A Chemical Stable And Radioisotopic Investigation Of An Alluvial Fill Groundwater System In A Semi Arid Environment Southern Utah Valley Utah

Author : Frank W. diemel
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.5/5 (346 download)

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Download or read book An Isotopic Investigation of the Sources of Recharge to the Coachella Valley Aquifer System, Riverside County, California written by Frank W. diemel and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: For stakeholders in the Coachella Valley, the Coachella Valley Aquifer system is the main source of water, and has been under drawdown conditions since 1936. Presently, Coachella Valley water authorities import up to ~225,000 Af/y of Colorado River water to combat continued over-development. In this investigation, stable and radioisotopes of water and carbon in approximately 80 samples of combined spring, surface waters and well waters from the study area are used to contrast and compare a stable water isotope water-budget versus the water-budget of the USGS 1974 "Analog Model Study of the Ground-Water Basin of the Upper Coachella Valley, California". Stable water isotope data (n = 56) demonstrate springs, surface waters, and wells located in the San Jacinto and San Bernardino mountains plot as a Local Meteoric Water Line defined as Î4D = 8.7Îþ18O + 19.4. Hot and warm springs (n = 6) of the Cahuilla Nation in the Palm Canyon watershed define a regional evaporation trendline written as Î4D = 5.2Îþ18O - 21. Stable water isotopes suggest San Gorgonio and Mission Creek subbasins underflow comprise ~72% of the groundwater recharge to the Indio subbasin. Snowmelt runoff from the Whitewater River and Mission Creek watersheds along with mountain front runoff from the flanking watersheds of the San Jacinto and Santa Rosa mountains are other sources of recharge to the Indio subbasin. There is very little mixing of groundwater from the Desert Hot Springs subbasin with the Indio subbasin groundwater. Nested wells located at the Windy Point recharge facility demonstrate shallow wells have stable water isotope values similar to imported Colorado River water, deep wells having stable water isotope values similar to wells and low elevation springs located in the San Gorgonio subbasin, validating underflow as a major source of recharge. Stable water isotope values in mid-depth Windy Point nested wells demonstrate an ~ 40% to 60% imported Colorado River water versus native Whitewater River surface water mixture. Piper diagram analysis of major-ion concentrations demonstrate mixing of imported Colorado River water and Whitewater River surface water in mid-depth Windy Point wells. Chloride versus Sulfate analysis of three mid-depth Windy Point wells show an ~40% to ~60% mixture of imported Colorado River water and Whitewater River surface water validating the stable water isotope observations. There is little to no underflow contribution from the Whitewater River watershed to the Indio subbasin. The Analog Model overstates the Whitewater River watershed groundwater contribution to the Indio subbasin, and understates the Mission Creek groundwater contribution to the Indio subbasin. Wells located At the Windy Point recharge facility Stable water isotopes datum points suggest the groundwater contribution to the Indio subbasin from the San Gorgonio Pass subbasin is ~48%, and Mission Creek subbasin ~24%. Or, approximately 12864 Af/y, and 6336 Af/y, respectively.Îþ18O and Î4D, C14 and Tritium in sample waters suggest recharge to the Coachella Valley Aquifer system occurs mostly as winter precipitation as snow in the watersheds of the flanking Santa Rosa, San Jacinto and San Bernardino mountains; with limited recharge occurring on the Coachella Valley floor. Taken together, stable water isotopes and radioisotopes of sample waters provide water managers and Engineering Geologist inexpensive tools for tracing groundwater recharge and groundwater movement in a compartmentalized aquifer system.