Southern Border Fuels Project

A pathway along the edge of the screen is lined with very tall reeds.

Invasive Arundo donax along the Tijuana river.

In 2019, the San Diego National Wildlife Refuge Complex initiated a multiple year program to mechanically and chemically control a range of non-native invasive plants along the tributaries of the Tijuana River within the Tijuana Slough National Wildlife Refuge (NWR or Refuge) and along the Sweetwater River on the San Diego NWR. Funding for the project has been provided through an Interagency Agreement between the Department of Interior, U.S. Fish and Wildlife Service (FWS) and the Department of Homeland Security, U.S. Customs and Border Protection.
The project site within the Tijuana Slough NWR includes approximately 250 acres of which approximately 205 acres would be treated to remove invasive plants. Approximately 242 acres along the Sweetwater River within the San Diego NWR will also be treated.

UPDATED TJ River Vallley Unit 

Project goals include reducing the risk of wildfire in sensitive habitat; improving habitat for riparian nesting bird species including the federally endangered least Bell’s vireo (Vireo pusillus belli) and southwestern willow flycatcher (Empidonax trailii extimus); mitigating safety risks to Refuge staff and Border Patrol personnel; and improving access and visibility for Border Patrol operations.

The mechanical removal of invasive vegetation, followed by application of herbicide to the cut stumps, began on the San Diego NWR in fall 2019. The second year of this fuels management project will begin in the Tijuana River Valley as early as August 31, 2020, while work along the Sweetwater River is expected to resume in early October. 

This habitat work is being conducted in accordance with the project’s Aquatic Pesticide Application Plan, which was approved by the California State Water Resources Control Board in October 2019. All vegetation removal and herbicide treatments are to be conducted between August 1 and March 20, when vireos are not present and birds are not nesting within these riparian areas. 

For more information about the Southern Border Fuels Management Project, contact Daniel O’Connor, Fire Management Officer, Southern California Zone, at For questions related specifically the invasive plant control activities occurring on the Tijuana Slough NWR, please contact Brian Collins, Refuge Manager, at

Official Notice to Begin Work (151 kB PDF)