With groundwater resources becoming less available in the physical, economic, and legal senses, water reuse is rapidly gaining momentum in the arid West. An institutional assessment of water reuse in the Tucson Basin in Arizona indicates that despite institutional changes encouraging the substitution of effluent for native groundwater, many opportunities for water reuse are precluded by existing water rights arrangements and insufficient economic incentives. An economic assessment compares potential benefits and costs of implementing water reuse plans for the Tucson area with potential benefits and costs of alternative water-supply scenarios in which similar quantities of water are provided from other sources. Alternative water sources include pumping native groundwater, "reallocating" water saved through reduction in low value water uses, and importing surface water and groundwater from other basins. The results of this study indicate that at the present time, there is no convincing economic justification for increasing water reuse as planned by the City of Tucson. Not only are reduction in use and importation alternatives less costly to implement than increasing effluent use, they also save more groundwater. The results of the economic assessment indicate that the citizenry of the Tucson Basin would be better served if planned increases in the use of effluent in the Tucson metropolitan area were postponed until the costs become more competitive with the costs of alternatives.

No description available.

No description available.

wo digital-computer models of the ground-water reservoir of the Tucson basin, in south-central Arizona, were constructed to study errors in digital models and to evaluate the worth of additional basic data to models. The two models differ primarily in degree of detail -- the large-scale model consists of 1,890 nodes, at a 1/2-mile spacing; and the small-scale model consists of 509 nodes, at a 1-mile spacing. Potential errors in the Tucson basin models were classified as errors associated with computation, errors associated with mathematical assumptions, and errors in basic data: the model parameters of coefficient of storage and transmissivity, initial water levels, and discharge and recharge. The study focused on evaluating the worth of additional basic data to the small-scale model. A, basic form of statistical decision theory was used to compute expected error in predicted water levels and expected worth of sample data (expected reduction in error) over the whole model associated with uncertainty in a model variable at one given node. Discrete frequency distributions with largely subjectively-determined parameters were used to characterize tested variables. Ninety-one variables at sixtyone different locations in the model were tested, using six separate error criteria. Of the tested variables, 67 were chosen because their expected errors were likely to be large and, for the purpose of comparison, 24 were Chosen because their expected errors were not likely to be particularly large. Of the uncertain variables, discharge/recharge and transmissivity have the largest expected errors (averaging 155 and 115 feet, respectively, per 509 nodes for the criterion of absolute value of error) and expected sample worths (averaging 29 and 14 feet, respectively, per 509 nodes). In contrast, initial water level and storage coefficient have lesser values. Of the more certain variables, transmissivity and initial water level generally have the largest expected errors (a maximum of 73 per feet per 509 nodes) and expected sample worths (a maximum of 12 feet per 509 nodes); whereas storage coefficient and discharge/ recharge have smaller values. These results likely are not typical of those from many ground-water basins, and may apply only to the Tucson basin. The largest expected errors are associated with nodes at which values of discharge/recharge are large or at which prior estimates of transudssivity are very uncertain. Large expected sample worths are associated with variables which have large expected errors or which could be sampled with relatively little uncertainty. Results are similar for all six of the error criteria used. Tests were made of the sensitivity of the method to such simplifications and assumptions as the type of distribution function assumed for a variable, the values of the estimated standard deviations of the distributions, and the number and spacing of the elements of each distribution. The results are sensitive to all of the assumptions and therefore likely are correct only in order of magnitude. However, the ranking of the types of variables in terms of magnitude of expected error and expected sample worth is not sensitive to the assumptions, and thus the general conclusions on relative effects of errors in different variables likely are valid. Limited studies of error propagation indicated that errors in predicted water levels associated with extreme erroneous values of a variable commonly are less than 4 feet per node at a distance of 1 mile from the tested node. This suggests that in many cases, prediction errors associated with errors in basic data are not a major problem in digital modeling.

No description available.

The Cienega Gap area, located about 27 miles southeast of Tucson, Arizona, has long been noted for its structural complexity. Discordances between sedimentary rocks of Paleozoic, Mesozoic, and Cenozoic age and between these rocks and their granitic basement have led previous workers to propose large -scale northward thrusting in an effort to explain the complex structures observed. An alternative hypothesis invoking southward gliding has been considered by several authors but has been assigned a subordinate role in explaining the deformation. The present study was undertaken in an effort to evaluate the relative suitability of dominantly northward versus dominantly southward movement. In the course of this study nine separate localities were examined and mapped in detail in an effort to evaluate movement direction. Evidence of displacement on low -angle faults or glide surfaces was found in each of the areas examined, and definite evidence of movement direction was recognized in five of these. Large-scale recumbent folding, previously unrecognized in the Colossal Cave and Agua Verde Wash areas, was found to be closely related to local uplift. The asymmetry of the folds, plus a very few observed offsets marginal to the uplifts, were the only criteria found for determining the direction of movement. Evidence of northward, southward, and nearly westward movement was found in the course of the study. Areas in the northern Empire Mountains south of Cienega Gap gave evidence of west – northwestward and northward movement. Areas in the southern Rincon Mountains north of Cienega Gap were found to have undergone dominantly southward movement. Involvement of the Pantano Formation in several of the localities suggests that deformation occurred at least as late as early Oligocene time and probably after middle Miocene time. Cienega Gap was therefore the focus of movement for material which was moving laterally away from areas undergoing uplift in Tertiary time.

Thesis (M.S. - Hydrology)--University of Arizona, 1984. / Includes bibliographical references (leaves 68-72).

Thesis (Ph. D.)--University of Arizona, 1994. / Includes abstract. Includes bibliographical references (leaves 320-352).

Similar projectile point types were used by groups living over a wide geographic region in central and southern Arizona and southwestern New Mexico during the thirteenth and fourteenth centuries A.D. Substantial changes that occurred in southeastern Arizona at this time include population aggregation, the arrival of northern migrant groups, and an increase in obsidian use. An analysis focusing on two sub-regions, the Tucson Basin and the San Pedro Valley, was conducted to explore how social, technological and environmental factors influenced projectile point technology during the Classic period (A.D. 1150–1450) in southeastern Arizona. Projectile point metric and morphological attributes and obsidian source data were used for comparisons within both of the sub-regions. Despite differences in social relations, obsidian exchange networks, and access to large game, comparisons between sites in the northeastern and northwestern Tucson Basin did not reveal significant differences in projectile point types. However, a good deal of variation in base morphology is evident regardless of type among the Tucson Basin sites. Projectile points from Kayenta enclaves in the Lower San Pedro Valley are overwhelmingly made of obsidian, but do not possess significantly different attributes from those used by local groups. Notable variation was seen in the small sample from the Upper San Pedro Valley, which may be attributed to the lack of influence from groups living to the north. Overall, the similarities in projectile point forms correspond with the growth of social networks during the Classic period. Although the small size of these points restricts their usefulness for signaling group identity, variation in base morphology, serrated blade edges, and other small details may continue to inform on the learning traditions or cultural preferences of groups in the region. Future research should expand the study area to include the Upper Gila region of New Mexico, where groups were living close to the extensive Mule Creek obsidian source.

A gravimetric survey has proved its usefulness in the Tucson Basin in locating important structural features, their geometric shapes and extensions. Interpretation was made possible through the correlation of available geologic and hydrologic data from water well logs and water table contour maps. Geophysical logs from a recently drilled test well in North Tucson have been interpreted and have confirmed the existence of another promising aquifer, namely, the deformed gravel which underlies the upper basin-fill aquifer. In most cases, it is apparently separated by a thin aquiclude of clay which results in artesian condition in the lower aquifer. Gravity interpretation discloses the presence of buried channels that may be of importance to groundwater exploration. The buried high basement ridges or faulted blocks as interpreted from gravity data add more information to the understanding of the hydrologic behavior of the basin. Deep drilling of test wells, such as the one drilled recently on Orange Grove Road, will be a useful check to the structures interpreted from gravity data. Geophysical logs of bore holes are of utmost importance in correlation of lithologic units and structures in addition to the hydrologic interpretation that is possible from these logs. The Pantano beds as described here are not promising for new groundwater sources that may be used for domestic needs due to the very low permeability and the expected poor quality of the water. Still more information is necessary to determine clear answers to many problems related to the geology and hydrology of this basin.