Impacts of Ten-Year Drought on the Water Quality and Lake Levels in Lake Mead

摘要

The Southern Nevada Water Authority (SNWA) and the Bureau of Reclamation havernconducted routine water quality monitoring on Lake Mead for a ten-year period. During thisrntimeframe the water level in Lake Mead has decreased by over 120 feet, a decrease in reservoirrnvolume of 46%. The ten-year water quality sampling program consisted of weekly and monthlyrnsampling within Lake Mead and its sources waters for nutrients, total organic carbon (TOC),rnbromide, and emerging contaminants of concern. Water quality profiles of temperature, pH,rndissolved oxygen and specific conductance were collected throughout Lake Mead from thernsurface to depths greater than 300 feet. The monitoring program included extensive nutrientrnanalysis, chlorophyll a, and disinfection byproduct precursors sampling at the SNWA drinkingrnwater intake. The water quality impacts will be discussed with respect to wastewater effluent,rninvasive species, and drought over the ten-year period. Discussions will consist of possiblernreasons on why water quality in Lake Mead improved over the last ten years, despite decliningrnwater levels.