Geology topics

K. T. Garcia

Publications and source records attributed to K. T. Garcia.

3 recordsLinked to original sources

USGS1989

Ground-water quality in Douglas County, western Nevada

A 182% increase in population within the last 10 years in Douglas County, Nevada, has raised concerns by county officials as to the possible effects land development may have on groundwater quality. Most groundwater in Douglas County meets the State of Nevada drinking water standards. Of the 333 water samples used in this analysis, 6 equaled or were greater than the drinking water standards for sulfates, 44 for fluoride, 4 for dissolved solids, 5 for nitrate as nitrate, 12 for arsenic, 33 for iron, and 18 for manganese. Groundwater in the west-central, northern, and northeastern part of Carson Valley is influenced by geothermal water. Some areas in the county may have septic-tank effluent contaminating the groundwater. Temporal changes in most municipal wells showed no overall trend for dissolved-solids and nitrate concentrations spanning the years 1969-83. However, a municipal well in the Topaz Lake area has shown a general increases in the nitrate concentration from 1961 to 1984, but the concentration does not exceed the drinking-water standard. A future groundwater quality monitoring program in Douglas County would include periodic sampling of primary or heavily pumped wells, long-term trend wells, and supplemental wells. (Thacker-USGS)

Nevada↗

USGS1988

Effect of erosion-control structures on sediment and nutrient transport, Edgewood Creek drainage, Lake Tahoe basin, Nevada, 1981-83

Three sites in the Edgewood Creek basin with a combined drainage area of about 1.2 sq mi were selected to assess the effect of erosion-control structures along Nevada State Highway 207, on sediment and nutrient transport. The flow at site one is thought to have been largely unaffected by urban development, and was completely unaffected by erosion control structures. The flow at site two was from a basin affected by urban development and erosion control structures. Site three was downstream from the confluence of streams measured at sites one and two. Most data on streamflow and water quality were collected between June 1981 and May 1983 to assess the hydrologic characteristics of the three sites. As a result of the erosion control structures, mean annual concentrations of total sediment were reduced from about 24,000 to about 410 mg/l at site two and from about 1,900 to about 190 ml/l at site three. Sediment loads were reduced from about 240 to about 10 tons/year at site two and from about 550 to about 110 tons/year at site three. At site one, in contrast, mean concentrations and loads remained low throughout the study period. At site two, sediment particle size changed from predominately coarse prior to construction, to predominately fine thereafter; at site three, it changed from about half coarse sediments to predominately fine. Mean concentration and loads of total iron also were significantly reduced after construction at sites two and three, whereas mean concentrations of nitrogen and phosphorus species did not change appreciably. (Author 's abstract)

Water-Resources Investigations Report↗

USGS1986

Water-quality characteristics and nutrient and suspended-sediment loads, Carson River and Truckee Canal, western Nevada, water year 1980

Lahontan Reservoir is a major recreational site in the Carson River basin in western Nevada. The reservoir is fed by the Carson River and by the Truckee Canal which transports water from the adjacent Truckee River. Water quality in both rivers is influenced by agriculture and urbanization. Specific conductance tended to increase in a downstream direction. Generally, pH values ranged from 7.0 to 8.8. Dissolved-oxygen concentrations were greater than 5 milligrams/L. Calcium and sodium were the dominant cations and bicarbonate the dominant anion. Suspended-sediment concentrations ranged from 3 to 1,790 milligrams/L. Ultimate carbonaceous biochemical oxygen demand ranged from 1.2 to 19.6 milligrams/L. The codominant algal groups were the blue-greens, greens, and diatoms. Background total nutrient and suspended-sediment loads were about 490 tons nitrogen, 130 tons phosphorus, and 200,000 tons suspended sediment. Total nutrient and suspended-sediment loads to Lahontan Reservoir were about 980 tons nitrogen, 300 tons phosphorus, and 300,000 tons suspended sediment. Loads to the lower Carson River from the reservoir were about 820 tons total nitrogen, 180 tons total phosphorus, and 26,000 tons suspended sediment.

Nevada↗