FIELD SCALE UTILIZATION OF THE SHALLOW SALINE AQUIFER IN CLARK
COUNTY NEVADA AS AN URBAN IRRIGATION SOURCE
- C. Schaan,
WRM, Graduate Student, University of Nevada, Las Vegas
L. Clark, Graduate Student, University of Nevada, Las Vegas
Dr.
Dale Devitt, Soil and Water Scientist, University of Nevada
Robert L. Morris, Cooperative Extension , University of Nevada
INTRODUCTION:
Continued population growth in the Las Vegas valley, associated with
fixed water resources, has compelled water managers, policy makers and scientists alike,
to look at all possible ways of addressing southern Nevada's water supply-demand
dilemma. Future growth and development in the valley (and
even the quality of life for residents) will be impacted to a great extent by how well
existing water resources are managed. As such, all water resources whether of good or poor
quality should be given consideration for incorporation into any water-use master plan
that is designed for the future. Careful thought should now be given to waste-water
utilization as a means of substituting and freeing up good quality water for higher
priority uses. Currently, a sizable fraction of water delivered by the Las Vegas Valley
Water District is used for landscape irrigation purposes.
Many poorer quality waters could be utilized as alternative
irrigation sources, if proper irrigation management is practiced. One potential water
resource that has so far gone untapped is the shallow saline aquifer that exists below
much of the
eastern part of the valley.
Estimates place the volume of this shallow system at 100,000 acre feet or more.
Preliminary research to investigate the potential use of this water as an alternative
irrigation source was conducted by our research team on a small scale basis (18: 44' x 6'
plots). Findings clearly indicated that this water could be used as an irrigation
supplement but not as a sole source for irrigating turfgrass. Under optimum management
conditions, no loss in color, quality or turfgrass stand vigor was observed when either
bermudagrass or tall fescue was irrigated with blended aquifer water possessing an
electrical conductivity of 6.0 dS/m over a two year period (approximately 6 times the salt
load of the Colorado River), which represented a 65% saline aquifer substitution rate.
Such results have encouraged us to transfer our findings to a larger scale on a more
applied level (real world!).
CURRENT STUDY:
We are investigating the use of a shallow saline aquifer as an
alternative
irrigation source for turfgrass. Two turfgrass areas (UNLV
Football Field and Valley High School Soccer Field) have been selected
for research. Shallow wells, storage reservoirs and irrigation system modifications have
already taken place. Each site has been instrumented with tensiometers, salinity 
sensors
and a weather station. Saline irrigation substitution began in 1997. The objectives of the
research are to:
1) Determine the percent substitution of shallow
aquifer water that could occur during summer months without objectionable results as
measured by scientists and local turfgrass managers.
2) Monitor the water and salt balances, soil physical
properties and the associated turfgrass response at each site to assess long-term impacts
of using such water.
3) Determine the economic impact of using such water at the
user level but also at the Water District level (peak demand delivery system costs).
4) Determine any difficulties that might exist in the
transfer of technology at the field scale level and determine ways of overcoming such
difficulties.
5) Summarize research results into an educational program to
implement such technology.
