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What is the Wash?

Mainstream Water Quality

Mainstream monitoring of the Las Vegas Wash is being done in order to establish data that reflects current water quality conditions. The data from the program, which began in August 2000, will provide an established mark for water quality comparisons as the Wash channel is stabilized and wetland areas are enhanced. In addition, the data collected in this study will be utilized when interpreting the results of the macroinvertebrate study.

The goal of these and other environmental monitoring programs is to help in the design and management of the Las Vegas Wash in order to maximize environmental benefits. The water quality data obtained will help provide us with a better understanding of current conditions in the Wash and the effects of wetland vegetation on water quality.

Collecting water samples at the Wash

Sampling Sites

Samples are collected at eight sites along the Las Vegas Wash. Beginning downstream of Lake Las Vegas, near Northshore Road (LW0.8), and progressing upstream towards Fire Station Weir (LW3.1), Calico Ridge Weir (LW4.95), Upstream of the Historic Lateral Weir (LW5.5), downstream of Pabco Weir (LW5.9), Upstream of Pabco Weir (LW6.85), and above the confluence of the Monson Channel (LW8.85). The eighth site is located above the City of Las Vegas Wastewater Treatment Plant (LW10.75).

Sampling Frequency and Parameters

Data collection and sampling procedures for each of the eight locations are performed using standardized methodologies. Samples are collected on a monthly basis and measured parameters include heavy metals, cation-anion, perchlorate, nutrients and bacteria. In addition, a Hydrolab multi-parameter water quality probe is used to measure water temperature, dissolved oxygen concentration, pH, and electrical conductivity.

Sample Type
Heavy Metals
Aluminum, Antimony, Arsenic, Barium, Beryllium, Cadmium, Calcium, Copper, Chromium, Iron, Lead, Manganese, Magnesium, Mercury, Nickel, Potassium, Selenium, Silver, Sodium, Thallium, Zinc
Sodium, Potassium, Calcium, Magnesium, Bicarbonate, Chloride, Fluoride, Sulfate, Electrical Conductivity, Total Dissolved Solids (TDS) Total Suspended Solids (TSS)
Previously manufactured in the Las Vegas Valley and has been detected in shallow ground water
Filtered and unfiltered samples for analyses of organic and inorganic nitrogen and phosphorus, total kjeldahl, ammonia, nitrate and nitrite
Samples of water for analyses of presence/absence and cell counts of both fecal coliforms and E.coli
A Hydrolab-brand water quality probe is used to collect temperature, dissolved oxygen concentration, pH, and electrical conductivity

Results - Example

The study has been ongoing for several years now and a significant amount of data has been generated. The chart below shows average Total Suspended Solids (TSS) concentrations at the four sampling locations along the Wash.

Average TSS in the Las Vegas Wash at LW10.75, LW5.9, LW5.5 and LW0.8

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