The Horse Creek Stewardship Program (HCSP) is a component of a legal settlement between Mosaic Fertilizer, LLC and the Peace River Manasota River Water Supply Authority (PRMRWSA) designed to monitor for and respond to potential mining impacts to Horse Creek, a tributary of the Peace River.

In addition to the program, an Impact Assessment was proposed to understand what factors contribute to the occasional exceedance of Total Dissolved Solids (TDS), Calcium, and Sulfate trigger levels in the HCSP. Our hypothesis was that exceedances were due to the stream being driven by groundwater flow during low-flow/low-precipitation conditions.

The Impact Assessment consisted of two components. Our team compiled and analyzed historical data collected through several publicly available and Mosaic-generated datasets. Second, Flatwoods performed a field study on two background monitoring sites from neighboring stream systems, not affected by mining, against variable flow conditions. At each site, we performed a Stream Condition Index and an Aquatic Habitat Assessment. Ongoing water quality sampling is being conducted over fifteen events.

All discrete and continuous field data as well as bench data goes through an in-house quality assurance and quality control (QA/QC) screening process and data is validated or flagged accordingly.