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Sub-Surface Water Resources in the Arid West: Prospects and Potential Problems

In the arid states of the western US, sub-surface water commonly referred to as groundwater provides a significant portion of the water resources needed for long-term ecologic and economic stability and sustainability. According to estimates of the Nevada Department of Conservation and Natural Resources, groundwater the allocation of which is effectively controlled by the State, provides about 40 percent of the State’s total water supply needs. A relatively small portion of that resource lies directly beneath tribal lands, a factor that implies that much of the groundwater available to reservations originates away from the reservations and that any additional tribal water needs will necessarily come from sources beyond those lands; sources controlled and distributed by non-Native entities.

Because supplies of surface water in Nevada are fully allocated either by agreements with the State or the US government, additional water needs for industrial and agricultural development as well as population expansion, will require either the extraction of portions of the 60 percent of unallocated groundwater or the transfer of existing groundwater rights. Prolonged periods of drought such as the one the western US has experienced for the last decade results in reduced quantities of surface water and additional demands on a groundwater resource that is further diminished by a reduction in recharge water from the surface. Thus as demands increase, supplies decrease.

Quantity is one term in the equation that describes the functioning of the groundwater system. Another term of equal importance is quality. Water quality is controlled by a number of factors including

· Regional and local geology

· Ecosystem demands

· Human uses both municipal and industrial

Water quality is complex and rather more subjective than quantity because it is based on the presence and abundance of a number of physical, chemical and biological parameters of the water that are governed by its intended use. For example, water for drinking or human contact must necessarily be of higher quality, i.e., fewer and lower levels of recognizable and measurable contaminants, than water to be used for industrial processes only. Quality of water needed to support ecosystem, though lying between the two extremes more closely approaches that of human needs.

Regardless of the intended use of the water, contaminants, some of which are pathogenic with varying levels of toxicity to humans and terrestrial and aquatic organisms, that may contribute to reduced water quality include

· Microorganisms

· Sediment

· Elemental chemical species – nitrate, phosphate, etc.

· Metals – lead, mercury, arsenic, etc.

· Pesticides & Herbicides

· Hydrocarbons – petroleum, PAH’s, NAPL’s, DNAPL’s, etc.

· Radioactive particulates

Those contaminants may enter the groundwater from both point and distributed (diffuse) sources that include

· Industry

· Agriculture

· Surface runoff

· Treated and untreated human wastes

Once in the system, removal may require extensive and expensive treatment at best and abandonment of the water bearing aquifer with total loss of supply at worst.

The effective and efficient management of groundwater resources in the arid western US grows in importance as more communities and industries, Native and non-Native alike, come to depend on this finite and environmentally sensitive resource for life sustaining activities. Native American communities must be proactive in the conservation of those resources if they are to protect their peoples, advance their culture and take their rightful places in the mainstream of the US economy.

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