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Southern Nevada Water Authority


Urban run off and treated wastewater travel through the Las Vegas Wash

Urban run off and treated waste water
travel through the Las Vegas Wash
to Lake Mead.

The Las Vegas Valley watershed includes Lake Mead and the valley's hydrographic basin, which measures approximately 2,200 square miles.

Snowmelt in the surrounding mountains and precipitation feed the hydrographic basin, which drains into the Las Vegas Wash and eventually empties into Lake Mead.

Protecting the Watershed

Several local water and wastewater agencies developed the Las Vegas Valley Watershed Advisory Committee in 2007 to help protect the area's watershed. Monitoring and management of the watershed are critical to protecting the region's overall water quality.

The committee considers all water sources in the hydrographic basin as part of the watershed. This includes groundwater, shallow groundwater, urban runoff, stormwater and treated wastewater flows.

The Las Vegas Wash serves as an "urban river," feeding treated wastewater, urban runoff and stormwater into Lake Mead. The Wash also provides wetland habitat for numerous species and wildlife.

Lower Colorado River Regional Water Quality

In an effort to share water quality data collected on the lower Colorado River, regional agencies have added their findings to the Southern Nevada Water Authority's Lower Colorado River Regional Water Quality Database. Please fill out the Lower Colorado River Regional Water Quality Database interest form for access to more information about water quality.

Water Sources

The Las Vegas Valley watershed has three distinct sources:

Colorado River

Fed by precipitation and snowmelt in the Rocky Mountains, the Colorado River runs through seven western states. It pools behind Hoover Dam to create Lake Mead, the largest reservoir in the United States. Nearly 90 percent of the area's water supply comes from the Colorado River.

Local Groundwater

The valley's principal aquifer supplies Clark County residents and businesses with about 10 percent of its water supply.

Non-Point Water Sources

Urban runoff, shallow groundwater and stormwater flow through the Las Vegas Valley and feed into Lake Mead by way of the Las Vegas Wash.

Shallow groundwater is both naturally occurring and created by excess landscape irrigation. This water typically lies within 50 feet of land surface.

Urban runoff includes water that begins in street gutters and travels through the storm drain system and enters Lake Mead untreated through the Las Vegas Wash. Stormwater runoff also enters Lake Mead via the Las Vegas Wash.

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Video: Las Vegas Wash

Learn how the Las Vegas Wash helps protect our water supply. Play

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