Diffuse Nutrient Pollution from Residential Catchments

Nonpoint source nutrient pollution is diffuse pollution lacking discrete origin and conveyance. This thesis synthesizes and critically reviews research on residential nitrogen and phosphorus loss to stormwater runoff and leaching. The evaluation pulls from research covering influential socio-demographic indicators, such as use of lawn maintenance services and homeowner fertilizer practices. The extent to which such social and economic factors may influence the prevalence and fate of diffuse nutrients in stormwater runoff from residential areas has not been adequately established. Understanding the source and influencing factors of diffuse nutrient pollution is important in order to effectively protect surface and groundwater resources. Research based on sampling campaigns of catchments, sampling of controlled turf systems and models of residential catchments were compiled for this review. Based on the compilation reviewed for this thesis, there are wide differences in approaches researchers have taken to attempt to quantify and understand diffuse nutrient pollution from residential and urban areas. There is not consistency in the chemical nitrogen or phosphorus species evaluated or in reported measurements (i.e. concentration vs. loading vs. yield). This review revealed several important knowledge gaps. Determination of correlation between residential system nutrient loss to the environment and social factors, demographic characteristics, local fertilizer ordinances or nutrient management education programs has not been substantiated. More exploration of nutrient leaching from different soil types and turf grass species is needed to develop a complete understanding of nutrient loss from turf grass systems. Further, other specific management practices such as leaving grass clippings on lawns has not been studied in depth for a variety of soil types and grass species. There is room for improvement in future research and additional studies are needed to guide future policy and implementation of best management practices. Based on these and other findings, I recommend a concerted effort to standardize a portion of the reporting details of future stormwater research and for reevaluation of nutrient/fertilizer education efforts