LANLoad NEEPP - Collier County: Landscape Assessment of Nutrient Loading to Waterbodies (LANLoad) in the Northern Everglades and Estuaries Protection Program (NEEPP) Region

This raster dataset consists of cells (9.6m x 9.6m) ranked to reflect the likelihood that nutrients applied to a given terrestrial location will reach the nearest downgradient surface waterbody. Possible ranks range from 1 to 9 with values increasing as the likelihood of nutrient transport to downgradient surface waterbodies increases. Ranks are based on six physical landscape parameters selected by Subject Matter Experts (SMEs) who also assigned relative weights to each parameter using the Analytical Hierarchy Process (AHP). During this exercise, the location considered by SMEs was the pilot study area, St. Lucie County, FL, and the focal nutrient source was Onsite Sewage and Treatment Disposal Systems (OSTDS). Despite the original focus on OSTDS, LANLoad NEEPP can be used to gauge the likelihood of nutrient transport to surface waterbodies from other, similar, nutrient sources. The resulting AHP model demonstrated high internal consistency (Consistency Ratio: 0.01) and resulted in the following parameters and weights, in order of importance: Distance to Waterbody, 30.0%; Depth to Water, 21.6%; Hydraulic Conductivity, 20.7%; Potential for Flooding, 10.9%; Slope, 9.8%; and Surficial Karstic Deposits, 7.0%. The weights assigned by SMEs in the St. Lucie County pilot were deemed applicable to the NEEPP region due to highly similar geologic/hydrologic conditions. Relative parameter weights might not be applicable to regions without such similarities. Geospatial datasets representative of these parameters were combined using a weighted overlay to produce LANLoad NEEPP. The performance of LANLoad NEEPP was evaluated across randomly selected, stratified locations within the NEEPP region. LANLoad NEEPP categories were classified into “lower” likelihood (LANLoad NEEPP categories ≤ 4) and “higher” likelihood (LANload NEEPP categories ≥ 6). We subjected these classifications to two independent, blind evaluation methods. First, SMEs evaluated 30 locations using their best professional judgment. This expert review yielded a 92% consistency rate with LANLoad NEEPP classifications. Second, the groundwater numerical model ArcNLET-Py was used to simulate uniform nutrient loading across 10 locations, analyzing a total of 500 model points. This yielded a 100% consistency rate with the LANLoad NEEPP classifications where the locations identified by LANLoad NEEPP as "higher likelihood" directly corresponded with the highest simulated nutrient loads, while "lower likelihood" locations matched the lowest simulated nutrient loads. LANLoad NEEPP was developed in ArcGIS Pro 3.5.2 (ESRI) at a 9.6-meter resolution, using the NAD83 (2011) Datum and the Florida GDL Albers Ellipsoid: GRS 1980 projection. Standard geoprocessing workflows and authoritative reference materials were utilized to cleanse data, fill spatial gaps, and eliminate null values for the hydraulic conductivity, depth to groundwater, the National Flood Hazard Layer, and the Surficial Geology of Florida geospatial datasets. Three geospatial datasets derived from source data, Waterbodies, Distance to Waterbodies and Slope, were developed by the Balmoral Group in collaboration with the University of South Florida - Ecohydrology Research Group. Table 1: The geospatial datasets incorporated in LANLoad NEEPP (2026). Abbreviations: Federal Emergency Management Agency (FEMA), Florida Department of Environmental Protection (DEP), National Resources Conservation Service (NRCS), United States Geological Survey (USGS), University of South Florida - Ecohydrology Research Group (USF-ERG) Parameter Geospatial Dataset Source Date Acquired Waterbodies Florida NHD Waterbody Polygons DEP 3/2026 Florida NHD Area Polygons DEP 3/2026 Florida NHD Flowlines DEP 3/2026 Soil Survey Geographic Dataset (SSURGO) - FL NRCS 3/2026 Statewide Land Use Land Cover (Codes 5000 and 6000) DEP 3/2026 Distance to Waterbodies Waterbodies The Balmoral Group 3/2026 DEM USGS 3/2026 Depth to Groundwater Soil Survey Geographic Dataset (SSURGO) -FL NRCS 3/2026 Hydraulic Conductivity Soil Survey Geographic Dataset (SSURGO) -FL NRCS 3/2026 Potential for Flooding National Flood Hazard Layer FEMA 3/2026 Slope Distance to Waterbodies The Balmoral Group 5/2026 DEM USGS 3/2026 Surficial Geology Surficial Geology of Florida DEP 11/2025 Contact Information Kai C. Rains, PhD, PWS – [e-mail] Dataset Citation Rains, Kai; Guerron-Orejuela, Edgar; Davis, Sara; Okonkwo, Moses; Rains, Mark (2026), “LANLoad NEEPP: Landscape Assessment of Nutrient Loading to Waterbodies (LANLoad) in the Northern Everglades and Estuaries Protection Program (NEEPP) region”, University of South Florida, v03, doi: 10.17632/7nw285j9bk.3 License CC BY 4.0 Links: USF Ecohydrology Research Group LANLoad Phase III Final Report Florida Geographic Information Office Logos: