Mesmer Low Flow Diversion Project

Photo of Centinela Creek near the Mesmer Pump Station.jpg

The Mesmer Low Flow Diversion Project proposes to divert dry-weather runoff from Centinela Creek, into the City’s’  decommissioned Mesmer Pump Station (Pump Station). Most of the dry-weather run-off originates from overwatered lawns, leaky mains or industrial flows. The Mesmer project will collect this water and   during pump into an existing sewer main to the City of Los Angeles’ Hyperion Reclamation Plant for treatment. Project will help the City meet its water quality compliance goals.

Project Detail

Project Description

The Mesmer low flow diversion system (LFD) can divert up to 1 Gallon Per Minute (GPM) of dry weather run-off from Centinela Creek into the Mesmer Pump Station. Dry weather run-off will be pumped into an existing sewer main and be taken to City of Los Angeles’ Hyperion Water Reclamation Plant for treatment and recycling.

The Centinela Creek is a tributary to Ballona Creek draining approximately 9.83 square mile area (6,288 acres) of Culver City, Inglewood, Los Angeles, and the County of Los Angeles unincorporated areas.

During wet weather and conditions with higher-than-normal flows in Centinela Creek, the proposed sluice gate will be closed for diversion allowing these higher flows to continue down the channel to Ballona Creek. The existing Pump Station and force main provides more than adequate capacity to convey the low flow from the channel. 

 Project overview is 1. divert dry-weather runoff, 2. Gravity flow pipe to new pump station and wet well, 3. Pump flow through PVC pipe to existing wet well pump station, 4. Flows go to existing force main and eventually to Hyperion. Photo also shows proposed low flow berm, low flow curb, grate inlet, proposed pipe, and pump station.jpg 

Project Overview

  1. Divert dry-weather run-off from Centinela Creek Channel
  2. Gravity flow pipe to new pump station and wet well
  3. Pump flow through PVC pipe to existing wet well pump station
  4. Flows go to existing force main and eventually to Hyperion 

Photo shows

  • Proposed low flow berm 
  • Existing low flow curb
  • Proposed grate inlet 
  • Proposed pipe 
  • Pump station 

 

Benefits

Water Supply – Help support demands of recycled water and support the Region’s goal of water resiliency by diverting dry weather urban runoff from the Centinela Creek to Hyperion Water Reclamation Plant. Water Quality – Helps reduce the current bacteria levels and other pollutants in Ballona Creek to meet compliance effort with Ballona Creek Total Maximum Daily Load’s (TMDL's).

Time Schedule Order

The City’s deadline to address dry weather bacteria and metals exceedances in storm drains was January 2016, and was extended by approval of the Los Angeles Regional Water Quality Control Board through a Time Schedule Order (TSO).  The Mesmer Project is one of three projects approved in the TSO to comply with the Ballona Creek Bacteria Total Maximum Daily Load (TMDL) for dry weather bacteria flows.

The following three regional projects collectively comply with the final water quality based effluent limitations during dry weather as specified by the Ballona Creek bacterial TMDL:

  1. Low Flow Treatment Facility (LFTF) #1 Project at Ballona Creek
  2. Low Flow Treatment Facility (LFTF) #2 Project at Sepulveda Channel
  3. Mesmer Low Flow Diversion Project at Centinela Creek

Culver City is taking the lead in managing both design and construction of the Mesmer Project, while the City of Los Angeles is managing the LFTF #1 and LFTF #2 Projects.

Project Partners

Mesmer LFD is a public partnership with City of Los Angeles, County of Los Angeles, City of Inglewood, and Culver City. Mesmer LFD is one of three TSO Projects being developed to address Bacteria TMDL in Ballona Creek. The other projects being led by City of LA are LFTF #1 and LFTF #2. 

 

Project Schedule

  • August – September – Advertise Project for Construction Bids 

  • October 2021 – Award Construction Contract and Construction Management Contract

  • October – December 2021 – Administer contracts, public outreach

  • February 2021 – May 2021 - Construction

Project Documents

Design Plans 

Completed design plans 

Environmental

The Mitigation Monitoring Report (MMRP) requires several measures to be complied with during the construction of the Mesmer project including protection of cultural resources; protection of hydrologic and water resources; and minimization of noise impacts during construction.  All potential impacts will be monitored by City staff, project inspectors and Native American tribal designated members.

Final Environmental Impact Report prepared by the City of Los Angeles 

US Army Corp of Engineers

The US Army Corps of Engineers granted its permission for the Mesmer Project, pursuant to its authority under federal law 33 USC 408 (408 Permit) in January 2021.  An agreement with Los Angeles County Flood Control District (LACFCD) to modify the Centinela Creek channel was approved by City Council on August 10, 2020.

Funding Sources

The City was awarded grant and Measure W funds to pay for the Mesmer Low Flow Diversion Project.

  • Awarded $607,846.99 through DWR’s Proposition 1  
  • Awarded $950,000 through the Measure W Regional Infrastructure Funds