From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona / Five rainfall distributions, four l-in rainfall depths and one 3-in rainfall depth were plotted on charts with five different combinations of time and depth scales. The plotted events were read on an analog-to-digital converter by four different researchers. Each reading of a plotted record was compared with the known simulated rainfall-rate distribution. The correspondence of the rainfall rates read from the charts with the actual rainfall rate distribution is measured by an integral squared error and correlation coefficient. The results showed a general correspondence between error and the chart scale and a strong influence of maximum recorded rate and rate distribution on the error. For the chart scales evaluated, error did not become more directly associated with scale, except when recorded rates were less than about 10 in/hr. Error was directly related to the number of points read in any given trace by the relation E = 16.3N^(-0•426).

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona / In the past, researchers have applied a variety of analytical techniques for maximizing the present value of net benefits derived from a stock resource-simulation, calculus of variations, stochastic dynamic programming, and optimal control theory. This paper presents a more operational approach - linear programming. Applying linear programming to this type of problem requires a set of internal accounting constraints that prevent the additivity assumption of linear programming from being violated. A simplified, broadly drawn example from Southwest agriculture is used for demonstrating the model's structure and output.

Complete issue of the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona / Throughout 1974 and 1975 the Department of Hydrology and Water Resources, University of Arizona, conducted a water quality study on Lake Havasu, Arizona, near the Central Arizona Project intake. This investigation was funded jointly by the Arizona Water Commission and the U.S. Bureau of Reclamation. The University study evaluated the hydrography and hydrology, sediments, turbidity, temperature, chemistry, dissolved oxygen (and biochemical oxygen demand), benthic invertebrates, phytoplankton, zooplankton, biomass analysis, and electrical conductivity to establish baseline data for the CAP intake area. The results showed weak stratification and generally good aeration in the lake and high turbidity in the Bill Williams River. Biological quality was good with low amounts of benthics and numerous zooplankton and phytoplankton species. The extensive data from chemical analysis generally conformed to public health standards.

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona / Lynx Lake Watershed consists of approximately 13,600 acres of the Agua Fria drainage. About 13 percent of the area is patented mining claims (mainly copper} with numerous mining shafts, waste dumps, and mill tailings. Lynx Creek itself was once mined for gold and the creek bed still shows the scars of the dredging operations. Drainage from the numerous old mining sites show a certain extent of toxic mineral and sediment pollution of the water resources in the area. Lynx Creek carries runoff which is slightly acidic in nature and has a high concentration of copper, manganese, iron, zinc, and sulfates. The Sheldon Mine complex is considered one of the major sources of pollution to the lake. Aquatic life and recreation potential of the watershed is greatly reduced by the water pollution problem. The pollutants from the abandoned mine sites enter into Lynx Lake, a trout fisheries lake, which was created by damming the creek in 1962 by the Arizona Game and Fish Department. The Sheldon Tailings pond was rehabilitated during the summer of 1975 as part of a reclamation study and demonstration project that is currently in progress and being sponsored by SEAM (Surface Environment and Mining}. The study is being conducted cooperatively by the School of Renewable Resources, University of Arizona, and the Prescott National Forest. An excellent vegetative cover is established on the site and studies are being conducted to measure the beneficial effects of the reclamation on water quality.

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona / The upper Gila River in Arizona and New Mexico contains extremely diverse geology and soils. One geological formation that is somewhat unique to the Southwest and the upper Gila drainage is the Gila Conglomerate formation. In New Mexico, this conglomerate is extensive on the main Gila River drainage, accounting for over 35 percent of the main basin area. A case study was done on the 22,580 hectare (55,793 acres) Lake Roberts Watershed to assess the current sedimentation problem and its sources. This study revealed interesting patterns of lake surface area changes with volume changes of the original 28.3 hectare (70 acres) man-made reservoir over the last 12 years. Surface area reduction (19%) has progressed at a rate over twice that for volume reduction (9%). The source of the problem stems primarily from soils derived from highly sensitive Gila Conglomerate. The watershed is not uncharacteristic of the unique geology and soils typical of the upper Gila drainage and may furnish insight into sediment production and sources for much of the Gila headwater drainage in New Mexico.

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona / Hydrographs of runoff from small watersheds in semiarid regions often have a sharp peak with a relatively short time of rise followed by a slower recession and a tail of low flow. This characteristic shape suggests the possible use of a double triangle unit hydrograph recently introduced to hydrology. The shape of this unit hydrograph is specified by four parameters, which may be estimated by an optimization procedure based on using the sum of absolute deviations or some other suitable criterion as an objective function. Rainfall and runoff data for a number of storm events on a small watershed in the Santa Rita Experimental Range in southeastern Arizona have been analyzed to test the above idea. Double triangle unit hydrographs were fitted to individual storm events. The differences in the shapes of individual unit hydrographs were found to be small so that they could be approximated by a single double triangle unit hydrograph.