From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada / Major events during the summer of 1974 led to the beginning of a new, progressive program of water resources management for the City of Tucson. Critical supply shortages during the 1974 peak demand period brought into sharp community focus the need to reassess the previously existing philosophy of meeting continually increasing demand for water with extensive capital construction. An analysis of the impacts resultant from unmanaged peak demands, increased water level declines, potential land surface subsidence, projected increased operational costs and changes in water quality led staff and consultants to formulate and recommend the "Beat the Peak" program. A new philosophy on basin -wide groundwater withdrawals was implemented along with additional programs designed to evaluate the effect of our continued dependence on local groundwater sources. The results of this new management approach have been impressive. Per capita water consumption has been voluntarily reduced, total groundwater pumpage has been reduced and the potential for land surface subsidence is being actively evaluated resulting in direct benefits to Tucson Water and the customers it serves.

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada / In May, 1979, the City of Tucson entered into contractual agreements with three private water companies to ensure 100 year adequacy and to manage scarce water resources within a large area northwest of Tucson. These agreements implemented the Northwest Area Water Plan. The Northwest Area Water Plan provides a mechanism by which local and imported water sources can be cooperatively managed by the City of Tucson and local private water companies within the Northwest Water Service Area. This plan has been developed to complement agreements for water service between the City of Tucson and private water companies and is an integral part of those agreements. The purpose of this plan is to identify those facilities and associated costs which provide, on a regional basis, a permanent, cost-effective water supply to new customers within the Northwest Water Service Area. The basic plan approach is to utilize existing local groundwater to the fullest extent possible while maintaining local water tables at their present levels. This will be accomplished through the planning, design, and construction of an import water supply system to meet the base demands of customers within the Northwest Water Service Area and the conjunctive management of local well capacity and storage reservoirs to meet the variable peak demands and fire flow requirements.

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada / A summary of factors which need to be addressed when drafting standards to protect groundwater is presented based on research of existing and proposed groundwater quality standards in several states. Options available for each factor are offered as possible choices.

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada / Water quality research of the Colorado River corridor of Grand Canyon examines important relationships between densities of fecal coliform bacteria in surface water and underlying bottom sediments. Surface water sampling alone does not accurately reflect baseline water quality status of natural recreational waters, as sediments often harbor microbial densities in several orders of magnitude of overlying waters. Water-based recreation activities and natural wave and current processes can resuspend sediment and associated microbial populations, including enteric pathogens. Data show significant associations between surface water and bottom sediment microbial populations, demonstrating the importance of a combined sampling approach to water quality analyses.

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada / The University of Arizona's Environmental Research Laboratory, with the Universidad de Sonora, has operated a research station at Puerto Peñasco, on the northeastern Gulf of California, since 1962. Controlled-environment shrimp aquaculture, the Laboratory's most recent research interest, requires a large, dependable supply of filtered, temperate seawater. A University Water-Supply Study Team explored for a supply in an 850-hectare site near the Estero Marua for a proposed ten-hectare shrimp farm. The study included geological, geophysical, and hydrological investigations, and consideration of groundwater, Gulf, estuarine, and combined seawater sources. A thick, fine sand, in the study area, has a very low permeability, contains highly saline water, and could sustain low yielding wells. A thin, coquinoid beachrock, along the Gulf coast near the study area, has a high permeability, contains seawater, and could sustain high yielding wells. Gulf and estuarine water sources have unacceptable temperature ranges, though they could be utilized if mixed with groundwater, stored, and insulated. Recommendations include: drilling, testing, and analysis of coquina; modeling of groundwater heat flow, water-quality effects, and potential well-field designs and impacts for beachrock development; analyzing well design and performance; relaxing temperature and salinity constraints; reusing aquacultural wastewater; and reducing water demand.

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada / The University of Arizona's Environmental Research Laboratory, with the Universidad de Sonora, has operated a research station at Puerto Peñasco on the northeastern Gulf of California, Sonora, Mexico, since 1962. Research projects have included solar distillation, greenhouse agriculture, shrimp aquaculture, and halophyte irrigation. These require a dependable supply of filtered, temperate seawater. Proposed aquacultural expansion requires a large water supply. The thin, coastal, water-table coquinoid-beachrock aquifer has a high permeability, contains seawater and could sustain high yielding wells from a limited area. Well performance indicators (yield, specific capacity, efficiency and losses) are influenced by design, drilling, development and siting, and aquifer properties and hydrogeologic boundaries. Design should include full aquifer penetration, open -area screens, sized gravel pack and proper pump sutmergence. Drilling should be by mudless reverse circulation. Development should consist of simultaneous air lifting and jetting. Siting should include proximity to the recharging Gulf and adequate well spacing. Total well-field production is controlled by individual and collective well performance, and by regional hydrogeologic conditions.

From the Proceedings of the 1980 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 11-12, 1980, Las Vegas, Nevada / Procedures have been developed to estimate transmission loss volumes in abstracting (losing) ephemeral streams. A two -parameter linear regression equation relates outflow volume for a channel reach to the volume of inflow. A simplified two-parameter differential equation describes the transmission loss rate as a function of length and width of the wetted channel. Linkage relationships between the regression and differential equation parameters allow parameter (and thus, transmission loss) estimation for channels of arbitrary length and width. The procedure was applied using data from 10 channel reaches. Maximum loss rates were observed on Walnut Gulch, Arizona, and minimum loss rates were observed on Elm Fork of the Trinity River, Texas. All other data were between limits established at these two locations. Examples illustrate typical applications and show step-by-step procedures required to use the proposed method. Results and interpretations were summarized, and needs for additional research were specified.