From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona / Potential groundwater contaminant sources in the upper Santa Cruz basin include copper mines, irrigated agriculture, and urban wastewater. Risks to human health are posed by groundwater contaminants. Analysis of these risks provides useful information to decision makers for comparing groundwater quality management alternatives. Alternatives include preventing the input of contaminants at their sources, preventing migration of contaminants in groundwater to withdrawal points, removal of contaminants at the points of groundwater withdrawal, relocation of withdrawal points, importation of water, and compensation for those who suffer damages. The framework for risk analysis is composed of hazard identification, hazard estimation, risk estimation, and identification and evaluation of risk response alternatives. Potential contaminants identified range from inorganic ions to complex organic molecules. Hazards have been estimated in terms of fate of potential contaminants in the environment and their toxicity. Risks to groundwater quality and human health in time and space are described with the use of a groundwater contaminant transport model. Because information for the analysis is incomplete, the estimation of risks is not without uncertainties. Major uncertainties remain in data on contaminant concentrations and toxicology of contaminants. The results of the risk estimation, including the uncertainties, may be used to evaluate the groundwater management alternatives.

Complete issue of the Proceedings of the 1985 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 27, 1985, Las Vegas, Nevada

Complete issue of the Proceedings of the 1986 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 19, 1986, Glendale Community College, Glendale, Arizona

Complete issue of the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona / Missing pages 49 & 50 from original

From the Proceedings of the 1988 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 16, 1988, University of Arizona, Tucson, Arizona

From the Proceedings of the 1988 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 16, 1988, University of Arizona, Tucson, Arizona / Seasonal and annual precipitation vary considerably in Arizona, primarily because of topographic influences. Precipitation data have been analyzed by several investigators over the years. Arizona has been subdivided into precipitation zones, and seasonal and annual precipitation isohyetal maps are available from several sources. Because of a paucity of raingages in the more mountainous regions, however, isohyetal lines in these regions have been largely estimated based on the assumptions of topographic influences. Now, with 158 raingages with 30 or more years of record, topographic factors can be combined with greater knowledge of the sources and paths of moisture into the state to better define annual and seasonal precipitation variability. Elevation and aspect appear to be the principal parameters for analyzing precipitation within the state, with the Mogollon Rim exerting the greatest influence on winter precipitation. Higher than anticipated summer rainfall in southeastern Arizona (based on elevation and aspect) suggest that sources and availability of atmospheric moisture may be a strong parameter in analyzing summer rainfall.

From the Proceedings of the 1988 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 16, 1988, University of Arizona, Tucson, Arizona / The classical methods for interpolating and spatial averaging of precipitation fields fail to quantify the accuracy of the estimate. On the other hand, kriging is an interpolation method for predicting values of regionalized variables at points (punctual kriging) or average values over an area (block kriging). This paper demonstrates the use of the kriging method for mapping and evaluating precipitation data for the state of Arizona. Using 158 rain gage stations with 30 years or more of record, the precipitation over the state has been modeled as a realization of a two dimensional random field taking into consideration the spatial variability conditions. Three data sets have been used: (1) the mean annual precipitation over the state; (2) the mean summer rainy season; and (3) the mean winter rainy season. Validation of the empirical semi-variogram for a constant drift case indicated that the exponential model was appropriate for all the data sets. In addition to a global kriging analysis, the data have been examined under an anisotropic assumption which reflects the topographic structure of the state.

From the Proceedings of the 1988 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 16, 1988, University of Arizona, Tucson, Arizona

From the Proceedings of the 1988 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 16, 1988, University of Arizona, Tucson, Arizona

From the Proceedings of the 1988 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 16, 1988, University of Arizona, Tucson, Arizona / A preliminary survey of several urban lakes in the Phoenix metropolitan area was undertaken to assess the degree of accumulation of priority pollutant metals and petroleum -based hydrocarbons in these impoundments. Three sediment samples were collected from each lake along a transect (from a probable point of stormwater addition to the opposite shore), and were composited on an equal weight basis prior to analysis. Total petroleum hydrocarbon concentrations ranged from 30 to 8000 mg /kg dry weight. The concentration ranges (mg /kg dry weight) of total metals were: arsenic 7-26, copper 25-2800, chromium 14-55, nickel 5-40, lead < 1-138, selenium < 0.5-1.1, and zinc 33-239. Silver and cadmium were undetectable (< 5.0 and < 0.5 mg /kg, respectively). Factors that may be associated with the magnitude of accumulation in urban lakes include lake age, primary source of influent, reception of stormwater runoff, mechanical aeration of the water, and direct chemical addition.