Journal of The American Water Resources Association最新文献

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.

Urban stormwater runoff is a major concern for water quality. Impervious surfaces, especially in urban environments, can allow stormwater direct access to receiving waterbodies and make up nearly 90% of land cover in downtown Minneapolis, Minnesota. A study of stormwater runoff from impervious surfaces in downtown Minneapolis, Minnesota, USA, was conducted to understand the potential impacts of different types of impervious surfaces (i.e., streets, sidewalks, parking lots, and rooftops). A rainfall simulator delivered water to the street, sidewalk, and parking lot sites and the rooftop runoff characteristics were studied separately using automated samplers and rain gauges. ANOVA statistical analysis was used to determine whether stormwater runoff pollutant concentrations (chloride, total suspended solids, and total phosphorus) varied significantly within surface types, between surface types, and across seasons. Results showed that the first flush of runoff contained higher pollutant concentrations than the whole rain event, and water quality differences for all surfaces were relatively minor for the summer and fall seasons. In contrast, pollutant concentrations were significantly higher in the spring, particularly on streets. Among all surface types, streets exhibited the highest event-mean concentrations (EMCs) for all pollutants. The study highlights the importance of surface-specific stormwater management strategies and the need for tailored BMP design and policies to enhance the effectiveness of mitigating water quality impairments in urban environments.

Water regulation, extraction, and application have major effects on water availability. We investigated the impact of anthropogenic water use on the water balance in two intensively irrigated headwater watersheds in Wyoming using geospatially comprehensive water right data in a watershed hydrologic-allocation modeling framework. Water balance variables were compared under natural flow conditions and scenarios representing water right appropriative demands. Across both watersheds, the full appropriative demand scenario resulted in a 54% decrease in streamflow, an 18% increase in evapotranspiration, and a 6% decrease in watershed storage during the growing season. The study watersheds exhibited distinct responses to the scenarios with incremental changes in potential return flow and appropriative demand, reflecting differences in water right network structure, spatial density, use, and appropriative demand. Testing the effects of spatial and non-spatial water right characteristics revealed significant relationships between changes in streamflow and factors such as trans-watershed transfers and water right spatial density. Resource distribution among water balance components varied by sub-watershed, with reduced variability at larger watershed scales. The differences in water balance changes between scenarios within the study watersheds highlight the importance of geospatially comprehensive water right data in incorporating abstractions in hydrologic models.

A two-stage constructed floating wetland with a 0.7% ratio of wetland to drainage area was studied for removing phosphorus from subsurface agricultural drainage. This system consisted of two stages, the first being a floating wetland containing Scirpus atrovirens, Carex vulpinoidea, Juncus effusus, Ranunculus hispidus, and Acorus americanus, and the second containing a filter media of pea stone. It was found that total phosphorus (TP) in plant tissues was not statistically different across macrophyte species; however, total biomass did differ. Therefore, to obtain maximum TP removal, plant shoots should be removed when they reach their maximum biomass. Scirpus had the highest average dry mass (17.1 g) and average TP shoot mass and was significantly greater than the other species examined. Total P removal by plant shoots ranged between 0.89% and 19.3% of the soluble reactive phosphorus (SRP) entering the wetland, depending on the year. The average annual SRP and total phosphorus reductions from discharge entering and exiting the system equated to 65 and 36%, respectively. Additionally, the average SRP concentration across all 3 years during the growing season was reduced from 0.087 mg/L to 0.029 mg/L, and TP was reduced from 0.168 mg/L to 0.068 mg/L, keeping both SRP and TP effluent concentrations below maximum concentrations recommended for flowing waters to minimize eutrophication and harmful algal blooms.