Document Type

Technical Report

Publication Date



U.S. Department of the Interior: Bureau of Reclamation


The purpose of the Las Vegas Wash Advanced Water Quality Study is to determine the existence, extent, and mechanisms of nutrient and toxin stripping in Las Vegas Wash under present conditions and under future conditions, both with and without construction of the proposed salinity control unit as described by the Bureau of Reclamation (USBR, 1982b). This study was performed for the Lower Colorado Region Division of Planning by personnel of the Environmental Sciences Section of the Division of Research and Laboratory Services, E&R Center, Denver, Colorado. Work on the study began in February 1983.

The general approach adopted for this study consisted of three parts:

1. Four regular field samplings (in February, June, July, and August 1983) and one storm event sampling (in March 1983) to assess present water quality conditions in the wash. Additional water samples were collected in September to identify changes, if any, in water quality following a major storm event.

2. A thorough review of all available data from previous studies of Las Vegas Wash to assess water quality changes and trends over the past 10 to 15 years.

3. A review of the technical literature on wetlands as water treatment systems to provide insight into the possible physical, chemical, and biological mechanisms operating in the marsh and to serve as a theoretical basis for extrapolating various future conditions.

Thirteen water quality sampling stations were established in and around Las Vegas Wash for the assessment of present conditions. They included the same stations used in the WQSS (Water Quality Standards Study) performed by Brown and Caldwell 1/ in 1979-81 (stas. 1 through 5). Three of these stations are located at USGS (U.S. Geological Survey) stream gaging stations (stas. 1, 3, and 5), and two of them (stas. 1 and 5) are also USGS water qua!ity monitoring stations.

Five stations are located on various "tributaries" of Las Vegas Wash and represent a range of water quality inputs to the wash and, in some cases, to the proposed bypass channel. These stations are located as follows:

1. MRF (Monson Road Floodway)

2. TAF (Tropicana Avenue Floodway)

3. DC (Duck Creek)

4. AD (Alpha Ditch)

5. GWD (the ground-water drain which crosses Pabco Road just south of the wash)

Finally, three additional stations (stas. 2A, 2B, and 3A) were established as the study progressed in an effort to better define changes between channelized and marsh sections of the wash…

This report is divided into two separate sections, dealing with toxics and nutrients, respectively. Field measurements and sampling for both aspects of this study were carried out as a single operation on the dates listed in table 1; however, data analyses and interpretation were performed separately. The final section of this report draws together and summarizes the main conclusions of both aspects of the Las Vegas Wash Advanced Water Quality Study.


Environmental monitoring; Las Vegas Wash (Nev.); Sedimentation and deposition; Water contamination; Water quality; Watersheds


Biochemistry | Biology | Desert Ecology | Environmental Health and Protection | Environmental Indicators and Impact Assessment | Environmental Monitoring | Fresh Water Studies | Natural Resources and Conservation | Water Resource Management