The Floridan Aquifer Collaborative Engagement for Sustainability (FACETS) project SWAT-MODFLOW Model of the Santa Fe River, Florida

Authors: Reaver, Nathan; LEE, DOGIL - University Of Florida; DE ROOIJ, ROB - University Of Florida; KAPLAN, DAVID - University Of Florida; GRAHAM, WENDY - University Of Florida

Submitted to: Consortium of Universities for Advances of Hydrological Sciences
Publication Type: Other
Publication Acceptance Date: 1/17/2025
Publication Date: 1/17/2025
Citation: Reaver, N.G., Lee, D., De Rooij, R., Kaplan, D.A., Graham, W.D. 2025. The Floridan Aquifer Collaborative Engagement for Sustainability (FACETS) project SWAT-MODFLOW Model of the Santa Fe River, Florida. Consortium of Universities for Advances of Hydrological Sciences. Hydroshare. https://doi.org/10.4211/hs.19e8b36afa614684bbb33bce426983d7.
DOI: https://doi.org/10.4211/hs.19e8b36afa614684bbb33bce426983d7

Interpretive Summary: Changes in land use, land management, and climate have the potential to significantly alter the quality and quantity of water resources within catchments. Understanding the likely magnitude and timing of potential water quality and quantity impacts is critical for informing management decisions and developing mitigation strategies, such as improved agricultural or silvicultural practices. Landscape hydrological models (LHMs) are tools that can provide this understanding by simulating the hydrological effects of changes in land and climate drivers. The SWAT-MODFLOW model described and presented in this publication is a LHM representing the agricultural and silvicultural region in North Central Florida. This model was co-developed with stakeholders to represent production systems within these region overlaying the Floridan Aquifer. It has been used in several studies to understand the impacts of various land use/management and climate scenarios to the Floridan Aquifer and its associated hydrological systems. The model is published and described in detail so that it is publicly available, reproducible, and so it can be used by scientists and decision makers.

Technical Abstract: This resource contains the SWAT-MODFLOW model for the Santa Fe River of North Central Florida that was used in the Floridan Aquifer Collaborative Engagement for Sustainability (FACETS) project. The FACETS project was funded by the USDA National Institute of Food and Agriculture (Award Number: 2017-68007-26319) and promotes economic sustainability of agriculture and silviculture in North Florida and South Georgia while protecting water quantity, quality, and habitat in the Upper Floridan Aquifer and the springs and rivers it feeds (https://floridanwater.research.ufl.edu/). SWAT-MODFLOW couples the Soil and Water Assessment Tool (SWAT) to the U.S. Geological Survey modular finite-difference flow model (MODFLOW) to produce an integrated surface-groundwater model (https://swat.tamu.edu/software/swat-modflow/). Within SWAT-MODFLOW, SWAT handles most surface and soil processes, MODFLOW handles groundwater processes, and both models interact to simulate stream flows. The SWAT portion of this model was developed using USGS digital elevation models, the 2017 Statewide Land Use / Land Cover map of the Florida Department of Environmental Protection (FDEP), Florida Department of Health septic tank data, STATSGO soil maps, the Public Land Survey System, and NLDAS weather data. Agricultural and silvicultural production land uses and management practices implemented within SWAT were co-developed with stakeholders in a participatory modeling process (PMP) and included row crops (corn-peanut and corn-carrot-peanut rotations) forage crops (bermudagrass hay and pasture), and production forestry (slash pine). Additional land uses implemented in SWAT included urban, low-density residential, septic tanks, rapid infiltration basins, fertilized lawns, natural grass, wetlands, and open-water. The MODFLOW portion of the model was developed from the larger North Florida Southeast Georgia (NFSEG) MODFLOW model (version 1.0) as developed by the St John’s River and Suwannee River Water Management Districts. A detailed description of the complete model development process can be found in a document within this resource. Calibration of the model was conducted using a Bayesian Sample-Importance-Resample method. Data used in the model calibration included: 1) USGS discharge data (Stations 02322500, 02322700, 02322800, and 02321500); 2) USGS operational Simplified Surface Energy Balance (SSEBop) actual evapotranspiration; and 3) Upper Floridan Aquifer potentiometric surfaces from FDEP. The calibration period of the model was 2010-2018 and the validation period was 1980-2009.