and retaining walls prior to the placement of steel and
concrete.
-The results of these inspections and the as -built conditions of the
project should be described by the geotechnical consultant in a letter
and submitted to the Town Engineer for review prior to final (as -
built) project approval.
LIMITATIONS
This review has been performed to provide technical advice to assist the Town
with discretionary permit decisions. Our services have been limited to review of the
documents previously identified, and a visual review of the property. Our opinions and
conclusions are made in accordance with generally accepted principles and practices of
the geotechnical profession. This warranty is in lieu of all other warranties, either
expressed or implied.
POS:TS:RR
Respectfully submitted,
COTTON, SHIRES AND ASSOCIATES, INC.
GEOTECHNICAL CONSULTANT
Ted Sayre"
ervismg Engineer}'ng Geologist
CEG 795 \ ]
�PatricR O. Shires
Principal Geotechnical Engineer
GE 770
COTTON, SHIRES & ASSOCIATES, INC.
ATTA
IT -
ENVIRONMENTAL DESIGN COMMITTEE
LANDSCAPE/HARDSCAPEEVALUATION JUS! 13 ?003
Applicant's Name:
i 1 t i�n?t' I'_i iG?Jfe OF1 +;h17Q5 ;115
Address:
Reviewed by: Date: (Q .13 3
Mitigation needed:
Visibility from off site: from distance (directions), from nearby
neighbors (directions) (include need for screening for privacy).
Noise: from pump/pool . air conditioner sport court
Light: from fndures . automobile headlights _.
Fencematerials: color open/solid _. Erosion control_.
Other.
Planting Plan Evaluation: (Circle required trees and shrubs on plan)
Are species appropriate: Deciduous?
Future height (view, solar, drive/path blockage)
Fire hazard
Hardiness/frost
Drought tolerance
Meet mitigation needs
Creeks and drainage: Is fhere a conservation easement? Kri there sufficient
protections in place. Will fences impact wildlife migration? Invasive species
should not be planted near a waterway.
Other: Are there obstructions to pathways, including future growth of plants? Are all
noise mitigations in place? No construction in road right-of-way.
ATTACHMENT Y
La Cresta Sewer and Access Road
TOWN OF LOS ALTOS HILLS
Draft Initial Study/Mitigated Negative Declaration
January 2005
Prepared for
Carl Cahill, Planning Director
Town of Los Altos Hills
26379 Fremont Road
Los Altos Hills, California 94022
Prepared by
MHA Environmental Consulting, Inc.
www.mha-inc.com
LOS..ALTOS HILLS
c.3Lleoa�Ia
INVIROXNINTRL CONSV LLIXO, IN[.
Celebrating 20 years
TABLE OF CONTENTS
TABLE OF CONTENTS
ProjectDescription.......................................................................................................................
1
Negative Declaration Mitigation Measures.................................................................................
1
Aesthetics..... ....................... . . ......... ........... .. . ... ......
.. . .... .... ... . .... 1
AirQuality.................................................................................................................................
1
BiologicalResources................................................................................................................
1
CulturalResources...................................................................................................................3
Geologicaland Soils.................................................................................................................
3
Hazards and Hazardous Materials............................................................................................
3
Hydrologyand Water Quality....................................................................................................4
Noise.......................................................................................................................................4
ReviewPeriod...............................................................................................................................4
ContactPerson(s) ........................................................................................................................4
EnvironmentalChecklist Form....................................................................................................5
Environmental Factors potentially Affected...............................................................................8
Determination...............................................................................................................................
9
EnvironmentalChecklist............................................................................................................
10
EnvironmentalAnalysis.............................................................................................................
17
1. Aesthetics...........................................................................................................................
17
2. Agricultural Resources........................................................................................................
18
3. Air Quality...........................................................................................................................
18
4. Biological Resources..........................................................................................................
19
5. Cultural Resources.............................................................................................................
21
B. Geology and Soils...............................................................................................................
22
7. Hazards and Hazardous Materials......................................................................................
23
8. Hydrology and Water Quality..............................................................................................
23
9. Land Use and Planning.......................................................................................................
24
10. Mineral Resources............................................................................................................
24
11. Noise...............................................................................................................................
24
12. Population and Housing....................................................................................................
25
13. Public Services.................................................................................................................
25
La Cresta Sewer and Access Road IS/MND - Draft MHA Inc. TOC i
January 2005
TABLE OF CONTENTS
14. Recreation.........................................................................................................................
25
15. Traffic and Transportation.................................................................................................
i
25
16. Utilities and Service Systems............................................................................................
26
17. Mandatory Findings and Significance................................................................................
26
Information Sources...................................................................................................................
26
Listof Prepares...........................................................................................................................
27
Prepares.................................................................................................................................
27
LosAltos Hills Staff.................................................................................................................
27
Mitigation, Monitoring and Reporting Program........................................................................
28
FIGURE
Figure 1: Project Locator Map for the La Cresta Sewer Line and Access Road ............................. 7
ii MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
TOWN OF LOS ALTOS HILLS
DRAFT MITIGATED NEGATIVE DECLARATION
PROJECT DESCRIPTION
Applicant: Mr. Bruce Asked, Purissima Lift Project, LLC, 452 E. EI Camino Real,
Sunnyvale, CA 94087
Proposed Location: Near the intersection of Elena Avenue with Purissima Road (see Figure 1);
Los Altos Hills; USGS 7.5 minute quadrangle (Sec 25, T6, R 3W); APN
175-73-035
Proposed Action: Construction of a sewer line and associated asphalt access driveway,
bridge, and gravel maintenance access road from Purissima Road at
Elena Avenue through Assessors Parcel Number 175-73-035. The bridge
will span Deer Creek with no proposed construction within the waterway.
NEGATIVE DECLARATION MITIGATION MEASURES
Aesthetics
Mitigation Measure 1-1: The applicant shall prepare and submit to the Town of Los Altos
Hills a landscape and revegetation plan subject to approval prior to issuance of any grading
permits. The landscape plan shall provide for landscape screening with a mixture of native
shrubs and trees, particularly along the upper road section, around the detention basin, and
in other disturbed areas. The plan shall also indicate the trees to be removed, the number
and size of replacement trees, replacement tree locations, and irrigation for all vegetation
until it is established.
Mitigation Measure 1.2: The applicant must comply with the Town's tree ordinance,
including consulting with Town representatives and following replacement
recommendations. Replacement should be at a ratio of 3:1 (15 -gallon size) and of the same
species as removed trees, unless otherwise approved by the Planning Director.
Air Quality
Mitigation Measure 3-1: The following basic control measures shall be implemented during
the project construction phase. Measures should also be incorporated into a revised grading
plan that is approved by the Town of Los Altos Hills prior to issuance of grading permits.
• Water all active construction areas at least twice daily.
• Cover all trucks hauling soil, sand, and other loose materials or require all trucks to
maintain at least two feet of freeboard.
• Pave, apply water three times daily, or apply (nontoxic) soil stabilizers on all
unpaved access roads, parking areas, and staging areas at construction sites.
• Sweep daily (with water sweepers) all paved access roads, parking areas, and
staging areas at construction sites.
• Sweep streets daily (with water sweepers) if visible soil material is carried onto
adjacent public streets.
Biological Resources
Mitigation Measure 4.1: The applicant shall develop an erosion control plan that includes
such measures as the placement of silt fences, hay bales, etc. between the areas of work
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 1
January 2005
TOWN OF LOS ALTOS HILLS
and the riparian habitat (outside of ACOE jurisdictional line) to ensure that sediments from
grading, digging, and placement of the central bridge pile do not erode into the creek. Water
bars shall be evaluated to prevent sheet flow and erosion off of the unpaved road along the
eastern side of the creek. The applicant shall also develop a SWPPP per Stale Water
Quality Control Board Stormwater Permit requirements. The required stormwater plan shall
be submitted for review and approval by the Town Engineer prior to issuance of grading or
building permits for the project.
Mitigation Measure 4-2: All disturbed areas shall be revegetated with drought tolerant and
native species to prevent erosion of the slopes and the introduction of sediments into Deer
Creek (also see Mitigation Measure 1-1).
Mitigation Measure 4.3: No equipment shall be fueled or maintained within 100 feet of the
creek.
Mitigation Measure 4.4: Biologists shall conduct an education training session for all
construction personnel prior to beginning grading or construction on the site. The program
shall consist of a brief presentation explaining endangered species concerns, to include 1) a
description of each of the sensitive species and their habitat needs, and 2) an explanation of
the status of the species during project construction and implementation. A fact sheet
conveying this information shall be prepared for distribution to the above-mentioned
personnel and anyone else who may enter the construction area.
Mitigation Measure 4-5: Construction shall be scheduled to avoid the rainy season when
California red -legged frogs are most likely to be moving between different bodies of water.
Construction shall be performed between April 15" and October le. If necessary, the
applicant shall seek approval from the CDFG, RWQCB and the USFWS to work outside this
time period.
Mitigation Measure 4.5: Pre -construction surveys shall be performed within 48 hours of
initial construction activities within a 50 -foot radius of the point of creek crossing for
California red -legged frog. If any individuals or active nests are identified in this area, work
shall not commence until the USFWS is contacted and appropriate protection measures are
determined. These measures could include delaying construction until individuals have
moved out of the project area. Pre -construction surveys shall also be performed for western
pond turtles. If any individuals of that species are identified within the construction zone,
they shall be relocated to a safe location by a qualified biologist before work can commence.
Mitigation Measure 4-7: A qualified biological monitor shall be present during all work to
ensure that there are no California red -legged frogs or western pond turtles that could be
affected by construction activities. If any red -legged frog individuals are identified, work shall
not commence until the USFWS is contacted and appropriate protection measures are
determined. These measures could include delaying construction until individuals have
moved out of the project area. If any western pond turtles are identified in the construction
area by the monitor, they shall be relocated to a safe location by a qualified biologist before
work can commence.
Mitigation Measure 4-8: A qualified ornithologist shall conduct a pre -construction survey for
nesting raptors on site within 30 days of the onset of ground disturbance, if ground
disturbance is to occur during the breeding season (between February 1`r and August 31m).
These surveys shall be based on the accepted protocols for the target species. If any
nesting raptor is detected, an appropriate construction buffer shall be established. Actual
size of the buffer would depend on species, topography, and type of construction activity
that would occur in the vicinity of the nest and should be determined by the ornithologist.
None of the trees slated for removal shall be removed or trimmed if there is an active nest in
the tree. Removal shall only commence after the young have fledged as determined by a
qualified ornithologist.
2 MHA Inc. La Cresta Sewer and Access Road ISIMND — Draft
January 2005
TOWN OF LOS ALTOS HILLS
Cultural Resources
Mitigation Measure 5-1: If any cultural or paleontological resources or human remains are
discovered during construction activities, work shall be halted within 50 feet of the discovery
until a qualified specialist is retained to inspect the discovery. If it is determined that an intact
cultural resource would be further damaged by construction activities, it shall be the
responsibility of the applicant to submit a plan for the evaluation and mitigation of any such
resource to the relevant lead agency and receive approval of that plan before construction
can resume in the area of the resource. If the cultural resources contain human remains, the
San Mateo County Coroner shall be notified. If the coroner determines the remains to be
Native American, the coroner shall contact the Native American Heritage Commission within
24 hours. Native American monitors shall be allowed to observe conditions following any
such discovery. Disposition of Native American human remains shall comply with CEQA
Guidelines Section 15064.5(e).
Geology and Soils
Mitigation Measure 6-1: The recommendations in the BAGG report for excavation and re -
compaction of soils beneath the proposed roadway to a depth of at least 2 feet, and keying
and benching of new fill into firm soil and/or bedrock shall be followed. A final grading plan
shall be submitted to the Town for review and approval by the Town Geologist and the Town
Engineer prior to issuance of grading or construction permits.
Mitigation Measure 6-2: Compliance with the Uniform Building Code, California Building
Code and other codes that govern bridge, road and utility design shall be implemented in
design plans and reviewed and approved of by the Town Engineer prior to issuance of any
building permit.
Mitigation Measure 6-3: The applicant shall have a qualified geotechnical engineer
evaluate whether cut slopes proposed for the roadway may destabilize adjacent slopes
mantled with colluvium and recommend any appropriate mitigation measures to be included
in revised design plans. The report and revised plans shall be resubmitted to the Town of
Los Altos Hills for review and approval by the Town Geologist prior to issuance of a grading
permit.
Mitigation Measure 64: The potential for the proposed detention basin to result in negative
slope stability impacts shall be evaluated. The feasibility of the proposed detention basin
shall be addressed by a qualified geotechnical engineer and recommendations made to
ensure stability, including provision of an outlet structure and liner, if appropriate. Project
design plans shall be revised to reflect any recommendations and evaluations made by the
geotechnical engineer and shall be resubmitted to the Town of Los Altos Hills for review and
approval by the Town Geologist prior to issuance of a grading permit.
Hazards and Hazardous Materials
Mitigation Measure 7-1: The applicant shall submit a spill response plan to the Town of Los
Altos Hills prior to the onset of construction to ensure a prompt and effective response to
any accidental spills or leaks of diesel, gasoline, oil or other contaminating materials that
might flow or migrate to the creek.
Mitigation Measure 7-2: Construction vehicles shall be equipped with appropriate fire
combatant equipment at all times.
Mitigation Measure 7-3: Smoking shall not be allowed outside of designated areas, which
would include anywhere with dry grass underfoot.
La Cresta Sewer and Access Road ISIMND - Draft MHA Inc. 3
January 2005
TOWN OF LOS ALTOS HILLS
Hydrology and Water Quality
Mitigation Measure 8.1: The project applicant shall revise the current drainage system and
coordinate with the Town Engineer to connect runoff outlets from the project into the existing
storm drainage system instead of allowing over bank drainage into Deer Creek.
Noise
Mitigation Measure 11-1: The project shall comply with Town regulations governing hours of
construction.
REVIEW PERIOD
All comments regarding the correctness, completeness, or adequacy of this Negative Declaration
must be received by the Town of Los Altos Hills by no later than 5:00 p.m. on February 22, 2005.
CONTACT PERSON(S)
Carl Cahill
Planning Director
Tel: (650) 941-7222
Fax: (650) 941-3160
ccahill@iosaltoshills.ca.gov
Carl Cahill, Planning Director
4 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
Project Location: Near the intersection of Elena Avenue with Purissima Road
(see Figure 1); Los Altos Hills; USGS 7.5 minute quadrangle
(Sec 25, T6, R 3W); APN 175-73-035
Project Sponsor's Name Mr. Bruce Askari, Purissima Lift Project, LLC, 452 E. EI
and Address: Camino Real, Sunnyvale, CA 94087
General Plan Designation: Residential
Zoning: R -A (Residential - one acre minimum)
Description of Project: The project includes construction of a sanitary sewer main, an
associated connecting maintenance road for the proposed line (and to provide maintenance to
an existing line to the south of the drive), a 100 -foot long bridge for the road and sewer line to
span Deer Creek, and a sediment detention basin.
The proposed sewer line will connect from an existing sewer manhole located at the
intersection of Elena Road and Purissima Road, through APN parcel 175-73-035, over Deer
Creek and into the adjacent hillside for hookup to residences west of La Cresta Drive that
currently rely on septic systems and leach fields. The proposed line would be a gravity flow
line. The sewer line will generally be located about 5 feet below the roadway surface; however,
the trench excavation may reach as much as 12 to 14 feet below the existing ground surface.
This proposed access road will be asphalt paved from Purissima Road to above the bridge
crossing. From there, the access road will consist of a 14 -foot wide gravel surface leading up
over the property to the eastern boundary of the site. The grading for the roadway will include
both cuts and fills on the order of two to four feet in height. The access road will be used for
maintenance of the proposed gravity flow sewer line located under the road as well as for the
parallel sewer force main located along the southern boundary of the site. The parallel main
currently ties into the sewer manhole and pump station located at the intersection of Purissima
Road and Elena Road.
The proposed 14 -foot wide bridge crosses Deer Creek. There will be two spans within the
bridge, with the western span about 66 feet long across the creek and the eastern span about
46 feet in length, ending near the top of the adjacent hill east of the creek. The middle pier will
be located at the site of an old roadway on the east side of the creek. The roadway approach
to the abutment on the west side of the creek will be graded with up to about 10 feet of fill,
while the eastern abutment will support roughly 5 feet of fill adjacent to cuts of similar depth.
The bridge will be sloped down from east to west at an approximately 16 -percent grade.
The project also includes a sediment detention basin located upslope on the east bank. The
basin will include outlet structures leading to energy dissipaters that discharge into Deer Creek.
Surrounding Land Uses and Setting: The study area is located in northwestern Santa Clara
County at the foothills of the Santa Cruz Mountains. The project site is located in an area of
large single-family estates. The majority of the area is open space with scattered development
associated with the residences (houses, tennis courts, pools, schools, parks, etc.) and a
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 5
January 2005
TOWN OF LOS ALTOS HILLS
ENVIRONMENTAL CHECKLIST
FORM
Project Title:
La Cresta Sewer Line and Access Road, Los Altos Hills
Lead Agency Name and
Town of Los Altos Hills, 26379 Fremont Road, Los Altos Hills,
Address:
CA 94022
Contact Person and
Carl Cahill, Planning Director
Phone Number:
Project Location: Near the intersection of Elena Avenue with Purissima Road
(see Figure 1); Los Altos Hills; USGS 7.5 minute quadrangle
(Sec 25, T6, R 3W); APN 175-73-035
Project Sponsor's Name Mr. Bruce Askari, Purissima Lift Project, LLC, 452 E. EI
and Address: Camino Real, Sunnyvale, CA 94087
General Plan Designation: Residential
Zoning: R -A (Residential - one acre minimum)
Description of Project: The project includes construction of a sanitary sewer main, an
associated connecting maintenance road for the proposed line (and to provide maintenance to
an existing line to the south of the drive), a 100 -foot long bridge for the road and sewer line to
span Deer Creek, and a sediment detention basin.
The proposed sewer line will connect from an existing sewer manhole located at the
intersection of Elena Road and Purissima Road, through APN parcel 175-73-035, over Deer
Creek and into the adjacent hillside for hookup to residences west of La Cresta Drive that
currently rely on septic systems and leach fields. The proposed line would be a gravity flow
line. The sewer line will generally be located about 5 feet below the roadway surface; however,
the trench excavation may reach as much as 12 to 14 feet below the existing ground surface.
This proposed access road will be asphalt paved from Purissima Road to above the bridge
crossing. From there, the access road will consist of a 14 -foot wide gravel surface leading up
over the property to the eastern boundary of the site. The grading for the roadway will include
both cuts and fills on the order of two to four feet in height. The access road will be used for
maintenance of the proposed gravity flow sewer line located under the road as well as for the
parallel sewer force main located along the southern boundary of the site. The parallel main
currently ties into the sewer manhole and pump station located at the intersection of Purissima
Road and Elena Road.
The proposed 14 -foot wide bridge crosses Deer Creek. There will be two spans within the
bridge, with the western span about 66 feet long across the creek and the eastern span about
46 feet in length, ending near the top of the adjacent hill east of the creek. The middle pier will
be located at the site of an old roadway on the east side of the creek. The roadway approach
to the abutment on the west side of the creek will be graded with up to about 10 feet of fill,
while the eastern abutment will support roughly 5 feet of fill adjacent to cuts of similar depth.
The bridge will be sloped down from east to west at an approximately 16 -percent grade.
The project also includes a sediment detention basin located upslope on the east bank. The
basin will include outlet structures leading to energy dissipaters that discharge into Deer Creek.
Surrounding Land Uses and Setting: The study area is located in northwestern Santa Clara
County at the foothills of the Santa Cruz Mountains. The project site is located in an area of
large single-family estates. The majority of the area is open space with scattered development
associated with the residences (houses, tennis courts, pools, schools, parks, etc.) and a
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 5
January 2005
TOWN OF LOS ALTOS HILLS
remnant orchard. Purissima Road runs parallel to and on the eastern side of Interstate 260,
with Deer Creek running adjacent to Purissima Road to its east. Deer Creek cuts through the
center of the project site and continues to flow north, joining Matadero Creek downstream.
Matadero Creek then becomes channelized, now labeled as Matadero Canal, before emptying
into the San Francisco Bay. An equestrian pasture, Page Mill Pastures, is located
approximately half of a mile to the north of the project area, and Fremont Hills Country Club is
located approximately half of a mile to the south of the project area.
Other public agencies whose approval is required: a) California Department of Fish and
Game, 1603 Streambed Alteration Agreement, and b) San Francisco Bay Regional Water
Quality Control Board, approval of Storm Water Pollution Prevention Plan.
6 MHA Inc. La Cresta Sewer and Access Road IS/MND - Draft
January 2005
TOWN OF LOS ALTOS HILLS
1: Project Locator Map for the La Cresta Sewer Line and Access Road
PROJECT SITE
0 1 miles
SOURCE: MHA2004
LOS ALTOS HILLS
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 7
January 2005
TOWN OF LOS ALTOS HILLS
ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED
The environmental factors checked below would be potentially affected by this project, involving
several impacts that are "Less than Significant with Mitigation Incorporated" as indicated by the
checklist on the following pages.
✓
Aesthetics
Agricultural Resources
✓
Air Quality
✓
Biological Resources
✓
Cultural Resources
✓
Geology/Soils
✓
Hazards &
✓
Hydrology/
Land Use/
Hazardous Materials
Water Quality
Planning
Mineral Resources
✓
Noise
Population/Housing
Public Services
Recreation
Transportation/Traf is
Utilities/Service
✓
Mandatory Findings of
Systems
Significance
8 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
TOWN OF LOS ALTOS HILLS
DETERMINATION
On the basis of this initial evaluation:
I find that the proposed project COULD NOT have a significant effect on the environment,
and a NEGATIVE DECLARATION will be prepared.
I find that although the proposed project could have a significant effect on the
environment, there will not be a significant effect in this case because revisions in the
X
project have been made by or agreed to by the project proponent. A MITIGATED
NEGATIVE DECLARATION will be prepared.
I find that the proposed project MAY have a significant effect on the environment and an
ENVIRONMENTAL IMPACT REPORT is required.
I find that the proposed project MAY have a "potentially significant impact" or "potentially
significant unless mitigated" impact on the environment, but at least one effect (1) has
been adequately analyzed in an earlier document pursuant to applicable legal standards,
and (2) has been addressed by mitigation measures based on the earlier analysis as
described on attached sheets. An ENVIRONMENTAL IMPACT REPORT is required, but
it must analyze only the effects that remain to be addressed.
I find that although the proposed project could have a significant effect on the
environment, because all potentially significant effects (a) have been analyzed
adequately in an earlier EIR or NEGATIVE DECLARATION pursuant to applicable
standards, and (b) have been avoided or mitigated pursuant to that earlier EIR or
NEGATIVE DECLARATION, including revisions or mitigation measures that are imposed
upon the proposed project, nothing further is required.
`--�"-'=- # January 21, 2005
Signature Date
Carl Cahill
Printed name
Planning Director
Title
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 9
January 2005
TOWN OF LOS ALTOS HILLS
ENVIRONMENTAL CHECKLIST
10 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
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1. AESTHETICS. Would the project:
a) Have a substantial adverse effect on a scenic vista?
✓
A, J
b) Substantially damage scenic resources, including but not
✓
A, C,
limited to bees, rock outcroppings, and historic buildings
J
within a stale scenic highway?
c) Substantially degrade the existing visual character or
✓
A, J
quality of the site and its surroundings?
d) Create a new source of substantial light or glare which
✓
A, J
would adversely affect day or nighttime views in the area?
2. AGRICULTURE RESOURCES. In determining whether Impacts to agricultural resources are
significant environmental effects, lead agencies may refer to the California Agricultural Land
Evaluation and Site Assessment Model (1887) prepared by the California Department of
Conservation as an optional model to use in assessing impacts on agriculture and farmland.
Would the project:
a) Convert Prime Farmland, Unique Farmland, or Farmland of
✓
A, J
Statewide Importance (Farmland), as shown on the maps
prepared pursuant to the Farmland Mapping and
Monitoring Program of the California Resources Agency, to
non-agricultural use?
b) Conflict with existing zoning for agricultural use, or a
✓
A. J
Williamson Act contract?
c) Involve other changes in the existing environment which,
✓
A. J
due to their location or nature, could result in conversion of
Farmland to non-agricultural use?
3. AIR QUALITY. Where available, the significance criteria established. by the applicable air
quality management or air pollution control district may be relied. upon to make the following
determinations. Would the project:
a) Conflict with or obstruct implementation of the applicable air
✓
D. J
quality plan?
b) Violate any air quality standard or contribute to an existing
✓
D, J
or projected air quality violation?
c) Result in a cumulatively considerable net increase of any
✓
D, J
criteria pollutant for which the project region is non -
attainment under an applicable federal or stale ambient air
quality standard (including releasing emissions which
exceed quantitative thresholds for ozone precursors)?
d) Expose sensitive receptors to substantial pollutant
✓
J
concentrations?
10 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
TOWN OF LOS ALTOS HILLS
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 11
January 2005
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e) Create objectionable odors affecting a substantial number
✓
J
of people?
4. BIOLOGICAL RESOURCES. Would the project:
a) Have a substantial adverse effect, either directly or through
✓
A, E,
habitat modifications, on any species identified as a
F, J
candidate, sensitive, or special -status species in local or
regional plans, policies, or regulations, or by the California
Department of Fish and Game, U.S. Fish and Widlife
Service, or NOAA - Fisheries?
b) Have a substantial adverse effect on any riparian habitat or
✓
A, E,
other sensitive natural community identified in local or
F, J
regional plans, policies, regulations or by the California
Department of Fish and Game or U.S. Fish and Widlife
Service?
c) Have a substantial adverse effect on federally protected
✓
A, E,
wetlands as defined by Section 404 of the Clean Water Act
F, J
(including, but not limited to, marsh, vernal pool, coastal)
through direct removal, filling, hydrological interruption, or
other means?
d) Interfere substantially with the movement of any native
✓
A, E,
resident or migratory fish or wildlife species or with
F. J
established native resident or migratory wildlife corridors, or
impede the use of native wildlife nursery sites?
e) Conflict with any local policies or ordinances protecting
✓
A, B,
biological resources, such as a tree preservation policy or
J
ordinance?
f) Conflict with the provisions of an adopted Habitat
✓
A, B,
Conservation Plan, Natural Community Conservation Plan,
J
or other approved local, regional, or state habitat
conservation plan?
g) Adversely affect previously established mitigation site(s) for
✓
A, J
other project(s)?
S. CULTURAL RESOURCES. Would the project:
a) Cause a substantial adverse change in the significance of a
✓
A, J
historical resource as defined in §15064.5?
b) Cause a substantial adverse change in the significance of
✓
A. J
an archaeological resource pursuant to §15064.5?
c) Directly or indirectly destroy a unique paleontological
✓
A. J
resource or site or unique geologic feature?
d) Disturb any human remains, including those interred
✓
A. J
outside of formal cemeteries?
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 11
January 2005
TOWN OF LOS ALTOS HILLS
12 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
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S. GEOLOGY AND SOILS. Would the project expose people or structures to potential substantial
adverse effects, including the risk of loss, Injury, or death Involving:
a) Rupture of a known earthquake fault, as delineated on the
✓
B, G,
most recent Alquist-Priolo Earthquake Fault Zoning Map
H, I, J
issued by the State Geologist for the area or based on
other substantial evidence of a known fault? Refer to
Division of Mines and Geology Special Publication 42.
b) Strong seismic ground shaking?
✓
B, G,
H, I, J
c) Seismic -related ground failure, including liquefaction?
✓
B, G,
H, I, J
d) Landslides?
✓
A, B,
H,J
e) Would the project result in substantial soil erosion or the
✓
A, B,
loss of topsoil?
J
I) Would the project be located on a geologic unit or soil that
✓
A, B,
is unstable, or that would become unstable as a result of
H. 1, J
the project, and potentially result in on- or off-site landslide,
lateral spreading, subsidence, liquefaction or collapse?
g) Would the project be located on expansive soil, as defined
✓
B, G.
in Table 18-1-B of the Uniform Building Code (1994),
H, I
creating substantial risks to life or property?
h) Would the project have soils incapable of adequately
✓
J
supporting the use of septic tanks or alternative waste
water disposal systems where sewers are not available for
the disposal of wastewater?
7. HAZARDS AND HAZARDOUS MATERIALS. Would the project
a) Create a significant hazard to the public or the environment
✓
A, J
through the routine transport, use, or disposal of hazardous
materials?
b) Create a significant hazard to the public or the environment
✓
A, J
through reasonably foreseeable upset and accident
conditions involving the release of hazardous materials into
the environment?
c) Emit hazardous emissions or handle hazardous or acutely
✓
A, J
hazardous materials, substances, or waste within a one-
quarter mile of an existing or proposed school?
d) Be located on a site which is included on a list of hazar-
✓
A, J
dous materials sites compiled pursuant to Government
Code Section 65962.5 and, as a result, would it create a
significant hazard to the public or the environment?
12 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
TOWN OF LOS ALTOS HILLS
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 13
January 2005
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e) For a project located within an airport land use plan or,
✓
A, J
where such a plan has not been adopted, within two miles
of a public airport or public use airport, would the project
result in a safety hazard for people residing or working in
the project area?
f) For a project within the vicinity of a private airstrip, would
✓
A. J
the project result in a safety hazard for people residing or
working in the project area?
g) Impair implementation of or physically interfere with an
✓
A, J
adopted emergency response plan or emergency
evacuation plan?
h) Expose people or structures to a significant risk of loss,
✓
A, B,
injury or death involving wildland fres, including where
J
wildlands are adjacent to urbanized areas or where
residences are intermixed with wildlands?
8. HYDROLOGY AND WATER QUALITY. Would the project:
a) Violate any water quality standards or waste discharge
✓
A. E,
requirements?
J
b) Substantially deplete groundwater supplies or interfere
✓
A, G,
substantially with groundwater recharge such that there
J
would be a net deficit in aquifer volume or a lowering of the
local ground water table level (for example, the production
rate of pre-existing nearby wells would drop to a level which
would not support existing land uses or planned uses for
which permits have been granted)?
c) Substantially alter the existing drainage pattern of the site
✓
A, G,
or area, including through the alteration of the course of a
J
stream or river, in a manner which would result in
substantial erosion or siltation on- or off-site?
d) Substantially alter the existing drainage pattern of the site
✓
A, G,
or area, including through the alteration of the course of a
J
stream or river, or substantially increase the rate or amount
of surface runoff in a manner which would result in flooding
on- or off-site.
e) Create or contribute runoff water which would exceed the
✓
A, G,
capacity of existing or planned storm water drainage
H, I,
systems or provide substantial additional sources of
J, K
polluted runoff?
f) Otherwise substantially degrade water quality?
✓
A, E,
G, H,
I,
g) Place housing within a 100 -year flood -hazard area as
✓
J
mapped on a federal Flood Hazard Boundary or Flood
Insurance Rate Map or other flood hazard delineation map7
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 13
January 2005
TOWN OF LOS ALTOS HILLS
14 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
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h) Place within a 100 -year flood -hazard area structures which
✓
J
would impede or redirect flood flows?
i) Expose people or structures to a significant risk of loss,
✓
J
injury or death involving flooding, including flooding as a
result of the failure of a levee or dam?
j) Inundation by seiche, tsunami, or mudflow?
✓
B, J
8. LAND USEAND PLANNING. Would the project:
a) Physically divide an established community?
✓
A, B,
J
b) Conflict with any applicable land use plan, policy, or
✓
A, B,
regulation of an agency with jurisdiction over the project
J
(including, but not limited to the general plan, specific plan,
local coastal program, or zoning ordinance) adopted for the
purpose of avoiding or mitigating an environmental effect?
c) Conflict with any applicable Habitat Conservation Plan or
✓
A, B.
Natural Community Conservation Plan?
E, J
10. MINERAL RESOURCES. Would the project:
a) Result in the loss of availability of a known mineral resource
✓
B, J
that would be of value to the region and the residents of the
state?
b) Result in the loss of availability of a locally -important
✓
B, J
mineral resource recovery site delineated on a local general
plan, specific plan, or other land use plan?
11. NOISE. Would the project result in:
a) Exposure of persons to or generation of noise levels in
✓
A. B,
excess of standards established in the local general plan or
J
noise ordinance or applicable standards of other agencies?
b) Exposure of persons to or generation of excessive ground
✓
A, J
borne vibration or ground borne noise levels?
c) Substantial permanent increase in ambient noise levels in
✓
A, J
the project vicinity above levels existing without the project?
d) A substantial temporary or periodic increase in ambient
✓
A, J
noise levels in the project vicinity above levels existing
without the project?
e) For a project located within an airport land use plan or,
✓
A, J
where such a plan has not been adopted, within two miles
of a public airport or public use airport, would the project
expose people residing or working in the project area to
excessive noise levels?
14 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
TOWN OF LOS ALTOS HILLS
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 15
January 2005
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f) For a project within the vicinity of a private airstrip, would
✓
A, J
the project expose people residing or working in the project
area to excessive noise levels?
12. POPULATION AND HOUSING. Would the project:
a) Induce substantial population growth in an area, either
✓
B, J
directly (for example, by proposing new homes and
businesses) or indirectly (for example, through extension of
roads or other infrastructure)?
b) Displace substantial numbers of existing housing,✓
J
necessitating the construction of replacement housing
elsewhere?
c) Displace substantial numbers of people, necessitating the
✓
J
construction of replacement housing elsewhere?
13. PUBLIC SERVICES. Would the project result In substantial adverse physical Impacts
associated with the provision of new or physically aftered governmental facilities or need for
new or physical altered governmental facilities, the construction of which could "use
significant environmental Impacts, in order to maintain acceptable service ratios, response
times, or other performance objectives for any of the public services:
a) Fire protection?
✓
I A, J
b) Police protection?
✓
I A, J
c) Schools?
✓
A.J
d) Parks?
✓
A,J
e) Other public facilities?
✓
A, J
14. RECREATION. Would the project:
a) Increase the use of existing neighborhood and regional
✓
A, B,
parks or other recreational facilities such that substantial
J
physical deterioration of the facility would occur or be
accelerated?
b) Include recreational facilities or require the construction or
✓
A, J
expansion of recreational facilities which might have an
adverse physical effect on the environment?
15. TRANSPORTATIONITRAFFIC. Would the project:
a) Cause an increase in traffic which is substantial in relation
✓
A, J
to the existing traffic load and capacity of the street system
(for example, result in a substantial increase in either the
number of vehicle trips, the volume to capacity ratio on
roads, or congestion at intersections)?
La Cresta Sewer and Access Road IS/MND — Draft MHA Inc. 15
January 2005
TOWN OF LOS ALTOS HILLS
16 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
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b) Exceed, either individually or cumulatively, a level of
✓
A, J
service standard established by the county congestion
management agency for designated roads or highways?
c) Result in a change in air traffic patterns, including either an
✓
A. J
increase in traffic levels or a change in location that results
in substantial safety risks?
d) Substantially increase hazards due to a design feature (for
✓
A, J
example, sharp curves or dangerous intersections) or
incompatible uses (for example, farm equipment)?
e) Result in inadequate emergency access?
✓
A, J
f) Result in inadequate parking capacity?
✓
A, J
g) Conflict with adopted policies, plans, or programs
✓
A, J
supporting alternative transportation (for example, bus
turnouts, bicycle racks?
16. UTILITIES AND SERVICE SYSTEMS. Would the project:
a) Exceed wastewater treatment requirements of the
✓
A. J
applicable Regional Water Quality Control Board?
b) Require or result in the construction of new water or
✓
A, J
wastewater treatment facilities or expansion of existing
facilities, the construction of which could cause significant
environmental effects?
c) Require or result in the construction of new storm water
✓
A, J,
drainage facilifies or expansion of existing facilities, the
K
construction of which could cause significant environmental
effects?
d) Have sufficient water supplies available to serve the project
✓
A, J
from existing entitlements and resources, or are new or
expanded entitlements needed?
e) Result in a determination by the wastewater treatment
✓
A, J
provider which serves or may serve the project that it has
adequate capacity to serve the project's projected demand
in addition to the provider's existing commitments?
f) Be served by a landfill with sufficient permitted capacity to
✓
A. J
accommodate the project's solid waste disposal needs?
g) Comply with federal, state, and local statutes and
✓
A, J
regulations related to solid waste?
17. MANDATORY FINDINGS OF SIGNIFICANCE. Does the project:
a) Have the potential to degrade the quality of the
✓
A, B,
environment, substantially reduce the habitat of a fish or
C, D,
wildlife species, cause a fish or wildlife population to drop
E. J
16 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
January 2005
TOWN OF LOS ALTOS HILLS
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ENVIRONMENTAL ANALYSIS
1. Aesthetics
The project is located in the Town of Los Altos Hills east of Interstate 280. Deer Creek cuts
through the center of the project site. The major habitats on the site include riparian woodland
along Deer Creek and non-native grassland mixed with oak woodland through the remainder of the
parcel. The majority of the surrounding area is open space with scattered development associated
with the residences and a remnant orchard.
The project would for the most part be located at -grade, with the sewer line either attached to the
bridge or buried in a trench. The upper portion of the access road would be situated on a steep
hillside and may be partially visible from off-site, but would only be 14 feet wide and would be of a
gravel surface to minimize its contrast with the adjacent ground. The detention basin would be of
an earthen material and would be landscaped to minimize its visibility. Allowing these disturbed
areas to remain exposed, however, would result in a potentially significant visual impact. The
landscaping and revegetation requirements of Mitigation Measure 1-1 would reduce the potential
impact to a less than significant level.
Mitigation Measure 1-1: The applicant shall prepare and submit to the Town of Los Altos
Hills a landscape and revegetation plan subject to approval prior to issuance of any grading
permits. The landscape plan shall provide for landscape screening with a mixture of native
shrubs and trees, particularly along the upper road section, around the detention basin, and
in other disturbed areas. The plan shall also indicate the trees to be removed, the number
La Create Sewer and Access Road IS/MND — Draft MHA Inc. 17
January 2005
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below self-sustaining levels, threaten to eliminate a plant or
animal community, reduce the number or restrict the range
of a rare or endangered plant or animal or eliminate
important examples of the major periods of California
history or prehistory?
b) Have the potential to achieve short-term, to the
✓
A, J
disadvantage of long-term environmental goals? (A short-
term impact on the environment is one which occurs in a
relatively brief, definitive period of time while long-term
impacts will endure well into the future).
c) Have impacts that are individually limited, but cumulatively
✓
A, J
considerable? ("Cumulatively considerable" means that the
incremental effects of a project are considerable when
viewed in connection with the effects of the past projects,
the effects of other current projects, and the effects of
probable future projects.)
d) Have environmental effects which will cause substantial
✓
A, J
adverse effects on human beings, either directly or
indirectly?
e) Have the potential to be controversial?
✓
A. J
ENVIRONMENTAL ANALYSIS
1. Aesthetics
The project is located in the Town of Los Altos Hills east of Interstate 280. Deer Creek cuts
through the center of the project site. The major habitats on the site include riparian woodland
along Deer Creek and non-native grassland mixed with oak woodland through the remainder of the
parcel. The majority of the surrounding area is open space with scattered development associated
with the residences and a remnant orchard.
The project would for the most part be located at -grade, with the sewer line either attached to the
bridge or buried in a trench. The upper portion of the access road would be situated on a steep
hillside and may be partially visible from off-site, but would only be 14 feet wide and would be of a
gravel surface to minimize its contrast with the adjacent ground. The detention basin would be of
an earthen material and would be landscaped to minimize its visibility. Allowing these disturbed
areas to remain exposed, however, would result in a potentially significant visual impact. The
landscaping and revegetation requirements of Mitigation Measure 1-1 would reduce the potential
impact to a less than significant level.
Mitigation Measure 1-1: The applicant shall prepare and submit to the Town of Los Altos
Hills a landscape and revegetation plan subject to approval prior to issuance of any grading
permits. The landscape plan shall provide for landscape screening with a mixture of native
shrubs and trees, particularly along the upper road section, around the detention basin, and
in other disturbed areas. The plan shall also indicate the trees to be removed, the number
La Create Sewer and Access Road IS/MND — Draft MHA Inc. 17
January 2005
TOWN OF LOS ALTOS HILLS
and size of replacement trees, replacement tree locations, and irrigation for all vegetation
until it is established.
Mayne Tree Expert Company, Inc. performed a tree assessment on February 17, 2004. Several
trees were identified within or near the proposed project's footprint and recommendations were
made regarding trees that may need to be removed or pruned or would otherwise be left
undisturbed. Project build -out would result in the removal of approximately eight trees. Some of
these trees would be considered significant under the Town of Los Altos Hills Tree Ordinance, as
defined in the Municipal Code. Proposed projects within the Town are generally required to
preserve and protect existing trees. Replacement planting is required along with a multi-year bond
to ensure the planted trees are maintained and cared for. Replanting would be necessary as
dictated by the ordinance. The implementation of Mitigation Measure 1-2 would ensure less than
significant impacts to the trees.
Mitigation Measure 1-2: The applicant must comply with the Town's tree ordinance,
including consulting with Town representatives and following replacement
recommendations. Replacement should be at a ratio of 3:1 (15 -gallon size) and of the same
species as removed trees, unless otherwise by the Planning Director.
2. Agricultural Resources
The general plan designation for the project site in Los Altos Hills is residential, very -low to low
density, and the zoning is Residential -Agricultural (R -A). The area in which the access road and
bridge would be constructed consists of single-family residences and open space. The site
contains remnant orchards with walnut and cherry trees, although the land is no longer used for
agriculture. The project would result in the permanent disturbance of 0.69 acres, a relatively small
portion of land, and would have no impact on agricultural resources in the region.
3. Air Quality
Los Altos Hills' air quality is regulated by the Bay Area Air Quality Management District
(BAAQMD), who enforces BAAQMD, State and Federal standards. There are no major sources of
air pollution in the Town, with the exception of automobiles. Meteorological conditions and mobile
emissions are the primary causes of problems leading to noncompliance with air quality standards.
Project construction would involve grading and trenching using large equipment. Sources of
emissions would include dust and exhaust emissions or particulate matter smaller than 10 microns
in diameter (PM10). PM10 is the pollutant of greatest concern with respect to construction activities.
Levels of PM10 in the Bay Area exceed State standards as of January 2004; the project area is
considered to be in non -attainment for this pollutant. The Bay Area is unclassified (equivalent to
an attainment designation) for the federal PM10 standard. Dust generation could present a short-
term potentially significant impact if mitigation is not implemented. The Bay Area Air Quality
Management District's (BAAQMD) approach to CEQA analyses of construction impacts is to
emphasize implementation of effective and comprehensive control measures rather than detailed
quantification of emissions. The BAAQMD has identified a set of feasible PM10 control measures
for construction activities. These "Basic Measures' should be implemented at all construction sites,
regardless of size. The proposed project would be less than 4 acres; therefore, the incorporation of
the BAAQMD Basic Control Measures into Mitigation Measure 3-1 below would reduce cumulative
impacts for PM10 emissions to less than significant levels during the construction phase of the
project.
Mitigation Measure 3.1: The following basic control measures shall be implemented during
the project construction phase. Measures should also be incorporated into a revised grading
plan that is approved by the Town of Los Altos Hills before issuance of grading permits.
18 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
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TOWN OF LOS ALTOS HILLS
Water all active construction areas at least twice daily.
Cover all trucks hauling soil, sand, and other loose materials or require all trucks to
maintain at least two feet of freeboard
Pave, apply water three times daily, or apply (nontoxic) soil stabilizers on all
unpaved access roads, parking areas, and staging areas at construction sites.
Sweep daily (with water sweepers) all paved access roads, parking areas, and
staging areas at construction sites.
Sweep streets daily (with water sweepers) if visible soil material is carried onto
adjacent public streets.
Emissions associated with the post -construction phase of the project are expected to be minimal.
The proposed maintenance road would only likely be accessed by one maintenance vehicle once
a month and possibly more frequently during the rainy season.
4. Biological Resources
Overview. Live Oak Associates Inc. conducted field surveys within the study area on April 22,
2003. The La Cresta Sewer Access, Los Altos Hills, Biological Resources, Initial Study report was
completed by Live Oak Associates, Inc. on May 23, 2003. This report was peer reviewed by
Thomas Reid and Associates on July 31, 2003.
Habitats. The three biotic habitats identified in the study area include non-native grassland, oak
woodlot (0.49 acres) and riparian woodland (0.10 acres). An additional terrestrial habitat was
identified as developedllandscaped (0.10 acres). Deer Creek is considered "waters of the U.S,"
which likely falls under the jurisdiction of the U.S. Army Corps of Engineers (USACE) and the
California Department of Fish and Game (CDFG). A habitat conservation plan does not exist for
the project area.
The project would involve removal of approximately eight trees, including one riparian willow (refer
to Section 1 regarding Aesthetics). Mitigafion Measure 1-2 would require replacement according to
the Town's tree ordinance and would reduce impacts to trees to less than significant levels. The
savanna and riparian habitat, while it provides value for a number of native wildlife species, is
relatively common in the region. Installation of the bridge would create permanent shade over the
creek approximately 14 feet wide. The area of crossing is currently heavily vegetated and shaded
by riparian shrubs; however, the bridge would only cover an already shaded area. The bridge
should have enough clearance over the creek and riparian corridor such that light can still
penetrate undemeath, limiting impacts to riparian shrubs.
Deer Creek water quality could be affected by project construction and post construction operation.
Water quality could be compromised by sedimentation and construction activities. Implementation
of the following mitigation measures would reduce impacts to less than significant levels.
Mitigation Measure 4-1: The applicant shall develop an erosion control plan that includes
such measures as the placement of silt fences, hay bales, etc. between the areas of work
and the riparian habitat (outside of ACOE jurisdictional line) to ensure that sediments from
grading, digging, and placement of the central bridge pile do not erode into the creek. Water
bars shall be evaluated to prevent sheet flow and erosion off of the unpaved road along the
eastern side of the creek. The applicant shall also develop a SWPPP per State Water
Quality Control Board Stormwater Permit requirements. The required stormwater plan shall
be submitted for review and approval by the Town Engineer prior to issuance of grading or
building permits for the project.
Mitigation Measure 4-2: All disturbed areas shall be revegetated with drought tolerant and
native species to prevent erosion of the slopes and the introduction of sediments into Deer
Creek (also see Mitigation Measure 1-1).
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TOWN OF LOS ALTOS HILLS
Mitigation Measure 4.3: No equipment shall be fueled or maintained within 100 feet of the
creek.
These mitigation measures are also intended to address water quality impacts discussed in the
Hydrology section (Section 8) of this Initial Study.
Special Status Species and Raptors. The majority of plants and wildlife that occur on the study
site are common species. Most of the special status plant and animal species that occur on or near
the study area were determined to either be absent or may occur rarely or occasionally on site
(Refer to Table 2 in the Live Oak Associates report). Twenty-seven special -status animal species
occur, or once occurred regionally. Five of these species are absent and six are unlikely to occur in
the project area. Fourteen other species may rarely or occasionally occur on site as foragers.
These include five raptors, four songbirds, three bats, the San Francisco dusky -footed woodrat,
and the ringtail. The remaining species are the California red -legged frog (Rana aurora draytonii)
and the western pond turtle (Clemmys marmorata), which may be found inhabiting the project site.
The California red -legged frog is a federally threatened species found in ponds or pools next to
streams, marshlands and sag ponds, in areas with stands of overhanging vegetation. The frog's
habitat extends several feet around the water's edge. California red -legged frogs traditionally
breed from late November to early March, but in Santa Clare County frogs are found to breed from
January through March (Jennings at al. 1997). California red -legged frogs have been documented
by the CNDDB four times, two of which were downstream of Deer Creek, within a three-mile radius
of the study area. The stretch of Deer Creek that runs along Purissima Road provides suitable
habitat and the species may periodically occur in the creek within the boundaries of the project
site.
The western pond turtle is a CDFG and federal species of concern. Adult western pond turtles
mate in late April to early May and the nesting season is from late April to early August. Females
emigrate from aquatic habitats to unshaded upland locations that may be a considerable distance
from riparian zones, where they build shallow nests. Hatchling turtles emerge from the nests and
move to aquatic habitats in the spring. In stream environments, western pond turtles show
considerable variation with regard to movements and timing of movements onto terrestrial
environments. Water temperatures above 59° Fahrenheit increase turtle activity. These turtles
often move from pool to pool in stream situations and can move several miles if their aquatic
habitat dries up (Jennings at al. 1999b). Western pond turtles inhabit the same habitats as the
California red -legged frog. The closest CNDDB occurrence of this species is over three miles to
the northwest in the Lagunita area south of Stanford; however, the stretch of Deer Creek that runs
through the project provides potentially suitable habitat for this species.
The project should have no effect on the breeding success of any potentially occurring sensitive
species except for the California red -legged frog and the western pond turtle. California red -legged
frogs may be found along the riparian corridor or could migrate through upland areas between
water sources. Western pond turtles may also occur along the stream bank or the upland area.
Both species could be negatively impacted by sedimentation or degradation of water quality
resulting from erosion at the project site. Individuals of the species could also be injured by project
construction in the upland area, although the warm weather during the proposed time of
construction is generally inhospitable and undesirable for frogs to spend much time away from
water. Turtles and turtle nests could be found in the upland, unshaded areas.
The following mitigation measures would reduce potentially significant impacts to California red -
legged frogs and western pond turtles to less than significant levels.
Mitigation Measure 4.4: Biologists shall conduct an education training session for all
construction personnel prior to beginning grading or construction on the site. The program
shall consist of a brief presentation explaining endangered species concerns, to include 1) a
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TOWN OF LOS ALTOS HILLS
description of each of the sensitive species and their habitat needs, and 2) an explanation of
the status of the species during project construction and implementation. A fact sheet
conveying this information would be prepared for distribution to the above-mentioned
personnel and anyone else who may enter the construction area.
Mitigation Measure 4.5: Construction shall be scheduled to avoid the rainy season when
California red -legged frogs are most likely to be moving between different bodies of water.
Construction shall be performed between April 15"' and October 15". If necessary, the
applicant shall seek approval from the CDFG, RWQCB and the USFWS to work outside this
time period.
Mitigation Measure 4.8: Pre -construction surveys shall be performed within 48 hours of
initial construction activities within a 50 -foot radius of the point of creek crossing for
California red -legged frog. If any individuals or active nests are identified in this area, work
shall not commence unfil the USFWS is contacted and appropriate protection measures are
determined. These measures could include delaying construction until individuals have
moved out of the project area. Pre -construction surveys shall also be performed for western
pond turtles. If any individuals of that species are identified within the construction zone,
they shall be relocated to a safe location by a qualified biologist before work can commence.
Mitigation Measure 4-7: A qualified biological monitor shall be present during all work to
ensure that there are no California red -legged frogs or western pond turtles that could be
affected by construction activities. If any red -legged frog individuals are identified, work shall
not commence until the USFWS is contacted and appropriate protection measures are
determined. These measures could include delaying construction until individuals have
moved out of the project area. If any western pond turtles are identified in the construction
area by the monitor, they shall be relocated to a safe location by a qualified biologist before
work can commence.
Five raptor species also have the potential to occur on the project site. Large trees such as coast
live oaks, California bay laurels, and redwoods provide nesting habitat for raptors. Construction
activities could result in the abandonment of active nests or direct mortality to these birds. Federal
and state laws protect raptors. Construction activities that adversely affect nesting, or result in
mortality of individual birds, would be a violation of state and federal law, and would be considered
a significant adverse impact per the CEQA Guidelines. Implementation of the following mitigation
measure would reduce impacts to less than significant levels.
Mitigation Measure 4-8: A qualified ornithologist shall conduct a pre -construction survey for
nesting raptors on site within 30 days of the onset of ground disturbance, if ground
disturbance is to occur during the breeding season (between February 15'and August 31").
These surveys shall be based on the accepted protocols for the target species. If any
nesting raptor is detected, an appropriate construction buffer shall be established. Actual
size of the buffer would depend on species, topography, and type of construction activity
that would occur in the vicinity of the nest and should be determined by the ornithologist.
None of the trees slated for removal shall be removed or trimmed if there is an active nest in
the tree. Removal shall only commence after the young have fledged as determined by a
qualified ornithologist.
5. Cultural Resources
The project is located in an area where there are no known historical resources, archaeological
resources, paleontological resources, unique geologic features, or human remains.
Under the rare circumstance of encountering a previously undiscovered resource during
excavation for installation of the sewer line and access road, implementation of the following
mitigation measure would reduce the any potential impact to a less than significant level.
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TOWN OF LOS ALTOS HILLS
Mitigation Measure 5-1: If any cultural or paleontological resources or human remains are
discovered during construction activities, work shall be hatted within 50 feet of the discovery
until a qualified specialist is retained to inspect the discovery. If it is determined that an intact
cultural resource would be further damaged by construction activities, it shall be the
responsibility of the project sponsor to submit a plan for the evaluation and mitigation of any
such resource to the relevant lead agency and receive approval of that plan before
construction can resume in the area of the resource. If the cultural resources contain human
remains, the San Mateo County Coroner shall be notified. If the coroner determines the
remains to be Native American, the coroner shall contact the Native American Heritage
Commission within 24 hours. Native American monitors shall be allowed to observe
conditions following any such discovery. Disposition of Native American human remains
shall comply with CEQA Guidelines Section 15064.5(e).
6. Geology and Soils
Bay Area Geotechnical Group (BAGG) conducted a Geotechnical Engineering Investigation that
was completed May 7, 2003. The site is underlain by alluvial fan and fluvial deposits of the
Pleistocene Age along the streambed, with the remaining portions of the site mapped as underlain
by the Santa Clara Formation of the lower Pleistocene and upper Pliocene Age.
Soils. The project is constrained by expansive soil conditions and slopes that increase erosion
potential. Erosion impacts would be minimized by the implementation of Mitigation Measures 4-1
and 4-2 from Section 4 (Biology). The following mitigation measure should also be incorporated to
reduce impacts related to soil instability to less than significant levels.
Mitigation Measure 6-1: The recommendations in the BAGG report for excavation and re,
compaction of soils beneath the proposed roadway to a depth of at least 2 feet, and keying
and benching of new fill into firm soil and/or bedrock shall be followed. A final grading plan
shall be submitted to the Town for review and approval by the Town Geologist and the Town
Engineer prior to issuance of grading or construction permits.
Seismicity. Several faults are located within the project region. The expected level of ground
shaking at the site from a seismic event on these faults is strong to very strong, but ground surface
rupture potential from these faults is considered low. The creek corridor may be susceptible to
liquefaction.
The project is located 470 meters from the closest fault. It is highly likely that the site will be
subject to very strong seismic ground shaking during the next major earthquake on a regional fault.
This ground shaking could cause damage to the asphalt of the access road, the sewer pipeline,
and to the bridge crossing. Implementation of the following mitigation measure would reduce
impacts to less than significant levels.
Mitigation Measure 6-2: Compliance with the Uniform Building Code, California Building
Code and other codes that govern bridge, road and utilities design shall be implemented in
design plans and reviewed and approved of by the Town Engineer prior to issuance of any
building permit.
According to the Bay Area Geotechnical Group's Geotechnical Engineering Investigation (2003),
the site's loose to medium dense sandy soils may liquefy during a large earthquake. Alluvial and
fluvial soils are located in the vicinity of the creek area and are considered to be highly lenticular
and discontinuous. It was determined that due to the limited extent of liquefiable soils and the
relatively stiff consistency of the soils overlying them, the observable effects of subsurface
liquefaction at the site will be slight to moderate and would be a less than significant impact.
Slope Stability. The site is generally characterized as moderately steep to precipitous (15-100
percent inclinations). The slopes of the site are considered to be generally stable under static and
22 MHA Inc. La Cresta Sewer and Access Road IS/MND — Drat
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TOWN OF LOS ALTOS HILLS
seismic conditions. The east banks of the creek have steep slopes that are generally stable;
however, a recent visit to the project site by engineers from Cotton, Shires and Associates noted
several small areas of shallow instability along the west -facing slope near the ridgeline in the
eastern part of the project site. The placement and location of the detention basin may have
negative slope stability impacts. Implementation of the following mitigation measures would reduce
impacts associated with slope stability.
Mitigation Measure 63: The applicant shall have a qualified geotechnical engineer
evaluate whether cut slopes proposed for the roadway may destabilize adjacent slopes
mantled with colluvium and recommend any appropriate mitigation measures to be included
in revised design plans. The report and revised plans shall be resubmitted to the Town of
Los Altos Hills for review and approval by the Town Geologist before a grading permit is
issued.
Mitigation Measure 6-4: The potential for the proposed detention basin to result in negative
slope stability impacts shall be evaluated. The feasibility of the proposed detention basin
shall be addressed by a qualified geotechnical engineer and recommendations made to
ensure stability, including provision of an outlet structure and liner, if appropriate. Project
design plans shall be revised to reflect any recommendations and evaluations made by the
geotechnical engineer and shall be resubmitted to the Town of Los Altos Hills for review and
approval by the Town Geologist before a grading permit is issued.
7. Hazards and Hazardous Materials
There are no known hazards or hazardous materials recorded in the Town of Los Altos Hills. The
site is not listed as a hazardous materials site or located in the vicinity of any airport land. The
project has the potential to cause water or ground contamination from the routine use of lubricants,
oils, diesel and other fuels used in construction equipment. Implementation of Mitigation Measure
4-3 in section 4 (Biology) and the following mitigation measure would reduce potential impacts
from hazardous materials to a less than significant level.
Mitigation Measure 7-1: The applicant shall submit a spill response plan to the Town of Los
Altos Hills prior to the onset of construction to ensure a prompt and effective response to
any accidental spills or leaks of diesel, gasoline, oil or other contaminating materials that
might flow or migrate to the creek.
The issue of wildland fire is a concern in Los Altos Hills due to steep terrain with dense but dry
vegetation. The project has the potential to spark wildland fires if precautionary measures are not
taken during construction. Some of the upper hillside to the east of the creek includes non-native
grassland among the oak woodlot that could pose a fire hazard during the dry summer months,
when construction would likely occur. Implementation of the following mitigation measures would
reduce impacts to less than significant levels.
Mitigation Measure 7-2: Construction vehicles shall be equipped with appropriate fire
combatant equipment at all times.
Mitigation Measure 73: Smoking shall not be allowed outside of designated areas, which would
include anywhere with dry grass underfoot.
8. Hydrology and Water Quality
Site Drainage. Deer Creek is a perennial creek that initiates at a spring in the foothills of the Santa
Cruz Mountains, south of Interstate 280. The creek continues flowing north, with a small stretch
within the project boundaries, and adjoins with Matadero Creek. Matadero Creek then becomes
channelized, now labeled as Matadero Canal, before emptying into the San Francisco Bay.
Drainage is characterized as partially controlled sheet flow to the northwest, which is intercepted
by a southwest -trending swale, and by sheet flow to the southwest intercepted by the channel of
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TOWN OF LOS ALTOS HILLS
Deer Creek. An existing storm drain is located a few hundred feet to the north of the proposed
project alignment, near the tennis courts.
The drainage pattern of the property would generally not be impacted by construction of the
asphalt access road, the bridge, the gravel access road or placement of the sewer line. The
increase in impervious surface would slightly increase surface sheet flow into Deer Creek. Deer
Creek could be affected by increased sedimentation resulting from sheet flow off of the gravel road
to the east of the creek. Implementation of Mitigation Measure 4-1 from Section 4 (Biology) would
reduce potential sedimentation impacts resulting from sheet flow down the steep gravel road.
Sedimentation impacts during construction would be mitigated to less than significant levels with
the implementation of Mitigation Measures 4-1 and 4-2.
The proposed plan shows outlet structures within the proposed sediment detention basin with
outfalls through dissipaters leading to over bank drainage into Deer Creek. The proposed drainage
system could cause sedimentation and water quality impacts in the creek, though the sediment
basin is proposed to minimize those impacts. The Santa Clara Valley Water District commented on
the proposed project and recommended using existing on-site storm drain systems to reduce
potential impacts to the creek and creek bank. The mitigation measure below would require
implementation of the District's recommendation.
Mitigation Measure 8-1: The project applicant shall revise the current drainage system and
coordinate with the Town Engineer to connect runoff outlets from the project into the existing
storm drainage system instead of allowing over bank drainage into Deer Creek.
Flooding. The 100 -year flood zone is identified on the project plans and extends up the bank of
Deer Creek. None of the project structures or the road would fall below the 100 -year floodplain
mark. There would be no impacts associated with the project that could create hazards resulting
from flooding, seiche, tsunami, or mudflow.
9. Land Use and Planning
The general plan designation for the project site in Los Altos Hills is residential, very -low to low
density and the zoning is Residential -Agricultural (R -A). The area in which the access road and
bridge would be constructed consists of single-family residences and open space. The project site
is located in an area of large single-family estates. The majority of the area is open space with
scattered development associated with the residences (houses, tennis courts, pools, schools,
parks, etc.) and a remnant orchard.
The proposed project would not divide an established community or have an impact on any
applicable conservation plans. The project would not conflict with any land use plans as related to
the RWQCB, the CDFG, the BAAQMD, or the Town of Los Altos Hills.
10. Mineral Resources
Mineral resources found in Santa Clara County include deposits such as sand, gravel, and stone.
There are no known or potential mineral resources in the project area. The area is zoned as a
residential area and development of a sewer line, access road and bridge on this parcel would
have a less than significant impact on mineral resources in the region.
11. Noise
The majority of Los Altos Hills consists of single-family residences. The only major source of noise
in the area is traffic and aircraft noise. Sensitive noise receptors would include the surrounding
residences and recreationalists in the area. The Town of Los Altos Hills does have a noise
ordinance that limits grading operations to the hours between 8:00 am and 5:30 pm, Monday
24 MHA Inc. La Cresta Sewer and Access Road IS/MND — Draft
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TOWN OF LOS ALTOS HILLS
through Friday, unless an emergency is determined. Work cannot be performed on weekends or
public holidays.
Anticipated construction noises are considered temporary in nature and can be mitigated by
standard project operations. Construction activities will be required to comply with the noise
ordinance as indicated in the following mitigation measure.
Mitigation Measure 11-1: The project shall comply with Town regulations governing hours
of construction.
12. Population and Housing
Los Altos Hills is a community of homes with a suburban to rural density, located in the rolling hills
of the San Francisco Peninsula. Several large, single-family homes are located in proximity to the
proposed project. The Town's population is about 8,000 persons with a predicted growth rate of
about 0.12 percent annually (ABAG Projections 2002).
The purpose of the project is to provide a maintenance access road to a parallel sewer pipeline
and to provide a tie in location to a new gravity feed sewer line for houses currently depending on
septic tank and leach field systems. The project would not displace any existing housing. The
project may induce limited growth due to existing constraints of leach field sewage, for the 23
homes to be served. Growth would occur within the bounds of the existing zoning for the vicinity
and would not have a negative impact on population and housing based on the Town's predicted
growth rate. The bridge and road are meant only for sewer access and would not provide access
to residences. There would be no impacts to population and housing from this project.
13. Public Services
The project only involves installation of a service road, sewer line, and bridge that would not be
used by the general public. Construction and operation of the project would not result in any
impacts to existing public services. The project is not located in the immediate vicinity of any
schools or parks.
14. Recreation
A pathway for pedestrians, bicyclists and equestrians traverses along Purissima Road at the
entrance to the proposed project and a pathway is proposed on the opposite side of Purissima
Road. A private tennis and basketball court is located within a few hundred feet to the north of the
proposed bridge and access road. The private property owner also maintains a small equestrian
corral with one horse currently in the location where the gravel road and detention basin are
proposed.
The proposed asphalt road would continue off of an existing gated driveway through a private
parcel of land. Construction would not affect the existing pathway along Purissima Road. The
privately owned tennis and basketball court would not be affected by the proposed project;
however, the equestrian corral and horse are currently within the proposed construction area. The
applicant would have to coordinate with the property owner to assure that the horse is secured
during construction.
15. Traffic and Transportation
Access to the proposed project would be provided from a gated private driveway at Purissima
Street at Elena Road. According to the Circulation Element of the Los Altos Hills General Plan,
Purissima Street is a Neighborhood Connector Street as is Elena Road. Neighborhood Connector
Roads would be expected to carry volumes on the order of 1,000 to 5,000 average daily trips.
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TOWN OF LOS ALTOS HILLS
The proposed project includes construction of a new single lane access road and bridge that would
be used to access an existing sewer line and the proposed sewer line. The road would likely be
used once a month and perhaps more frequently during the winter months. The project would not
increase traffic on Purissima or Elena Road in any significant manner due to its limited use.
The proposed bridge and connecting gravel road to the east of the bridge are very steep. This may
present a hazard to access vehicles, especially if these vehicles are large or do not have four-
wheel drive. The applicant is expected to coordinate with the Town Engineer and maintenance
personnel to assure continued maintenance of the road and that appropriate vehicles are used to
ensure safety.
16. Utilities and Service Systems
The project would not have an impact on utility and service systems. Sewage and wastewater
collection is provided by the Town through the City of Palo Alto's system. The proposed sewer line
would improve service to the residences located uphill to the east of Deer Creek. These houses
are currently on septic systems, some of which have been documented as failing or in poor repair
(Chavez 2004).
17. Mandatory Findings of Significance
The project includes a bridge that spans Deer Creek, which is a riparian habitat that could support
some sensitive biological species. Water quality would have to be protected and measures taken
to prevent harm to any sensitive species. Water quality and species protection measures are
outlined in Section 4 (Biology) and Section 8 (Hydrology). Mitigation measures include applying
erosion controls, revegetating disturbed areas, replanting trees at approved ratios, and surveying
for listed species and halting work if any are found in the work area.
The project would not have cumulative impacts with any existing or reasonably foreseeable future
projects and does not have any environmental effects that could cause substantial adverse
impacts to human beings.
INFORMATION SOURCES
The following information sources were used in the preparation of this document and referenced
throughout the Initial Study Checklist:
A) Field Inspection, MHA, September 23 and October 7, 2004
B) The Town of Los Altos Hills General Plan, 2003, and Zoning Ordinance, Ordinance No. 332.
C) Mayne Tree Expert Company, February 21, 2004 letter to Bruce Askari
D) Bay Area Air Quality Management District, 2000 Clean Air Plan
E) Live Oak Associates, June 30, 2004, La Cresta Sewer Access Biological Resources Initial Study
F) Thomas Reid and Associates, July 31, 2004, letter to Angelica Herrera
G) Bay Area Geotechnical Group, March 7, 2003, Geotechnical Engineering Investigation
H) Bay Area Geotechnical Group, May 19, 2004, Addendum to the Geotechnical Engineering
Investigation
1) Cotton, Shires and Associates, Inc., July 27, 2004, Letter to Angelica Herrera
J) Project Plans, dated August 20, 2004
K) Santa Clara Valley Water District, July 2, 2004, Letter to Angelica Herrera
L) Association of Bay Area Governments, Projections 2002
M) Chavez, Nabor, letter to Bruce Askari, dated June 25, 2004
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TOWN OF LOS ALTOS HILLS
LIST OF PREPARERS
Preparers
Curtis Wlliams, Senior Associate, Project Manager
Tania Treis, Environmental Scientist
MHA Environmental Consulting, Inc.
4 W Fourth Avenue, Suite 303
San Mateo, CA 94402
Los Altos Hills Staff
Carl Cahill, Planning Director
Dave Ross, Town Engineer
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TOWN OF LOS ALTOS HILLS
LA CRESTA SEWER AND ACCESS ROAD
Mitigation, Monitoring and Reporting Program
MITIGATION MEASURE
TIMING
RESPONSIBLE
COMPLIANCE
PARTY
DATE
Mitigation Measure 1-1: The applicant shall prepare
Approval of plan
Review of
and submit to the Town of Los Altos Hills a landscape
prior to
plans by the
and revegetation plan subject to approval prior to
issuance of
Planning
issuance of any grading permits. The landscape plan
grading permit
Department
shall provide for landscape screening with a mixture of
native shrubs and trees, particularly along the upper
road section, around the detention basin, and in other
disturbed areas. The plan shall also indicate the trees to
be removed, the number and size of replacement trees,
replacement tree locations, and irrigation for all
vegetation until it is established.
Mitigation Measure 1-2: The applicant must comply
Approval of
Review of
with the Town's tree ordinance, including consulting with
replacement
plans by the
Town representatives and following replacement
plan prior to
Planning
recommendations. Replacement should be at a ratio of
issuance of
Department
3:1 (15 -gallon size) and of the same species as removed
grading permit;
trees, unless otherwise approved by the Planning
planting during
Director.
construction
Mitigation Measure 3-1: The following basic control
Provide notes
Review of
measures shall be implemented during the project
on revised
plans by the
construction phase. Measures should also be
grading plan
Planning and
incorporated into a revised grading plan that is approved
prior to
Engineering
by the Town of Los Altos Hills prior to issuance of
issuance of the
Departments;
grading permits.
grading permit;
construction
• Water all active construction areas at
implement
inspection by
least twice daily.
measures
the Building
during
and
• Cover all trucks haulingsoil, sand, and
construction
Engineering
other loose materials or require all
Departments
trucks to maintain at least two feet of
freeboard.
• Pave, apply water three times daily, or
apply (nontoxic) soil stabilizers on all
unpaved access roads, parking areas,
and staging areas at construction sites.
• Sweep daily (with water sweepers) all
paved access roads, parking areas, and
staging areas at construction sites.
• Sweep streets daily (with water
sweepers) if visible soil material
is carried onto adjacent public
streets.
Mitigation Measure 41: The applicant shall develop anPlan
approval
Review and
erosion control plan that includes such measures as the
prior to
approval by
placement of silt fences, hay bales, etc, between the
issuance of
the
areas of work and the riparian habitat outside of ACOE
En ineerin
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jurisdictional line) to ensure that sediments from grading,
grading permits
Department
digging, and placement of the central bridge pile do not
erode into the creek. Water bars shall be evaluated to
prevent sheet flow and erosion off of the unpaved road
along the eastern side of the creek. The applicant shall
also develop a SWPPP per State Water Quality Control
Board Stormwater Permit requirements. The required
stormwater plan shall be submitted for review and
approval by the Town Engineer prior to issuance of
grading or building permits for the project.
Mitigation Measure 4-2: All disturbed areas shall be
Prior to final
Inspection and
revegetated with drought tolerant and native species to
approval
approval by
prevent erosion of the slopes and the introduction of
the Planning
sediments into Deer Creek (also see Mitigation Measure
and
1-1).
Engineering
Departments
Mitigation Measure 43: No equipment shall be fueled
During
Ongoing
or maintained within 100 feet of the creek.
construction
inspections by
and reclamation
the Building
and
Engineering
Departments
Mitigation Measure 4-4: Biologists shall conduct an
Prior to
Planning
education training session for all construction personnel
construction
Department
prior to beginning grading or construction on the site.
The program shall consist of a brief presentation
explaining endangered species concerns, to include 1) a
description of each of the sensitive species and their
habitat needs, and 2) an explanation of the status of the
species during project construction and implementation.
A fact sheet conveying this information shall be prepared
for distribution to the above-mentioned personnel and
anyone else who may enter the construction area.
Mitigation Measure 45: Construction shall be
Construction
Approval of
scheduled to avoid the rainy season when California red-
timeframe
construction
legged frogs are most likely to be moving between
should be
timing by the
different bodies of water. Construction shall be
planned prior to
Planning
performed between April 1e and October 1e. If
issuance of
Department
necessary, the applicant shall seek approval from the
grading permit
CDFG, RWQCB and the IJSFWS to work outside this
time period.
Mitigation Measure 45: Pre -construction surveys shall
Surveys should
Approval of
be performed within 48 hours of initial construction
be performed
survey findings
activities within a 50 -foot radius of the point of creek
within 48 hours
by Planning
crossing for California red -legged frog. If any individuals
of construction:
Department
or active nests are identified in this area, work shall not
submit results
commence until the USFWS is contacted and
to the Planning
appropriate protection measures are determined. These
Department
measures could include delaying construction until
prior to
individuals have moved out of the project area. Pre-
issuance of
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Y GIVAi!G7at[ib7t1gribs;IIflIN
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construction surveys shall also be performed for western
grading permit.
pond turtles. If any individuals of that species are
identified within the construction zone, they shall be
relocated to a safe location by a qualified biologist before
work can commence.
Mitigation Measure 4-7: A qualified biological monitor
During
Applicant with
shall be present during all work to ensure that there are
construction
oversight by
no California red -legged frogs or western pond turtles
the Planning
that could be affected by construction activities. If any
Department
red -legged frog individuals are identified, work shall not
commence until the USFWS is contacted and
appropriate protection measures are determined. These
measures could include delaying construction until
individuals have moved out of the project area. If any
western pond turtles are identified in the construction
area by the monitor, they shall be relocated to a safe
location by a qualified biologist before work can
commence.
Mitigation Measure 4-8: A qualified ornithologist shall
Surveys should
Applicant with
conduct a pre -construction survey for nesting raptors on
be performed
oversight by
site within 30 days of the onset of ground disturbance, if
within 48 hours
the Planning
ground disturbance is to occur during the breeding
of construction
Department
season (between February 1" and August 31"). These
surveys shall be based on the accepted protocols for the
target species. If any nesting raptor is detected, an
appropriate construction buffer shall be established.
Actual size of the buffer would depend on species,
topography, and type of construction activity that would
occur in the vicinity of the nest and should be
determined by the ornithologist. None of the trees slated
for removal shall be removed or trimmed if there is an
active nest in the tree. Removal shall only commence
after the young have fledged as determined by a
qualified ornithologist.
Mitigation Measure 5-1: If any cultural or
During
Applicant with
paleontological resources or human remains are
construction
oversight by
discovered during construction activities, work shall be
the Planning
halted within 50 feet of the discovery until a qualified
Department
specialist is retained to inspect the discovery. If it is
determined that an intact cultural resource would be
further damaged by construction activities, it shall be the
responsibility of the applicant to submit a plan for the
evaluation and mitigation of any such resource to the
relevant lead agency and receive approval of that plan
before construction can resume in the area of the
resource. If the cultural resources contain human
remains, the San Mateo County Coroner shall be
notified. If the coroner determines the remains to be
Native American, the coroner shall contact the Native
American Heritage Commission within 24 hours. Native
American monitors shall be allowed to observe
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conditions following any such discovery. Disposition of
Native American human remains shall comply with
CEQA Guidelines Section 15064.5(e).
Mitigation Measure 6.1: The recommendations in the
The final
Review and
BAGG report for excavation and re -compaction of soils
grading plan
approval by
beneath the proposed roadway to a depth of at least 2
should be
the
feet, and keying and benching of new fill into firm soil
submitted prior
Engineering
and/or bedrock shall be followed. A final grading plan
to issuance of
and Building
shall be submitted to the Town for review and approval
grading permits,
Departments
by the Town Geologist and the Town Engineer prior to
reflecting the
issuance of grading or construction permits.
report
recommenda-
tions
Mitigation Measure 6.2: Compliance with the Uniform
Prior to
Review and
Building Code, California Building Code and other codes
issuance of
approval by
that govern bridge, road and utility design shall be
building permit
the Building
implemented in design plans and reviewed and
and
approved of by the Town Engineer prior to issuance of
Engineering
any building permit.
Departments
Mitigation Measure 6-3: The applicant shall have a
Report
Review and
qualified geotechnical engineer evaluate whether cut
submittal and
approval by
slopes proposed for the roadway may destabilize
approval prior to
the Town
adjacent slopes mantled with colluvium and recommend
issuance of a
Geologist and
any appropriate mitigation measures to be included in
grading permit
Engineering
revised design plans. The report and revised plans shall
Department
be resubmitted to the Town of Los Altos Hills for review
and approval by the Town Geologist prior to issuance of
a grading permit.
Mitigation Measure 6.4: The potential for the proposed
Revised plan
Review and
detention basin to result in negative slope stability
submittal and
approval by
impacts shall be evaluated. The feasibility of the
approval prior to
the Town
proposed detention basin shall be addressed by a
issuance of a
Geologist and
qualified geotechnical engineer and recommendations
grading permit
Engineering
made to ensure stability, including provision of an outlet
Department
structure and liner, if appropriate. Project design plans
shall be revised to reflect any recommendations and
evaluations made by the geotechnical engineer and shall
be resubmitted to the Town of Los Altos Hills for review
and approval by the Town Geologist prior to issuance of
a grading permit.
Mitigation Measure 7-1: The applicant shall submit a
Plan submittal
Review and
spill response plan to the Town of Los Altos Hills prior to
and approval
approval by
the onset of construction to ensure a prompt and
prior to
the Planning
effective response to any accidental spills or leaks of
issuance of a
and
diesel, gasoline, oil or other contaminating materials that
grading permit
Engineering
might flow or migrate to the creek.
Departments
Mitigation Measure 7-2: Construction vehicles shall be
During
Applicant with
equipped with appropriate fire combatant equipment at
construction
oversight by
all times.
the Building
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01111 "o-11.1111111-1
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Department
Mitigation Measure 7-3: Smoking shall not be allowed
During
Applicant with
outside of designated areas, which would include
construction
oversight by
anywhere with dry grass underfoot.
the Building
Department
Mitigation Measure 8-1: The project applicant shall
Drainage plan
Review and
revise the current drainage system and coordinate with
submittal and
approval by
the Town Engineer to connect runoff outlets from the
approval prior to
the
project into the existing storm drainage system instead
issuance of
Engineering
of allowing over bank drainage into Deer Creek.
grading permits
Department
Mitigation Measure 11-1: The project shall comply with
During
Applicant with
Town regulations governing hours of construction.
construction
oversight by
the Building
Department
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