Stormwater Engineering Projects

Picture of Pacoima Spreading Grounds


Pacoima Spreading Grounds was built in the 1930s and is one of the major water conservation facilities that provide groundwater recharge for the San Fernando Basin. Currently, the spreading grounds' percolation rate is reduced due to a low permeability clay layer underlying the infiltration basins. The proposed project will increase the spreading grounds' storage capacity and percolation rate and simplify operations by combining basins and constructing new interbasin structures.

The proposed project will result in increased groundwater recharge in the San Fernando Groundwater Basin. Primary project objectives include:

  • Increasing the percolation rate from 65 cfs to 140 cfs by removing existing clay layers underlying the spreading basins;
  • Expanding the storage capacity of the spreading basins from 530 acre-feet to 1,200 acre-feet by combining and slightly deepening the existing 12 spreading basins by approximately 5 to 10 feet;
  • Eliminating potential localized flooding risk by replacing the intake canal with RCPs; and
  • Creating 6.5 acres of additional open space by replacing the intake canal with RCPs.

This project is funded by a State Proposition 84 grant through IRWMP, the Los Angeles Department of Water and Power, and the Los Angeles County Flood Control District.


The comment period has been extended until December 31, 2018 by 5:00 PM.

The Draft Mitigated Negative Declaration was released on November 14, 2018 for a 30-day public review and comment period. However, the deadline has been extended until the end of the year. Please submit any comments on the Recirculated IS/MND in writing to the LACFCD by 5:00 PM on December 31, 2018. Comments should be titled with "Pacoima Spreading Grounds Improvement Project" in the subject line. Comments can be submitted in the following ways:

Attention: Ernesto Rivera
Los Angeles County Flood Control District
900 South Fremont Avenue, 11th Floor
Alhambra, CA 91803


Fax: (626) 457-1526

A public meeting was held on November 29, 2018 at the Laborers' Local 300 Union Hall.



For more information on the project or to be added to the project mailing list, please contact

Updated on: 12/18/2018