A Streamlined Methodology for Identifying Point Source Inputs from Rural and Agricultural Sources

Rural and agricultural runoff continues to pose a threat to water quality and human health despite a plethora of research identifying likely causes. Large livestock operations and leaking septic systems have proven to be significant sources of both nutrients and bacteria in the form of algal blooms and antibiotic-resistant Escherichia coli. Many times, these impacts are witnessed on a watershed scale. Implementing remedies are complicated by livestock operations defined as point source facilities under the USA Clean Water Act (CWA) but regulated as non-point source agricultural runoff. Additionally, the State of Michigan is the only state in the USA without a comprehensive rural septic system law. Pollutant assessment of watersheds involves a wide array of sampling parameters that focus primarily on impacts after-the-fact. Non-point source pollution, particularly in rural areas, lacks regulatory teeth; this watershed management approach is not sustainable as evidenced by continual degradation of our rural watersheds. This study lays out a streamlined methodology incorporating focused parameters that can infer pollutant pathways and processes. We illustrate the methodology using data collected in the Pine River watershed (central Michigan) where multiple pollutant inputs were defined as exceeding water quality standards in channels and reservoirs. The results of this work beg for better understanding of what should be defined as sustainable and unsustainable land use/watershed management. Using simplified field and laboratory techniques, it is possible for local communities, educational institutions, and regulatory agencies to identify likely pollutant sources violating water quality standards regardless of point or nonpoint designation.