Journal of The American Water Resources Association最新文献

Accurate streamflow forecasts are critical for modeling and managing estuarine water quality, as freshwater fluxes significantly influence coastal dynamics. The National Water Model (NWM) provides high-resolution streamflow predictions, which are valuable for hydrodynamic modeling in poorly gauged coastal regions. However, inaccuracies in NWM forecasts can limit our ability to predict estuarine and nearshore water quality effectively. First, this study evaluates the accuracy of NWM predictions for 14 coastal reaches in southwest Florida's Charlotte Harbor and Caloosahatchee River estuaries from 2018 to 2024, where hydrologic management has impacted water quality. NWM forecasts showed varying bias and variance, with Nash-Sutcliffe efficiencies (NSE) ranging from −2.26 to 0.77. Next, hydrodynamic simulations for the flow-managed Caloosahatchee River Estuary (CRE) were performed using both NWM forecasts and observed streamflows, revealing that errors in NWM predictions during high-flow events caused significant deviations in the position of ecologically relevant isohalines, lasting weeks. Finally, to address these issues, a Long Short-Term Memory (LSTM) network was developed to bias-correct NWM forecasts, improving NSE from 0.41 to 0.53. However, the LSTM's inability to “learn” managed discharge schedules highlights the need for advanced data assimilation and simulation techniques in flow-managed coastal systems.

China is facing a serious water shortage. The government's implementation of a water resource tax policy is an important step in the ecological protection of water resources. This paper constructs a stochastic frontier production function model to measure the industrial water resource utilization efficiency in Hebei Province under the consideration of water resource tax. Then, this paper constructs a model of the impact of water resource tax policy on industrial water resource utilization efficiency using the double difference method to evaluate the causal effect of the policy. The research findings of this article are: (1) Through discontinuity regression, it was found that the water resources tax policy has a significant positive correlation with the improvement of water resource utilization efficiency in Hebei Province. The implementation of the water resources tax policy has successfully improved the industrial water resource utilization in Hebei Province. (2) Although the implementation of the water resources tax policy has improved the efficiency of industrial water use in Hebei Province, the overall efficiency of industrial water use in Hebei Province is still low, and many problems have arisen during the advancement of the water resources tax policy. In response to the problems that occurred during the pilot period in Hebei Province, this article proposes some policy solutions to accelerate the advancement of water resource tax policies across the country.

This study proposes a distributed unit hydrograph (DUH) method to address the challenge of simulating overland flow concentration in plain river network regions. The DUH framework defines generalized river network polygons (RNPs) to represent flow convergence zones and estimates runoff travel times based on a calibrated confluence velocity parameter, circumventing the need for high-resolution topographic data. The method was applied to the Taihu Basin, where 16 subregions were analyzed under different spatial scales and overland flow velocities. Results show that the DUH method significantly enhances model performance compared to the traditionally used proposed unit hydrograph (PUH) approach. Specifically, DUH reduced the root mean square error (RMSE) of simulated water levels by up to 40%, improved the coefficient of determination (R²) by 0.1–0.2, and reduced the average flood peak lag from 2.1 days to 0.7 days. The model exhibited optimal accuracy at a grid scale of 200 × 200 m, achieving a balance between smooth hydrograph formation and computational efficiency. These findings underscore the DUH method's applicability for flood simulation and decision-making in low-relief, hydraulically complex regions with limited microtopographic data availability.

Watershed management must be prioritized in Mexico due to environmental degradation. To address the issue, an instrument to assess watershed functional status and specific governance conditions is needed. We assessed the functional conditions of a microwatershed (a watershed of less than 5000 ha) located in the headwater of the Querétaro River watershed using the Index of Catchment Integrity (ICI) to evaluate local conditions and the Index of Watershed Integrity (IWI) to evaluate the cumulative conditions. Implementing the IWI in La Laborcilla Microwatershed (LMW) required some adaptations to the available information. We integrated data generated through two indices: The Environmental Water Quality Index (EWQ(i)), which evaluates the physicochemical conditions of water from an ecosystem perspective, and the Hydrogeomorphological Index (IHG), which assesses the conditions of naturalness or alteration of riparian ecosystems. These complementary indices generated detailed information on the stressors that affect the six functional components of the watershed. To complete the assessment, we evaluated the LMW management process within local decision-making and policy instruments. The watershed had medium-low integrity (IWI = 0.43). The integrity of the catchments (ICI) spanned from 0.27 to 0.58. Watershed integrity is a relevant perspective for effective watershed management in operational forms within the territorial planning process and environmental policy instruments.

The United States SECURE Water Act states that a study of water use is critical for assessing impacts on water and ecological resources and forecasting whether or not available surface and groundwater supplies will meet future needs. The United States Geological Survey (USGS) plays a key role in the SECURE Water Act by providing nationally consistent information on water quantity, quality, and use. Water-use data maintained by States and Territories are critical for the USGS water-use estimation and modeling techniques that underlie these efforts. However, water-use data availability has not been systematically assessed. This study addresses this gap through a survey of USGS Water Science Centers (WSCs). The results indicate that water-use information varies in its content and level of detail across the United States. Spatially discrete and comprehensive information about water use, such as site-specific consumptive use, withdrawals, diversions, return flows, and interbasin transfers, is not widely available to and/or shared between State and Territory water-resource agencies and USGS WSCs. This article presents the survey results and discusses reported barriers to water-use data availability and sharing, as well as potential implications of limited water-use information. This study advances understanding of water-use data availability and sharing and contributes to broader research on US water data governance.

River system changes are widely observed in urbanization areas, but the relationship between urbanization and river system is poorly understood. We investigate the interaction between urbanization and river system in a plain river network region. Results show that the structure and morphology of the river system became simplified. In most areas, the higher the initial river density, the more river channel loss occurs. The interaction between urbanization and river system consists of three stages: (1) with the development of urbanization, a large amount of low-order channels were encroached, filled, and transformed into construction land, (2) urban expansion and channel loss change the process of runoff generation and concentration and increase the risk of rainstorm and flood disasters, and (3) to relieve these negative effects, humans add main channels by widening and excavating. Low-order channels fall victim to urbanization. Effective measures, including legislation, must be taken to protect low-order channels in the process of urbanization.