HomeMy WebLinkAboutStaff Report 2401-2556CITY OF PALO ALTO
CITY COUNCIL
Special Meeting
Monday, February 05, 2024
Council Chambers & Hybrid
5:30 PM
Agenda Item
11.SECOND READING: Adoption of an Ordinance Authorizing the Improvements to the Palo
Alto Baylands as Part of the Horizontal Levee Pilot Project and Approval of a Cooperative
Agreement with the Association of Bay Area Governments to Construct the Horizontal
Levee Pilot Project (WQ‐22001); CEQA – exempt under Section 15133 (FIRST READING:
January 22, 2024 PASSED 7‐0)
City Council
Staff Report
Report Type: CONSENT CALENDAR
Lead Department: City Clerk
Meeting Date: February 5, 2024
Report #:2401-2556
TITLE
SECOND READING: Adoption of an Ordinance Authorizing the Improvements to the Palo Alto
Baylands as Part of the Horizontal Levee Pilot Project and Approval of a Cooperative Agreement
with the Association of Bay Area Governments to Construct the Horizontal Levee Pilot Project
(WQ‐22001); CEQA – exempt under Section 15133 (FIRST READING: January 22, 2024 PASSED 7-
0)
BACKGROUND
This was heard by the City Council on January 22, 2024 for a first reading and was approved 7-0.
No changes were made to the ordinance; it is now before you for a second reading.
ATTACHMENTS
Attachment A: Park Improvement Ordinance for Horizontal Levee Pilot Project Improvements
APPROVED BY:
Mahealani Ah Yun, City Clerk
*NOT YET APPROVED*
ORDINANCE NO. _____
Ordinance of The Council of The City of Palo Alto Approving a Plan for
Improvements to the Palo Alto Baylands as part of the Horizontal Levee
Pilot Project
The Council of the City of Palo Alto does ORDAIN as follows:
SECTION 1. Findings. The City Council finds and declares that:
Article VIII of the Charter of the City of Palo Alto and Section 22.08.005 of the Palo Alto(a)
Municipal Code (PAMC) require that, before any substantial building, construction,
reconstruction or development is commenced or approved, upon or with respect to any land
held by the City for park purposes, the Council shall first cause to be prepared and by ordinance
approve and adopt a plan therefor.
(b)The Horizontal Levee Pilot Project (Project) is part of the Marsh Front Trail (Trail). The
Project site is located in the City’s Baylands, which is dedicated parkland (See PAMC § 22.08.020
et seq.) Based on the current habitat quality of the Project site, the location has been identified
as in need of enhancements to better provide refugia for many species including the endangered
Salt Marsh Harvest Mouse.
(c)The City of Palo Alto intends to authorize the construction of a horizontal levee pilot
system that will enhance habitat, maintain public access, provide educational opportunities,
provide regionally-beneficial information on nature-based sea level rise adaptation options, and
beneficially reuse treated wastewater.
(d)The Plan of improvements shall comprise, as follows:
(1) The Project will construct a horizontal levee along Harbor Marsh and install along
Embarcadero and Harbor Roads an underground treated wastewater pipeline for
irrigation of the horizontal levee. The horizontal levee will be planted with various native
plants to restore diverse transitional habitats including freshwater marsh, wet meadow,
and riparian scrub. The Project will re-align a portion of the Trail as required to
accommodate the horizontal levee and reconnect habitats. The Project will install
educational signage and provide opportunities for public participation in community
science activities such as photo-point monitoring of habitat restoration and water quality
testing.
(2)The Project will require temporary rerouting of a portion of the Marsh Front Trail
and temporary traffic restrictions to a portion of Harbor Road to accommodate
construction.
1
0004_20240124_ca29
*NOT YET APPROVED*
(e)The Project described above and as otherwise depicted in the attached exhibit is
consistent with recreation and conservation purposes
(f)The Council desires to approve the Plans for the Project described above and as depicted
in Exhibit "A".
SECTION 2. The Council hereby approves the Plan for construction of the Horizontal
Levee Pilot Project as described in this Ordinance.
SECTION 3. City of Palo Alto is the Lead Agency for the Project under the California
Environmental Quality Act (CEQA) and finds that the Project is categorically exempt under CEQA
Section 15333, Class 33 for small habitat restoration projects.
SECTION 4. This ordinance shall be effective on the thirty-first day after the date of its
adoption.
INTRODUCED:
PASSED:
AYES:
NOES:
ABSENT:
ABSTENTIONS:
ATTEST:
____________________________
City Clerk
____________________________
Mayor
APPROVED AS TO FORM:APPROVED:
____________________________
Chief Assistant City Attorney
____________________________
City Manager
____________________________
Director of Community Services
2
0004_20240124_ca29
EXHIBIT A
Palo Alto
Airport
Harbor
MarshPalo Alto
RWQCP
Byxbee
Park
Project Boundary
0 650 1,300
Feet
Palo Alto Horizontal Levee Pilot Project. D201801306
Figure 1SOURCE: USGS 7.5' Topographic Quadrangle (Mountain View, CA); ESA 2022
Project Location
EXHIBIT A
Palo Alto
Airport
Install pump in effluent
junction box and connect
to new effluent line
H a r b o r
M a r s h
Palo Alto
RWQCP
0 100 200
Byxbee ParkFeet
Project Boundary
Project Component
Horizontal Levee Area
Access
Effluent Line in
Roadway
Equipment Staging Area
Contractor Parking Area
Palo Alto Horizontal Levee Pilot Project. D201801306
Figure 2SOURCE: ESRI 2021; ESA 2022
Project Components
EXHIBIT A
Harbor Marsh
Palo Alto RWQCP
Legend
Project Boundary
Major Contour 2'
Minor Contour 0.5'
Existing Overhead Power Lines
Demo Abandoned W4 Line
Demo 18-Inch Storm Drain
Preserve 18-Inch Storm Drain
Existing Renzel Marsh Intake
Structure
k
Riparian Bufferkkùù ù Riparian Scrub (Transition)Remove Existing Trail
Preserve 18-Inch Renzel Marsh
Pipeline Seasonal Wet MeadowBrackish Marsh (Clear & Grub,
No Grading)
Subsurface Treatment ZoneNew 18-Inch Culvert Freshwater Marsh
Upland (Levee and Staging Area
Seeding)New 4-Inch Effluent Line
New Distribution Lateral
New Distribution Trench
Freshwater Swale
Relocated Marsh Front Trail
Perennial Wet Meadow, , ,à 0 30 60ààFeet
Palo Alto Horizontal Levee Pilot Project. D201801306
Figure 3SOURCE: ESRI 2021; ESA 2022
Draft Horizontal Levee Plan
EXHIBIT A
25
20
15
10
5
25
20
15
10
5
HARBOR ROAD HABITAT SLOPE ~68' TO 93'
30'12'
BERMSWALE TREATMENT AREA
8'3' THICK
DISTRIBUTION
TRENCH
SEE FIGURE 5
HORIZONTAL LEVEE
DESIGN GRADE, TYPTRAIL
EL
12'EXISTING GRADE, TYP
APPROX. (E) EDGE
OF MARSH @ EL 8'3
1
2' THICK
151 EL 10'
30EL 13'1 1 EL EL1129'8'MATCH GRADE
EL 7'±1 1 1
2 1 ~15 1 ~10COARSE MATERIAL (NOTE 4)
SAND FILTER (NOTE 3)
OVER EXCAVATE
& PLACE 1' LAYER
OF COARSEBERM KEYWAY
EFFLUENT LINE (N) FENCE, TYP 1' THICK SUBSURFACE NATIVE MATERIAL
TREATMENT LAYER, TYP (NOTE 2)
0 00+00 0+50 1+00 1+50 2+00 2+26
STATION
TYPICAL SECTION - RIDGES/HIGH & WIDEA
-PROFILE C L : 1" 10 H
25
20
15
10
5
25
HARBOR ROAD HABITAT SLOPE ~68' TO 93'
30'12'SWALE TREATMENT AREABERM
8'
TRAIL
20
15
10
5
HORIZONTAL LEVEE
DESIGN GRADE, TYP
APPROX. (E) EDGE
OF MARSH @ EL 8'EL 11.5'
3 TOP OF BANK
(BEYOND)2' THICK
151EL 13'EL
9.5'
EL 9'1 1
1 1 CONFORM TO
(E) TIDAL
CHANNEL
2 15 1EXISTING GRADE, TYP 1 2011 1
FINE MATERIAL (NOTE 4)15
BASE SWALE/
DEPRESSIONBERM KEYWAY SAND FILTER (NOTE 3)
(N) FENCE, TYP
1' THICK SUBSURFACE OVER EXCAVATE & PLACE 1'
EFFLUENT LINE
SEE MECHANICAL PLANS
TREATMENT LAYER, TYP (NOTE 2)LAYER OF FINE NATIVE MATERIAL0 0
-2
0+00
-2
2+110+50 1+00
STATION
1+50 2+00
TYPICAL SECTION - SWALES & DEPRESSIONSB
-PROFILE
NOTES
1. SEGREGATE FINE AND COARSE MATERIAL ENCOUNTERED DURING EXCAVATION OF SITE TO
SUBGRADE. DURING FILL OPERATIONS, PLACE COARSE MATERIAL ON THE RIDGES AND FINE
MATERIALS IN THE SWALES.
4. COARSE AND FINE MATERIAL INCLUDES A BLEND OF NATIVE MATERIAL WITH COMPOSTED WOOD
FINES.
5. FUTURE FLOOD CONTROL LEVEE MAY OR MAY NOT BE CONSTRUCTED, BUT THIS LAYOUT PLANS
FOR ITS POTENTIAL SPACE SHOULD IT BE CONSTRUCTED.2. SUBSURFACE TREATMENT LAYER COMPRISED OF A BLEND OF DRAIN ROCK AND COMPOSTED
WOOD CHIPS.6. ALL ELEVATIONS ARE ON NORTH AMERICAN VERTICAL DATUM 1988 (NAVD88).
3. SAND FILTER COMPRISED OF A BLEND OF SAND AND WOOD CHIPS.
Palo Alto Horizontal Levee Pilot Project . D201801306
Figure 4
Draft
EXHIBIT A
NEW TRAIL
~4.5' (VARIES)~0.5' SOIL CAP
QUICK4 EQUALIZER 24 LOW
PROFILE INFILTRATOR, OR
APPROVED EQUAL
FILTER FABRIC 1.5'± SOIL WITH
COMPOSTED
WOOD FINES
DISTRIBUTION
LATERAL, TYP
DISTRIBUTION BOX 1.0' TREATMENT LAYER
0.5' SAND AND WOOD CHIPS
FILTER FABRICEFFLUENT SUPPLY LINE
DRAIN ROCK & COMPOSTED WOOD CHIPS
DISTRIBUTION CONNECTION AND TREATMENT ZONE MATERIAL 2 1 0 2 4
1"=2'
SECTION SCALE: 1" = 2'SCALE FEET
Palo Alto Horizontal Levee Pilot Project . D201801306
Figure 5
Draft