Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1968. / Includes bibliographical references. Includes bibliographical references (leaves 78-80).

Abstract available in file 07summary.pdf / Thesis (PhD (Microbiology))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted

From Imperial Dam downstream, in addition to Mexico, the Colorado River supplies water to Arizona and California for predominantly agricultural use. In Arizona, the Colorado River is the major source of water supply to the various irrigation districts in the Yuma area. Due to legal constraints, the amount of Colorado River water available to the State of Arizona is limited. On the other hand, it was discovered that the amount of water applied to the soil in irrigation exceeds that amount needed for crop-growing. Two areas where the amount of water considerably exceeds the requirements, the mesa section of the Wellton-Mohawk Irrigation and Drainage District and the Yuma Mesa Irrigation and Drainage District, were studied in detail. The excess water applied on the mesa of the Wellton-Mohawk Irrigation and Drainage District flows into the Wellton-Mohawk Valley whence it is pumped into a conveyance channel and then discharged into the main channel of the Colorado River. This drain water has a very high salt content and therefore it adversely affects the quality of the river water. Since the drain water is discharged into the Colorado River above the point of diversion to Mexico and it is considered to be part of the Mexican water allotment, the quality of the Colorado River water has become a source of friction between the United States and the Republic of Mexico. The excess irrigation water from the Yuma Mesa Irrigation and Drainage District flows into the adjacent valleys as well as into uncultivated areas. In the adjacent valleys it is raising the water table and thus causing drainage problems. When it flows underground into the uncultivated lands, in large measure it constitutes a loss of water that otherwise could be put to beneficial use by Arizona. It is known that flood irrigation is not conducive to efficient application of water in the sandy soils that are predominant in these areas, and that the effects of this application of excess water are diverse and far-reaching. The change to sprinkler irrigation would be advantageous in many ways and beneficial to all concerned. The change to sprinkler irrigation on the mesa of the Wellton-Mohawk Irrigation and Drainage District would benefit both the farmers and the district financially. At the same time, it would decrease the salinity of the Colorado River water, thereby improving the quality of the water that Mexico receives and, consequently, the relations between the United States and the Republic of Mexico. In the Yuma Mesa Irrigation and Drainage District, the change in the method of irrigation would increase the amount of water available for use by the State of Arizona. Furthermore, it would alleviate the drainage problem of the adjacent valleys and would thereby decrease the amount of drain water flowing back into the channel of the Colorado River. In this district, such a change may entail a small added cost to the farmer. Alternatives for augmenting the flow of the Colorado River, such as importation of water from other basins, desalting sea water, phreatophyte eradication, and evaporation suppression, were found to be economically unfeasible at present or still in the experimental stages.

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references. / by Matthew Lee White. / M.C.P.

Forecasts of hydrological information are vital for many of society's functions. Availability of water is a requirement for any civilization, and this necessitates quantitative estimates of water for effective resource management. The research in this dissertation will focus on the forecasting of hydrological quantities, with emphasis on times of anomalously low water availability, commonly referred to as droughts. Of particular focus is the quantification of uncertainty in hydrological forecasts, and the factors that affect that uncertainty. With this focus, Bayesian methods, including ensemble data assimilation and multi-model combinations, are utilized to develop a probabilistic forecasting system. This system is applied to the upper Colorado River Basin for water supply and drought forecast analysis. This dissertation examines further advancements related to the identification of drought intensity. Due to the reliance of drought forecasting on measures of the magnitude of a drought event, it is imperative that these measures be highly accurate. In order to quantify drought intensity, hydrologists typically use statistical indices, which place observed hydrological deficiencies within the context of historical climate. Although such indices are a convenient framework for understanding the intensity of a drought event, they have obstacles related to non-stationary climate, and non-uniformly distributed input variables. This dissertation discusses these shortcomings, demonstrates some errors that conventional indices may lead to, and then proposes a movement towards physically-based indices to overcome these issues. A final advancement in this dissertation is an examination of the sensitivity of hydrological forecasts to initial conditions. Although this has been performed in many recent studies, the experiment here takes a more detailed approach. Rather than determining the lead time at which meteorological forcing becomes dominant with respect to initial conditions, this study quantifies the lead time at which the forecast becomes entirely insensitive to initial conditions, and estimating the rate at which the forecast loses sensitivity to initial conditions. A primary goal with this study is to examine the recovery of drought, which is related to the loss of sensitivity to below average initial moisture conditions over time. Through this analysis, it is found that forecasts are sensitive to initial conditions at greater lead times than previously thought, which has repercussions for development of forecast systems.

This research presents the Colorado River basin as a social-ecological system. Utilizing event data on cooperative and conflictive interactions over fresh water, the system is decomposed to look for evidence of outcomes of resilience enhancement. The Animas-La Plata Project in the upper San Juan basin is presented as a case study, and qualitative methods are used to analyze interactions that led to its construction in order to assess social-ecological outcomes. In the upper San Juan basin, cooperative interactions over fresh water outnumbered conflictive ones. Interactions over water rights and infrastructure were most common, and the most cooperative interactions focused on these issue types. Many of these interactions focused on the Animas-La Plata Project compromise, which ultimately enhances social-ecological resilience in the Colorado River basin. / Graduation date: 2012