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 / Two experimental paired watersheds on Black Mesa Mine, in the Four -Corners region of Arizona were compared by several hydrologic variables in order to determine their relative capabilities for vegetative reestablishment. From July 1977 to the present, precipitation ranged from 5 to 7 inches; runoff was 7 times lower on the topsoiled watershed. Because of its structureless nature, the non-topsoiled watershed tended to crust and seal the surface. In general, the sediment yield was lower on topsoiled spoils; however, increased sediment yields were observed during intense storms, possibly reflecting the fact that the topsoil was not anchored to the underlying spoils. The non-topsoiled watershed was found to have a higher soil moisture at wilting point (13.8%) and high soluble salts (3,000-5,000 ppm), making water unavailable at higher suctions. The range of available water was higher on the non-topsoiled watershed. Tests indicated that most soil moisture water storage results from winter frontal storms of long duration. A vegetation survey indicated a more successful rate of seedling establishment (8.1 plants/m) on the topsoiled watershed, but with a high subsequent die off rate due to drought conditions. Mechanical treatment of and chemical amendments to spoils and topsoils are discussed. It is concluded that the practice of topsoiling will greatly enhance revegetation of mine spoils in arid environments. If it is necessary to directly revegetate spoil materials without topsoiling, salt and drought tolerant species are recommended.

Complete issue of 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 1981 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - May 1-2, 1981, Tucson, Arizona

From the Proceedings of the 1981 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - May 1-2, 1981, Tucson, Arizona / Water Yield improvement opportunities were estimated for National Forest lands in Arizona. The land base available for treatment was reduced in a stepwise manner to account for administrative, climatic, and ownership constraints. Research relationships were built upon, and then applied to the remaining land base to project water yield estimates. A continuum of management prescriptions was then displayed to show the range of opportunities. Only the chaparral, ponderosa pine, and mixed conifer types show opportunities of significance. Water yield increases can be realized principally from conversion of chaparral to grass and could add an additional 25 to 70 thousand acre-feet. The ponderosa pine zone could add an additional 15 to 30 thousand acre-feet with intensive management by reducing stocking levels on the commercial National Forest lands. Little opportunity exists within the mixed conifer zone and increases would amount to less than 10 thousand acre -feet. Annual contributions of National Forest lands are likely to range from 40 thousand to 100 thousand acre feet; this will be highly variable depending upon precipitation quantities.

From the Proceedings of the 1981 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - May 1-2, 1981, Tucson, Arizona

From the Proceedings of the 1981 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - May 1-2, 1981, Tucson, Arizona

From the Proceedings of the 1981 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - May 1-2, 1981, Tucson, Arizona

From the Proceedings of the 1981 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - May 1-2, 1981, Tucson, Arizona / A modified tidal efficiency algorithm, ESTA, was developed to correct observed water well levels in tidally responsive coastal areas to get best estimates of aquifer properties and well production characteristics. The algorithm was developed during groundwater studies in Puerto Peñasco, northeastern Gulf of California, Sonora, Mexico. ESTA predicts standing water well levels in response to tides. ESTA requires initial sea and well calibration data, from which sea-well relationships are calculated. It needs tidal data for the time period when projected standing water well levels are desired. The method uses a single cosine or sine function for rising or falling tides, respectively. ESTA tended to overpredict water levels, especially on rising tides, on the average of about 0.05 ft, as shown in analyses at five coastal well sites completed in low to moderately permeable sand and coquina. ESTA can be improved by application of error analysis, but this will not be necessary in most cases, as errors are generally very small for most aquifers and tidal ranges. When ESTA was applied to an aquifer test in highly permeable coral near Kahuku, northehore Oahu, Hawaii, rising -tide water well levels were overpredicted and falling -tide water well levels were underpredicted by 0.10 and 0.33 ft, respectively. Error analysis reduced these errors to 0.06 and 0.16 ft.

From the Proceedings of the 1981 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - May 1-2, 1981, Tucson, Arizona / Errors in the estimation of the aquifer parameters T and S derived from aquifer test data are examined as to their cause and effects. The analysis is based on the Theis equation. The basic causes of error are in the measurements of drawdown and pumping rate, in fitting the model to the data and in violations of model assumptions. Measurement errors were studied experimentally. Curve fittings by hydrologists were compared to "automatic" curve fittings obtained by nonlinear regression. The covariance matrix of T and S obtained in this manner was used, in conjunction with sensitivity analysis, to estimate the error in prediction of future drawdown. While automatic fitting is not a perfect substitute for graphical fitting, there is a definite relation between the two methods which allows the use of the statistics developed by nonlinear regression theory to be used to study the cause, effects and risks inherent in aquifer analysis.

From the Proceedings of the 1981 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - May 1-2, 1981, Tucson, Arizona