MODFLOW and MODFLOW Conduit Flow Process data sets for simulation experiments of the Woodville Karst Plain, near Tallahassee, Florida with three different approaches and different stress periods

This Data Release has 18 different groundwater flow simulation applications for the Woodville Karst Plain area near Tallahassee Florida with three variations of distributed parameter model approach. The site model files provided include both calibrated and uncalibrated simulations of various steady-state and transient hydrologic conditions. Simulations were accomplished with equivalent porous media models that allow laminar flow only (MODFLOW) or laminar and non-laminar flow in a model layer (MODFLOW-CFP mode 2) and hybrid model simulations (MODFLOW-CFP mode 1 one-dimensional pipe network linked to equivalent porous media model). The test examples of the application of equivalent porous media model (the sponge) with and without turbulence and a hybrid model (sponge with pipes) to the Woodville Karst Plain near Tallahassee, Florida, indicated that for annual, monthly, or seasonal average hydrologic conditions, all methods met calibration criteria (matched observed water levels and average flow). Thus, the increased effort, such as the collection of data on conduit location and the computational time of a hybrid model, is not necessary for simulation of average hydrologic conditions (simulation of non-laminar flow was not critical). However, simulation of a large storm event in the Woodville Karst Plain with daily stress periods (52-day period beginning August 13, 2008) indicated that turbulence is important for matching daily springflow hydrographs and models calibrated to average conditions did not match daily storm spring hydrographs. All models were developed from an equivalent porous media model for the area calibrated by J. Hal Davis, USGS, Tallahasee Florida Office that is documented in Davis, J.H., Katz, B.G., and Griffin, D.W., 2010, Nitrate-N movement in groundwater from the land application of treated municipal wastewater and other sources in the Wakulla Springs springshed, Leon and Wakulla Counties, Florida, 1966–2018: U.S. Geological Survey Scientific Investigations Report 2010–5099, 90 p. (https://pubs.usgs.gov/sir/2010/5099/). The hybrid model was developed by Josue J. Gallegos and documented in Gallegos, J.J., Hu, B.X., and Davis, Hal, 2013, Simulating flow in karst aquifers at laboratory and sub-regional scales using MODFLOW-CFP: Hydrogeology Journal, v. 21, no. 8, p. 1749–1760.