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What is the Wash?

Real-time Water Quality Monitoring

Current Sampling Sites

Historical Sampling Sites

Real-time Water Quality Monitoring

Water Quality Monitoring Continues

The Las Vegas Wash is the sole drainage from the entire Las Vegas Valley to Lake Mead and contributes approximately 1.5 percent of the total flows to the lake. With an average flow of more than 200 million gallons per day (MGD), the Wash conveys highly treated wastewater, urban runoff, shallow groundwater and stormwater from the valley. Water quality protection in the Wash is crucial because any contaminants from those sources will eventually enter Lake Mead and could pollute our drinking water source. The Wash also is an important habitat for many wildlife species.

In collaboration with federal, state and local agencies, the Southern Nevada Water Authority (SNWA) is working diligently to monitor water quality in the Wash and most of its sources. Programs include real-time water quality monitoring stations using on-site instruments (Hydrolabs), and sample collection and analysis on a regular basis from various strategic locations in the Wash and its tributaries.

A Hydrolab unit is a water quality monitoring device with multiple probes that measure temperature, pH, electrical conductance, turbidity and dissolved oxygen of water. There are currently three stations monitoring real-time water quality in the Wash and its tributaries. The water quality data from these stations is downloaded regularly.

Robert Huening of SNWS setting a Hydrolab in place at the Wash

Detailed water quality studies have been accomplished by intensive collection and analysis of surface and groundwater samples from the Wash and its tributaries. Besides field measurements, water samples are analyzed for their major ion chemistry, nutrients, metals, organic compounds, bacteria and other concerned water quality parameters, such as selenium and perchlorate.

Water Quality Parameters

The Hydrolab is used to measure water temperature, dissolved oxygen (DO) concentration and saturation, pH, and electrical conductivity (EC). It records these parameters every 20 minutes.

Data in Real-time

Currently, sites LW 0.8 and DC 1 are accessible via modem. Data from these telemetry sites is downloaded hourly, meaning that we have access to it nearly at the same time it was measured. Data collected at all of the sites is downloaded weekly, and maintained in a database which can be put into a graph or chart format.

Flow Components

Four components make up the water flowing in the Wash: urban runoff, reclaimed water, shallow groundwater, and stormwater runoff. The sites chosen for monitoring are characterized by one or more of these flow components.

Las Vegas Wash Project Coordination Team • 100 City Parkway, Suite 700 • Las Vegas, NV 89106 • (702) 822-3300