Professional Engineering Services for the American Martyrs Stormwater Sump Hydrology and Capacity Study

The City of Manhattan Beach (“City”) invites sealed proposals on the project described herein to be submitted via OpenGov. Proposals will be received until 10:00 am on Thursday, December 18, 2025 .

Bid Valid: 120 Days

Anticipated Start: March 2026

Anticipated Completion: July 2026 or sooner

Project Area

The project’s address is 721 15 ^th Street, Manhattan Beach, CA. Refer to Appendix E for Location Map. The American Martyr’s Sump is located directly adjacent to American Martyrs School and is situated in a localized low point, where stormwater runoff from the adjacent developed areas is transferred to the sump.

Project Background

On occasion during periods of heavy stormwater runoff, American Martyr’s Sump capacity has overflowed and encroached into the adjacent school play and building areas. In 1999, a hydrology report (Appendix F) was created which calculated peak flow, volume of runoff for three storm periods (including Los Angeles County Department of Public Works criteria), and presented four possible solutions for remediation. The hydrologic method was able to identify the 50-year, 4-day storm as the leading design plan for recommendations lowering the risk of flood damage.

The study analyzed infiltration rates and options for gravity systems, a pump station, and discharge directly to the ocean via a new underground storm drain system. The California Coastal Commission, Los Angeles County Department of Public Works, and California Regional Water Quality Control Board all expressed concern for protection of marine life, health, water quality, stormwater treatment, necessary clearances, and permits if water would not be retained. For these reasons, and the fact that the existing sump was determined to percolate with reasonable efficiency at the time, it was recommended to City Council that no further action be taken regarding the American Martyrs stormwater sump.

Stormwater has flooded adjacent areas again, indicating that the sump’s capacity and/or infiltration rates may no longer be sufficient. With changes that occur due to the environment, rainfall, agency requirements, and overall hydrology over the years, an update to the 1999 hydrology report is necessary to verify the required sump capacity and to propose drainage options and maintenance protocol along with their associated costs.