Development and Calibration of a Watershed Hydrologic Model, Florida

Overview

For the Southwest Florida Water Management District (SWFWMD), HGL developed a comprehensive watershed hydrologic model of the area that includes the Northern District Model (NDM) and the SWFWMD-Wide Regulatory Model (DWRM). The model was used to estimate recharge and evapotranspiration based on climatic factors, and the findings were used to improve the calibration and simulation capabilities of the NDM and to provide time-dependent recharge to the DWRM. The calibration of the NDM was refined using the new recharge datasets.

This project comprised two phases. The objective of the first phase was to construct and calibrate HSPF-based models that simulate watershed hydrology and surface water flow in the NDM and DWRM domains. Data used in the development of the models included NEXRAD-based and National Oceanic and Atmospheric Administration-gauged precipitation, U.S. Geological Survey GOES-based ET, landuse, soil types, stream flow time series, and anthropogenic stresses. Calibration metrics, based on specific comparisons between simulated and observed values, included annual and monthly runoff volumes; daily time series of flow; storm event periods (e.g., hourly values); and flow frequency (flow duration) curves. Once calibrated, the models were used to generate recharge for the current steady-state and transient NDM and DWRM. The DWRM was the first calibrated continuous flow surface water model to simulate the hydrology of all the watersheds within and immediately beyond SWFWMD boundaries, accounting for major hydrological processes and infrastructure.