Abstract
The effects of phosphorus in the Snake River Water Basin are under-studied and there is risk for future issues in water quality. In part, this is due to a lack of a framework to study water quality from publicly available sources. This thesis used an Exploratory Spatial Data Analysis (ESDA) framework to explore the relationship between impaired stream locations and various point and non-point sources of phosphorus. ESDA tools utilized are histograms to highlight distributions, Global Moran’s I to understand spatial autocorrelation, and principal component-based clustering to highlight patterns in data. Based on the findings of the analysis, spatial econometric modeling will establish if there is a need for further investigations into water quality, what questions the data might produce, and who needs to answer these questions. More specifically, hydric soils, waste holding capacity, aquaculture, manure application, hydroelectric dams, confined animal feeding operations (CAFOs), food processors, crop type, septic systems, synthetic fertilizer, and surface flow accumulation were tested for spatial correlation against EPA designated stream impairments of phosphorus. My analysis shows the strongest support for a Spatial Durbin Model (SDM) regression to appropriately visualize spillover effects of phosphorus sources. Insights gained by this study discover previously unknown associations and form hypotheses that can provide future policy makers a starting point for further investigation into managing phosphorus in southern Idaho.