V. D. Adams and V. A. Lamarra

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Aquatic Resource Management of the Colorado River Ecosystem


Ann Arbor Scientific Publishers, Ann Arbor, Mich.

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The Las Vegas Wash is a wetlands ecosystem that acts to buffer the effects of wastewater discharges on the receiving waters of Lake Mead. The wash is the terminus for the 4,144 km2 Las Vegas Valley drainage basin, emptying into Las Vegas Bay of Lake Mead (Colorado River). It is in the northern Mojave desert, which receives an average of only 10 cm of rainfall annually. The Las Vegas Wash is technically an artificial wetland supported almost entirely by the perennial flows from sewage treatment plants. These flows contribute an average of 3-7 t of nutrients (nitrogen and phosphorus) and 4 t of oxygen consuming organic material (BOD5) to Lake Mead per day. High nitrate and total dissolved solid loads (2.7 and 603 t/day respectively) are derived primarily from groundwater inputs in the lower wash [1,2,3]. The contaminated groundwater originates from large underground salt mounds that were formed from discharges of industrial effluents into unlined evaporation ponds until 1978.

Conflicting interests among municipal, recreational, and down-river users make the Las Vegas Wash a focal point in current legal disputes regarding the need for advanced wastewater treatment (AWT). In light of rapidly escalating costs, especially for energy and chemicals needed for AWT, many municipalities nation-wide are investigating alternative treatment techniques. Public Law 92-500, Section 210 (parts d and f) specifically encourages the reclamation and recycling of wastewaters. Operation of treatment facilities to produce revenue through the production of agriculture, silviculture, or aquaculture products is encouraged. Combinations of open space and recreational uses with waste treatment management techniques are also emphasized in PL 92-500.

The Las Vegas Wash ecosystem has been identified as a potential wastewater treatment system. Previous investigations [4,5] indicate that the ecosystem could be removing substantial amounts of nutrients from wastewaters. Goldman and Deacon [5] recommended "that a specifically designed nutrient removal management program be developed and implemented with the flow distribution and erosion control program necessary to maintain wetland wildlife habitat."

The purpose of this paper is to describe historical and current water quality and to quantify the degree of nutrient removal presently occurring in the Las Vegas Wash.


Effluent quality; Engineered wetlands; Impoundments; Las Vegas Bay (Nev.); Las Vegas Wash (Nev.); Limnology; Nitrogen concentrations; Solid waste management; Waste water reclamation


Biochemistry | Desert Ecology | Environmental Health and Protection | Environmental Indicators and Impact Assessment | Environmental Monitoring | Environmental Sciences | Fresh Water Studies | Natural Resources and Conservation | Sustainability | Terrestrial and Aquatic Ecology




"Proceedings of the 1981 Symposium on the Aquatic Resources Management of the Colorado River Ecosystem, November 16-18, 1981, Las Vegas, Nevada sponsored by Office of Water Research and Technology (U.S. Department of Interior), Utah Water Research Laboratory, and Utah State University"--P. [iii]

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