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1	Simple Time-Power Functions for Rainwater Infiltration and Runoff Dixon, R. M., Simanton, J. R., Lane, L. J. 15 April 1978 (has links) From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / The equations of Darcy, Kostiakov, Ostashev, Philip, and four modified Philip equations were evaluated for use in predicting and controlling rainwater infiltration and rainfall excess in crop and rangelands. These eight equations were least- square fitted to data from ring, border-irrigation, closed-top, and sprinkling infiltrometers. Kostiakov's equation satisfied the evaluation criteria better than the other seven equations. The parameters of Kostiakov's equation were physically interpreted by relating their magnitudes to some physical, biological, and hydraulic characteristics of the infiltration system. These characteristics included several infiltration abatement and augmentation processes and factors that are controlled at the soil surface by land management practices. The eight equations were also fitted to rainfall data to permit calculating runoff from small surface areas about the size of a typical crop plant. Comparison of the regression curves for infiltration and rainfall suggested that land management practices that appropriately alter the soil surface will permit wide-range control of infiltration, runoff, and erosion; and thereby achieve conservation and more efficient use of soil and water resources for crop production. The most important soil surface conditions affecting infiltration were microroughness, macroporosity, plant litter, and effective surface head. Hydrology -- Arizona. Water resources development -- Arizona. Hydrology -- Southwestern states. Infiltration Rainfall-runoff relationships Runoff Runoff forecasting Soil water movement Infiltrometers Irrigation practices Rain water Rainfall disposition Air-earth interfaces Equations Forecasting Regression analysis Erosion
2	Assessing Soil-Water Status Via Albedo Measurement Idso, Sherwood B., Reginato, Robert J. 20 April 1974 (has links) From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / Reliable information on soil-water status is required in order to make accurate water balance studies of watersheds, to determine the survival probabilities of various types of vegetation between rainfalls in low rainfall areas, and to determine the susceptibility of the uppermost soil to wind erosion. Simple solarimeters may help to accomplish this objective. Bare soil albedo was a linear function of the water content of a very thin surface layer of soil, and albedo correlated well with water contents of thicker soil layers. In addition, albedo measurements could be used to delineate the 3 classical stages of soil drying. Albedo may also be used to differentiate between the initial potential rate phase of evaporation following an application of water, and the succeeding falling rate phase. Results of applying this technique to a field of Avondale clay loam indicate that 20% to 25% of the water applied by either irrigation or rain will be lost by stage 1 potential evaporation, independent of seasonal variations in evaporative demand. Presently the techniques developed are applicable only to bare soil surfaces. Hydrology -- Arizona. Water resources development -- Arizona. Hydrology -- Southwestern states. Soil moisture Albedo Moisture content Soil surfaces Evaporation Topsoil Water balance Water loss Radiation Soil physical properties Soil water movement Drying Air-earth interfaces Clay loam Vegetation effects Irrigation Rainfall Bare soil albedo Solarimeters Soil drying

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Simple Time-Power Functions for Rainwater Infiltration and Runoff

Assessing Soil-Water Status Via Albedo Measurement