Integrated surface and groundwater modeling to enhance water resource sustainability in agricultural watersheds

Authors: MOMM, HENRIQUE - Middle Tennessee State University; Bingner, Ronald - Ron; MOORE, KATY - Middle Tennessee State University; Herring, Glenn

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2022
Publication Date: 7/1/2022
Citation: Momm, H., Bingner, R.L., Moore, K., Herring, G.E. 2022. Integrated surface and groundwater modeling to enhance water resource sustainability in agricultural watersheds. Agricultural Water Management. 269:1-13. https://doi.org/10.1016/j.agwat.2022.107692.
DOI: https://doi.org/10.1016/j.agwat.2022.107692

Interpretive Summary: Sustaining agricultural productivity, while preserving groundwater and surface ecosystems requires effective management of available water. The long-term sustainability of these systems depends on understanding all the interactions of complex surface-groundwater flows at different scales of time and space. This also includes understanding the impacts of agricultural practices on water use. USDA modeling technology was developed to support these efforts by combining the capability of a surface water model to characterize the impact of farming practices on groundwater levels with a subsurface flow model. The integrated technology was evaluated in the Upper Sunflower River watershed located in northwest Mississippi within the Lower Mississippi River Alluvial Plain. The integrated modeling technology was used to evaluate various irrigation strategies at varying time and space scales with observed values of streamflow at the outlet and well water levels throughout the watershed. Use of improved irrigation strategies demonstrated the sensitivity of streamflow and groundwater levels to irrigation strategies. Reduction of irrigation application rates by 20%-40% produced higher groundwater levels as estimated by the technology. This indicates the potential to positively impact the long-term sustainability of the aquifer with the adoption of more efficient irrigation strategies. The developed technology provides a management tool that action agencies can apply critical to understanding and evaluating the impact of agricultural practices, irrigation, and aquifer recharge strategies that are important to sustaining water resources in irrigated agricultural watersheds.

Technical Abstract: Management of water resources is essential to maintain sustainable agricultural productivity and preserve groundwater and surface ecosystems. The long-term sustainability of these systems depends on the understanding of complex surface-groundwater flow interactions at different temporal and spatial scales, and the impacts of agricultural practices on water use. To support these efforts, an integrated AnnAGNPS-MODFLOW modeling technology is proposed and evaluated. It combines the capability of the AnnAGNPS model to detailed characterization of farming practices with groundwater water flow estimation tools of the MODFLOW model. The AnnAGNPS-MODFLOW model was evaluated in Upper Sunflower River watershed at the Lower Mississippi River Alluvial Plain. The integrated modeling technology in conjunction with observed values of streamflow at the outlet and well water levels were used to estimate irrigation strategies with application rates varying in time and space at field scale. Utilization of improved irrigation characterization have provided evidence of the sensitivity of streamflow and groundwater levels to irrigation strategies. Reduction of irrigation application rates by 20%-40% yielded higher simulated groundwater heads therefore indicate the potential to positively impact on the long-term sustainability of the aquifer with the adoption of more efficient irrigation strategies. The proposed technology provides a management tool critical to understanding and evaluating the impact of agricultural practices, irrigation, and aquifer recharge strategies that are important to sustaining water resources in irrigated agricultural watersheds.