DATE:
May 23, 2023
CATEGORY:
Consent
DEPT.:
Public Works
TITLE: Shoreline Park Water Control Structures
Improvements, Project 23-44—Authorize
Professional Services Agreement
RECOMMENDATION
Authorize the City Manager or designee to execute a professional services agreement with AECOM Technical Services, Inc., to provide design engineering and environmental clearance and permitting services for Shoreline Park Water Control Structures Improvements, Project 23-44, in a not-to-exceed amount of $850,000.
BACKGROUND
The Shoreline Park Water Control Structures Improvements project is located in Shoreline at Mountain View (Shoreline Regional Park). Figure 1 show s the location s of the project improvements, which include Charleston Slough Tide Gates, Sailing Lake, and Coast-Casey Pump Station. Figure 2 provides more detail on the location of the project components within the Sailing Lake, which include the Sailing Lake Access Ro ad Boardwalk, Sailing Lake Habitat Island, and Sailing Lake Outlet.
The City owns Charleston Slough, which is located immediately north of Shoreline at Mountain View along the western limit of the City boundary between the Palo Alto Flood Basin to the west and Pond A1 owned by U.S. Fish and Wildlife Services (USFWS) to the east. Charleston Slough is currently a muted tidal marsh and mud flat with tidal connection from San Francisco Bay via a series of tidal gates for flow control. The City has three main management objectives at Charleston Slough: tidal marsh restoration, providing a water supply for the Sailing Lake, and flood management.
When the City acquired Charleston Slough from the Leslie Salt Company in 1980, the City inherited mitigation requi rements from the San Francisco Bay Conservation and Development Commission (BCDC), including the need to restore 53 acres of tidal marsh within the parcel. The mitigation goal involves conversion of the open water environment to tidal marsh through deposition of sediment brought in with the tides. The tide gates and the levees between inner and outer Charleston Slough provide some level of flood protection for Shoreline at Mountain View and minimize tidal flow from overtopping the levee shared with t he Palo Alto Flood Basin.
Shoreline Park Water Control Structures Improvements, Project 23-44— Authorize Professional Services Agreement
May 23, 2023
The Sailing Lake intake pump station, located at the southern limit of Charleston Slough, provides water supply to the Sailing Lake to maintain the lake water quality for habitat and recreational use.
Figure 1: Project Location Map at Shoreline at Mountain View and Charleston Slough
Shoreline Park Water Control Structures Improvements, Project 23-44— Authorize Professional Services Agreement
May 23, 2023
Figure 2: Project Components at Sailing Lake in Shoreline at Mountain View
The Sailing Lake, also known as Shoreline Sailing Lake, is an artificial water body in Shoreline at Mountain View, with an area of 45 acres and an average depth of 18’, used for kayaking, sailing, and windsurfing. The Sailing Lake is a closed -water body with the Sailing Lake water supply provided by the Sailing Lake pump station. The lake level is maintained constant by a concrete outlet structure that discharges to Permanente Creek. At the western limit of the Sailing Lake, adjacent to the Coast -Casey Foreb ay, is the Sailing Lake Access Road . The road serves as a California Department of Water Resources, Division of Safety of Dams (DSOD), jurisdictional dam which was improved in 2021 to enhance its stability and to reduce its breaching risk to the Coast- Casey Forebay. It also provides an access route for construction and maintenance projects along the shoreline.
The Coast-Casey Forebay is located west of Sailing Lake. This detention basin collects stormwater runoff from over a quarter of the City’s urban watershed. The detention basin drains to Palo Alto Flood Basin via the Coast-Casey Pump Station. The pump station was renovated in 1994. While the pump station in general is in good condition, the 6” sump pump discharge pipe requires repair.
Shoreline Park Water Control Structures Improvements, Project 23-44— Authorize Professional Services Agreement
May 23, 2023
The Shoreline Park Water Control Structures Improvements project was created to address ongoing operation and maintenance issues at Charleston Slough, Sailing Lake, and Coast -Casey Pump Station, including the following:
• Charleston Slough Tide Gates (Figure 3): The existing tide gates were installed in 1997. The tide gates have deteriorated over time due to corrosion. While the City is evaluating the feasibility to remove the tide gates in the future to support the tidal marsh restoration at Charleston Slough, the tide gates need to be repaired in the interim to prolong their service life.
Figure 3: Charleston Slough Tide Gates Project Component
• Sailing Lake Access Road Boardwalk (Figure 4) : The existing wooden boardwalk provides access to an underwater gate for the interconnection pipe between Sailing Lake and Coast- Casey Forebay which is no longer needed. This project will remove the boardwalk and gate from the lake so they will not be potential safety hazards to lake users.
Shoreline Park Water Control Structures Improvements, Project 23-44— Authorize Professional Services Agreement
May 23, 2023
Figure 4: Sailing Lake Access Road Boardwalk Project Component
• Sailing Lake Outlet (Figure 5) : The Sailing Lake outlet is a concrete structure with an overflow weir to drain water from the Sailing Lake to Permanente Creek. The concrete structure has a gate for a drainage pipe network at the lake floor. In a recent gate exercise, the gate could not be closed. This project will replace the gate and may replace the concrete structure with a new outlet and drain inlets at lower elevations.
Figure 5: Sailing Lake Outlet Project Component
Shoreline Park Water Control Structures Improvements, Project 23-44— Authorize Professional Services Agreement
May 23, 2023
• Sailing Lake Habitat Island (Figure 6) : The island at the Sailing Lake provides significant habitat for a number of special -status bird species. The island has been eroding over the years due to wind and wave actions and impacts from recreational lake users. This project will develop and evaluate alternatives to improve barriers around the island perimeter to limit lake user access, provide erosion improvements, and restore the island to its original design.
Figure 6: Sailing Lake Habitat Island Project Component
• Coast-Casey Pump Station (Figure 7): The pump station sump pump discharges to a 6” pipe with an outfall to the Palo Alto Flood Basin. The pipeline currently has reduced capacity, possibly due to misalignment caused by differential settlement. This project component will repair the pipeline and restore its conveyance capacity.
Shoreline Park Water Control Structures Improvements, Project 23-44— Authorize Professional Services Agreement
May 23, 2023
Figure 7: Coast-Casey Pump Station Sump Pump Discharge Pipe Repair Project Component
ANALYSIS
On March 16, 2023, the City issued a Request for Proposals (RFP) for services to provide California Environmental Quality Act (CEQA) clearance, environmental permitting, design, and construction support services for the project components identified above . The RFP was posted on the City website and Integrated Marketing Systems (IM S), an online RFP posting service. On April 17, 2023, the City received one proposal from AECOM Technical Services, Inc. (AECOM). A review panel of Public Works and Community Services staff reviewed the proposal and deemed AECOM is well-qualified to perform this work based on the project team’s understanding of th e project and their knowledge and experience from similar projects performed at Shoreline at Mountain View and other San Francisco Bay Area locations.
The recommended not -to-exceed contract amount of $ 850,000 includes $ 713,065 for basic services and reimbursable expenses and an additional services amount of $136,935 for potential additional field investigations, regulatory permitting, engineering design work, and unforeseen items. The recommended fees are within the range typically charged for such services based on similar types of projects at Shoreline at Mountain View. Staff considers the fees to be fair and reasonable.
With the approval of this contract, AECOM could begin the project in summer 2023. The project design is scheduled to be completed in fall 2024, pending CEQA clearance and environmental regulatory permitting required for the project.
Shoreline Park Water Control Structures Improvements, Project 23-44— Authorize Professional Services Agreement
May 23, 2023
FISCAL IMPACT
Shoreline Park Water Control Structures Improvements, Project 23-44, is funded with $1,350,000 from the Shoreline Regional Park Community Fund. There are sufficient funds for the recommended agreement of $850,000, and no additional appropriations are required.
ALTERNATIVES
1. Do not approve the recommended contract and direct staff to reissue an RFP for the project.
2. Provide other direction.
CONCLUSION
Staff is seeking Council approval of a consultant agreement with AECOM for $850,000 to perform field investigations, regulatory permitting, engineering design, and construction support work for Shoreline Park Water Control Structures Improvements, Project 23 -44. The work is need ed to complete operations and maintenance projects at the City’ s Charleston Slough, Coast -Casey Forebay, and Sailing Lake. In addition, the project will explore options and provide design services to restore the Sailing Lake Habitat Island that is home to special-status bird species.
PUBLIC NOTICING—Agenda posting.
Prepared by:
Raymond Wong
Senior Civil Engineer
Reviewed by:
Lisa Au
Assistant Public Works Director
Approved by:
Dawn S. Cameron
Public Works Director
Audrey Seymour Ramberg
Assistant City Manager
RW/LL/6/CAM
931-05-23-23CR
203093
cc: CSD, SM, USM, SMA—Doan, File (23-44)