This study examines the impact of changing climatic conditions on groundwater recharge in the Riu Mannu catchment in southern Sardinia. Based on an ensemble of four downscaled and bias corrected combinations of Global and Regional Climate Models (GCM-RCMs), the deterministic distributed water balance model mGROWA was used to simulate long-term mean annual groundwater recharge in the catchment for four 30-year periods between 1981 and 2100. The four employed GCM-RCM combinations project an adverse climatic development for the study area: by the period 2071-2100, annual rainfall will decrease considerably, while grass reference evapotranspiration will rise. Accordingly, ensemble results for our base scenario showed a climate-induced decrease in the median of annual groundwater recharge in areas covered by Macchia from 42-48mm/a to 25-35mm/a between the periods 1981-2010 and 2071-2100, corresponding to a reduction of 17-43%. To take into account the influence of additional plant available water storage in weathered bedrock on groundwater recharge generation, the model was extended by a regolith zone for regions covered by Mediterranean Macchia. In a set of model runs ("scenarios"), parameter values controlling the water storage capacity of this zone were increased step-wise and evaluated by comparison to the base scenario to analyze the sensitivity of the model outcome to these changes. The implementation of a regolith zone had a considerable impact on groundwater recharge and resulted in a decrease of the median in annual groundwater recharge: by 2071-2100, the 35% scenario (available water content in the regolith of 3.9 to 5.7vol.%) showed a reduction of 67-82% as compared to the period 1981-2010 in the base scenario. In addition, we also examined the influence of changes in the crop coefficients (Kc) as well as different soil texture distributions on simulated groundwater recharge.
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http://dx.doi.org/10.1016/j.scitotenv.2015.04.122 | DOI Listing |
Sci Rep
January 2025
USDA, ARS, Sustainable Agricultural Water Systems (SAWS) Unit, UC Davis, 239 Hopkins Road, Davis, CA, 95616, USA.
This study explores innovative drywell designs for managed aquifer recharge (MAR) in agricultural settings, focusing on smaller diameter and deeper drywells, including the repurposing of dried or abandoned wells. Numerical simulations assessed the impact of drywell diameter (5-120 cm), depth (15-55 m), screen height, and subsurface heterogeneity on infiltration (I) and recharge (R) volumes over a one-year period under constant head conditions. Results indicate that smaller diameter drywells can effectively infiltrate and recharge significant water volumes.
View Article and Find Full Text PDFSci Total Environ
January 2025
Geological Survey of Denmark and Greenland (GEUS), Department of Hydrology, Copenhagen, Denmark.
Machine learning (ML) methods continue to gain traction in hydrological sciences for predicting variables at large scales. Yet, the spatial transferability of these ML methods remains a critical yet underexamined aspect. We present a metamodel approach to obtain large-scale estimates of drain fraction at 10 m spatial resolution, using a ML algorithm (Gradient Boost Decision Tree).
View Article and Find Full Text PDFEnviron Pollut
January 2025
Xi'an Center of Mineral Resources Survey, China Geological Survey, Xi'an, China.
Understanding the geochemical mechanisms governing hexavalent chromium (Cr(VI)) in groundwater is essential for mitigating health risks. However, the processes driving Cr(VI) accumulation and migration in loess regions remain insufficiently understood. This study investigated the occurrence, release, and migration mechanisms of Cr(VI) across different groundwater environmental units (GEUs) in the south-central Loess Plateau, China.
View Article and Find Full Text PDFEnviron Geochem Health
January 2025
Korea Institute of Geoscience and Mineral Resources, Daejeon, 34132, Republic of Korea.
Long-term intake of high-fluoride water can cause fluorosis in bones and teeth or damage to organs. Fluoride in groundwater is primarily derived from reactions with rocks containing fluorine-related minerals, and fluoride concentrations are elevated in groundwater that has been reacting with these rocks for a long time. The purpose of this study is to investigate the origin and distribution of fluoride in groundwater and to assess the influence of various factors, including geology, on fluoride concentrations in groundwater.
View Article and Find Full Text PDFSci Data
January 2025
Department of Civil, Construction and Environmental Engineering, University of Alabama, AL, Tuscaloosa, USA.
High quality baseflow data is important for advancing water resources modeling and management, as it captures the critical role of groundwater and delayed sources in contributing to streamflow. Baseflow is the main recharge source of runoff during the dry period, particularly in understanding the interaction between surface water and groundwater systems. This study focuses on estimating baseflow using deep learning algorithms that enhance the estimation capabilities in both gauged and ungauged basins.
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