Excess sediment in the Walker River has been a concern for land managers because of its effects on aquatic and riparian resources. Flow regulation and diversion structures have altered the balance between sediment supply and transport, causing sediment to no longer be carried downstream or deposited across floodplain areas. For The Walker River sediment study, Otis Bay established sampling sites and a sampling protocol for collection of bedload and suspended sediment samples throughout the Walker River, Nevada. Otis Bay sieved and conducted particle size and suspended sediment analyses of the collected samples. In a continuing collaborative effort with the USFWS and other scientists, Otis Bay’s fluvial geomorphologist, Dr. Edmund Andrews, analyzed the sediment data to develop relationships between sediment transport and streamflow of the Walker River.
The Walker River sediment transport analysis included the following tasks:
- Establishment of sampling sites along the East Fork, West Fork and main stem of the Walker River.
- Collection of bedload and suspended sediment using wading, cableway, and raft sampling techniques.
- Sieving and filtering of samples in the laboratory for determination of sediment particle size.
- Comparison of particle size distributions with associated discharge.
This project aimed to develop stream flow prescriptions to improve aquatic and riparian habitat as well as maintain Walker River ecosystem function.
A final report was submitted to USFWS in August 2013. Specific flow prescriptions are being developed.