Now showing items 14730-14749 of 14895

    • Water temperature as a groundwater tracer in fractured rock

      Flynn, Timothy Joseph.; Simpson, Eugene S. (The University of Arizona., 1985)
      Characterization of transport in fractured media is based on observation of the movement of labeled water. Difficulties in labeling water with chemicals include the removal of sample water, residual background concentration, and expensive analytical equipment. These difficulties are avoided with the use of heated (or cooled) water as a groundwater tracer in site characterization. Heated water was successfully used as a tracer in a fractured granite near Oracle, Arizona. The temperature sensing device consisted of 20 thermistors on a down-hole string, distributed over a 62-foot interval. In a three-hole recirculation test, a heat source was placed in a borehole 20 feet from the hole housing the thermistors. A third borehole was pumped with the outflow returned to the borehole containing the heat source. Differential breakthrough of the thermal pulse allowed delineation of flow paths between boreholes.
    • Water transfers in Arizona: Measuring effects on areas of origin

      Nunn, Susan Christopher; Davis, Donald R.; Checchio, Elizabeth, 1957- (The University of Arizona., 1990)
      Thousands of acres of irrigated farmland in rural Arizona have been purchased recently with the hope of transporting the associated water to cities. Many Arizonans believe that this "water farming" can solve Arizona's water supply problems. Others, however, fear that water transfers will have serious adverse effects on the areas of origin. To evaluate the effects of transfers, their path must be traced through the regional economy and environment. This requires sophisticated modeling and detailed data. It is possible, however, to make interregional comparisons with much less data, contrasting regional sensitivity to particular categories of effects. The most important are economic, fiscal, environmental, and limitations on future development potential. In this research, indices of relative sensitivity to economic and fiscal effects of water farming are constructed based on readily available secondary data. The values for these indices are calculated for four Arizona counties: Paz, Maricopa, Pima, and Pinal.
    • Water Tunnel Experiments on Span-wise Variation of Laminar Separation Bubbles for Swept and Unswept Wings using Particle Image Velocimetry

      Fasel, Hermann; Gluck, Jeffrey Weston; Little, Jesse; Kerschen, Edward (The University of Arizona., 2016)
      An inverted airfoil mounted above a flat plate was used to create laminar separation bubbles on a flat plate in water tunnel experiments at low Reynolds numbers. Boundary layer suction ensured that the flow remained attached to the wing. Two-dimensional PIV measurements were used to qualitatively and quantitatively characterize the spanwise bubble variation on an unswept wing and on the same wing featuring a 22 degree sweep. The separation bubbles were recorded at varied span-wise locations in a 31.5 cm wide region of the flow. The limitations of this measurement region were dictated by the focal length of the laser optic used for PIV measurements. The straight wing exhibited approximately uniform time averaged separation positions across the span of the wing. The reattachment locations varied only slightly which was expected due to the transition to turbulent flow before reattachment. A form of bubble "breathing" was observed in the laminar separation bubbles on the straight wing and is believed to have affected the mean reattachment locations for two data points recorded. The shedding frequencies on the straight wing were slightly higher than those obtained from CFD simulations. The swept wing planform showed significantly more variation in the mean separation and reattachment locations with respect to the leading edge of the wing. There is a general trend of the separation locations moving upstream in the direction of the aft leading edge. The reattachment points are shown to move downstream as the separation points move upstream relative to the leading edge and visa versa, displaying an inverse relationship between the two. The bubble lengths were found to be slightly longer on the swept wing compared to the straight wing usually by about 10%. The shedding frequencies on the swept wing were found to be lower than the straight wing. The quality of flow in the water tunnel may have degraded over time, showing signs of increased free stream turbulence. After data collection, it was also discovered that the boundary layer suction on the wing was not constant at all span-wise locations. It is believed that the introduction of wing sweep intensified the effect of insufficient suction on the structure of the bubbles observed. The present results were in agreement with previous research for bubble structure but the dynamic instabilities were found to differ slightly.
    • The Water Use and Climate Effects on Farm Profitability in Colorado River Basin

      Frisvold, George B.; Qiao, Xin; Aradhyula, Satheesh; Colby, Bonnie G. (The University of Arizona., 2018)
      The Colorado River is the lifeblood of the southwestern United States. The imbalance between water supply and demand in this basin has been increasing and conditions are projected to worsen with climate change and population growth. Because agriculture is a major user of groundwater and surface water in this region, federal and state agencies suggest that substantial cuts in agricultural water use will be required to re-balance water supply and demand. Such cutbacks, though, impose opportunity costs in the form of lost agricultural production and farm income. This study considers the regional distribution of net returns to irrigated agriculture in Colorado Basin states to address where such opportunity costs will be low and high. In some counties, net farm returns per acre of irrigated land or per acre-feet of water applied are quite high, while in others areas are low. The study also examines which factors determine why farm profitability is low or high across counties. The relationship between net farm income and a set of climate, water resource availability and farm characteristic variables for the seven Colorado Basin states is examined using county-level data from 2005 and 2010. Regression results indicate that county level farm income per irrigated acre and per acre foot of water applied are significantly influenced by temperature, precipitation and reliance on groundwater relative to surface water. A simple rationing model is applied to examine potential costs of large reductions in water use that might occur under land fallowing programs. If fallowing were concentrated in areas with the lowest gross revenues per acre foot of water, even substantial reductions in water use would have only a minimal effect on the value of regional production.
    • Water use and crop coefficient determination for irrigated winter wheat in Arizona

      Gold, H. David; Gay, Lloyd W.; Zwolinski, Malcolm J.; Brown, Paul (The University of Arizona., 1995)
      Estimates of evapotranspiration (ET) were irrigated winter wheat in the spring of 1988 9 made for based on measurements of latent heat flux using Bowen ratio systems at the University of Arizona's Maricopa Agricultural Center (MAC). Data were examined over a 132 day period. For the same time period, reference ET estimates were made in the same region using a modified Penman equation based on data from the Arizona Meteorological Network (AZMET). A comparison of ET estimates for 118 days prior to wheat senescence shows excellent agreement (r^2 = 0.94). This implies that a simple crop coefficient can be used as a basis for irrigation scheduling for winter wheat grown under climatic conditions similar to those at MAC in 1988. In addition, the ET estimates were used to test the validity of a previously determined crop coefficient for winter wheat based on heat units and to assess current groundwater allocations in Arizona.
    • Water use and diurnal ranges of Coues white-tailed deer

      Smith, Norman S.; Maghini, Mark Thomas, 1963- (The University of Arizona., 1990)
      I evaluated water use by female Coues white-tailed deer (Odocoileus virginianus couesi) and calculated their diurnal ranges relative to available water in southeastern Arizona during hot-dry and hot-wet summer seasons. Developed water sources were scarce in 1988 and abundant during 1989. Freestanding water was not the only determinant of diurnal seasonal ranges. Not all diurnal seasonal ranges contained permanent water, but a water source density of 1/km² was sufficient during the 1989 hot-dry season and ephemeral water was common in hot-wet seasons. Deer visited developed water sources regularly during hot-dry seasons and infrequently 14 days after the summer rains began. Large amounts of preformed water were available in hot-wet season diets, but permanent or ephemeral water was necessary to meet total water requirements. Visits of cattle to troughs did not preclude deer use because of different activity patterns between the 2 species. Wildlife managers should provide free-standing water in Coues white-tailed deer ranges during hot-dry seasons and in the early part of hot-wet seasons. If winter precipitation is substantially below normal, available free-standing water in summer is especially critical.
    • Water use by Emory oak in southeastern Arizona: Estimation by sap-flow measurements

      Ffolliott, Peter F.; Folkerts, Shaun Hajo, 1972- (The University of Arizona., 1999)
      Water use by mature and sprout (coppice) forms of Emory oak (Quercus emoryi) was estimated by the sap-flow method. Five standards and five coppice trees were sampled in an area that had been harvested for fuelwood and five mature trees were sampled in an uncut area. Differences were recognized between coppice and standards in the cut area and between coppice trees and mature trees from the uncut area. Regression equations were derived relating estimated annual water use to tree diameter, height, and crown measurements for both cut- and uncut-area trees. Seasonal water use by each tree form showed relationship to precipitation, but little relationship to temperature and relative humidity. Woodland density and tree size measurements facilitate extrapolation of water use from the 15 sampled trees to a per area basis. Water use was approximately 1900 cubic meters per hectare per year, based upon drc measurements, for the uncut area and 3168 cubic meters for the cut area. Estimated water use on a per unit area was approximately 1.67 times greater for the cut area than the uncut area.
    • Water, Energy and Carbon Dioxide Exchange of a Riparian Mesquite Woodland

      Edwards, Eric Alan.; Shuttleworth, William James (The University of Arizona., 2002)
      Fluxes of water, energy and carbon dioxide were measured above a riparian mesquite woodland for an entire growing season using the eddy covariance method. Measurements of water vapor and carbon dioxide concentration were contaminated by erroneous measurements caused by sunlight incident on the bottom window of the Infrared Gas Analyzer, although a procedure was developed to remove this influence from the calculated fluxes. Data analysis suggests that daytime fluxes were underestimated by approximately 10%, while nighttime fluxes are difficult to measure accurately as a result of atmospheric stability. The growing season appears approximately bounded by freeze events in the spring and fall. Within the growing season there are two distinct periods characterized by different precipitation regimes. During the early summer months there is little rainfall, and high vapor pressure deficits appear to cause partial stomata' closure in the afternoon, resulting in reduced fluxes of water vapor and carbon dioxide. Later in the year, during the summer monsoons, this closure no longer occurs and the fluxes remain high throughout the afternoon. Annual water vapor flux is approximately 60% of the atmospheric demand, indicating the mesquite trees limit transpiration despite having access to groundwater. Nighttime respiration appears to increase with soil moisture during the summer months, while there is little or no effect of temperature during this time.
    • Water-awareness in Tucson, Arizona : a pilot study

      Buckley, Kebba Emunah.; Dworkin, Judith M.; Bradley, Michael D.; DeCook, K. James (The University of Arizona., 1981)
      A random sample survey of 100 city residents was conducted in Tucson, Arizona, to evaluate water-awareness and to test a survey instrument. Respondents were found to view water issues simplistically, but most believe that there is some degree of water shortage. Tucsonans appear to feel optimistic about affecting the water supply/ demand problem through their use patterns, and while they have misconceptions, they want to know more about "water realities." They think of their water use in terms of cost and are evenly divided on whether voting may provide them any control over water management policies. The research design was moderately successful, providing for the achievement of the objectives, but with less well-defined results than had been hoped. The study results may be applied in developing future information campaigns, or the refined research approach may be utilized in designing future studies of water-awareness and related concepts.
    • Water-harvesting on arid coal mine soil for vegetable and fruit production

      Powelson, David.; Thames, John L.; Ffolliott, Peter F.; Cluff, C. Brent (The University of Arizona., 1982)
      The Black Mesa Water-Harvesting Agrisystem is testing the feasibility of using water-harvesting techniques to reclaim strip mined land. Two different treatments, fiberglass-asphalt-chipcoat and salt, were applied to increase the runoff from the catchment areas. The water is stored in ponds to provide ample irrigation to a variety of vegetables and fruits. This system would generate an estimated net annual revenue of $1400 per irrigated acre or approximately $348 per acre for the whole system. This income is a great improvement over the estimate of no net income from the conventional reclamation alternative of establishing forage. The potential high quality of Black Mesa spoil as agricultural soil is indicated by its loam texture, neutral pH, and high nitrogen level. After three years of fertilization with phosphate, irrigation, cropping and cultivation, the spoil is developing a friable, granular structure. Some of the problems encountered in operating the system are: land subsidence on the regraded spoil, crop pests, and weed growth on the catchments. Nevertheless, it appears that the establishment of water-harvesting instead of, or in conjunction with, grazing would increase the future benefits from the land without increasing the costs of reclamation.
    • Water-sediment ejections of the 1964 Alaska earthquake

      Waller, Roger M. (The University of Arizona., 1969)
    • Water-use efficiency of seven cultivars of alfalfa (Medicago sativa L.).

      Cole, Darrell Franklin, 1941-; Dobrenz, Albert K.; Massengale, M. A.; Wright, L. N. (The University of Arizona., 1969)
      Two experiments were conducted in a greenhouse environment at Tucson, Arizona to determine the water-use efficiency of five cultivars and two experimental lines of alfalfa (Medicao sativa L,) at both the seedling and mature stages of plant development. Another experiment was conducted to determine differences in water-use efficiency among genotypes within the cultivars Mesa-Sirsa and Ladak. Significant differences were found in water-use efficiency among cultivars in both the seedling and mature stages of plant development. Cultivars did not maintain their rank between the stages of plant development in either water-use efficiency or dry matter production. Plants of Mesa-Sirsa transpired more water than those of other cultivars in both experiments. Significant differences were found among plants of different cultivars in dry forage and transpired water in the seedling stage; however, no significant differences for these factors were found among cultivars in the mature stage of plant development. More variatior in water-use efficiency was found within cultivars than was found among cultivars. Transpired water, dry forage production, stomate density, leaflet to stem and petiole ratios, and percentage protein were each correlated with water-use efficiency.
    • Waterbud: A spreadsheet-based model of the water budget and water management systems of the Upper San Pedro River Basin, Arizona

      Lord, William B.; Maddock, Thomas, III; Braun, David Philip, 1950- (The University of Arizona., 1992)
      Spreadsheet programming is used to model the water budget and water management systems of the Upper San Pedro River Basin, Arizona, to examine how hydrologic, demographic, climatic, and economic conditions affect this budget; and how water management policies may affect the budget over the next twenty years. The model represents relationships among urban and rural population and median incomes; urban and rural domestic water consumption; agricultural and industrial consumption; domestic, agricultural, and industrial return flows; phreatophyte and other evapotranspiration losses; natural surface and ground-water recharges and discharges; head-dependent flow between a floodplain aquifer and the river; head-dependent flow between a regional aquifer and the floodplain aquifer; and changes in aquifer storage. Applications indicate that stringent conservation measures and reductions in irrigation are necessary to significantly reduce ongoing losses to storage in both aquifers, which also threaten river discharges and the viability of riparian habitat in the basin.
    • Watershed Modeling by Remote Sensing and AGWA - SWAT for Western Portion of Cusco Watershed - Peru

      Guertin, D. Phillip; Pumayalli, Rene; Guertin, D. Phillip; Shaw, William; Hiller, Joseph G.; Wissler, Craig (The University of Arizona., 2008)
      Erosion and flooding in the Cusco watershed have increased over the last 30 years due to urban growth and incorrect use of natural resources. New data for a section of the watershed were created with satellite image, spatial data, and geoprocessing software including Erdas Imagine 9.1 and ArcInfo and free information and software in the public domain on the internet. AGWA2.0 - SWAT modeling software used the data to assess the actual conditions of the study area (Model 1) including sediment yield, water yield, percolation, and stream flow. Then, two models were created by altering the conditions of the land cover/use grid: Model 2 changed the bare soil class into contour trenches, and Model 3 changed bare soil class into trees or forest. A comparison of Models 2 and 3 with the current state (Model 1) found that forestation, Model 3, would greatly decrease flooding and increase water infiltration.
    • A watershed volume response model considering contributing area

      Patten, Richard Thomas,1945-; Thames, John L. (The University of Arizona., 1975)
      Modeling watershed response from a contributing area concept rather than a lumped parameter viewpoint may be of value to land managers. In order to develop and examine an expression representing the contributing area, a runoff model has been determined with the use of multivariate linear regression. The model is designed to predict the volume response of a watershed to rainfall events. The variables in the model are related to the current and recent previous precipitation events and other historical climatic information. Parameters in the model, determined by regression, are related to physical characteristics of the watershed. Contributing area, a significant parameter, is found to be variable over time depending on the climatic conditions of the season. When several watersheds are compared using independent data in the model, their contributing areas vary in response to physical properties of the watersheds, such as soil types and distribution.
    • A waveguide power balance theorem applied to a parallel plate waveguide with an iris

      Dudley, Donald G.; Trantanella, Charles Joseph, 1967- (The University of Arizona., 1991)
      We study the problem of wave propagation in a parallel plate waveguide with an iris. We use Green's function techniques to model the field behavior inside the waveguide. We formulate an integral equation whose solution will allow us to solve for the fields everywhere within the guide. We solve the integral equation by employing both the method of moments and a low-frequency approximation. We next develop a power balance theorem which relates the modal coefficients of the propagating modes in an exact relation. From the numerical solution, we can generate numerical approximations to the modal coefficients. We investigate if and when our numerical approximations to the modal coefficients satisfy the power balance theorem. Finally, we derive a generalized power balance theorem for scattering by obstacles and junctions inside a waveguide of arbitrary, uniform cross-sectional area.
    • "We Were Recruited From the Warriors of Many Famous Nations," Cultural Preservation: U.S. Army Western Apache Scouts, 1871-1947

      Nichols, Roger L.; Barbone, Paul Joseph; Nichols, Roger L.; Parezo, Nancy J.; Colombi, Benedict J. (The University of Arizona., 2010)
      The Western Apache Scouts of the 1870s who assisted the United States Army in tracking down the Chiricahua Apaches that had escaped from the federal reservations in the Arizona Territory laid the foundation for what became seventy-six years of military service in the U.S. Army. Consolidated and reassigned to Ft. Huachuca, Arizona in 1922, these scouts continued to serve with distinction long after the Army needed their skills as trackers. In 1947, the final four scouts retired from United States military service, each having served for over twenty-five years. This thesis explores how these men used their military service in order to survive, serving with honor while maintaining their cultural traditions within a changing world.
    • "We, too, Are Americans": African American Women, Class, and Citizenship in Detroit and Richmond, 1940-1954

      Anderson, Karen; Shockley, Megan N. Taylor (The University of Arizona., 2000)