Comstock water has mother-lode potential

The historic water source for the Comstock lode may become an important part of plans to meet the needs of Western Nevada residents for years to come.

Prepared for the Carson Water Subconservancy District by Brown & Caldwell engineering services, a recently completed report on the status and potential of the Hobart-Marlette Lake water system states the system "Is a source of exceptionally high-quality water for municipal use. Its value may best be realized as a primary source of water for municipal; and industrial use by Carson City, Virginia City and other municipalities within the Carson River watershed."

Identified as a critical component within the overall plan to increase flexibility of future water supplies throughout the Carson River water basin, the historic system was studied from its origins in the Carson Range between Lake Tahoe and Carson City to its final point of delivery to the Ash Canyon Water Treatment facility west of Carson City. Alternatives evaluated to find the most cost efficient means of accomplishing their goals in a phased manner included:

-- Repair and maintenance of specific portions of the existing system.

-- Construction of a parallel pipeline between the Incline Tunnel exit and Red House diversion facility.

-- Construction of a borehole from Marlette Lake to Hobart Reservoir.

-- Construction of a permanent pumping station attached to the existing pipeline from Marlette to the Hobart Creek drainage.

-- Increasing storage capacity of Marlette Lake and/or Hobart Reservoir.

-- Construction of a parallel pipeline between the Tanks and Ash Canyon Water Treatment facility.

-- Construction of higher capacity delivery systems, recharge basins and supply well on the alluvial fan immediately to the west of Carson City.

The report recommends a four phased construction plan for the repair and replacement of current water system components, beginning with the repair of the existing east slope collection system. Total estimated costs for completion range between $5.8 million to $14.4 million, depending upon whether gas, diesel or electricity is used to power a proposed Marlette pumping station. If a borehole is built between the Marlette and Hobart reservoirs, allowing gravity to move the water, the cost is estimated at $10.7 million.

The State of Nevada currently owns 12,400 acre feet of Marlette-Hobart water rights; however, Subconservancy District General Manager Ed James cautioned, "That is a theoretical number based on what the state has filed on. It is saying what you can do on paper, but physically there is not that much water there."

James noted "You can not get water quality better than this. There is extra water available and opportunities to enhance the flow, but up until now there has not been a demand."

He noted that grants should be available to help alleviate the costs of the project.

Using a 22-year period of recorded data, the report set the calculated average yearly flow (runoff) of 6,108 acre-feet as a reasonable target goal. A firm yield (based on dry year runoff) of approximately 1,880 acre feet can presently be counted on.

The report will be presented for comment to the Carson City board of Supervisors, and a special legislative committee dealing with Marlette water issues.

The Marlette-Hobart system was originally used to divert water for use in the Comstock mining era. The system currently delivers water to Carson City, Virginia City, Gold Hill and Silver City. The state owned water rights are sold to various municipal and regional entities. The major sources of surface water for the Marlette-Hobart system comes from runoff in three drainage basins - Marlette Lake Basin, Hobart Creek Basin and the East Slope Basin.