7 research outputs found
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Snowmelt Runoff Efficiencies on Arizona Watersheds
This item is part of the Agricultural Experiment Station archive. It was digitized from a physical copy provided by the University Libraries at the University of Arizona. For more information, please email CALS Publications at [email protected]
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An assessment of snowpack depletion-surface runoff relationships on forested watersheds.
A technique was developed for determining daily values of runoff efficiencies from small watersheds by coupling a computer model that simulated Arizona snowmelt processes with graphical techniques of runoff hydrograph separation. The computer program was a USDA Forest Service model modified to better simulate Arizona conditions, A complete explanation of modifications and limitations of the model is given, along with equations for estimating some of the model input variables, Seven small watersheds with a total of 14 years of record were used in evaluating changing patterns of runoff efficiencies within a year. Additionally, many physical, biological, and climatic variables were correlated with seasonal runoff efficiencies not only among years and among watersheds, but also within a watershed among years, and among watersheds within a season, Prediction equations were also formulated that could be of use in the identification of high water yielding watersheds,hydrology collectio
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Evaluating and Displaying Watershed Tradeoffs for Management
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, NevadaRelating water concerns and interactions to land managers has been a challenge met with only partial success. A methodology was developed that incorporates graphical techniques to visually display potentials, tradeoffs, and effects of resource management activities. This technique was applied to chaparral and ponderosa pine ecosystems to show applications to the scientist and also the nontechnical manager. Up to five variables can be displayed in a way that enable quick understandable tradeoff evaluations.This article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]
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Water Yield Opportunities on National Forest Lands in 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, ArizonaWater 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.This article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]
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Distribution of Ponderosa Pine Forest Densities on the Salt-Verde River Basin
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Determining Watershed Conditions and Treatment Priorities
From the Proceedings of the 1982 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 24,1982, Tempe, ArizonaA method is presented for evaluating watershed conditions and alternative watershed treatments. A computer model simulates runoff responses from design storms. The model also simulates runoff changes due to management prescriptions that affect ground cover and structural treatments. Techniques are identified for setting watershed tolerance values for acceptable ground cover and establishing treatment priorities based on the inherent potentials of the watershed.This article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]
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Importance of Short Duration Rainfall Intensities
From the Proceedings of the 1983 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona-Nevada Academy of Science - April 16, 1983, Flagstaff, ArizonaFlood flows and water quality in the Southwest are roust dramatically influenced by short, intense rainstorms. Runoff from these storms has been modeled with some success. One key element that has often been overlooked, however, is the importance of intra-storm rainfall distribution on runoff response. Actual storms were modeled for small experimental watersheds in the Southwest using different time increments of intra-storm rainfall. Increments of 5 minutes or less proven satisfactory for accurate hydrograph simulation. As increments became longer than 5 minutes, the ability to simulate actual hydrographs became increasingly difficult. Increments of 30 minutes or longer proved unacceptable for most storms. Hydrologic models must be sensitive to short time increments of intra-storm rainfall to accurately predict peak flows in the Southwest. Watershed treatments will be more cost-effective if their design considers intense bursts of intra-storm rainfall in addition to total storm volume.This article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]