Browsing by Author "Jordan, Wayne R."
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item Economic and Hydrologic Implications of Proposed Edwards Aquifer Management Plans(Texas Water Resources Institute, 1993-03) Dillon, Carl R.; Jones, Lonnie L.; Williams, R. Lynn; Jordan, Wayne R.; McCarl, Bruce A.The Edwards Aquifer underlies a large region in south central Texas extending from west of Uvalde to Austin. The karstic aquifer supports irrigated agriculture in the western part of the region, provides the sole source of water supply for San Antonio in the central portion and provides for spring flow-based recreation and municipal water supply in the eastern part of the region. In addition, spring flows and return flows from cities provide water supplies for downstream users and freshwater inflows to maintain productivity of bays and estuaries. The spring flows also support several threatened and endangered species unique to that ecosystem. Despite the varied and growing demand on Edwards Aquifer water, pumpage is unregulated since, according to Texas water law, ground water is a property right vested with the land owner. Throughout at least the past two decades, attempts to negotiate voluntary management plans to restrict pumpage have been unsuccessful, even though demand is projected to exceed average recharge near the turn of the century. A recent court ruling has increased the pressure for adoption of an Aquifer management plan. Acting on a suit brought to ensure spring flow and aquatic habitat protection under the Endangered Species Act, the court ruled that a management plan be developed and approved by the Texas Legislature by May 31, 1993. Should the Legislature fail, the court would implement its own plan. In 1992, two management plans were drafted by the Texas Water Commission (TWC) but were not adopted. Since Texas Legislature is considering plans similar to the TWC plans, a study was undertaken to evaluate the hydrologic and economic implications of these TWC plans. Both plans propose imposition of pumping limits based on water elevation in a reference well located in San Antonio. Four variants of the plans were analyzed using an annual economic/hydrologic simulation model of the aquifer. The model simulates water use by the agricultural, industrial and municipal sectors while simultaneously forecasting annual spring flow and year-end water elevations. Model solutions depict optimum water allocations among sectors based on economic welfare maximization. The model also accounts for uncertainty in the incidence of elevation-triggered pumping limits and recharge amounts. When the value of water is optimized in an economic sense, the model predicts an annual loss in regional economic activity of between $6.26 and $19.58 per acre foot that pumpage is reduced. Under a 1988 demand scenario, annual welfare is reduced between $0.73 and $1.57 million across the plans. The annual loss rises to between $2.38 and $6.60 million under estimated year 2000 demand conditions. Agricultural water use is the most pivotal: under year 2000 demands, irrigated acres decline by 32% to 84% while net agricultural income falls annually by $1 million (13%) to $2.5 million (36%). Simultaneously, the municipal and industrial sector welfare is reduced annually by between $0.8 million (2%) and $5.7 million (8%). The benefits from all management plans are increased spring flows at Comal and San Marcos springs and higher ending aquifer levels. However, none of the proposed plans is forecast to guarantee flows at Comal springs given a repeat of the 1950's drought. The model assumes that low valued users would allow higher valued users to displace their water use, a result that is unlikely in the absence of compensation. Thus, a rights structure was also examined where the irrigated agriculture sector (generally a low valued user) is guaranteed water usage at the 1988 level. The results demonstrate that while agricultural welfare is raised, municipal, industrial and total welfare is reduced by more than the agricultural gain. In other words, agricultural gains are achieved at the expense of municipal and industrial welfare. Equivalently, without an agricultural guarantee, the municipal and industrial gains are achieved at agriculture's expense. One set of results reveals a year 2000 agricultural use value equals about $19 per acre foot while non- agricultural values are about $109 per acre foot. The results suggest the desirability of simultaneously implementing water market mechanisms to allow water use reallocation along with plan-induced pumpage restrictions. An unchanging allocation of pumping use causes growing disparity in sectoral water values as demand grows ($90 per acre foot in the above example). The simultaneous imposition of pumpage limits, water rights and water markets appears necessary to maintain economic efficiency. The results show that allowing water sales through a market mechanism could return as much as $11 million annually, while allowing both water sales and leasing is worth an additional $1 million. Markets would allow economic agents to seek out the highest valued uses of scarce aquifer water resources and provide compensation to those users reducing their usage.Item Environmental Issues of the U.S.-Mexico Border Region: A Workshop Summary(Texas Water Resources Institute, 1994-10) Jordan, Wayne R.; Malstrom, Howard A.A July, 1994 workshop was held in College Station to examine information available on environmental issues facing the Rio Grande River basin along the U.S.-Mexico border in Texas. The objectives of the workshop were: 1. to identify current university, state, and federal data bases for the region; 2. to inventory research and analytical capabilities; and 3. to determine future research plans and projects of interest. This report summarizes the workshop, which was organized and conducted by the Texas Water Resources Institute, a unit of the Texas Agricultural Experiment Station. Additional development of the border region may result in the degradation of many aspects of the environment and ecosystem. Factors leading to this deterioration might include: population growth and urbanization, industrial growth, shifts in agricultural practices, and international politics. The impact of changes in these factors would be felt in, among other things, water availability, water quality, air quality, land use and management, food safety, coastal resources, and information coordination. Consequences of changes in both physical and social systems could include the degradation of human health, biodiversity, and quality of life. Whether an increase in general economic well-being in the region will come about as the k result of increased trade and development is not yet certain. An economic increase l could help compensate for the loss and damage to natural resources caused by l urbanization and industrialization. On the other hand, a lack of economic improvement or, worse yet, an economic backslide, in conjunction with resource degradation could mean irreversible problems for the region's development, [ economic survival and quality of life. Border region environmental problems are being addressed by both countries, but they suffer from lack of communication and coordination; lack of organization in assembling, analyzing, and interpreting existing data; and lack of a well-defined, comprehensive, and coordinated research plan for the region. Part of the mission of the College Station Workshop was to identify and recommend ways to contribute to the resolution of border environmental problems with a binational focus to evaluate the latter. The purpose of this report is to list and discuss each of the major suggestions, which are: 1. to develop an organizational structure to improve coordination between U.S. and Mexican agencies; 2. to provide incentives to encourage better cooperative research ventures; and 3. to name an umbrella coordinating agency for the development, assessment, and distribution of existing data from the region. This report also presents major components of a strategic research plan for the border region, including the needs and expected research outcomes. Workshop participants identified the following natural resource and environmental problems as having greatest need for research: public health, water quantity and quality, agricultural land use, environmental conservation, ecosystem management, transboundary institutions, and transportation and international commerce. It is likely that collaborative research and planning will be required to provide solutions to these and other problems. Collaborative research activities will likely be shared among U.S. and Mexican universities, and State, Federal, and local agencies. This report contains abstracts of presentations from the following speakers: * Economic Impacts of NAFTA in the Border Region: Prospects for Texas Agriculture - Parr Rossen, Department of Agricultural Economics, Texas A&M University System, College Station, Texas * The Demography of the Texas-Mexico Border Region - Rogelio Saenz, Department of Rural Sociology, Texas A&M University, College Station, Texas * The Sustainable Development Initiative for the Rio Grade/Rio Bravo Basin - Dan Sisbarro, Center for Global Studies, HARC, Houston, Texas * The Bureau of Reclamation's Future on the U.S.-Mexico Border - Dan Page and Roberta Ries, United States Department of the Interior, Bureau of Reclamation, Rio Grande Project, El Paso, Texas and Denver, Colorado * Hydrologic Modeling of the Rio Grande Basin - C. Alan Jones, Blackland Research Center, Texas Agricultural Experiment Station, Temple, Texas * Border Programs of the Texas Natural Resources Conservation Commission (TNRCC) - Steve Niemeyer, Texas Natural Resources Conservation Commission, Austin, Texas * The Role of the Frank Hernandez Environmental Laboratory in Support of Environmental Science Programs - A. Mehdi Ali, Agricultural Research and Extension Center, Texas A&M University, El Paso, Texas * Senate Bill 503 and 319(h) Activities on the Border - Bryan "Bo" Spoonts, Texas State Soil and Water Conservation, Board, Temple, Texas * Gap Analysis: An Assessment of Biodiversity in Texas - Lloyd B. McKinney, Department of Forest Science-Mapping Sciences Division, Texas A&M University, College Station, Texas in cooperation with Nancy Mathews, TX Cooperative Fish and Wildlife Research Unit, National Biological Survey, Texas Tech University and Joy Winckel, Department of Range and Wildlife Management, Texas Tech University * Overview of Extension Water Quality and Conservation Programs in the Lower Rio Grande Valley - Guy Fipps, Department of Agricultural Engineering, Texas A&M University, College Station, Texas * Microbiological Research on Transboundary Water Quality Problems at El Paso - Suresh D. Pillai, Texas Agricultural Research and Extension Center, El Paso, Texas * An Overview of the U.S. Fish and Wildlife Service Land Management Program in the Lower Rio Grande Valley, Texas - Larry R. Ditto, Project Leader, Lower Rio Grande Valley National Wildlife Refuge Complex, McAllen, Texas * Texas Parks and Wildlife Department Programs to Identify and Minimize Impacts to Natural Resources Along the Texas Mexico Corridor - Texas Parks and Wildlife Department Programs to Identify and Minimize Impacts to Natural Resources Along the Texas-Mexico Border - Ismael "Smiley" Nava, Texas Parks and Wildlife Department, Resource Protection DivisionItem Irrigation Water Management for the Texas High Plains: A Research Summary(Texas Water Resources Institute, 1987-08) Jordan, Wayne R.; Sweeten, John M.The four main crops produced in the Texas High Plains have been the subject of water management research for several decades by the Texas Agricultural Experiment Station and the USDA/Agricultural Research Service. As expected, experimental results for yield and water use efficiency have varied for these four major crops, but many common principles have likewise emerged from this research. Definite improvements in water use efficiency have been made, and widespread application of these management principles is underway. Limited irrigation is now being widely practiced on drought tolerant crops that take advantage of expected rainfall. A 30-day period of fairly reliable rainfall occurs from mid-May through mid-June which coincides with sorghum and cotton planting and follows typical corn planting. Sorghum has good ability to adjust to water stress. Sorghum grain requires 13 to 24 inches (330-610 mm) of seasonal water use (evapotranspiration) from precipitation, stored soil moisture and irrigation to achieve 3,000 to 6,700 pounds per acre (3,400-7,500 kg/ha) of grain sorghum yield. Dryland sorghum yields average about 1,600 pounds per acre (1,800 kg/ha), and yields up to 3,000 pounds per acre (3,400 kg/ha) are not uncommon. Peak water use rate is about 0.30 inches per day (7.6 mm/day). Irrigations should be timed to avoid water stress during periods of peak water use--boot, heading and flowering stages--to achieve reasonably good yields and maximum irrigation water use efficiency. Two well-timed seasonal irrigations of 4 inches (100 mm) per irrigation or the equivalent are adequate in normal years for good yields of medium maturity hybrids. Preplant irrigation is often not needed, and the same amount of water may be more efficiently used if applied at later stages of crop growth especially for conventional graded furrow irrigation systems. Conservation tillage can reduce the need for preplant irrigation of sorghum through improved soil moisture storage. Irrigation water use efficiencies may reach 400-500 pounds per acre-inch (1.8-2.2 kg/m3) with limited but well-timed irrigations as compared to about 200-250 pounds per acre-inch (0.88-1.10 kg/m^3) with adequate irrigation. Saving irrigation water by withholding a 4-inch (100 mm) irrigation reduces sorghum grain yields by only about 10 percent during the early 6-8 leaf stage but by almost 50 percent if withheld at the heading and bloom stage. : Corn is much more sensitive to water stress than sorghum, wheat or cotton. Corn is planted earlier than sorghum which typically allows more efficient use of the May-June wet season than for sorghum. However, early planting dates required for corn increases the need for preplant irrigation for stand establishment. Moisture stress caused by low soil water availability or hot, dry conditions during the flowering (tasseling, silking and pollination) stage can severely restrict corn yield. Preplant irrigation is often necessary, and 3 or 4 seasonal irrigations of 4-inch (100 mm) each are essential for high corn yields in most years in the Texas High Plains. Drought seasons require one or two additional irrigations. Reduced irrigation of corn has generally resulted in significant yield decreases. Irrigation water use efficiency values are usually 250-450 pounds per acre-inch (1.1-2.0 kg/m^3) with adequate irrigation, although peak IWUE values of 500 pounds per acre-inch (2.2 kg/m^3) or more have been obtained with limited irrigation in good rainfall seasons. Center pivot irrigation allows frequent irrigations of 1 to 1.5 inches (25-38 mm) during peak water use periods on corn. The total seasonal water use (ET) for corn to achieve any grain yield is about 13 inches (330 mm), while seasonal ET's for peak yields are around 28-32 inches per year (710-810 mm). Peak ET rates are 0.3-0.4 inches per day (8-10 mm/day), depending upon weather conditions. Planned water deficits into the stress range are feasible only on soils with moderate to high water storage and during the early vegetative or grain ripening stages. Reduced acreage, rather than reduced irrigation, offers the primary way to adjust corn irrigation to limited water supplies. Winter wheat is a major drought tolerant crop with a 9-month growing season. Wheat grows vegetatively during the drier fall to early spring period and develops grain during a period of increasing spring rainfall. Wheat is normally planted around October 1 and requires available 8011 moisture for germination and early growth, plus perhaps one late fall irrigation followed by 2 to 3 spring irrigations for good production. About one additional early irrigation (and additional applied fertilizer) is needed for early planted wheat that is grazed and also managed for grain production. Seasonal water use is around 26 to 28 inches (660-710 mm) for wheat (grain only) yielding 4,700-5,800 pounds per acre, or 85-100 bushels per acre (5,270-6,500 kg/ha). The highest yield response to irrigation usually occurs during jointing and boot stages (a relatively low rainfall period), during which irrigation water use efficiency values of about 230 pounds per acre-inch (1.0 kg/m^3) are realized from a 4 inch (100 mm) irrigation. Spring irrigations totaling 4 to 12 inches (100-305 mm) have resulted in good irrigation water use efficiencies above 170 pounds per acre-inch (0.75 kg/m^3). The least efficient irrigation is during grain filling, where IWUE values have been less than 115 pounds per acre-inch (0.51 kg/m^3), and is associated with increased rainfall. Short wheat varieties in recent tests have exhibited 50 percent higher irrigation water use efficiency values than tall wheat varieties in earlier tests. Wheat yields have been increased in some experiments using no-till, limited tillage, or furrow diking as compared to conventional tillage. Cotton is a drought-tolerant long-season crop that lends itself to limited irrigation despite a somewhat complicated pattern of water use, deficits, and application. Cotton is the major irrigated crop on the Texas High Plains and is second to Wheat in dryland production acreage. Widespread production under limited irrigation has major impact on water demands and the state's water budget. Production, placement, and retention of fruiting sites are sensitive to soil water status. Early fruit set is important. Under dryland conditions, expected lint yields are in the range of 250 to 300 pounds per acre (280-336 kg/ha). Cotton requires over 13 inches (330 mm) of seasonal water use to produce good yields, and maximum yields occur at about 27 inches (685 mm) of seasonal water use. High water levels can decrease lint yield through excessive vegetative development and fall immaturity. A preplant irrigation of 4-inches (100 mm) is usually advantageous especially if spring rainfall is not excessive, but heavier preplant irrigations are not warranted. Cotton has the ability to overcome moisture stress at most growth stages, but the growing season length may not accomodate late-season regrowth. The most critical period for irrigation is early to mid-bloom. If available, a second irrigation should be applied at peak to late bloom. The irrigation cut off date for cotton is mid- to late August. For irrigated cotton, yield results generally favor narrow-row with high plant populations. Irrigation water use efficiencies for cotton have ranged from as little as 20-30 pounds per acre-inch (0.09-0.13 kg/m^3) for full irrigation to as high as 80-100 pounds per acre-inch (0.35-0.44 kg/m^3) for two well-timed furrow irrigations (preplant and peak bloom) in some experiments. A reasonable target for limited furrow irrigation appears to be 50 pounds per acre-ineh (0.22 kg/m^3). Cotton Irrigated with LEPA Sand drip systems produced around 90 pounds lint per acre-inch (0.40 kg/m^3). Land leveling on slopes of 0.5 percent or greater have increased yields by more than 100 pounds lint per acre (110 kg/m^3) for both furrow irrigated and dryland cotton.