{"title":"An integrated hydrological model to simulate terrestrial water storage in a large river basin: Evaluation using GRACE data","authors":"Sai Srinivas Gorugantula, BVN P Kambhammettu","doi":"10.1016/j.ejrh.2025.102309","DOIUrl":null,"url":null,"abstract":"<div><h3>Study region</h3><div>Krishna River Basin, India</div></div><div><h3>Study focus</h3><div>Integrated hydrological models that simulate surface and subsurface processes, and their interactions in a single framework are essential for effective management of large-scale river basins. This research is aimed at developing an integrated hydrological model for the Krishna River Basin (KRB), India by tightly coupling a semi-distributed hydrological model (SWAT) with a fully distributed groundwater model (MODFLOW).</div></div><div><h3>New hydrological insights for the region</h3><div>For the first time, the coupled SWAT-MODFLOW model was applied to a large (>250,000 km<sup>2</sup>), conjunctively managed, complexly interacted river basin. SWAT simulated streamflows and evapotranspiration (ET) for the seven sub-basins agree with gauge flows (R: 0.45–0.85; NSE: 0.2–0.69) and MODIS-derived ET fluxes (R: 0.18–0.81; NSE: −3.18–0.66). However, MODFLOW simulated heads are in less agreement with observed groundwater levels (R: −0.6–0.6) due to spatial averaging. The coupled SWAT-MODFLOW is used to estimate terrestrial water storage anomalies (TWSA) at sub-basin level and validated with downscaled GRACE data at 0.25<sup>°</sup> resolution. Model performance is good for the lower reaches (NSE >0.3; R >0.65) with high flow exchanges and is low for the upper reaches due to underestimation of individual fluxes (NSE <0.3; R <0.65). We observed a basin-wide decline in TWSA during the simulation at a rate of 1.45 mm/month. Our findings can help in developing contextual plans for effective management of water resources.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"59 ","pages":"Article 102309"},"PeriodicalIF":4.7000,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Hydrology-Regional Studies","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2214581825001338","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"WATER RESOURCES","Score":null,"Total":0}
引用次数: 0
Abstract
Study region
Krishna River Basin, India
Study focus
Integrated hydrological models that simulate surface and subsurface processes, and their interactions in a single framework are essential for effective management of large-scale river basins. This research is aimed at developing an integrated hydrological model for the Krishna River Basin (KRB), India by tightly coupling a semi-distributed hydrological model (SWAT) with a fully distributed groundwater model (MODFLOW).
New hydrological insights for the region
For the first time, the coupled SWAT-MODFLOW model was applied to a large (>250,000 km2), conjunctively managed, complexly interacted river basin. SWAT simulated streamflows and evapotranspiration (ET) for the seven sub-basins agree with gauge flows (R: 0.45–0.85; NSE: 0.2–0.69) and MODIS-derived ET fluxes (R: 0.18–0.81; NSE: −3.18–0.66). However, MODFLOW simulated heads are in less agreement with observed groundwater levels (R: −0.6–0.6) due to spatial averaging. The coupled SWAT-MODFLOW is used to estimate terrestrial water storage anomalies (TWSA) at sub-basin level and validated with downscaled GRACE data at 0.25° resolution. Model performance is good for the lower reaches (NSE >0.3; R >0.65) with high flow exchanges and is low for the upper reaches due to underestimation of individual fluxes (NSE <0.3; R <0.65). We observed a basin-wide decline in TWSA during the simulation at a rate of 1.45 mm/month. Our findings can help in developing contextual plans for effective management of water resources.
期刊介绍:
Journal of Hydrology: Regional Studies publishes original research papers enhancing the science of hydrology and aiming at region-specific problems, past and future conditions, analysis, review and solutions. The journal particularly welcomes research papers that deliver new insights into region-specific hydrological processes and responses to changing conditions, as well as contributions that incorporate interdisciplinarity and translational science.