Study overview:
The U.S. Army Corps of Engineers Los Angeles District conducted the Los Angeles County Drainage Area (LACDA) Project disposition study under Section 216 of the Flood Control Act of 1970, as a review of the completed project to determine if federal interest still exists and the project continues to meet the authorized purpose of flood risk reduction and management.
The four-year study evaluated:
- Existing conditions
- Federal interest
- Comparative costs
- Risks and impacts to the environment and socioeconomic analysis
- Life safety impacts
The study concluded in May 2024, and USACE has just released its Report of Findings, which can be found in the accompanying link on this page, along with an overview and frequently asked questions. The LACDA Project continues to meet its authorized purpose and provides significant flood-risk management for the greater Los Angeles area, along with significant economic and public benefits. Federal interest continues to exist in the federal project; therefore, disposition cannot be recommended.
The LACDA Disposition Report of Findings is available HERE.
Report of Findings highlights:
Life-safety is always our priority, and the LACDA project continues to provide flood-risk management, protecting millions of residents and businesses.
- The LACDA project continues to provide critical flood-risk management within the Los Angeles County drainage area and for approximately 10 million residents.
USACE values our partnership with state and local communities, and we will continue to work together on behalf of the public.
- Close coordination, communication between the USACE Los Angeles District and LA County are key to the ongoing success of the LACDA Project.
- USACE and LA County have a long-standing, strong relationship grounded in consistent, coordinated communications.
- Opportunities were identified for USACE to partner with local governments on drought resiliency and levee safety.
USACE is better positioned to respond to emergency actions involving federal projects, including where a local entity is responsible for operations and maintenance.
- Deauthorization would remove the features from the PL 84-99 federal emergency assistance program, which allows USACE to make repairs quickly after disasters.
Frequently Asked Questions
1. What is LACDA, the LACDA Project, and its benefits?
The Los Angeles County Drainage Area (LACDA) is a comprehensive system the includes all flood risk management features along the Los Angeles River and its tributaries that work in concert as asystem to drain the watersheds within LA County.
The LACDA Project (federal project) is comprised of flood control and other features authorized by Congress within the Los Angeles River watershed.
The LACDA Project provides critical flood risk management within the Los Angeles County drainage area and for approximately 10 million residents.
2. What is a disposition study?
USACE can review the operations of completed USACE projects under a reexamination authority (33 U.S.C. §549a), established by Section 216 of the Flood Control Act of 1970 (P.L. 91-611). If the project no longer meets its authorized flood control purpose, and therefore no federal interest exists to retain the project for its authorized purpose, an evaluation and comparison of the benefits, costs, and impacts of the project is conducted to support a recommendation for deauthorization, re-operation, or programmatic changes to the project purposes and disposal of the property.
3. Why is the U.S. Army Corps of Engineers doing a disposition study on the Los Angeles County Drainage Area?
The purpose of this disposition study was to determine whether or not continued operation and ownership of the Los Angeles County Drainage Area (LACDA) by the U.S. Army Corps of Engineers (USACE) is in the federal interest. If the study showed the project did not meet its authorized purpose and that there is no longer a federal interest in continuing to retain the project for its authorized purpose, USACE would provide supporting information to recommend deauthorization, re-operation, or programmatic changes to the project and disposal of the property.
The study was initiated in 2020 and concluded as a Report of Findings in May 2024.
4. Even if the overall LACDA Project continues to meet its flood-risk management purposes, can the U.S. Army Corps of Engineers deauthorize some of the features?
The various segments and features within the LACDA Project work together as an inseparable, interconnected system to provide flood-risk reduction and management benefits to the Greater Los Angeles area. Deauthorization of individual LACDA features would impact the ability of USACE to efficiently address emergencies and natural disasters, as well as during routine water management operations.
The channels within the LACDA Project are crucial to the safe passage of flood waters. Safety and operability of the overall LACDA Project and flood-risk management within the adjacent downstream communities are reliant on continued USACE management of releases from the federal dams in the LACDA Project, including associated channels.
USACE has broad latitude to move quickly to implement emergency actions at federal projects, including those where a local sponsor is responsible for operations and maintenance like the LACDA Project. Emergency actions at non-federal projects are limited in nature, require a Cooperative Agreement with the relevant non-federal interest and may require extensive non-federal costs to implement.
5. Why did the U.S. Army Corps of Engineers find that the LACDA Project continues to serve its authorized purpose and chose not to recommend any elements of the project to be deauthorized?
The LACDA Project continues to provide significant, effective flood-risk management and flood-risk reduction benefits to the Greater Los Angeles Area. It continues to provide the flood damage reduction, life safety, and property damage reduction benefits as originally conceived when it was built. Because the LACDA Project continues to meet its authorized flood control purpose, disposition or deauthorization cannot be recommended.
6. What is the U.S. Army Corps of Engineers doing in terms of Operations and Maintenance along the river?
USACE prioritizes O&M work in the LACDA Project, with an emphasis on safety and operability of the flood risk management system. In fiscal year 2023, the Corps awarded a $13.5-million invasive species and sediment management contract for the Glendale Narrows. Work will consist of excavating 100,400 cubic yards of sediment and non-native vegetation as part of a multi-year plan to restore the as-built capacity of the soft-bottom section of the Los Angeles River.
Work in 2024 includes:
- Removal of concrete damaged from recent rain events downstream of Los Feliz Boulevard
- Debris removal and cleanup from more than 100 homeless encampments
- Monitoring 35 additional encampments for flood risk (notifying agencies to help move people out of harm’s way in the event of a storm)
- Removal of sediment on concrete surfaces of the channel
- Disposal of non-native vegetation on a weekly basis
- Inspection and assessment of 38 storm and subdrain pipes, and,
- Removal of graffiti along 250,000 square feet of the channel on an annual basis.
7. What is the U.S. Army Corps of Engineers doing to support effective partnerships with LA communities and stakeholders?
USACE values the local and state partners of the Great Los Angeles area. The frequent, close coordination between the Corps' Los Angeles District and Los Angeles County Department of Public Works are key to the ongoing success of the LACDA Project to protect the drainage area.
USACE and the LA County Department of Public Works have a strong, long-standing relationship and have had many significant successes that provide many benefits to the Greater Los Angeles area. During the unprecedented rainfall events, including Hurricane Hillary, USACE and LA County Department of Public Works were in close coordination to manage the excess flood waters, capture storm water runoff, and coordinating early notices to local agencies for general USACE Los Angeles District - LACDA Report of Findings FAQ - June 2024 public safety allowing timely evacuation of channels prior to major storms, preventing flood-related drownings in the channel during the recent winter storms of 2023 and 2024.
8. How can I stay involved?
Questions and comments can be submitted here: LACDADS@usace.army.mil