Journal of The American Water Resources Association最新文献

A set of analytical equations has been derived to directly quantify the average hydrologic performance of low-impact development facilities such as bioretention cells and green roofs. These analytical equations, collectively referred to as the analytical probabilistic stormwater models (APSWMs), have been previously validated for representing regional rainfall conditions for regions across the US using selected example locations. This study evaluates APSWMs' capability to accurately represent small temporal changes in rainfall conditions at the same locations and small spatial changes in rainfall conditions between nearby locations. Results from the US EPA's Stormwater Management Model (SWMM), a continuous simulation tool representing rainfall conditions using long-term observed series, are used as the basis for comparisons. For the 176 hypothetical cases of bioretention cells and 208 cases of green roofs, the temporal performance differences between early and recent periods as determined by APSWM and SWMM were within ±0.03 for green roofs and up to ±0.08 for bioretention cells, while the spatial performance differences between paired locations averaged about 3% in relative terms. These results demonstrate that APSWM is capable of consistently and accurately representing the small spatial and temporal rainfall-condition changes. They also provide additional evidence of APSWMs' reliability and support jurisdictions to use APSWMs in the planning and design of LID facilities.

Sea level rise and storm surges resulting from climate change are expected to increase the frequency and intensity of floods. Aging and/or inefficient drainage systems can significantly exacerbate flood damage. Effective flood defense policies must categorize flood damage and provide a detailed assessment of each contributing factor. In this study, we evaluated the cost of flood damage in Busan—the second most populous city on the coast of South Korea. Flood damage costs were analyzed based on an object-based approach across 10 scenarios, which accounted for variations in storm surge frequency, climate change impacts, and drainage efficiency. Flood damage costs for four categories, namely buildings, agriculture, human casualties, and vehicles, were examined across different administrative regions. Results reveal that flood damage costs increase with higher storm surge frequencies and climate change effects, while reduced drainage efficiency further amplifies these costs. Given that damage costs are predominantly concentrated in coastal areas, future data-based flood defense policies should be developed to reflect the specific vulnerabilities and damage patterns of each administrative region.

Recent updates and recalibration were made to a groundwater model of Shelby County, Tennessee, to simulate groundwater flow dynamics more accurately in and between aquifers and to be utilized for predictive simulations. The modified CAESER-II model extends the simulation period from 1960 to 2021 and incorporates several improvements: updated hydraulic parameters for the Memphis aquifer, refined aquitard breach characterization, and enhanced historical records for pumping and river stage. The recalibrated model achieved a mean absolute residual (MAR) of 3.31 m across the domain and 3.70 m at the Sheahan well field, demonstrating improved performance over the original CAESER-I model. Calibrated values for hydraulic conductivity and specific storage fell within literature-reported ranges, and the average vertical conductivity of breaches (0.076 m/day) closely matched values obtained from core samples and falling head tests. These enhancements enable better simulation of inter-aquifer leakage and provide utility managers with a robust tool for assessing well field vulnerability and evaluating the risk of contaminant migration through aquitard breaches.

Determination of recharge rates for an urban setting is a complicated process that is subject to variation based on the chosen methodology, as well as the suitability and constraints of each method. The recharge mechanism and rates to the shallow aquifer within Shelby County were assessed using multiple approaches, including the water-table fluctuations (WTF) method (using two approaches), the vadose zone pulsing method, the chemical tracer method, and the identification of areas with potential infrastructure leaks. The WTF method generated a total annual recharge rate ranging from 0.12 m/year, or 9% of precipitation (for S_y = 0.1), to 2.17 m/year, or 158% of precipitation (for S_y = 0.3), using the master recession curve (MRC) method. The large disparity in results could be due to the influence of surface-water features, additional recharge from underground water infrastructure, and high specific yield. However, the vadose zone pulsing method failed to yield any definitive outcomes, while the chemical tracer method revealed no significant presence of fluoridated municipal water flowing into the shallow aquifer. The results of WTF appeared to be more coherent and more reasonable than the other approaches. Additional regional-scale techniques and a comprehensive investigation of artificial recharge computation via leakage should be conducted to obtain more accurate estimations of recharge rate.

In the moist, coniferous forests of Oregon and Washington, a dense network of headwater streams supports high levels of amphibian species endemism and diversity, including the torrent salamanders (Rhyacotriton spp.). The Columbia and Cascade torrent salamanders (R. kezeri and R. cascadae, respectively) are species of greatest conservation need, but current information is insufficient for an adequate status assessment. We aimed to determine the current distributional extent, occurrence, and abundance of both species across their respective ranges, and to characterize watershed-scale habitat suitability. We conducted rangewide surveys for both species and used a novel, robust model development and refinement process to characterize habitat suitability based on climatic, topographic, forest-structure, hydrological, and water-balance drivers of their distributions. Results supported interspecific differences in rangewide occurrence and abundance patterns, as well as ecological associations that provide insights into potentially divergent patterns of resilience. Topographic, water-balance, and streamflow metrics were top predictors of Columbia torrent occurrences, whereas metrics of seasonal temperature and atmospheric moisture were top predictors of Cascade torrent occurrences. Our findings can inform regional conservation planning efforts to identify likely climate refugia and habitat-connectivity pathways for gene flow and watershed-scale ecological resilience.

Water availability in river basins is a global concern due to its increasing demand, thus making it essential for a nation's development. Understanding the future effect of climate and land use land cover (LULC) changes on the water cycle is fundamental for consistent access to water resources. This study's objective is to use a physically based semi-distributed model to explore streamflow seasonal projection of the Rokel-Seli River basin (RSRB) using separate and combined impacts of climate and LULC changes from 2021 to 2060, under projected scenarios (RCP2.6 and RCP8.5). The LULC results showed agricultural, urban, and bare land expansion at the expense of forest land historically, with a projected increase in bare and urban land. The hydrological model calibration and validation of statistical indicators for R and P factors, NSE, R², and KGE performed very well, despite limited data, in replicating the flows. The mean seasonal streamflow is projected to decrease due to different LULC changes, with urban and bare land expansion. The projected streamflow decrease is noticeable under climate change compared with LULC change. As various aspects are responsible for both changes (farming, deforestation, infrastructural development, mining and hydropower supply), this study will enable land and water management authorities to develop suitable strategies to enhance streamflow sustainability in a changing environment.

The coordinated development of water resources and socio-economy is a crucial component in achieving global sustainable development goals. Currently, there is a lack of an effective evaluation method for assessing their coordinated development. Therefore, this study proposes a novel quantitative model for evaluating coordinated development, which is based on the connection number and risk matrix. This method is applied to 11 provinces within the Yangtze River Economic Belt (YEB) of China, and its spatiotemporal characteristics and constraining factors of the coordinated development between water resources and socio-economy are identified. The results indicate that the evaluation results obtained through this method exhibit higher discriminatory power. From 2011 to 2020, the coordinated development level between water resources and socio-economy of YEB has increased by 1–2 grades. The coordinated development state of the central and eastern regions is better than that of the western regions. Jiangxi, Sichuan, Guizhou, and Yunnan are the four provinces with the lowest coordinated development state. Additionally, some practical suggestions are presented for the coordinated development of water resources and the socio-economy in YEB. The findings of this study help to elucidate the physical mechanisms of coordinated development between water resources and the socio-economy and provide policy insights for the sustainable development of YEB.