Document Type


Publication Date


Publication Title

Journal WPCF





First page number:


Last page number:



Wastewater effluent-laden waters from Las Vegas Wash (LVW) form a density current that may be detected in Boulder Basin of Lake Mead at considerable distances from the wash estuary. This led to the suspicion that water from the inflowing stream [40 mgd (1.5 X 105 cu m/day)] might not be rapidly diluted in the enormous volume of the lake [19 mil acre-ft (2.3 X 1010 cu m)], but might persist as a recognizable entity to the vicinity of the intake of a major water source for populous Clark County, Nev.

Because of the detection sensitivity implicit in the use of bacteria as tracers, the signal amplification factor inherent in their growth on media, and precedent in work on streams and air, it was decided to investigate the possibility that they might be used to study the practical problem under consideration.

Ideally, certain thermophilic spore-forming bacteria may be deliberately added as tracers. The next best choice would be a rnesophilic spore former (such as Bacillus subtilis var. niger), and a third alternative would be naturally occurring populations of bacteria indigenous to LVW. The last alternative was adopted because of the health hazards (though slight) inherent in adding large numbers of spores to the envirqnrnent under investigation.


Density currents; Effluent quality; Hydrobiology; Hydrochemistry; Lake Mead (Ariz. and Nev.); Las Vegas Wash (Nev.)


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