Fact Sheet

O&M - Los Angeles County Drainage Area, CA

U.S. Army Corps of Engineers, Los Angeles District
Published Sept. 11, 2023


Located four miles east of the City of San Fernando. Project Elements: Dam and Appurtenances (97- feet-high; 10,475-feet-long; 51,000-acre-feet cap at spillway crest - 1983) Recreation Area, number of visitors to Recreation Area in FY 2018 was approximately two million. Initially Operational/Fully Operational FY 1940/FY 1949. LOPEZ DAM
Located 2.2 miles NE of the city of San Fernando Project Elements: Dam and Appurtenances (50 feet-high; 1,330-feet-long; 1,248-acre-feet cap at spillway crest - 1979) Initially Operational/Fully Operational: 1954/1955

Located 15 miles NE of the City of Los Angeles Project elements: Dam and Appurtenances (92 feet-high; 23,800 feet-long; 32,109 acre-feet cap at spillway crest 1983). Recreation Area, number of visitors to Recreation Area in 2018 – 500,000. Initially Operational/Fully Operational: 1949/1949

Located 25 miles NW of the City of Los Angeles. Project elements: Dam & Appurtenances (57 ft-high; 15,444 ft-long; 17,425 acre-ft cap at spillway crest 1982). Recreation Area, No. of visitors to Recreation Area in 2018: 3,500,000 Initially Operational/Fully Operational: 1949/1949.

Located 10 miles east of the City of Los Angeles. Project elements: Dam and Appurtenances (56 feet-high; 19,960 ft-long; 49,143 acre-feet cap at spillway crest 1982). Recreation Area, number of visitors to Recreation Area in 2013: 1,500,000.  Initially Operational/Fully Operational 1957/1957.

Consists of 517 miles of channel, 45 miles are maintained by the Corps, the remainder is maintained by LA County Department of Public Works.

AUTHORIZATION: Flood Control Act of 1944

ACTIVITIES FOR FY 2023: Funds will be used for the following: 
OPERATIONS – The high priority sediment and vegetation removal project will continue at the San Gabriel River and San Jose Creek confluence, while the initial levee repair design will continue this FY. The Santa Fe Dam will receive a complete electrical upgrade within the control house, and the exterior concrete stairwell on the embankment will be demolished, upgraded, and replaced. Also at Santa Fe, we will be testing the pressurized pipes that bring water into the control house for possible weak or corroded areas. We will continue repairs at Sepulveda Dam by repairing the leaking inlet pipes. Compton Creek will have a much needed trash rack installed that will collect floating debris and keep the downstream area cleaner. A 9,000 linear foot section of the Los Angeles River Toe Access Roads will be repaired with new concrete for improved and efficient access in the river. While we work to improve the access in the Los Angeles River, we will continue to regain capacity through a large sediment and vegetation removal project through the Glendale Narrows section of the river. We will also be removing sediment and vegetation from Compton Creek and within the Sepulveda Basin section of the LAR. Water Control Manual updates will continue for Hansen Dam and Sepulveda.

MAINTENANCE – Annual sediment removal will continue at 5 dams and 1 debris basin; non-native vegetation removal within the soft bottom section of the LA River; fence repair throughout the LACDA operational area, channels, levees, and rivers; continuous debris removal and homeless encampment clean-ups throughout all the LACDA Program areas; burrowing animal and other pest control will continue at all projects.

IIJA ACTIVITIES: Repairs at several dams include the stairwell embankment repair at SFD, repair of leaky inlet pipes at Sepulveda, the installation of a trash rack in the Compton Creek, and a major repair of the Toe Access Roads in the Los Angeles River. We will begin a boundary survey for the Sepulveda basin while working with the City of Los Angeles on a Vision Plan for Sepulveda in preparation for an updated Master Plan. We are researching pest deterrent through natural or non-chemical methods.

FY 2024 PLANNED ACCOMPLISHMENTS: Optimal funds could be used for: 

OPERATIONS – Water Control Manuals for five LACDA dams (Lopez, Sepulveda, Santa Fe, Whittier Narrows and Hansen); Updating Hansen, Sepulveda and finalizing Santa Fe Master Plans; Collaborating with the County Fire Department to develop a Fire Management and Prevention Plan; continuation of a boundary survey for the Sepulveda basin.

MAINTENANCE – Routine maintenance and repairs include annual sediment and vegetation management, fencing repairs, gate testing, pest control, small concrete repairs throughout the LACDA Dams; continuing FEM Work Order scrub.  

STATUS - Project condition of Dams is UNSAFE to CONDITIONALLY UNSAFE. All of the dams within the system have a DSAC II or DSAC III rating with the exception of Whittier Narrows dam which has a DSAC I rating. The Whittier Narrows dam has been downgraded and re-classified as a dam safety action class (DSAC) 1 (from a DSAC 2) dam meaning that the dam is critically near failure or extreme high risk. A Dam Safety Modification Study is underway that will address failure modes including potential for seepage and piping at the west and central embankments, and the potential for overtopping of the dam.

DSAC I dams are classified as critically near failure or extreme high risk. DSAC II dams are classified as potentially unsafe. DSAC III dams are classified as significantly inadequate, moderate to high risk, high priority, conditionally unsafe. Project condition of channels and levees is poor and requires extensive rehabilitation and repair. A failure of any of the dams within the system would cause large economic loss and catastrophic loss of life within Los Angeles County and the surrounding Cities. Screening Portfolio Risk Assessments (SPRA) have been completed for all dams within the LACDA system resulting in the following
Dam Safety Action Classification (DSAC) ratings: DSAC I: Whittier Narrows Dam; DSAC II: Lopez Dam and Santa Fe; DSAC III: Sepulveda Dam, Hansen Dam, and Haines Canyon Debris Basin. Interim Risk Reduction Measures Plans (IRRMP) are required for all DSAC I, II, & III dams. IRRMP’s were finalized in FY12.

The six (6) District flood control projects within the LACDA system are reaching over 65 years of service and are in need of rehabilitation of dam component repair, such as hydraulic systems, motors, gates, and generators, prior to component failure at projects. Component failures have already started to occur.
The concrete lined portions of the Los Angeles River flood control channel invert has begun to erode away resulting in large pieces of the channel invert being lifted and transferred downstream during large rain events. The LA River concrete invert overlays require repair and replacement. The levee systems throughout the LACDA system are in need of extensive maintenance and repair as a result of the FY2011-2013 levee inspections.

Current project funding received through the O&M program does not meet growing deferred maintenance requirements for the six flood risk management projects and 45 miles of flood risk management channels and levees within the flood control system. The project is currently funded at 25% of O&M capability; causing a continued increase in deferred maintenance, repairs, and inspections needed to properly O&M the LACDA system.

Homeless Population Challenges
Each of the Los Angeles County Drainage Area Dams contains thousands of open acres used for flood risk mitigation. Basins hold water during the flood season from November to April but water levels return to normal during the spring, summer and fall months. This open acreage provides exceptional habitat for homeless personnel living in tents and temporary constructed shelters. A gathering of six shelters and tents is considered an encampment. A survey was conducted of homeless encampments along the San Gabriel River within Whittier Narrows in 2019 and found 53 homeless encampments. Sepulveda Dam has several locations and areas that are perfect homeless habitat which contain numerous homeless encampments. The San Gabriel River and the San Gabriel Dam Spillway also contains many homeless encampments. Every Flood Risk Mitigation Basin and many miles of the Los Angeles River and channels are home to thousands of homeless personnel.

Mental illness is a major factor of homelessness. Many individuals collect discarded items and debris found along highways, in dumpsters and around the community. Their collection of items are strewn about their tent areas and encampments creating large debris piles within the waterways. During heavy rains and flooding, these items become floatable debris and are carried away and lodged in vegetation, trash racks or embankments along the river. Large quantities of floatable debris can cause blockage under bridges and overpasses reducing the flow and creating a dam effect at certain locations.

In addition, drug addiction is a large cause for homelessness. It is estimated that 90% of homeless individuals have a severe drug addiction. The acreage, remoteness and vegetative cover of the riparian areas provide a perfect habitat and location for drug usage. The paraphernalia of drug use, (i.e. syringes, needles, bowls, etc.) are discarded in the river and migrate downstream to get caught in vegetation or soft bottom reaches of the river. This bio-hazardous debris causes major health and injury concerns for pedestrians and persons recreating along the river.

Vandalism and criminal activity are a regular challenge at all of the LACDA projects. Hansen Dam has had several burglaries and thefts this year. A Los Angeles County tenant of Santa Fe Dam has had seven break-ins this year and the Corps Base Yard has had a number of automobiles broken into this year. This is an ongoing and continuous concern at all of the LACDA projects which has caused the Division to contract for security at the Base Yard. The vandalism and criminal activity increases as the homeless encampments increase.

Homeless clean-up is an extremely expensive and time consuming endeavor and must be coordinated with local law enforcement, sanitation districts and city and county officials.

At current funding levels, LACDA is severely underfunded to continue maintenance requirements directly related to homeless activity in the river, replace stolen or damaged property and to coordinate and participate in community based clean-up efforts. Keeping these areas cleared of homeless would require additional law enforcement patrols and continuous maintenance.

As of 01 MAR 23

Estimated Federal Cost                   $61,296,770

Estimated Non-Federal Cost                                    $0
Total Estimated Project Cost                  $61,296,770

Allocation thru FY22                  $29,080,000
President’s Budget for FY23             $25,884,540 1/
Conference Add for FY23                                   $0
Approved IIJA FY23                  $33,722,000
Workplan for FY23                      1,690,230
President's Budget for FY24            $ 23,165,010 2/
Approved IIJA FY24                                   $0
Workplan for FY24                                TBD
Balance to Complete After FY24                                N/A
1/ Decreased 1% from $26,146,000
2/ Decreased 1% from $23,399,000


CONGRESSIONAL INTEREST: Senators Butler and Padilla, Representatives: Judy Chu (CA-28), Cardenas (CA-29), Schiff (CA-30), Napolitano (CA-31) Sherman (CA-32), Kamlager (CA-37), Sanchez (CA-38), and Barragan (CA-44).





Congressional Liaison