Authors: Christopher Woltemade*, Shippensburg University
Topics: Water Resources and Hydrology, Environmental Science, Resources
Keywords: California, water budget, salmon, irrigation, water conservation
Session Type: Paper
Presentation File: No File Uploaded
The Navarro River watershed in coastal northern California provides critical habitat for Coho Salmon and steelhead trout, but low summer streamflow limits habitat quality due to poor hydrologic connectivity, warm water temperatures, and low dissolved oxygen. Strategies to improve salmonid habitat include managing agricultural irrigation and other water use to increase summer streamflow. One such strategy is adding water storage ponds and tanks to replace summer diversions from streams with winter diversions to fill storage. A monthly water budget was developed for the watershed to assess the potential for flow enhancement via such water conservation efforts and the Heat Source stream temperature model was used to assess impacts of flow rate on thermal conditions. Results indicate that adding 12,335 m^3 (10 acre-feet) of storage in key tributary sub-watersheds would increase summer streamflows by 0.8 to 1.1 L/s. That represents up to a 12 percent increase in summer streamflow during a moderate drought and up to 100 percent or greater increase during a severe drought. Adding sufficient water storage to eliminate summer diversions could increase streamflow by up to 21 L/s in tributaries and up to 58 L/s in the mainstem Navarro River. Warm water temperatures associated with solar heating of low-volume summer flows would be moderated by increased flow volume. Given the sensitivity of California salmonids to minor changes in summer streamflow, the calculated flow benefits of water conservation would markedly improve salmonid habitat.