Water Availability Modeling Research Articles

Evaluation of gridded precipitation data in water availability modeling in CONUS

Water availability estimates are affected by the quality of data used. In this study precipitation data from meteorological forcing datasets specifically compiled for large-scale hydrological modeling are evaluated over the Conterminous United States (CONUS). The performance of the datasets was evaluated using Pearson Correlation (r), Nash Sutcliff Efficiency (NSE), Percent Bias (PBIAS), and Kling Gupta Efficiency (KGE) criterion. Three observation-based gridded precipitation data from the Inter-Sectoral Impact Model Intercomparison Project – ISIMIP (EartH2Observe, WFDEI and ERA-Interim data Merged and Bias-corrected for ISIMIP (EWEMBI), WATCH Forcing Data methodologyapplied to ERA-Interim data (WFDEI), and WFDE5 over land merged with ERA5 over the ocean (W5E5)) and one regional dataset (GRIDMET) were compared. The datasets were compared using more than 3300 gage precipitation observations. For grid-level comparisons, the Climate Prediction Center's Unified gage-based gridded precipitation dataset (CPC) was used as a reference dataset after verification with gage observations. The grid-to-grid comparison was made on daily, monthly, annual, and seasonal time steps. Grid runoff and discharge were simulated using the Community Water Model (CWatM) model. The flow estimations using the datasets were compared with CPC estimations and with more than 900 discharge observations distributed over the nine climate regions of CONUS. Furthermore, the per capita water availability was estimated and compared. In comparison with gage precipitation observation, CPC had superior performance, followed by GRIDMET. CPC resulted in daily KGE, NSE, and r above 0.5, and PBIAS within 25 % in 79 %, 69 %, 87 %, and 90 % of the stations, respectively. Grid-to-grid precipitation comparisons resulted in overall comparable performance between the datasets. In grid discharge estimation, GRIDMET (median KGE = 0.68) had the highest correlation with CPC. WFDEI, W5E5, and EWEMBI show close performance to each other in estimating grid discharge with median KGE values of 0.43, 0.25, and 0.45 respectively. The performance of the datasets as compared to observed stream flow gages also showed comparable performance with above zero KGE in 73, 56, 71, 60, and 70 stations by GRIDMET, EWEMBI, W5E5, and WFDEI, and CPC respectively. In estimating water availability per capita, W5E5 showed an overestimation as compared to ISMIP datasets. The estimations from CPC and GRIDMET were close to each other. This study serves as a valuable resource for guiding the selection of a suitable dataset for large-scale modeling over the CONUS. By providing performance information for the compared datasets, it assists in making informed data selection and contributes to our understanding of how the selection of input datasets affect water availability modeling.

Estimating Future Surface Water Availability Through an Integrated Climate‐Hydrology‐Management Modeling Framework at a Basin Scale Under CMIP6 Scenarios

AbstractClimate change and increasing water demand due to population growth pose serious threats to surface water availability. The biggest challenge in addressing these threats is the gap between climate science and water management practices. Local water planning often lacks the integration of climate change information, especially with regard to its impacts on surface water storage and evaporation as well as the associated uncertainties. Using Texas as an example, state and regional water planning relies on the use of reservoir “Firm Yield” (FY)—an important metric that quantifies surface water availability. However, this existing planning methodology does not account for the impacts of climate change on future inflows and on reservoir evaporation. To bridge this knowledge gap, an integrated climate‐hydrology‐management (CHM) modeling framework was developed, which is generally applicable to river basins with geographical, hydrological, and water right settings similar to those in Texas. The framework leverages the advantages of two modeling approaches—the Distributed Hydrology Soil Vegetation Model (DHSVM) and Water Availability Modeling (WAM). Additionally, the Double Bias Correction Constructed Analogues method is utilized to downscale and incorporate Coupled Model Intercomparison Project Phase 6 GCMs. Finally, the DHSVM simulated naturalized streamflow and reservoir evaporation rate are input to WAM to simulate reservoir FY. A new term—“Ratio of Firm Yield” (RFY)—is created to compare how much FY changes under different climate scenarios. The results indicate that climate change has a significant impact on surface water availability by increasing reservoir evaporation, altering the seasonal pattern of naturalized streamflow, and reducing FY.

Statistical Assessments of River Flow Alterations and Environmental Flow Standards

A water availability modeling (WAM) system consisting of the Water Rights Analysis Package (WRAP) and input datasets for all Texas river basins has been used for statewide, regional, and operational planning and water allocation regulatory purposes for many years. The modeling system was recently expanded to support integration of environmental flow requirements in comprehensive water management. A strategy is presented in this paper for combining the WRAP-WAM modeling system with data management and statistical analysis tools to expand capabilities for analyzing stream flow alterations and the effects on flows of environmental flow standards. A Trinity River Basin case study demonstrates the utility of the modeling and analysis strategy in addressing relevant issues in the river systems of Texas and elsewhere. Dams and reservoirs constructed on the Trinity River and tributaries supply water for the Dallas–Fort Worth and Houston metropolitan areas, which are among the most rapidly growing large metro areas in the United States. Ecologically relevant statistical analyses of observed flows presented in this paper are designed to quantify flow alterations. Analyses of simulated flows representing natural and specified conditions of development are performed to assess the impacts of both water resources development and the establishment of environmental flow standards.

A Multi-Reservoir Study of the Impact of Uncertainty in Pool Evaporation Estimates on Water-Availability Models

Quantifying evaporative loss from reservoirs plays a critical role in sound water-availability management plans and in reservoir management. Various methods are used to quantify reservoir evaporation; however, each method carries a degree of uncertainty that propagates to model predictions of available water within a reservoir or a reservoir network. Herein, we explore the impact of uncertainty in reservoir evaporation on model outputs of historical and future water availability throughout the five major reservoirs in the Savannah River Basin in South Carolina, USA, using four different evaporation methods. Variability in the total available water is evaluated using the United States Army Corps of Engineers (USACE) 2006 Drought Contingency Plan hydrologic model of the Savannah River Basin, which incorporates recent water-management plans and reservoir controls. Results indicate that, during droughts, reservoir evaporation plays a large role in water-availability predictions, and uncertainty in evaporative losses produces significant uncertainty in modeled water availability for extreme events. For example, the return period for an event in which the availability of water in Lake Hartwell was reduced to 50% of full pool capacity varied from 38.2 years to 53.4 years, depending on the choice of evaporation parameterization. This is a variation of 40% in the return period, depending on the choice of evaporation method.

Water Rights Analysis Package Modeling System

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.

Water availability model based on system dynamic: Sadar sub-watershed case study

Sadar Sub-watershed is one of 32 Brantas sub-watersheds located in the southern part of Mojokerto district and parts of the city of Mojokerto. Based on government regulation (PP) No 26 of 2008, Mojokerto is one of the national strategic areas from the point of view of economic interests. The National Strategic Area (KSN) with an economic interest point of view has an important role for national development, because these areas have the potential for a fast-growing economy and a leading sector capable of driving the national economy. This economic growth must be supported by the availability of various supporting facilities, one of which is the provision of clean water. The current condition of the existence of clean water is decreasing due to various reasons. The purpose of this research is to predict the availability of water in the future as a basis a water resources planning. The stages of the research are as follows: (1). Secondary data collection in the study. The data is used to calculate current water availability and predict future water availability. Primary data is in the form of interviews with groundwater users and experts. (2) Data Analysis. (3) Build the model of water availability in the study area. (4) Simulation of water availability in the study area under various scenario (5). Model validation. The results of this study indicate that there is an effect of land-use change on water availability in the sub-basin. Water conservation scenarios can maintain water availability in the future.

Monthly river flows in Texas for natural and developed conditions

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.

Estimating quick-flow runoff at the monthly timescale for the conterminous United States

The quantitative estimation of the quick-flow runoff component of streamflow is required for many hydrologic applications. Estimation at the monthly timescale and national spatial scale would be particularly useful for national water availability modeling. This paper reviews a sample of commonly used equations for quick-flow runoff, including several currently in use in continental-scale models. The review shows the wide range of equation forms or heuristics currently in use to predict quick-flow runoff, the limited spatial scale over which these equations are often developed or calibrated, and the scarcity of well-tested equations available for quick-flow runoff at the monthly timescale. Data were gathered from a set of 1301 gaged watersheds across the United States to test a range of equations from the literature, along with several alternative equations, to assess and compare their performance in predicting quick-flow runoff at the monthly timescale. The highest-performing equation was selected for application to monthly maps of explanatory variables to produce monthly quick-flow runoff water budget contribution maps. This equation is a regression against precipitation, soil saturated hydraulic conductivity, surficial geology type, and slope data. Its application indicates that average quick-flow runoff across the conterminous United States in the winter exceeds that in the summer by up to a factor of three. The monthly maps were explored and evaluated for the timespan of 2000–2015. The comparison of equation forms and produced monthly maps will be useful for a variety of hydrologic modeling and monitoring applications.

Environmental flow requirements in a water availability modeling system

Abstract The Texas Water Availability Modeling (WAM) System consists of the generalized Water Rights Analysis Package (WRAP), which is applicable for river systems located anywhere, and WRAP input datasets for the river basins of Texas. The WRAP/WAM system has been applied for over a decade in planning studies and administration of a water rights allocation system. Environmental flow standards for selected river systems in Texas have recently been established through a legislatively mandated process based on flow regimes with subsistence, base, pulse, and overbank flow components that describe the magnitude, frequency, duration, and timing of flows required to maintain sound ecosystems. WRAP and WAM capabilities for integrating environmental flow requirements in water allocation and associated water availability modeling have been greatly expanded as necessary to implement the new environmental flow standards. The modeling system and lessons learned in its implementation in Texas are relevant elsewhere.

Environmental Flow Attainment Metrics for Water Allocation Modeling

AbstractEnvironmental flow standards established according to a consensus-based, legislatively mandated process are being incorporated in the water rights permitting system for selected priority river systems in Texas. The flow standards for several of the rivers have been simulated as a part of a university research study using the new daily version of the Water Rights Analysis Package (WRAP) modeling system with modified input data sets from the Texas Commission on Environmental Quality (TCEQ) Water Availability Modeling (WAM) system. Metrics have been evaluated using time series of simulated streamflows and flow targets to characterize the engagement and attainment of the environmental flow standards. The metrics help determine the extent to which the standards are achieved within a river system water allocation simulation and enable the comparison of results between the different environmental flow regime components, different locations, and alternative river system development scenarios.

단일 저수지 운영에서 우선 수리권 영향성 평가

Nowadays, global warming derived from urbanization makes impact on the climatical and natural environment in the world. Also, water shortage from sharp population growth has increased because of impossible condition of the new reservoir construction that is one of sustainable water resource development. Accordingly, data survey for water rights have been required for limited water resources distribution effectively. Now, Water Management Information System(WAMIS) has gathered domestic water rights data according to various criteria as follows: living, industrial, and agricultural use purposes for specific year based on watershed, basin, river size. In this study, Water Rights Analysis Package (WRAP), one component of Texas Water Availability Model (WAM) system, is applied to multi-purpose Soyang Dam with monthly flow, evaporation, and precipitation. Also, water rights data are utilized into two types: natural and priority order water rights. The application results indicated that two types of water rights provided the insight for establishing various reservoir operation plans under flood, normal, and drought periods.

Analysis of Water Availability Model of Ngunut Sub-Watershed, Upper Bengawan Solo

The aims of this research is 1) formulating a model for water availability in order to know the input-output process in Ngunut Sub Watershed; 2) knowing the condition of water availability components for each landuse; 3) determining the best alternative landuse in Ngunut sub watershed. Data used in this researh were mean rainfall and temperature in ten years, water content in soil, groundwater flow, crop coefisien, landuse area, and the agricultural production value. There are 3 main outcomes of this research. The first, one is in form of software, concerning the water availability model in Ngunut Sub watershed. The second outcome, for mixed plantation, infiltration, water storage, and percolation had high values but surface runoff has a low value. For the rice field, evapotranspiration has the highest value, with interception, infiltration, and water storage having low values. For the dry fields; interception had the highest value. For the settlement, surface runoff had the biggest value. The third outcome, is that the landuse changes from irrigated rice fields and dry fields to form of mixed plantations, constitute the best alternatives in the spatial organization of Ngunut watershed, whose values are high.

Sustainable Statewide Water Resources Management in Texas

AbstractKey integrated components of the Texas sustainable water management enterprise include a regional and statewide planning process, water rights permit system and other water allocation mechanisms, process for establishing environmental flow standards, and water availability modeling system. These statewide endeavors mandated by the Legislature are implemented by a water management community comprised of state, local, and federal agencies, private industry, stakeholders, interests groups, consulting engineering firms, and university researchers. Texas is a large state with a rapidly growing population, declining groundwater supplies, intensifying demands on limited surface water resources, extreme hydrologic variability including severe droughts, and very diverse climate, geography, economic development, and water management practices. The Texas experience is illustrative of fundamental concepts and issues involved in state-level efforts to achieve sustainable water management.

Integrated assessment of global water scarcity over the 21st century under multiple climate change mitigation policies

Abstract. Water scarcity conditions over the 21st century both globally and regionally are assessed in the context of climate change and climate mitigation policies, by estimating both water availability and water demand within the Global Change Assessment Model (GCAM), a leading community-integrated assessment model of energy, agriculture, climate, and water. To quantify changes in future water availability, a new gridded water-balance global hydrologic model – namely, the Global Water Availability Model (GWAM) – is developed and evaluated. Global water demands for six major demand sectors (irrigation, livestock, domestic, electricity generation, primary energy production, and manufacturing) are modeled in GCAM at the regional scale (14 geopolitical regions, 151 sub-regions) and then spatially downscaled to 0.5° × 0.5° resolution to match the scale of GWAM. Using a baseline scenario (i.e., no climate change mitigation policy) with radiative forcing reaching 8.8 W m−2 (equivalent to the SRES A1Fi emission scenario) and three climate policy scenarios with increasing mitigation stringency of 7.7, 5.5, and 4.2 W m−2 (equivalent to the SRES A2, B2, and B1 emission scenarios, respectively), we investigate the effects of emission mitigation policies on water scarcity. Two carbon tax regimes (a universal carbon tax (UCT) which includes land use change emissions, and a fossil fuel and industrial emissions carbon tax (FFICT) which excludes land use change emissions) are analyzed. The baseline scenario results in more than half of the world population living under extreme water scarcity by the end of the 21st century. Additionally, in years 2050 and 2095, 36% (28%) and 44% (39%) of the global population, respectively, is projected to live in grid cells (in basins) that will experience greater water demands than the amount of available water in a year (i.e., the water scarcity index (WSI) > 1.0). When comparing the climate policy scenarios to the baseline scenario while maintaining the same baseline socioeconomic assumptions, water scarcity declines under a UCT mitigation policy but increases with a FFICT mitigation scenario by the year 2095, particularly with more stringent climate mitigation targets. Under the FFICT scenario, water scarcity is projected to increase, driven by higher water demands for bio-energy crops.

Institutional and Hydrologic Water Availability in Texas

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.

Potential Economic Impacts of Environmental Flows Following a Possible Listing of Endangered Texas Freshwater Mussels

AbstractTexas water resources, already taxed by drought and population growth, could be further stressed by possible listings of endangered aquatic species. This study estimated potential economic impacts of environmental flows (EFs) for five freshwater unionid mussels in three Central Texas basins (Brazos, Colorado, and Guadalupe‐San Antonio Rivers) that encompass 36% of Texas (~246,000 km2). A water availability model projected reductions in water supply to power, commercial and industrial, municipal, and agriculture sectors in response to possible EFs for mussels. Single‐year economic impacts were calculated using publicly available data with and without water transfers. Benefits of EFs should also be assessed, should critical habitat be proposed. Potential economic losses were highest during droughts, but were nominal (<$1 M) in wetter years — even with high EFs. Reduced supplies to San Antonio area power plants caused worst‐case impacts of a single‐year shutdown up to $107 million (M) during drought with high EFs. For other sectors in the study area, water transfers reduced worst‐case losses from $80 to $11 M per year. Implementing innovative water management strategies such as water markets, conjunctive use of surface water and groundwater, aquifer storage and recovery could mitigate economic impacts if mussels — or other widely distributed aquatic species — were listed. However, approaches for defining EFs and strategies for mitigating economic impacts of EFs are needed.

Modeling river/reservoir system management with the expanded WRAP

The Water Rights Analysis Package (WRAP) is a generalized modeling system for simulating water resources development, management, allocation, and control in river basins located anywhere in the world. WRAP is used to assess reliabilities in meeting water supply, hydroelectric power, and environmental instream flow needs. Capabilities for tracking salinity, assessing short-term reliabilities, and simulating reservoir operations for flood control were recently added. The modeling system continues to be expanded to address a broadening range of applications with major new modeling capabilities being released during 2009–2010. The Texas Water Availability Modeling (WAM) System consists of the generalized WRAP and input datasets for the 23 river basins of Texas. The Texas WAM System supports regional and statewide planning, administration of a water allocation permit system with over 8,000 active permits, and other water resources management functions. Activities of an array of water management entities operating 3,435 reservoirs and other facilities in accordance with various water allocation systems and other institutional arrangements are modeled.

Development of monthly naturalized flow using Water Rights Analysis Package (WRAP)-based methods

This paper addresses the methodology for developing monthly naturalized flow of the Texas Water Availability Model (WAM) system datasets by developing and applying Water Rights Analysis Package (WRAP)-based methods. The methodology is based on converting gaged stream flows adjusted to remove human impacts to naturalized flows using a current use WRAP model input dataset from the WAM System modified to represent actual use. An actual use scenario dataset is developed by modifying the current use scenario dataset to better represent actual water resources development, allocation, management, and use. The simulation iterations continue until the regulated flows very closely match the actual gaged flows. The regulated flow computed using the new naturalized flow shows the close match to gaged flow. The methodology developed in this study could potentially be used to update the other river basin datasets in the statewide WAM System.

Incorporation of salinity in Water Availability Modeling

Summary Natural salt pollution from geologic formations in the upper watersheds of several large river basins in the Southwestern United States severely constrains the use of otherwise available major water supply sources. The Water Rights Analysis Package modeling system has been routinely applied in Texas since the late 1990s in regional and statewide planning studies and administration of the state’s water rights permit system, but without consideration of water quality. The modeling system was recently expanded to incorporate salinity considerations in assessments of river/reservoir system capabilities for supplying water for environmental, municipal, agricultural, and industrial needs. Salinity loads and concentrations are tracked through systems of river reaches and reservoirs to develop concentration frequency statistics that augment flow frequency and water supply reliability metrics at pertinent locations for alternative water management strategies. Flexible generalized capabilities are developed for using limited observed salinity data to model highly variable concentrations imposed upon complex river regulation infrastructure and institutional water allocation/management practices.

Partitioning of anthropogenic watering sites by desert carnivores

AbstractWe investigated the role of water features as focal attractors for gray foxes (Urocyon cinereoargenteus), coyotes (Canis latrans), and bobcats (Felis rufus) in west Texas to determine if they were foci for interspecific interaction. Mixed effects models indicated that species partitioned use of water features spatially and temporally. Linear models indicated factors influencing relative activity at water features varied by species. For coyotes and bobcats, the water availability model, containing days since last rainfall and nearest‐neighbor distance to water was best supported by the data, with relative activity increasing with time between rainfall and distance between waters. For gray foxes, the best approximating model indicated that relative activity was inversely correlated to coyote and bobcat activity indices, and positively correlated to topographical complexity. Encounters between carnivore species were low, with most occurring between coyotes and gray foxes, followed by coyotes and bobcats, and bobcats and gray foxes. These findings suggest a behavioral‐environmental mechanism that may function to modulate resource partitioning by carnivores in the arid West. © 2011 The Wildlife Society.