Atmospheric noble gases (He, Ne, Ar, Kr, and Xe) dissolved in groundwater are a valuable tool in hydrology. Numerous studies have relied on groundwater recharge temperatures calculated from dissolved noble gas data (noble gas temperatures, NGT) to infer paleoclimate conditions. This research investigated gas dissolution during groundwater recharge and critically examined the use of dissolved noble gas data in groundwater research. A detailed investigation of an agriculturally impacted shallow aquifer allowed comparison of measured water table temperatures (WTT) with calculated NGT. Results suggest that NGT calculated from widely used noble gas interpretive models do reflect measured WTT, supporting the use of dissolved noble gases to deduce recharge temperatures. Samples having dissolved gas concentrations below the equilibrium concentration with respect to atmospheric pressure were attributed to denitrification induced gas stripping in the saturated zone. Modeling indicated that minor degassing (<10% [Delta]Ne) may cause underestimation of groundwater recharge temperature by up to 2 °C. In another study a large dissolved noble gas data set (905 samples) from California was analyzed. Noble gas modeling using the same interpretive models indicates that multiple models may fit measured data within measurement uncertainty, suggesting that goodness-of-fit is not a robust indicator of model appropriateness. A unique aspect of this study was the high Ne and excess air concentrations associated with surficial artificial recharge facilities. A final study examined whether climatic/hydrologic changes occurring over glacial-interglacial time periods could impact the accuracy of NGT used in paleoclimate studies. Numerical modeling experiments estimated WTT sensitivity to changes in: 1) precipitation amount, 2) water table depth, and 3) air temperature. Precipitation and water table depth had a minor impact on WTT (~0.2 °C). In contrast, the impact of air temperature changes on WTT was more pronounced. Results suggest that air temperatures inferred from NGT data may underestimate actual air temperature change since the last glacial maximum by ~1 °C at sites having seasonal snowcover. These results suggest despite uncertainty in the exact physical processes controlling gas dissolution during groundwater recharge, NGT do reflect WTT. However, inferring paleo-air temperatures from NGT are subject to error, especially locations with seasonal snowcover. / text

Project Completion Report, OWRR Project No. A-011-ARIZ / Agreement No. 1071 / Project Dates: July 1967 - June 1969. / Acknowledgment - The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Research Act of 1964. / The purpose of this investigation was to characterize salvageable water resources in the semi-arid Tucson basin and to evaluate appropriate treatment and control methods and management procedures for reuse of these salvageable waters. A preliminary inventory of salvageable water resources in the Tucson basin indicated a conservatively estimated annual total of 30,000 acre-feet available, as follows: municipal system effluents, 25,000 acre-feet; industrial cooling effluents, 1,000 acre-feet; urban runoff, 2,000 acre-feet; and industrial processing waters and other minor sources, 2,000 acre-feet per year. The City water utility has ample information on hand regarding quality of municipal effluents; data collected during this study are sufficient to define representative quality of industrial effluents; and presently developed processes evidently are adequate for the control and treatment of salvageable waters. However, little was known of the quality of urban runoff in this semi-arid environment, and efforts were directed toward exploratory sampling and analysis as indicators of potential problem areas in runoff quality. A ground-water recharge investigation at the Rillito Creek recharge site near Tucson produced a mathematical model which can be used to represent fluctuations of ground-water levels resulting from line-source recharge. Findings can be applied to alternative management schemes in the utilization or storage of salvaged waters. Initial formulation of management alternatives by examination of local salvaged-water subsystems appeared not to require elegant mathematical solution but rather an improved system framework defining community objectives and criteria for salvaged water allocation.

Introduction: A trip was taken from July 3 to July 17, 1985 to Sudan to study the El Obeid compartmented reservoir system. This system supplies most of the domestic water for the city of El Obeid which has a population of 200,000 to 250,000 people. This water supply was exhausted in March of 1985 and the town was out of water until the monsoon rains began July 2, 1985. Approximately one week was spent in El Obeid and Kadugli. The remainder of the time was spent in Khartoum where the IBM PC was used. Some time was also spent in Khartoum in obtaining flattened ceramic spheres for evaporation control.

No description available.

Estimation of recharge in a small southern Arizona basin by means of hydrological, hydrochemical, and environmental isotope data / A completion report for the Office of Water Research and Technology, U.S. Department of the Interior, Project No. A-099-ARIZ, Grant No. 14-34-0001-1103 / Principal Investigator: Shlomo P. Neuman, by Eilon Adar / December 1983

Identification of recharge waters, groundwater flowpaths, and solute sources is needed to best manage the increasing salinity of the Hueco Bolson aquifer, the primary water resource for El Paso, Texas and Juárez, Mexico. To address these issues, we have analyzed for a suite of geochemical tracers on water samples collected from 33 discrete vertical zone test holes. On the basis of δD and δ¹⁸O data, two regional recharge sources were recognized, one originating from western mountain-fronts and one from through-flow of the adjacent Tularosa aquifer. Chloride concentrations were strongly correlated with lithologic formations and both Cl/Br and ³⁶Cl ratios suggested halite dissolution within the Ft. Hancock formation as the primary chloride source. In contrast, sulfur isotopes indicated that most sulfate originates from Tularosa Permian gypsum sources. These sources suggested that chloride salinization of wells is the result of direct upconing of waters from the Ft. Hancock formation.

The Middle San Pedro Basin in southeastern Arizona is a typical alluvial basin in the semi-arid southwestern United States with a rapidly growing population that is dependent upon groundwater resources for water supply. This study investigated recharge areas, compartmentalization and potential mixing of water sources, and travel times of groundwater throughout the basin using variations in major ion chemistry (water type, Ca/Sr ratios, SO4/Cl ratios) and isotope ratios (18O, 2H, 3H, 34S, 13C, 14C) of groundwaters, surface waters and precipitation in conjunction with hydrogeologic data (e.g. hydraulic head and hydrostratigraphy). Recent recharge (<50 years) has occurred within mountain systems along the basin margins, and in shallow floodplain aquifers adjacent to the San Pedro River. Groundwaters in confined aquifers in the central basin were recharged at high elevation in the fractured bedrock and have been extensively modified by water-rock reactions over long timescales (up to 34,600 years). These results can be used to constrain physical assumptions of future groundwater flow models designed to help make improved water management decisions.

Groundwater levels in the Wheatbelt of Western Australia are rising and causing severe and widespread land salinisation. Evidence from northern Victoria showed that episodic recharge pulses following floods had caused significant groundwater rises. The aim of this study was to determine: 1. whether episodic recharge was significant compared to regular recharge in the Wheatbelt; 2. the conditions under which episodic recharge occurs. (For complete abstract open document)

Thesis (M.S.)--University of Arizona, 1969. / Partially funded by U.S. Dept. of the Interior, Office of Saline Water, under research grant no. 14-01-0001-630. Includes bibliographical references (leaves 92-94).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Sept. 18, 2008). PDF text: ix, 228 p. : ill. (some col.) , maps (some col.) ; 4 Mb. UMI publication number: AAT 3297902. Includes bibliographical references. Also available in microfilm and microfiche formats.