Effective water resources management requires assessments of water availability within a framework of complex institutions and infrastructure employed to manage extremely variable stream flow shared ...by numerous, often competing, water users and diverse types of use. The Water Rights Analysis Package (WRAP) modeling system is fundamental to water allocation and planning in the state of Texas in the United States. Integration of environmental flow standards into both the modeling system and comprehensive statewide water management is a high priority for continuing research and development. The public domain WRAP software and documentation are generalized for application any place in the world. Lessons learned in developing and implementing the modeling system in Texas are relevant worldwide. The modeling system combines: (1) detailed simulation of water right systems, interstate compacts, international treaties, federal/state/local agreements, and operations of storage and conveyance facilities, (2) simulation of river system hydrology, and (3) statistical frequency and reliability analyses. The continually evolving modeling system has been implemented in Texas by a water management community that includes the state legislature, planning and regulatory agencies, river authorities, water districts, cities, industries, engineering consulting firms, and university researchers. The shared modeling system contributes significantly to integration of water allocation, planning, system operations, and research.
•We developed scenarios of agricultural intensification at farm scale.•We applied indicators to assess regional sustainability impacts of farm-level scenarios.•Scenario impacts showed regional ...variations depending on yield potentials and landscape features.•We discussed trade-offs of scenario impacts with policy stakeholders.•The method is exemplary for regional sustainability assessment of agricultural land use changes.
Decisions for agricultural management are taken at farm scale. However, such decisions may well impact upon regional sustainability. Two of the likely agricultural management responses to future challenges are extended use of irrigation and increased production of energy crops. The drivers for these are high commodity prices and subsidy policies for renewable energy. However, the impacts of these responses upon regional sustainability are unknown. Thus, we conducted integrated impact assessments for agricultural intensification scenarios in the federal state of Brandenburg, Germany, for 2025. One Irrigation scenario and one Energy scenario were contrasted with the Business As Usual (BAU) scenario. We applied nine indicators to analyze the economic, social and environmental effects at the regional, in this case district scale, which is the smallest administrative unit in Brandenburg. Assessment results were discussed in a stakeholder workshop involving 16 experts from the state government.
The simulated area shares of silage maize for fodder and energy were 29%, 37% and 49% for the BAU, Irrigation, and Energy scenarios, respectively. The Energy scenario increased bio-electricity production to 41% of the demand of Brandenburg, and it resulted in CO2 savings of up to 3.5milliontons. However, it resulted in loss of biodiversity, loss of landscape scenery, increased soil erosion risk, and increased area demand for water protection requirements. The Irrigation scenario led to yield increases of 7% (rapeseed), 18% (wheat, sugar beet), and 40% (maize) compared to the BAU scenario. It also reduced the year-to-year yield variability. Water demand for irrigation was found to be in conflict with other water uses for two of the 14 districts. Spatial differentiation of scenario impacts showed that districts with medium to low yield potentials were more affected by negative impacts than districts with high yield potentials.
In this first comprehensive sustainability impact assessment of agricultural intensification scenarios at regional level, we showed that a considerable potential for agricultural intensification exists. The intensification is accompanied by adverse environmental and socio-economic impacts. The novelty lies in the multiscale integration of comprehensive, agricultural management simulations with regional level impact assessment, which was achieved with the adequate use of indicators. It provided relevant evidence for policy decision making. Stakeholders appreciated the integrative approach of the assessment, which substantiated ongoing discussions among the government bodies. The assessment approach and the Brandenburg case study may stay exemplary for other regions in the world where similar economic and policy driving forces are likely to lead to agricultural intensification.
River flow characteristics and computational methods for converting sequences of monthly flows between natural and regulated conditions are explored based on experience in assessing water ...availability throughout the state of Texas in the United States. Diverse climate, hydrology, economic development, and water management practices across the state combined with continual population growth and implementation of a statewide water availability modeling system makes Texas an excellent case study of stream flow characteristics and modeling and analysis methods that are relevant worldwide. Stream flow is extremely variable, subject to severe multiple-year droughts, intense floods, seasonality, and continuous fluctuation. The effects of population and economic growth, water resources development and management, and climatic variability on river flows vary with different conditions found across the state. The modeling system provides capabilities for adjusting observed river flows to represent natural conditions, simulating regulated flows representing specified conditions of development, and performing statistical frequency and reliability analyses.
•River flows in Texas are characterized by extreme temporal and spatial variability.•River flows have been altered by water resources development, regulation, and use.•Observed flows are adjusted to reflect natural conditions.•Simulated flows reflect specified scenarios of water development and use.•River flows for natural versus regulated conditions are compared.
Water management in Texas is driven by dramatic spatial and temporal hydrologic variability, continual rapid population growth, declining groundwater supplies, and intensifying demands on surface ...water resources. Dams and reservoirs are essential for providing reliable water supplies and reducing flood risks. Numerous reservoir projects, most constructed during the 1940s through 1980s era of large scale water project construction nationwide, are operated throughout the state to store and regulate extremely variable river flows for beneficial purposes. This paper explores river system hydrology in Texas, operation of dams and reservoirs statewide to deal with extreme flow fluctuations, and associated complexities, issues, and water management strategies. The central focus of the paper is the role of large reservoirs in managing hydrologic variability and associated future uncertainty in an environment of growing demands on limited resources.
Received 18 October 2019, Accepted 5 January 2021, Published online 22 February 2021
Citation: Wurbs RA. 2021. Storage and regulation of river flows by dams and reservoirs. Texas Water Journal. 12(1):10-29. Available from: https://doi.org/10.21423/twj.v12i1.7106.
The water rights analysis package simulates surface water development, allocation, management, and use and performs reliability and frequency analyses of simulation results. The computer modeling ...system facilitates assessments of hydrologic and institutional water availability and reliability in satisfying requirements for reservoir storage, water supply diversions, environmental instream flows, and hydroelectric energy generation. Reservoir system operations for flood control can be simulated. Capabilities are also provided for tracking salinity concentrations. Basin-wide impacts of water resources development projects and management practices are modeled. The modeling system is generalized for application anywhere, with input datasets being developed for particular river systems of concern. The water availability modeling system maintained by the Texas Commission on Environmental Quality and routinely applied by the professional water management community consists of the water rights analysis package and simulation input datasets for all of the river basins of Texas. Model-users modify the input datasets as appropriate to evaluate alternative water use scenarios, development projects, and management strategies of interest. This paper explores concepts and methodologies incorporated in the water rights analysis package and other comparable modeling systems, implementation of water availability modeling in Texas, and contributions to effective water management.
The state of Texas has implemented a modeling system for assessing the availability and reliability of water resources that consists of a generalized simulation model called the Water Rights Analysis ...Package (WRAP) and input datasets for the state's 23 river basins. Reservoir/river system management and water allocation practices are simulated using historical naturalized monthly streamflow sequences to represent basin hydrology. Institutional systems for allocating streamflow and reservoir storage resources among numerous water users are considered in detail in evaluating basinwide impacts of water management decisions. The generalized WRAP model is a flexible tool that may be applied to river basins anywhere. The Texas experience in implementing a statewide modeling system illustrates issues that are relevant to water management in many other regions of the world.
A water availability modeling system was implemented during 1997–2004 by the Texas Commission on Environmental Quality and its contractors, in collaboration with the water management community, under ...a mandate provided by comprehensive water management legislation enacted by the Texas legislature in 1997. The availability and reliability of water resources are assessed based on simulating river/reservoir system management and water allocation practices using sets of historical naturalized monthly streamflow sequences to represent basin hydrology. The prior appropriation water rights permit system and other institutional mechanisms for allocating streamflow and reservoir storage resources among numerous water users are considered in detail in evaluating basinwide impacts of water management decisions. The generalized modeling system and lessons learned in its implementation in Texas are applicable to river basin management throughout the world.
Reservoir evaporation in Texas, USA Wurbs, Ralph A.; Ayala, Rolando A.
Journal of hydrology (Amsterdam),
03/2014, Letnik:
510
Journal Article
Recenzirano
•Reservoir evaporation in Texas equals about 126% of total municipal water use.•The impacts of reservoir evaporation are greatest during extended droughts.•Evaporation greatly affects the river ...system water budget and water management.
The role of reservoir surface evaporation in river/reservoir water budgets and water management is explored using a modeling system that combines historical natural hydrology with current conditions of water resources development and management. The long-term mean evaporation from the 3415 reservoirs in the Texas water rights permit system is estimated to be 7.53 billionm3/year, which is equivalent to 61% of total agricultural or 126% of total municipal water use in the state during the year 2010. Evaporation varies with the hydrologic conditions governing reservoir surface areas and evaporation rates. Annual statewide total evaporation volumes associated with exceedance probabilities of 75%, 50%, and 25% are 7.07, 7.47, and 7.95 billionm3/year, respectively. Impacts of evaporation are greatest during extended severe droughts that govern water supply capabilities.
An institutional framework and supporting water availability modelling capabilities are presented for integrating ecological needs into water resources management. Concepts illustrated by the Texas ...experience are relevant worldwide. Environmental flow standards with subsistence, base, in-bank pulse and over-bank flow components are established through a legislatively mandated process by stakeholder committees and science teams working in collaboration with government agencies. The flow standards incorporate ecosystem needs into water allocation and associated water availability modelling. Recognizing the complexities of defining and preserving environmental stream flows, expedited present action is combined with an adaptive management process for future improvements.
The Water Availability Modeling (WAM) System created and maintained by the Texas Commission on Environmental Quality (TCEQ) and its partner agencies and contractors consists of the generalized Water ...Rights Analysis Package (WRAP) developed at Texas A & M University, which may be applied anywhere in the world, and WRAP input datasets for the 23 river basins of Texas. WRAP is designed for assessing river/reservoir system reliabilities in meeting water supply, hydroelectric power, environmental flow, flood control, and reservoir storage needs. The Texas WAM System supports regional and statewide planning, administration of water allocation systems, and other water resources management endeavors. Activities of numerous water management entities operating 3,435 reservoirs and other facilities in accordance with treaties between the United States and Mexico, five interstate compacts, two water right permit systems with 6,000 active permits, and other institutional arrangements are simulated. The modeling system contributes greatly to water management in Texas and continues to be expanded to address additional water management issues. The Texas experience in implementing the WAM System illustrates key aspects of evaluating water availability from institutional as well as hydrologic perspectives.
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