Stormwater Engineering Projects

Picture of Big Tujunga Dam


Final IS/MND:

Thank you for your interest in the project. A Final Revised and Recirculated Initial Study/Mitigated Negative Declaration (IS/MND) has been prepared and will be considered by the Los Angeles County Board of Supervisors for adoption in January 2023.

Click here to access the Final Revised and Recirculated IS/MND (excluding appendices).
Click here to access the Final IS/MND Technical Appendices.

Click here to access the Responses to Comments on Draft IS/MND.

Availability of Big Tujunga Dam Habitat Conservation Plan:

The Los Angeles County Public Works and the Los Angeles Department of Water and Power have prepared a Big Tujunga Dam Low-Effect Habitat Conservation Plan (HCP) pursuant to Section 10 of the Federal Endangered Species Act to support consultation with the U.S. Fish & Wildlife Service.

Click here to access the Big Tujunga Dam Low-Effect Habitat Conservation Plan.
Click here to access the ADA compliant version of the Big Tujunga Dam Low-Effect Habitat Conservation Plan.
Click here to access the Screening Form for Low-Effect Habitat Conservation Plan.

Draft IS/MND Public Meeting:

A public meeting was held virtually on Thursday, October 14, 2021. The presentation slides and a recording of the public meeting can be accessed in the Resources Section below.

Submitting Comments:

The Draft Revised and Recirculated IS/MND comment submission period ended on October 25, 2021. Thank you to everyone who submitted comments. All submitted comments will be responded to and included with the Final IS/MND, anticipated in Summer 2022.

Tentative Schedule:

The project bid period is anticipated in Early 2024. Activities at Maple Canyon Sediment Placement Site are scheduled to begin in Late 2024 before sediment removal activities at Big Tujunga Reservoir begin in Spring 2025.


The 2009 Station Fire was the largest fire in Angeles National Forest (est. 1892) recorded history and burned over 160,000 acres in the San Gabriel Mountains. Approximately 87% of the watershed tributary to Big Tujunga Reservoir was burned, making sediment deposition inevitable during subsequent storm events. The storms that occurred in the wet seasons after the fire increased sediment accumulation in the reservoir by more than one million cubic yards.

The sediment in the reservoir can impact the operation of the valves and reduce the capacity for water conservation and flood control. Sediment removal is necessary to maintain the operability of the dam and protect the communities and environment downstream of the dam.

Pursuant to the California Environmental Quality Act (CEQA), an Initial Study/Mitigated Negative Declaration (IS/MND) was originally prepared in 2013. A Revised and Recirculated IS/MND has been prepared and circulated for public review in October 2021.

Big Tujunga Reservoir before the Station Fire
Big Tujunga Reservoir after the Station Fire
Pursuant to the National Environmental Policy Act (NEPA) an Environmental Assessment (EA) is being prepared. A public scoping meeting will be conducted by the United States Army Corps of Engineers.

Maple Canyon Sediment Placement Site Big Tujunga Reservoir Project Map Photo Taken After Big Tujunga Dam Seismic Rehabilitation and Spillway Modification Project


For more information about the project, or to be added to the project mailing list, please email or call (626)458-6119

Updated on: 12/22/2022