The Lahontan National Fish Hatchery Complex
Pacific Southwest Region

River Restoration Program

Under the Desert Terminal Lakes Program, the goal of the River Restoration Program is to address threats to the Walker Basin and develop strategies for restoring the natural balance and biological diversity of the river and its flood plain. Key threats include invasive Tamarisk shrub, noxious weeds, erosion and sediment deposition. Photo courtesy of USFWS

Biophysical Assessment

The Service initiated a report on the historical and current conditions of the river to help prioritize restoration activities and funding ofimages/graph.jpg projects. The report provides a general overview of the watershed followed by a focused description of the river channel and river processes.
The objectives of the study are to assess the physical and biological environment of the Walker River, characterizing historical and current conditions. The information is being used to identify opportunities that will restore river function and habitat.

For this study, aerial photos of the basin dating back to 1938 were compared to more recent photos to determine how the river channel has changed over the decades. Scientists used aerial imagery to develop a digital map of the channel to understand how floods, drought and diversions have altered the river channel.
We will update this site with highlights from the basin report of how the river and basin have changed over the years and how those changes have affected the river’s function.

Tackling Tamarisk

Tamarisk is a deciduous shrub introduced to the western U.S. in the 1800’s as an ornamental plant for windbreaks. It was introduced in the Walker basin around 1837.Originating in central Asia, tamarisk has an extensive root system that grows deep into the soil. This allows tamarisk to grow farther back from the river, occupy a large area, and use more water across the floodplain than native plants. It is well suited to hot, arid climates and alkaline soils common in the western U.S. These adaptations have allowed it to effectively exploit many of the degraded conditions found in southwestern river systems. By the 1900’s tamarisk stands dominated many low-elevation river, lake, and stream banks across the west, and today covers an estimated 1 to 1.5 million acres of land in the western U.S.
Tamarisk reproduces primarily through wind and water-borne seeds and requires a wet, open surface to become established. In the presence of established native vegetation, tamarisk seedlings are not as competitive. However, when native vegetation is suppressed by conditions such as late flooding, fire, drought, and animals eating native saplings, tamarisk is better able to invade. Once established, tamarisk grows so densely that it pushes out native vegetation. It also has a higher tolerance for fire, drought, and salinity than native plants and can actually increase fire frequency and intensity, drought, and salinity. It is water intensive, with an average annual water usage of up to 4.2 acre-feet/acre. Removing this invasive plant and re-establishing native vegetation is a major goal of the River Restoration program.

East Walker Noxious Weed Program

The Walker River Basin Cooperative Weed Management Area (CWMA) has finished year one (2008) of a noxious weed project. They mapped and removed non-native weeds such as tamarisk along the East Walker River. This is part of a multi-year project that in the future will address weeds on the West Walker and mainstem. The project is in collaboration with private landowners, federal, state, and local agencies and funded primarily through the Desert Terminal Lakes Program.
This weed partnership received national attention in a recent National Association of Conservation Districts report that highlighted 25 out of 3,000 Conservation District programs.

Rosaschi Ranch Re-vegetation

The Service is working with Dr. Tara Forbis of the US Department of Agriculture’s (USDA) Agricultural Research Service, Dr. Jeanne Chambers of the USDA Rocky Mountain Research Station, the Natural Resource Conservation Service and the US Forest Service to restore native vegetation to retired agricultural land at Rosaschi Ranch on the East Walker River. We are funding research on various native seed mixtures and site preparation techniques with the intent to restore less water-intensive native plants that will also support the native wildlife. The research involved two years of experimental planting techniques followed by two years of data collection (Chambers et al. 2013). The results will be applied to determine the best seeds and techniques to use for a full-scale restoration of the Ranch. This information will also be used for future native re-vegetation efforts on retired agricultural land in the Walker basin.

Sediment Transport Sampling

The Service is funding research to understand sediment transport throughout the Walker River basin, this research will lead to development of projects to reduce excessive sediment in the river and improve the sediment transport capacity of the river. In addition, the Service is working with the Walker River Paiute Tribe and the local National Resources Conservation Service office to reduce erosion throughout the portion of the Walker River that runs through tribal lands. Projects include stabilizing the river from any further incision and reducing impact of grazing along the riparian corridor. Understanding the sediment processes in the basin will help us address some of the root problems landowners face with their river property and sediment flows.

Habitat and Conservation Project on Private Land

The Service is working on developing projects with private landowners focused on preserving the riparian corridor and promoting native habitat. The Service is available to provide technical assistance and assist landowners in identifying potential projects and funding sources for restorative actions. Depending on the scope and scale of the project the Service may be able to provide funding through the Desert Terminal Lakes Program for funding on private lands.

Stabilizing banks on the Lower Walker River

We are working with the Walker River Paiute tribe and the National Fish and Wildlife Foundation to remove a defunct irrigation structure in the lower Walker River. This unused structure crosses the river bed and has functioned as a barrier to the erosion caused by lowered lake levels (headcut) that is working its way up the river. The structure is in danger of failing, which would cause significant damage to the lower river. This project will replace the current structure with a gradient control structure that will stabilize the banks, preventing further erosion and allow for fish passage. Native vegetation will be added to further stabilize the river banks.


Lower Walker River Restoration Projects

The U.S. Fish and Wildlife Service’s Lahontan National Fish Hatchery Complex has recently contracted with Otis Bay Ecological Consulting to complete restoration plans for the Mason Valley WMA and the Walker River Paiute Reservation. This planning builds on a previous biophysical assessment completed by Otis Bay (Otis Bay Ecological Consultants 2009). The restoration planning is expected to be completed in late 2013, with restoration implementation in 2014-2015. Implementation for the MVWMA has begun with the planting of

Walker Basin Fisheries Monitoring

In 2009-2011, the LNFHC conducted fish community and habitat surveys at eighteen sites on the West Walker, East Walker, and Walker River. This is the first system wide standardized survey of the Walker River fish community.


Walker Basin Legislation

The first form of legal protection of the water resources of the Basin came in a 1963 agreement between the California Department of Fish and Game, and the Walker River Irrigation District (WRID) that allowed for the enlargement of Bridgeport Reservoir under the condition that WRID would maintain a minimum pool of 1,500 acre-feet during years when conditions allowed. WRID would also have to agree to a minimum instream flow of the lesser of 50 cubic feet per second or the natural flow on the East Walker River.
During the following decade, national environmental legislation was passed that would eventually be instrumental in paving the way for more formal conservation efforts in the Basin. This legislation included the National Environmental Protection Act (1969) and the Clean Water Act (1972). The California Wild and Scenic River Act, passed in 1972 as well, would come to provide protection for some of the upper sections of the West Walker River.

The steady decline of Walker Lake’s base elevation has resulted in dramatically increased levels of total dissolved solids** (TDS) in the lake that has severely impacted the fishery. The threat of loss of this terminal lake system and its fishery has mobilized a coordinated effort to improve the ecological integrity of the Basin. In 2006, through the legislation of the Desert Terminal Lakes Program, Public Law 109-103, Section 208 (c)(1), $10 million dollars was provided to the U.S. Fish and Wildlife Service (USFWS) to address riverine restoration and noxious weed eradication. This funding has prompted the USFWS to commence a Watershed Assessment of the Basin to prioritize restoration activities and guide funding of restoration projects.
**The amount of all dissolved solids in water, primarily consisting of minerals and salts, but may also include organic matter.

Walker River Basin Decree (7.2MB PDF)
Walker River Basin Decree Amendment

The Walker Advisory Group:

US Fish & Wildlife Service’s Lahontan National Fish Hatchery Complex
Walker River Paiute Tribe
Nevada Division of Conservation Districts
Mason Valley Conservation District
Smith Valley Conservation District
Natural Resource Conservation Service
Nevada Department of Wildlife
The Nature Conservancy
Walker River Irrigation District


Last updated: April 23, 2015