Journal of The American Water Resources Association最新文献

The agriculture sector is a significant consumer of water, and sustainable water use begins with monitoring irrigated land. Delineating irrigated land supports decision-makers and promotes the sustainable use of this crucial resource. This study focuses on the Nubian Sandstone Aquifer System (NSAS), the largest aquifer in the world, which spans Egypt, Sudan, Libya, and Chad. Built upon long-term satellite remote sensing observations, the study aims to: (1) quantify the increase in irrigated hectares (both pivot and non-pivot) during the last decade; (2) identify major irrigated crop types and their water requirements; and (3) quantify the increase in crop water use from the NSAS from 2000 to 2024. The findings indicate that irrigated areas fluctuate over time, but the overall irrigated area under the NSAS has increased. The total irrigated area nearly doubled from 14,635 km² in 2000 to 24,811 km² in 2024, while the area irrigated directly from the NSAS increased from 1257 to 3268 km² over the same period. Correspondingly, crops water use from the NSAS increased from an estimated 1.4 km³ in 2000 to 3.64 km³ in 2024. These results have important implications for water and land use, and policymakers in NSAS to ensure the sustainable use of these vital resources for the present and future generations.

Stream assessments are needed to inform regulatory decisions, mitigation and restoration design, and other management practices. Many methods have emerged to meet regional needs and specific management contexts. The number of available approaches creates confusion over the relative merits of methods and appropriate use cases. Furthermore, the complexity of these approaches ranges from rapid evaluations requiring minutes to complete to detailed methods needing weeks of effort. However, the level of effort associated with approaches is rarely tracked for method selection. Differences in measurement metrics and data collection create obstacles to consistent, meaningful comparisons across methods and regions. We compiled and analyzed 188 stream assessment methods, revealing four core challenges: (1) inefficient identification of methods, (2) diverse metrics for ecosystem condition, (3) a wide range of resource needs, and (4) limited comparability of results. While geomorphic (59%) and biological (46%) metrics are common, few methods (5%) comprehensively evaluate a broader set of ecosystem functions. Although many methods exist, the most pressing challenges in stream assessment are choosing appropriate methods, ensuring adaptability, and enabling comparability. Finally, we identify recommendations for improving the practice of stream assessment, including clearer guidance and standardized protocols for assessment.

The study is focused on the evaluation of multi-site and multi-variable calibration of the Soil and Water Assessment Tool model. The variables used for the multi-calibration approach comprised snow water equivalent, soil water content, and discharge. The calibrated model was further used to investigate the influence of small water reservoirs on the runoff regime in the Upper Vydra catchment, Czech Republic (89.9 km²). The multi-calibration approach led to significantly improved estimation of snow accumulation/melt, soil water storage, as well as discharge at incorporated subbasins. The values of the Nash-Sutcliffe coefficient in the validation period improved from 0.65 to 0.82 for snow water equivalent, from −25.6 to 0.13 for soil water storage, and from 0.39 to 0.41 for discharge on average for all measuring stations. At the expense of the multi-calibration approach, the Nash-Sutcliffe coefficient decreased from 0.61 to 0.53 for discharge simulation in the closing profile. Due to their small storage volumes, the small water reservoirs had a modest effect on mitigating low-flow conditions. In two pronounced drought periods in 2015 and 2018, the number of days with the discharge below minimum sustainable flow was reduced by 7 and 8 days, respectively. The volume of four inspected peak flows was reduced by less than 1%, indicating minimal impact of the reservoirs when used as the only flood mitigation measure.

The U.S. Geological Survey is developing nationally consistent water-use modeling approaches to replace previous methods relying on locally specific reported and estimated data. These national assessments require datasets that incorporate water withdrawal variability across the United States and over long periods. However, source data often have unclear definitions, missing or varied units, differing temporal resolutions, varied data quality, and inconsistent formats, which hinder automation and require individualized processing. The public-supply datasets described in this paper were used in machine learning models to estimate annual and monthly public-supply water use for 2000–2020 for the conterminous United States (CONUS) and in a model to estimate public-supply deliveries. Public-supply withdrawal data were acquired for the CONUS and the District of Columbia; however, 11 states had annual data for only 1 year, and 10 states had no monthly data. Annual withdrawal data were acquired for 81% of public-supply water service areas, and monthly withdrawal data were acquired for 47% for at least 1 year from 2000 to 2020. These datasets and methods provide the most comprehensive collection of reported public-supply withdrawals to date and can be used by water-use managers, the scientific community, and the broader public. The extensive data processing described herein can be applicable to datasets representing other categories of water use.

The lower Yellow River is a key watershed between the Haihe and Huaihe Rivers. The Kaifeng section, as a key river segment, holds significant geographical and ecological importance, and studying its shallow groundwater hydrochemistry is crucial for sustainable groundwater use. This study systematically analyzes the hydrochemical characteristics of shallow groundwater in the region using methods like Piper diagrams, Gibbs plots, ion ratios, and mathematical analysis to elucidate groundwater formation mechanisms, thereby filling a critical gap in systematic research on the influence of the Yellow River on adjacent groundwater systems. The findings show that shallow groundwater in the Kaifeng section is weakly alkaline, dominated by $��{\mathrm{HCO}}_3^{-}�$, Ca²⁺, Na⁺, and Mg²⁺, with HCO₃-Ca (Mg, Na) type water accounting for 88.7%. The main hydrochemical mechanism is water-rock interaction, with silicate and carbonate minerals as the primary sources. Moreover, groundwater composition is significantly influenced by lateral seepage from the Yellow River, especially on $��{\mathrm{HCO}}_3^{-}�$, Na⁺, and Ca²⁺ concentrations. $��{\mathrm{HCO}}_3^{-}�$ accounts for > 65.0% of anions, and Na⁺ + Ca²⁺ exceed 75.0% of cations. Groundwater recharge mainly comes from precipitation and river inflow. The ratios of $��{\mathrm{HCO}}_3^{-}�$, Na⁺, and Ca²⁺ indicate that Yellow River seepage influence diminishes with distance, while rainfall impact increases.

The complementary relationship of evapotranspiration (CRE) hypothesis has been widely used to estimate actual evapotranspiration (AET) indirectly under various climatic conditions. However, its applicability in monsoon-dominated regions remains underexplored. This study investigates the dynamics of potential evapotranspiration (PET) and AET in the Yongdam dam basin, a representative monsoon climate region in Korea, using flux tower observations and meteorological data. PET and wet-environment evapotranspiration (WET) were calculated using the FAO Penman–Monteith and Priestley–Taylor equations, respectively. Our findings reveal significant deviations from the expected CRE pattern in monsoon regions due to the dominant influence of external air mass inflow, which disrupts the correlation between soil moisture and atmospheric humidity. These results empirically demonstrate the deviation of the CRE hypothesis in monsoon climates, emphasizing the need for region-specific evaluations of evapotranspiration dynamics. This study provides critical insights into evapotranspiration processes, offering valuable directions for refining hydrological models and improving water resource management in dynamic climatic regions.

Access to safe and sustainable wastewater treatment is a challenge for many people in the United States. Data describing the location and status of wastewater infrastructure are critical for addressing infrastructure gaps. Onsite wastewater treatment systems (OWTSs) are an important component of wastewater infrastructure; however, there is a dearth of available OWTS data across the United States, making it difficult to locate, evaluate, maintain, and improve wastewater systems. Where data are available, it can be an arduous task to acquire and transform them into usable formats. Thus, the purpose of this study was to create an interactive inventory of OWTS data to increase data accessibility and inform the development of a national OWTS data repository. Here, we identified (1) where OWTS data are available and (2) the attributes of available data (e.g., data format). We conducted an iterative internet search for OWTS data at state and local scales (by county, or town in Connecticut) in all 50 states. We discovered that OWTS data were available at parcel resolution for 41% of the United States and 30% of the contiguous United States (by area). The resulting inventory can be accessed at https://aub.ie/owtsdatainventory and will increase accessibility to currently available data for the OWTS community, from OWTS professionals to regulators to scientific researchers. Additionally, this work provides commentary on potential data challenges and the next steps necessary in building a complete national OWTS database.