Browsing by Subject "Water conservation"
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Item Agroecology of three integrated crop-livestock systems in the Texas High Plains(2012-05) Zilverberg, Cody; Allen, Vivien G.; Johnson, Phillip N.; Galyean, Michael L.; Moore-Kucera, Jennifer; Villalobos, Carlos; Kellison, RickTechnological advances have enabled agriculture to feed and clothe a growing global population with great success. It is now imperative that we remain productive while halting the natural resource degradation that often accompanies high productivity. In the semi-arid Texas High Plains, sustainability of current agricultural practices is threatened by depletion of the Ogallala aquifer and soil erosion. Perennial grasses, the region’s historic vegetation, can build soil rather than lose it and require little or no supplemental irrigation. We designed and tested three agroecosystems that integrated crop and livestock production using a base of perennial forages. All systems were designed to decrease water withdrawals from the Ogallala aquifer relative to conventional irrigated agriculture. The experiment covered a total of 42 ha in a randomized block design with three blocks. The non-irrigated system, DRY (evaluated from 2004 to 2008), included a paddock of native perennial grasses and a rotation of cotton (Cynodon dactylon [L.] Pers.) and foxtail millet (Setaria italica [L.] P. Beauv.). The buffer-irrigated system, LOW (evaluated from 2009 to 2011), was the same as DRY except that LOW added an irrigated paddock of ‘WW-B. Dahl’ old world bluestem (Bothriochloa bladhii [Retz] S.T. Blake; hereafter bluestem), which was harvested for grass seed as well as grazed. The limit-irrigated system, MED (evaluated from 2007 to 2011), included two irrigated paddocks of bermudagrass that were grazed and harvested for hay, and one paddock of bluestem that was grazed and harvested for grass seed. Angus beef stocker steers (Bos taurus L.; initial BW: 245 kg) sequence-grazed each system. We evaluated these systems with a variety of criteria, including forage and animal production, water use, crop yields and quality, forage quality, soil C fractions, soil penetration resistance, forage species stability, economic performance, fossil fuel energy use, and C emissions associated with fossil fuel use. We found that each system had strengths and weaknesses. Annual irrigation water use by each system was: DRY, 0 mm; LOW, 44 mm; and MED, 229 mm. The MED system was the most productive, yielding 446 kg steer live weight gain ha-1, compared with 107 for LOW and 57 for DRY. Bermudagrass yielded the most animal unit grazing days ha-1 (644; bluestem: 246; native grasses: 90; annuals: 41) of any forage and was the highest quality forage with the exception of the annual, foxtail millet. Bermudagrass also had the highest soil concentration of particulate organic matter C (3.1 g kg-1 soil in top 5 cm; native grass: 2.5; bluestem: 2.1), an indicator of higher potential nutrient mineralization and soil C accumulation. The annual fields had the lowest levels (1.3 g kg-1 soil in top 5 cm); however, the MED system was the worst economic performer and emitted the most C (774 kg C ha-1; LOW: 226; DRY: 205) as a consequence of fossil fuel use. In contrast, DRY produced the least amount of grazing (72 animal unit grazing days ha-1; LOW: 76; MED: 434), but was the most profitable and used no irrigation water. Although productivity of DRY and LOW were less than MED, LOW and MED beef carcasses were of equivalent quality (68% USDA Choice; DRY was not evaluated) and cotton lint from DRY and LOW received price premiums in all years (mean $0.024 and 0.106 kg-1, respectively). The lessons learned from this experiment should be used to design future agroecosystems that conserve soil and water while producing agricultural goods. Relative to annual and perennial non-irrigated paddocks, applying irrigation and N to introduced forages increased productivity and accelerated soil C sequestration, but the additional inputs were not justified economically. It may be more profitable to integrate, at the farm or landscape scale, large areas of non-irrigated native grasses in combination with smaller areas of intensively farmed, high-value crops that receive irrigation and fertilizer. Ley farming, which includes long rotations of perennial grass with annual crops, is one option that may hold promise for the future.Item Analytical methods and strategies for using the energy-water nexus to achieve cross-cutting efficiency gains(2013-12) Sanders, Kelly Twomey; Webber, Michael E., 1971-Energy and water resources share an important interdependency. Large quantities of energy are required to move, purify, heat, and pressurize water, while large volumes of water are necessary to extract primary energy, refine fuels, and generate electricity. This relationship, commonly referred to as the energy-water nexus, can introduce vulnerabilities to energy and water services when insufficient access to either resource inhibits access to the other. It also creates areas of opportunity, since water conservation can lead to energy conservation and energy conservation can reduce water demand. This dissertation analyzes both sides of the energy-water nexus by (1) quantifying the extent of the relationship between these two resources and (2) identifying strategies for synergistic conservation. It is organized into two prevailing themes: the energy consumed for water services and the water used in the power sector. In Chapter 2, a national assessment of United States' energy consumption for water services is described. This assessment is the first to quantify energy embedded in water at the national scale with a methodology that differentiates consistently between primary and secondary uses of energy for water. The analysis indicates that energy use in the residential, commercial, industrial, and power sectors for direct water and steam services was approximately 12.3 quadrillion BTU or 12.6% of 2010 annual primary energy consumption in the United States. Additional energy was used to generate steam for indirect process heating, space heating, and electricity generation. Chapter 3 explores the potential energy and emissions reductions that might follow regional shifts in residential water heating technologies. Results suggest that the scale of energy and emissions benefits derived from shifts in water heating technologies depends on regional characteristics such as climate, electricity generation mix, water use trends, and population demographics. The largest opportunities for energy and emissions reductions through changes in water heating approaches are in locations with carbon dioxide intensive electricity mixes; however, these are generally areas that are least likely to shift toward more environmentally advantageous devices. In Chapter 4, water withdrawal and consumption rates for 310 electric generation units in Texas are incorporated into a unit commitment and dispatch model of ERCOT to simulate water use at the grid scale for a baseline 2011 case. Then, the potential for water conservation in the power generation sector is explored. Results suggest that the power sector might be a viable target for cost-effective reductions in water withdrawals, but reductions in water consumption are more difficult and more expensive to target.Item Beyond the Aquifer : planning for San Antonio's future water supply(2010-05) Laughlin, Nathan Daniel; Butler, Kent S.; Schuster, StefanThis report examines water supply planning issues in San Antonio, Texas. San Antonio is unique among large cities in the United States in that it relies almost exclusively on a single source, the Edwards Aquifer, for its water supply. Because San Antonio’s water demand is projected to outgrow the Aquifer’s capacity, the city must consider other options to extend and augment its current water supply. After describing the hydrogeology and water supply history of San Antonio, this report explains the multitiered water planning structure and current and future water needs for the city. It then studies and evaluates three short-to-mid term water supply options. By continuing to develop its already successful water conservation programs and water reclamation system, San Antonio can delay the need for more costly and environmentally impactful water supply options down the road, and wisely manage the resources it already draws from.Item Climate action strategies for the University of Texas at Austin(2010-05) Hernandez, Marinoelle; Eaton, David J.; Walker, Jim H.This report analyzes the current greenhouse gas emissions inventory for The University of Texas at Austin (UT-Austin), reviews the carbon reduction strategies being implemented at UT-Austin and other peer institutions, and offers recommendations for strategies that could reduce greenhouse gas emissions at UT-Austin in the future.Item Developmental responses of cotton genotypes to varying water application regimes(Texas Tech University, 2004-05) West-Emerson, Cora LeaNot availableItem Habitat for Humanity housing project: a case study emphasizing water conservation design for a semi-arid land site(Texas Tech University, 2001-05) Henry, Jane UThe objective of this thesis is to make clear the extent and urgency of the crisis in the water situation for the twenty one counties in the Texas Panhandle known as the Llano Estacado, and to suggest ways in which all citizens can take practical and affordable steps to be a part of the solution to that crisis. The water from the Ogallala Aquifer, primary freshwater supply for this region, is being drawn down at a rate that far exceeds its recharge. Therefore, beginning with a summation of the facts, the project reviews the problems of the semi-arid region, created by nature and exacerbated by the actions of mankind, and looks at the choices being made about using the limited water supply. A discussion of the natural forces that impact water use explains how these same forces can be garnered to help solve the problem of water shortage. A review of historic precedents from semi-arid climates around the world gives suggestions for water conservation methods that can be adapted today in areas of limited water supply. Suggestions then are made for specific solutions citizens of the region can adapt to have a positive impact on problem of water shortage. The solutions are applied specifically to site of Habitat for Humanity in Lubbock as a microcosm of the problem and a case study for changes that can conserve water in the region. The solutions focus quite specifically on site design based on needs of the Habitat community, harvesting and storing rain water, recycling greywater, holding water on the land to be absorbed into the soil, landscaping with native plants and building with local materials.Item Public perception in determining water management in water conserving landscapes(Texas Tech University, 2000-05) Lockett, Landry L.Implementing xeriscape principles can save a hmeowner an estimated 0 to 80% of the water used in the landscape. However, limited research has evaluated public opinion of the performance of plants grown in xeriscapes. A survey instrument was designed to determine public opinion of the performance of five Texas native plant species grown at Lubbock, TX under 30, 60 and 90% of reference evapotranspiration (ETQ). Four hundred ten experience stratified survey participants rated plant performance once a month during a twenty-week survey period in the summer of 1999, Soil moisture levels between treatments differed only in three of the twenty test weeks. Consequently, no significant differences in the rated performance or height of plants were detected at the different irrigation levels. This research has documented public opinion as it relates to xeriscapes and found that xeriscapes irrigated with less than one-third of the ETo were able to maintain the same level of public acceptance as those irrigated with 90% of the ETQ. Public acceptance of xeriscaping will grow as homeowners become more confident in the beauty and utility of water conserving alternative landscapes. Public gardens and horticulture institutions could use projects such as this to demonstrate how appropriately designed xeriscapes reduce landscape water consumption, and maintain plants that are acceptable to the public.Item Saving water in farming : methodology for water conservation verification efforts in the agricultural sector(2013-05) Ramirez Huerta, Ana Karina; Eaton, David J.This dissertation develops, tests and validates statistical methods for verifying the amount of water conserved as a result of investments in precision leveling, other on-farm conservation measures in place, weather variation and farmer behavior. This evaluation uses a sample of 328 unique fields from Lakeside Irrigation Division in Texas over a six-year period, totaling 966 observations. Results show that precision leveling accounts for a 0.30 acre-feet reduction of irrigation water per acre leveled. This Mixed-Level Model (MLM) estimate for precision leveling water savings is more precise than the estimates either from an Ordinary Least Square Model or a Fixed Effect Model. A meta analysis combines the results from this model with other similar studies. Although the mean estimate of the meta-analysis is similar to the MLM estimate, the meta-analysis further reduces the standard error of the mean precision leveling estimate by 2 percent. A better approximation of the acre-feet water savings per acre farmed translates into less uncertainty for water regulators, managers and policymakers regarding the volume of conserved water that is available for transfer.Item Item Underground water management in arid and semiarid regions: alternative strategies and measurement issues(Texas Tech University, 1994-12) Al-Hmoud, Rashid B.The objective of this study is to develop three essays related to underground water management in the arid and semiarid region of the United States (southwestem states). One essay discusses the socially optimal management policies of underground water resources as suggested by the economics theory. The second essay examines actual policies and management regimes in the southwestern states. DiflFerent management regimes are evaluated and their pros and cons are examined to arrive to the second-best solution. The second-best solution for the managerial problem is the one that comes very close to that suggested by the theory, and is the most successfiil in maximizing social welfare. A key variable for underground water policy-makers is the value of the resource in its natural place. Sufificient knowledge of underground water values is essential for underground water authorities, who direct their eflForts to manage the use of the resource and ensure that underground water is being used efficiently. A scarce resource, such as underground water, should be used efficiently, and the provision of the resource should be based on the values that it generates when utilized. A scarce resource should be used at its highest valued uses. Underground water is used in its highest valued uses when water users are confronted with its tme value. The last essay introduces techniques to estimate the value of underground water, and it estimates values for underground water in the High Plains Underground Water Conservation District No. I, which is located in the State of Texas.Item Water conservation on campuses of higher education in Texas(2014-08) Zellner, Hannah Marie; Pierce, Suzanne Alise, 1969-Facing drought and water shortages, many regions of the United States and the world have been forced to improve water resources management. In water-stressed areas of the US, water conservation has become the most economically viable water supply option available. As such, water conservation efforts are an increasingly popular method of demand management and have proven effective at various scales throughout the country. Many states in the arid southwest, including Texas, have incorporated water conservation strategies into their state water plans to reduce demand during drought conditions. At the 2013 Summit for the Texas Regional Alliance for Campus Sustainability (TRACS), water conservation was identified as a critical issue for higher education institutes (HEI) across the state. HEIs are analogous to small cities in terms of their resource use, and can also serve as test labs for sustainability concepts and resource management strategies. In response to concerns about water scarcity, TRACS launched an evaluation of water conservation strategies across Texas’ HEI campuses. The project collected data focused on the use of water conservation methods and their perceived effectiveness in irrigation and landscaping, building use, and utilities. Additionally, water conservation educational efforts, and the goals and policies of HEIs were considered. The objectives of the project were to collaborate with Texas HEIs, compile a database of best practices, and identify regional preferences in a state with varying climates and water resources. The results of the survey determined that native and adaptive plants were the most-widely used water conservation method for irrigation and landscaping as well the most effective strategy. In buildings, low-flow plumbing was reported to be the most widely-used and also most effective water conservation method. A variety of water conservation measures were used in utilities; metering, maintenance, and recycling water were viewed as most effective. While many HEIs reported offering opportunities for students to learn or participate in research about water conservation, only half reported offering workshops or courses for managerial staff and faculty. Education for staff and faculty is a particularly important area for improvement, as many staff members are closely involved in managing water use across campuses. Many of the HEIs reported having water conservation policies in place or pending and some participating HEIs reported having target reduction plans and involvement with agencies related to water conservation. It is important for the administration of educational institutions to put policies and plans in place to guide the everyday operations of a campus. HEIs in the state are making great strides in water conservation, but establishing a network to share best practices and improvements could significantly enhance campus water conservation initiatives.