RFQ #26-0407 - Water Resources Engineering and Environmental Consulting Services for Preparation of a Planning Feasibility Study for a Project to Repair High Mountain Lakes and Enhance Flows for Salmonids in the Scott River System

The United States Fish and Wildlife Service (Service) issued an award to the County of Siskiyou to perform work as described in Exhibit A, Planning Project: High Mountain Lakes Repair to Enhance Flows for Salmonids in the Scott River System. In addition, The California Department of Fish and Wildlife (CDFW) has committed to providing technical and scientific assistance and support as part of the planning study.

The High Mountain Lakes are 33 reservoirs located within the mountain ranges surrounding Scott Valley, and many are within three Wilderness areas, the Marbles, Russians, and Trinity Mountain Wildernesses. These reservoirs are naturally existing, however, outflow and maintenance structures were constructed in the early 1900's by hand prior to the Wilderness Act. After construction of the outflow and maintenance structures, these reservoirs were utilized for irrigation and/or hydraulic mining. Many of the constructed structures were later destroyed during the 1964 floods and were not repaired afterward as they were no longer being actively used for irrigation or mining.

The reservoirs currently continue to fill through natural inflow, however, outflow is no longer maintained and storage capacity as a result of the damaged maintenance structures has decreased. For several decades, the use of these reservoirs has come up in discussion for potential in-stream flow benefits. These discussions have centered around the possibility of storing winter precipitation and inflow to be later utilized to supplement stream and river flows during critical salmon migration, ideally July-September. Proponents of repairing the High Mountain Lakes to enhance summer flows for salmonids have agreed that all stored water would be utilized solely for in-stream benefits. It is estimated that the 33 reservoirs could provide upwards of 3,520 acre-feet of additional flow to the tributaries to Scott River and the main stem Scott River, however in-depth analysis is needed to verify this information.

The proposed project could provide clear and defined information on the effort and resources needed, and benefits of, restoring the High Mountain Lakes, and will define a clear path forward to accomplishing their restoration. The future use of the High Mountain Lakes could provide a dependable supply of approximately 3,520 acre feet of cold, clean water to tributaries of the Scott River and to the mainstem of the Scott River. Such supply of cold, clean water would aide in resolving long-standing issues for salmon fisheries during late summer months.