Research

Project Spotlight

Landscape Assessment of Nutrient Loading to Waterbodies (LANLoad)

The flow of water and fate and transport of nutrients across terrestrial landscapes is a dynamic process governed by the interplay of hydrologic, geologic, and geomorphic parameters. In the Northern Everglades and Estuaries Protection Program (NEEPP) region, we developed the Landscape Assessment of Nutrient Loading to Waterbodies (LANLoad-NEEPP), a GIS-based decision-support tool designed to assess the potential for a location to contribute to nutrient loading to the nearest waterbody.

LANLoad-NEEPP provides a first-order estimate of nutrient delivery that is both scientifically defensible and easy to implement. In our evaluation, LANLoad-NEEPP was 100% consistent with ArcNLET-Py results and 92% consistent with subject-matter experts (SMEs) best professional judgment. LANLoad-NEEPP is not intended to supplant SME best professional judgment or ArcNLET-Py modeling but rather is intended to be another tool in the decision-support toolbox, thereby increasing and improving communication among and between decision-makers.

While sophisticated numerical modeling (such as ArcNLET-Py) and expert consultations are the standard for managing non-point source pollution, these methods can be resource-intensive or require specialized technical workflows that may not be readily available for every local planning decision. LANLoad-NEEPP fills this critical gap by providing an accessible, "expert system" approach. It integrates six key physical parameters (distance to waterbody, depth to groundwater, hydraulic conductivity, potential for flood, slope, and the presence of karstic deposits within 20ft) into a single, interpretable map.

Central to the development of LANLoad-NEEPP was the use of the Analytic Hierarchy Process (AHP), a multi-criteria decision analysis methodology used to determine the relative importance of these physical parameters in the overall model. By convening a workshop with SMEs, we leveraged AHP to calculate relative weights for each parameter, ensuring the model's logic reflected both empirical data and best professional judgement. The AHP analysis achieved a consistency ratio of 0.01, indicating high internal consistency among experts.

By translating complex physical parameters into a streamlined decision-support tool, LANLoad-NEEPP empowers local governments and resource managers to easily and rapidly assess the potential for a location to contribute to nutrient loading to the nearest waterbody, identify high priority locations for intervention, and inform proactive management decisions, even when staff capacity is limited.