Analysis of Hungry Valley Groundwater Pumping and Management, Washoe County, Nevada

Margaret Shanafield, Jennifer Johnson, Emile Sawyer, Jena Green, Jason Assam, Hesham Becket, Scott Brown, William Carlos, Deeta Fosbury, Darren Meadows, Michael Meinert, Brian Rasmussen, Gitane Royce, Chad Stein, Kurt Unger, Mervin Wright, David Hunkup, Dominic Wolf, Rick Susfalk, and Scott W. Tyler

ABSTRACT
Static water levels and aquifer response in Hungry Valley, Nevada, have been monitored since 2000 by University of Nevada, Reno students in the Graduate Program of Hydrologic Sciences. The ground water of Hungry Valley provides the sole water source for the 152 homes of the Hungry Valley Community. Static water levels in the aquifer have been declining at about 10 feet/year (3 meters/year) since 1989, when pumping began. In 2002, it was estimated that the lifespan of the existing wells was only 1-2 additional years if pumping continued at then current rates. In 2003, new variable speed pumps were installed in both production wells to allow them to operate concurrently and collectively meet the required production of 150 gallons per minute (568 liters per minute). This measure was taken to reduce the net drawdown in both wells. In March 2004, a 24-hour aquifer test was performed to verify the effectiveness of this strategy. The new pumping regime improved the efficiency of Well #5 (the main production well) from 50% to 80%. This improvement in efficiency was also anticipated to result in lower operating costs and an increase in the usable life of the pumps through a reduction in turbulent losses at the previously higher pumping rates. Based on these aquifer test results, it was predicted that the usable life of the existing wells will be extended up to about 9 years at best if these wells are used as the sole supply for the distribution system. The addition of new wells to the distribution system, however, has resulted in a reduced reliance on Wells #4 and #5 and static water levels in these wells have rebounded in 2005.

Keywords:
Citation:
DOI:

Comparison of Bowen-Ratio and Eddy-Correlation Data from an Irrigated Pasture in Carson Valley, Nevada, April-June, 2004 .

Mary L. Tumbusch and Michael J. Johnson

ABSTRACT
Accurate estimates of evapotranspiration are needed to help refine water-budget components in Carson Valley, Douglas County, Nevada. Evapotranspiration from irrigated pasture land in Carson Valley is a major outflow element that contibutes to the water-budget. Two methods to quantify evapotranspiration, the Bowen-ratio and eddy-correlation methods, were applied to instruments collocated at an irrigated pasture for 65 days in April-June, 2004. A Bowen-ratio station and two eddy-correlation stations, one with a one-dimensional and one with a three-dimensional sonic anenometer, were used.
The estimated evapotranspiration calculated for the Bowen-ratio station was 11 to 15 percent higher compared to the two eddy-correlation stations. Total evapotranspiration for 38 days free of equipment malfunction was 217 mm at the Bowen-ratio station, 193 mm at the one-dimensional station, and 185 mm at the three-dimensional eddy-correlation station.
To determine how the three stations compared, estimated evapotranspiration values for daytime hours between 8:00 a.m. and 4:00 p.m. were used. Estimates of total evapotranspiration were 180 mm from the Bowen-ratio station, 149 mm from the one-dimensional eddy-correlation station and 144 mm from the three-dimensional eddy-correlation station. The average evaporative fraction obtained from the eddy-correlation stations was 2 percent higher than that obtained from the Bowen-ratio station. The average estimated Bowen-ratio obtained from the eddy-correlation stations was 16 percent lower than that obtained from the Bowen-ratio station. The Bowen-ratio method compared favorably with the eddy-correlation method in partitioning the sensible- and latent-heat fluxes, but their estimated evapotranspiration values did not compare as favorably. The Bowen-ratio method relies on available energy to derive absolute flux values and the available energy equation did not account for energy lost as heat storage in flood-irrigation water. Not removing this expended energy caused the Bowen-ratio station to, sometimes, overestimate the available energy that is partitioned into latent heat, thus overestimating the amount of evapotranspiration.

Keywords:
Citation:
DOI:

Spring-Water Quality of Owens Valley California through Biological Procedures

Anpalaki J. Ragavan
ABSTRACT
Toxic contaminants are known to cause physiological disorders in aquatic organisms. Such physiological affects are differential in nature, affecting different aquatic macro-invertebrates in measurable ways. The present study investigates the relation between occurrence of taxa in springs and spring-water quality. Specifically, the study 1) compares a suite of biological indices to measures of water quality, and 2) assesses the use of biological indices to make inferences about water quality in the selected springs.
Sampling sites include 11 randomly selected springs from the 11 spring provinces of the Inyo and Mono counties of the Owens Valley in the Sierra Nevada region. The macro-invertebrate population in each spring was characterized by sampling and counting taxa at two locations (source and 25 meters downstream) in each spring. Simple (taxa-richness, enumerations, abundances of the pollution sensitive and pollution non-sensitive species) and complex (biodiversity, species dominance, community stability, and family biotic indices) biological assessment indices were applied to the counts and compared with the measured water quality indices and standards.
The results show that, 1) pollution tolerant and intolerant species exist and respond differentially to contaminants in springs, 2) biodiversity is an important measure of the biological conditions of springs and could be positively or negatively related to dominance, 3) taxa-richness alone is inadequate to assess the water quality in springs, 4) FBI values are good indicators of spring water quality, and 5) man caused site disturbances affect community stability, long-term taxa-richness, and biological conditions to become an important determinant of water quality in springs.

Keywords:
Citation:
DOI:

Sediment-Related Road Effects on Stream Channel Networks in an Eastern Sierra Nevada Watershed

Becky Maholland and Thomas F. Bullard

ABSTRACT
Squaw Creek, a small (21.1 km2), subalpine watershed located approximately 9.6 kilometers northwest of Lake Tahoe, California between the towns of Tahoe City and Truckee, is listed as an impaired waterway for excessive non-point source sedimentation under section 303(d) of the Clean Water Act. The watershed was evaluated from a geomorphic perspective to identify and characterize sources of sediment, including impacts from road networks on sediment delivery to the stream network.
Roads in the watershed contribute to sediment production by concentrating runoff, thereby increasing sediment load to the stream network. Most unimproved (dirt) roads connect either directly or indirectly with streams and, therefore, act as extensions of stream networks by effectively increasing watershed drainage density and subsequently sediment loads to streams. In the South Fork subwatershed of Squaw Creek, road connectivity has resulted in an increase in effective drainage density of approximately 250%. Throughout the Squaw Creek watershed, it is estimated that dirt roads potentially contribute as much as 7,793 metric tons/year to the watershed sediment budget.

Keywords:
Citation:
DOI: