The groundwater level in Pinal County has been dropping steadily since large scale expansion of irrigated agriculture began in the early 1940s. The current average rate of decline of the water table of about nine feet per year means steadily increasing pumping costs. Since over 95 percent of the water in Pinal County is used by farmers, the initial impact of increasing pumping costs fall almost entirely on farmers, resulting in continuous adjustments in resource use, cropping patterns, output and income. The principal objective of this dissertation is to estimate the extent and significance of the adjustments Pinal County farmers will make over time as their water costs increase due to increasing pumping lifts. Farmer adjustments to increasing pumping costs are analyzed in two major steps. First, an economic model of typical Pinal County farms is developed for four size groups and three pumping lifts within each size class. This model provides estimates of net return over variable costs for the various field crops in Pinal County for each farm size and pumping lift. Second, data provided by the analysis of typical Pinal County farms is incorporated in a linear programming model which estimates enterprise combinations, output, and income from typical farms subject to restrictions regarding factor supplies, and assuming profitmaximization as a goal. Changes in cropping patterns, output and income over time are estimated by comparing the result from a linear programming model based on 1965 water costs to the results from a model based on projected water costs in the years 1966, 1976, 1986, 1996, and 2006. The results from this model suggest that Pinal County farmers do not face an immediate "water crisis", as often suggested. While the declining water supply will require large adjustments over time in acreage of low-valued hay and feed grain crops, this will not substantially affect net farm income because these crops provide a relatively small portion of the net income to Pinal County farmers. Cotton provides Pinal County farmers with most of their net income and the return to cotton is more dependent on lint price and Government programs and payments than on water costs. Certain assumptions regarding prices, technology and institutions are implicit in this model. Changes in these assumptions can generally be reflected by general or relative price changes. A sensitivity analysis of the effect of price changes shows that net income is very sensitive to changes which affect cotton, but not very sensitive to price changes in other crops in the model. Cotton acreage is determined by Government acreage allotments. However, price decreases in cotton do not result in decreases in cotton acreages with current Government payments, while price decreases in other crops generally result in substantial decreases in output. Pinal County farmers, like the users of any stock resource, will continue to face declining net returns as the cost of tapping the stock of water increases. Adjustments in land values, net income, and number of farms will continue. The continued overdraft of water by Pinal County farmers apparently presents no particular threat to nonagricultural water users in the foreseeable future because nonfarm consumption is small relative to the total supply. Costs of supplying the nonagricultural sector with water would increase, but would be small relative to the productivity of water in these uses.

Interindustry, or input-output analysis is a widely used economic tool in regional analysis. This study investigates the relative worth of alternative types of input data for such models. Primary data are defined as first-hand, or survey data; secondary data are defined as second-hand, or published data. Procurement of primary data is generally much more expensive than for secondary data. Most regional economists have long held that, in general, primary data are superior to secondary data for regional investigations. This study attempts to assess the value of primary versus secondary data in view of the wide variation in collection costs. Two recently published input-output studies for the 1958-60 Arizona economy were utilized to accomplish this goal. One model used mostly primary data; the second model was compiled entirely from secondary data sources. Following careful considerations of base-period differences, geographical overlap, and sector definitions, two models-- the ARZ and the CRB--were constructed from the two source studies so as to be commensurable for statistical comparisons. The ARZ model was derived from the source study that was compiled entirely from secondary data sources; the CRB model was compiled from the source study that used mostly primary input data. Several nonparametric statistical tests were utilized on several components of the ARZ and CRB models to test for statistical similarities and dissimilarities. In general, analyses indicate strong statistical similarity between the two derived models for aggregative I-0 characteristics such as entire matrices and output multipliers, but less similarity for less aggregative components such as sub-matrices and columns of matrices. For example, comparisons between entire technical and between interdependency matrices fail to reject the null hypothesis of no median difference at the alpha level of 5 per cent. At still more unaggregated component analysis, such as for columns within technical and interdependency columns a reasonable degree of statistical similarity persisted. One chapter (V) focuses on the two derived models as they relate to water resources planning implications for Arizona. Results are similar to those for the non-water analyses; however, in the case of weighted water multipliers the similarities between the ARZ and CRB models are remarkably close. Based on an assumed short-run change of 10 per cent in deliveries to final demand for all sectors in the economy, the models differed in predictions of induced aggregate water requirements by only 9000 acre-feet of water, or less than 2 per cent. Results from the study cast doubt on the commonly held assumption of primary-data supremacy in regional interindustry studies. Results also indicate that the most important component for regional economic analysis is the final demand for each sector rather than the interindustry flows. This follows from the narrow clustering of values for output multipliers consistently observed in regional I-0 studies, and reaffirmed in this study. Therefore, students of regional economies are advised to spend marginal resources (money, time, energy) compiling more accurate final demand vectors rather than developing more accurate endogenous interindustry flows.

With the population of urban areas rapidly increasing, a much greater demand is being placed on existing water supplies. The arid southwestern region of the United States, in particular, is experiencing large population increases while possessing limited water resources. Tucson is a representative city in the region facing problems of providing an adequate water supply to the public in the future. Presently, Tucson is being supplied entirely with groundwater. Increases in population and industrial activities, however, have caused a steady decline of the groundwater table in the Tucson Basin. The reclamation of wastewater and the importation of water have been studied as alternatives in alleviating the annual decline of the groundwater table. Problems still exist, however, preventing the immediate use of both aforementioned supplies of water. In developing the water resources of an area, every possible source of water must be evaluated. A source which has not received much attention, but which merits much attention, is the water occurring as urban runoff following intense storms. In order to evaluate the potential of urban runoff as a water supply, the study includes investigations of water quality, water treatment through storage and coagulation, and problems involved with the utilization of storm water. Samples of runoff from three diversified urban watersheds in the Tucson area were analyzed for bacterial, mineral, pesticide, solids, and chemical oxygen demand concentrations. The watersheds were characterized according to the percentage of the total area devoted to a particular land use. In addition, the hydrologic characteristics of each storm were tabulated. Correlation coefficients were determined between the quality parameters and the watershed and hydrological characteristics. Development of regression equations equating quality parameters as a function of both watershed and hydrological characteristics was also undertaken. The final analysis of the quality study involved the determination of relationships between quality parameters of chemical oxygen demand, total coliforms and suspended solids and the point of time on the hydrograph at which runoff was sampled. Prior to beneficial use of the urban runoff, treatment to varying degrees will be required. In the second phase of this study, the efficiency of treatment by the simple methods of storage and alum coagulations was studied. Five gallon samples were collected from randomly selected storms and used either in the storage or coagulation study. Changes in chemical oxygen demand, solids and bacterial concentrations were evaluated at selected intervals during storage for a period of a week. Jar test studies utilizing varying doses of alum were undertaken on water collected from each of the watersheds, determining the efficiency of chemical oxygen demand, turbidity, and total coliform removals. The final phase of the study involved discussion of the problems attendant with the planning and design of treatment facilities. Included in this phase were sections involving water quality standards and the related treatment processes, waste sludge production and treatment methods, and costs pertaining to treatment. Legal aspects of appropriating the urban runoff were considered and the possible conflicts between upstream and downstream interests noted. The study concluded with a demonstration of the application of dynamic programming for optimally planning the location and capacity of storage treatment facilities at urban sites.

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"Pure and simple" is an expression that does not fit when water quality is the topic. To assure the delivery of good quality, pure water is not a simple matter at all, as water quality managers well know.

The Arizona Groundwater Management Act (GMA) of 1980 confronts a problem that has concerned state officials since the early 1930s: the overdraft of Arizona's groundwater resources. The GMA was not the first legislative effort in Arizona to control groundwater use. Advised that a groundwater law was a prerequisite to authorization of the Central Arizona Project (CAP), the state Legislature enacted the Critical Groundwater Code in 1948.

The continued funding of the Central Arizona Project depended upon Arizona implementing water conservation measures in several critical areas in the state. Water consumption patterns in these Active Management Areas (AMAs) will be guided between 1980 and 2025 by a series of five management plans to be developed by the Arizona Department of Water Resources (ADWR).

That water, so common, essential and basic, should be a cornmodity to be bought and sold, marketed and transferred, may seem odd. Yet social and economic conditions in Arizona, and throughout the West, have evolved in such a way that water transfers appear as an attractive option to some and a controversial issue to others

The changing of the Earth's climate, which is a topic of increasing concern, is a cornplex issue. Much more than a meteorological phenomenon, climate is a force that helps define our social environment, as well as our relationship to the natural world. Therefore, the effects of climate change -- whether parts of the earth are becoming wetter or drier, or hotter or colder -- would be broad and profound.