| Abstract: | Rapid population growth in Douglas County, an area of approximately 750 square miles in west-central Nevada, has led to concern about the present and future effects of development on ground water. This report describes the results of two nonparametric statistical procedures applied to detect trends in concentrations of chloride, dissolved solids, and nitrate in ground water. The water-quality data consist of analytical results from ground-water samples collected and analyzed by the U. S. Geological Survey and ground-water-quality data provided by the Nevada Bureau of Health Protection Services for the Carson Valley and Topaz Lake areas of Douglas County, Nevada. For purposes of this study, statistical significance, expressed as the p-value, was set at 0.1. The Mann-Whitney-Wilcoxan rank-sum test detected increasing step-trends for nitrate in one of seven residential areas and for dissolved-solids concentrations throughout the study area. Decreasing step-trends for chloride and dissolved-solids concentrations were detected in the west Carson Valley area. Kendall‘s Tau detected monotonic trends for increasing nitrate concentrations at four domestic wells and for increasing dissolved-solids concentrations at two domestic wells. No other statistically significant trends were indicated by either test. Land-use relations to areas where increasing trends were detected suggest that the density of individual wastewater-treatment systems may exceed the capacity of soils to treat wastewater leachate. |
| Genre: | USGS Numbered Series |
| ProdID: | 30106 |
| Citation Author: | Thodal, C. E. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | - |
| Citation Editor: | |
| Citation End Page: | |
| Citation Issue: | |
| Citation Keywords: | |
| Citation Language: | ENGLISH |
| Citation Larger Work Title: | |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | iv, 32 p. :ill., maps ;28 cm. |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | U.S. Geological Survey ;
Information Services [distributor], |
| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 95-4254 |
| Citation Search Results Text: | Trends in chloride, dissolved-solids, and nitrate concentrations in ground water, Carson Valley and Topaz Lake Areas, Douglas County, Nevada, 1959-88; 1996; WRI; 95-4254; Thodal, C. E. |
| Citation Start Page: | |
| Citation Volume: | |
| Citation Year: | 1996 |
| Type: | citation/reference |
| Text: | Trends in chloride, dissolved-solids, and nitrate concentrations in ground water, Carson Valley and Topaz Lake Areas, Douglas County, Nevada, 1959-88; 1996; WRI; 95-4254; Thodal, C. E. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/wri/1995/4254/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/wri/1995/4254/report.pdf |
| Date Other: | Sun, 1 Sep 1996 00:00 -0500 |
| Publisher: | U.S. Geological Survey ;
Information Services [distributor], |
