Unit hydrographs are derived for four watersheds in the Lower Fraser Valley using a computerized least squares technique. These unit hydrographs are then related to specific basin characteristics so that synthetic unit hydrographs can be constructed for the ungauged basins in the area. After attempting several techniques to relate the unit hydrographs to basin characteristics both the time-to-peak and the peak flow were related to the basin slope, shape, channel length and degree of urbanization. To more fully define the synthetic unit hydrograph shape, the unit hydrograph widths at 50 per cent and 75 per cent of the peak flow were related to the peak flow. In this way five points can be used to establish the unit hydrograph shape (one for the peak and four for the widths). Other results included estimates of average infiltration rates for each basin calculated from rainfall and runoff data. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Veterinarians in Tucson and Phoenix were surveyed by mail, requesting information about their patients recently diagnosed or treated for Valley Fever. Information obtained included risk factors and outcome.

Thesis (S.M. in Architecture Studies)--Massachusetts Institute of Technology, Dept. of Architecture, 2013. / Cataloged from PDF version of thesis. "June 2013." / Includes bibliographical references (p. 156-161). / As the flagship of the New Deal, the Tennessee Valley Authority (TVA) was a triumph of regional and environmental design that has since fallen on hard times. When writer James Agee toured the region in 1935, he described the massive dam construction underway as a great skeleton across the valley, to be fleshed with social programs; economic incentives; navigation; flood control; power; and economic development. There were planned towns, parkways, jobs, and cheap energy - a regional utopia. Eighty years later, what remains of that skeleton is a static system of dams and their reservoirs, and an aging power grid more reliant on heavily polluting fossil fuels than hydroelectric power. The program is heavily in debt, regularly challenged to privatize and decentralize. Meanwhile, the TVA's region has reoriented itself along new programmatic and spatial lines, increasingly relegating the TVA to irrelevant anachronism. Today's TVA is an important American landscape facing obsolescence, largely due to organizational ossification and a failure to adapt to changing attitudes towards environmental management. Using the Tennessee River as a conceptual and physical bounding device, this thesis revisits the original goals of the TVA and critically examines their contemporary incarnation. The thesis then maps the TVA's remant components in order to explore how a relatively rigid and anachronistic regional plan may be retrofitted within a wholly different economic and political climate in order to rescue it from gradual decline. Ultimately, the thesis argues that rather than reinstituting the original New Deal toolkit, a contemporary retrofit could instead take the form of a flexible series of minimal components around three lenses of intervention: the public; ecology; and energy. These can then be layered onto the existing network to reframe its symbolism for the 21st century. In this way, the project identifies points of entry for grafting contemporary uses and meanings onto the TVA's remnant spine. / by Kristen Zeiber. / S.M.in Architecture Studies

No description available.

A marked change in ground water quality in the Safford Valley of Graham County, Arizona, averaging approximately +0.129 x 103 mhos electrical conductivity per year and +35 parts per million chloride per year, has been documented between 1940 and 1972 with data from ten long -term sample wells. A chloride change map constructed between these two years shows a general increase of 200 to 400 ppm chloride. The 1972 iso- chemical maps show areas of up to 1600 ppm chloride and 8.0 x 103 mhos electrical conductivity, which is extremely saline and considered threshold level for agricultural waters. The Safford Valley, a structural trough with approximately east -west orientation, averages 12 miles in width and 30 miles in length in the study area. Bounded by typical basin and range province mountains on the northeast and southwest, the valley contains a perennial stream flowing toward the west. A bi- aquifer system constitutes the ground water reservoir of the area with a deep, artesian aquifer of several thousand feet thickness overlaid by a water table aquifer averaging 400 feet in thickness and with the water table rarely over fifty feet from the surface on the eastern end of the valley, deepening to over 5000 feet at the western end. This bedrock -alluvium interface is the lower vertical constraint for the artesian system, thus the thickness of this aquifer increases downstream (to the west). The basin fill consists of a basal conglomerate overlaid by lacustrine evaporite beds, the aquifer cap beds, and recent alluvial material. The artesian aquifer is shown to be up to ten times as saline as the water table aquifer, and appears to increase in temperature and salinity in a downstream direction (corresponding to increasing thicknesses of lacustrine beds included in the extent of this aquifer). The decrement in the water quality of the surficial aquifer seems to be attributable to four major mechanisms. An increase in salinity may be expected from leakage of saline water from the artesian aquifer. Suck leakage would be stimulated by pumping- caused reduction of confining pressure, and by the puncture of the cap beds by deep wells. Water reaching the aquifer from natural recharge may contribute salts to the system. Such recharging water, if passed through soluble beds, could contribute to the salt content of the aquifer. Lateral movement of water through similar deposits may be a contribution, and the concentration and infiltration of agricultural water could also add to aquifer salinity. Ground water applied to the land surface is concentrated by evaporation and dissolves salts in the unsaturated zone as it re- enters the water table aquifer. Iso- salinity and salinity -change maps show the quality situation of the water table aquifer to be broken up into three major sections. From the eastern limit of the study area to Safford, the quality is relatively high and stable. From Safford to Pima there appears a uniform increase of low magnitude but continued decrement. Beyond Pima the area exhibits extremely irregular salinity conditions with marked increases and high salinity gradients. The salinity pattern corresponds to the extent of the underlying artesian aquifer but may be influenced to an unknown extent by the down- gradient transport of salts. The 1972 iso -chemical maps show chevrons of high quality water protruding into the aquifer at points corresponding to the locations of washes. Such wash bottoms are the principal zones of recharge in arid regions. Recharge from the Gila River is of extremely high quality relative to the salinity of the aquifer. There appear no configurations of iso -chemical lines which are attributable to internal movement through saline deposits. The hydraulic gradient of the water table aquifer is relatively constant and follows the gradient of the land surface. Concentration of irrigation water by evaporation and subsequent leaching while in conveyance to the water table seems to increase the salinity of this percolating water by approximately three -fold. The magnitude of this increase at any one point in space and time is a function of the volume of water applied to the land surface, the amount of evaporation, the initial chemical composition of the water, the chemical characteristics of the unsaturated zone through which it penetrates, and the transmission properties of the aquifer. The salinity increase seems significant but the extent of the contribution to the salinity of the aquifer is dependent on the amount of infiltration to the aquifer. This amount is currently undetermined, but is probably a sizable volume -- especially from pre- irrigation applications. A sociologic investigation based on responses from a detailed questionnaire - interview program of 41 farmers (25 percent of the farming population), indicated that there is an awareness of the high salinity of ground water being used for irrigation but relatively little concern about the rate of increase of that salinity. The farmers seem reluctant to leave the area and are willing to take somewhat greater economic losses than expected. Since the farmers of the area are principally Mormon, there may be a tie to this historically Mormon region which is stronger than usual. The economic analysis of the Safford Valley based on the modeling of a "Representative Farm" analog indicates that cotton will remain economical to produce on the basis of the projected salinity trends and ceteris paribus conditions, for a significant time beyond limits of prediction. The analysis indicates that the optimum salt-resistant crops for the area are being cultivated, and that of these, alfalfa, the least tolerant, will cease to be productive in large areas of the valley by 1990. The entire valley will not be able to economically produce alfalfa by 2040, but will remain in production since it is a necessary crop for cotton and the cotton profits should be sufficient to cover the alfalfa losses. Pumping is the only element in the operation of the social, physical and economic systems by which salinity change could be influenced significantly. The area east of Safford is the optimal pumping region while that west of Pima is the worst. The employment of surface water should be maximized, and salt- oriented field methods should be employed. Although agriculture does not seem in danger in predictable time, these practices would increase yield (or slow the decrease) and postpone the day when farming will no longer by profitable in the Safford Valley of Graham County, Arizona.

The Santa Cruz valley in Arizona is a rapidly urbanizing area. Complaints by residents of the area about pest mosquitoes prompted the investigation of mosquito breeding sources and a search for management techniques that would reduce mosquito populations. Many types of mosquito breeding sites were found in the area, and eight species of mosquitoes were identified. The greatest source of mosquitoes was a 2400 hectare irrigated pecan orchard. The most numerous and annoying mosquitoes were Aedes vexans (Meigen) and Psorophora columbiae (Dyar and Knab). The orchard is irrigated ca. every two weeks from April through October by flooding level areas, called borders, between rows of trees. Mosquitoes hatched with every irrigation studied, from April through September, but reached annoying numbers from late April through mid-September. A. vexans was the dominant species in early spring and P. columbiae was dominant in summer. Highest populations were reached coincident with the summer rainy season in July and August. Tests were performed to determine the efficacy of Bacillus thuringiensis israelensis (B.t.i.) as an additive to irrigation water for control of mosquito larvae. The larvicidal material was effective at all concentrations from .586 to 2.344 l/ha and with all techniques used. The most cost-effective application technique was to use fertilizer tanks to drip a mixture of B.t.i. into irrigation water in ditches before the water ran into fields. The general rate of three parts larvicide per million parts irrigation water was found to be effective, especially when supplemented with a spray of one part larvicide to 64 parts water applied to the ends of borders two to three days following irrigation. An increase in larvicide concentration was found to be necessary during the peak of mosquito season. A successful management program was developed and applied for 1 year, during which no mosquito complaints were made by citizens, the population of mosquitoes in the orchard was reduced to a point where farm laborers were no longer annoyed, and farm managers were satisfied that the program was cost effective.

For one hundred years Cache Valley has been a growing segment of the American economy. Alternating periods of national financial stress and prosperity have been reflected in this Valley. In addition, Cache Valley has been confronted with certain distinct economic and financial problems and has produced her own solutions to these problems. Although her economy is based in large part on agriculture, the existence of the state agricultural college and a number of industries in her midst has induced economic growth and influenced economic development. Cache Valley provides fertile ground for study of a representative segment of the American economy. Likewise, it offers a fruitful case-study of Utah, Western, and Mountain economic development. Few of the men who lived during the making of Cache Valley's early history are living today to tell its story with their own lips. With the help of those who are today living a new Cache Valley financial story, the writer has completed a history of finance using both primary and secondary sources.

Timber management of coastal watersheds in southwest Oregon has been complicated by the need to protect anadromous fish habitat from accelerated stream sedimentation resulting from management activity. The rugged terrain of the Elk and Sixes River basins is underlain by the complex geological province of the Klamath Mountains, in which landslides are a common, natural, and important process of sediment production. A landslide investigation, using sequential aerial photographs which covered a time period of 37 years, was used to determine relationships between mass-wasting, geologic types, and timber harvest practices. Averaged over all rock types, harvested areas showed an increase in failure rate of 7 times, and roaded areas an increase of 48 times that of forested terrain. Terrane underlain by dioritic intrusions was the most sensitive to road-related activity, with an increase in failure rate of up to 108 times that of comparable unmanaged land. The complexity of lithologies and deformational history in the area strongly influence slope morphology, and produces characteristic soil types which experience predictable modes and rates of slope failure. Debris slides and torrents are the dominant form of mass-wasting in dioritic and Cretaceous sedimentary terrane. Areas underlain by more clay-rich metamorphic bedrock are prone to slumps and planar streambank failures. Stream morphology is profoundly influenced by both rock type and geologic structure. Within an area characterized by steep, deeply incised streams, several persistent low-gradient reaches were delineated. These low-gradient stream reaches occur where (1) large landslides have locally raised channel bed elevation and (2) valley-floor widening has occurred in sheared rocks along fault zones or in more readily eroded rock types upstream of rock types resistant to fluvial erosion. / Graduation date: 1987

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisor: Fred Valdez, Jr. Vita. Includes bibliographical references. Available also from UMI Company.

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