Study suggests diverting spring flows to restore aquifer

A study by Glorieta Geoscience recommended drawing water from springs east of Pahrump, piping it and injecting it into areas of greatest draw down.

This would include where the density of wells is the highest. The study suggested this was the preferred choice of six alternatives for managing future water supply issues in the valley.

The consultants also endorsed water conservation measures.

Nye County paid Glorieta Geoscience $139,611 for the water supply appraisal investigation report using a grant from the U.S. Bureau of Reclamation, the agency that will receive the report.

In the Pahrump groundwater basin, water use exceeds the perennial yield, the report states. The study notes the 2011 Pahrump population was 36,995. Over the next 10 to 20 years, expansion of business and industry is expected to create 855 new jobs in Pahrump, the study said, projections are for annual increases of 1 to 1.75 percent growth, translating to a 2030 population between 46,000 and 53,000 people.

The U.S. Geological Service estimates an average water use of 266 gallons per capita per day in Nye County, which with 2.42 people per household estimated by the U.S. Census Bureau would mean an annual withdrawal per domestic well of .72 acre feet per household, according to the Glorieta Geoscience report.

Aquifer storage and recovery could take two to four years to construct, but consultants said planning and permitting could take much longer. The proposal assumes 1,000 gallons per minute of spring water could be injected into four wells in the areas of greatest historic draw down in the basin. Test wells would be drilled to 1,000 feet. A 12-inch water pipeline traveling 16 miles is projected to cost $5.06 million, consultants estimated the total cost of the aquifer recovery project at $17.8 million, not including water rights and possible water treatment.

Water rights and land would have to be purchased, but consultants said ownership of water rights doesn’t guarantee approval by the Nevada Division of Water Resources and Nevada Division of Environmental Protection. The change of use for 1,610 acre feet of water per year could also be protested.

Consultants said, “An ASR system will reduce the rate of draw down of the valley alluvial aquifer in portions of Pahrump Valley where the effects of over-pumping are the greatest, which will in turn prolong the life of existing domestic and municipal wells. In addition, capturing spring flow and injecting it into the aquifer had the effect of increasing the perennial yield of the basin.”

A no-action alternative would create the perception Nye County isn’t concerned with resource protection or planning, Glorieta Geoscience states. Indirect costs could include loss of property values from subsidence and increased costs of drilling deeper wells; a general economic decline as residents and businesses leave when water supply runs low or the cost of acquiring water rises; and a potential loss of funding from state and federal agencies on cooperative water projects.

The study reviewed the alternative of imposing land restrictions, including increasing the amount of water rights that have to be retired for future subdivisions.

The study notes: “There are 8,542 parcels in the Pahrump Basin that have the right to drill a domestic well and divert up to two acre feet per year. Because the Board of County Commissioners does not have the ability to retroactively restrict wells or water use with regard to these existing lots, restricting domestic well use may only be a viable alternative for addressing basin over-diversion in the near future. However the legal and political ramifications need to be fully vetted before such severe measures are considered.”

A basin-wide water utility was considered, which consultants said has the potential to better control and significantly reduce water use. However consultants said the creation of one or an aquifer recovery program would be necessary before the county could import water. They said the cost of a water importation project pumping for example 5,000 acre feet of water per year into Pahrump Valley from 70 miles away that could serve 30,000 people could cost $172.5 million. Pipeline installation alone would cost $46.9 million.The cost divided by 30,000 people would amount to a fee of $12.15 per month over 40 years.