Predictive Mapping of Solute‐rich Wetlands in the Canadian Prairie Pothole Region Through High‐resolution Digital Elevation Model Analyses

Abstract

Prairie Pothole Region wetlands are integral in reducing nutrient mobility in prairie watersheds. Wetland soil CaCO3 content likely plays an important role in wetland phosphorus retention capacity. Accurate predictions of the spatial distributions of wetlands with CaCO3-enriched soils would allow for further study on these relationships and prioritized wetland conservation efforts to encourage this ecosystem service. Solute accumulations (including CaCO3) within wetlands are largely determined by the wetland’s topographic position and relationship with groundwater. These characteristics were estimated by predicting spill channel connections between wetlands using LiDAR-derived digital elevation models. Spatial distributions of solute-rich wetlands were predicted with a simple decision tree model that predicts wetlands as either fresh or solute-rich based on approximated hydrologic characteristics (Strahler order and terminal status) determined from the predicted active spill channel networks. The model was trained and tested using measurements of wetland pond water and soil electrical conductivity (i.e., solute-richness) in three study areas within the Saskatchewan Prairie Pothole Region. The model achieved acceptable predictive accuracies based on training and independent validation tests. The proposed methodologies could be incorporated into more complex multivariate models for the purposes of predictive soil mapping or hydrologic studies in the Prairie Pothole Region.