Investigating Total and Reactive Phosphorus Concentration and Suspended Solids Particle Size Class in a Mixed-Use Appalachian Watershed

The relationships between soil nutrient losses from upland areas to receiving water bodies continues to confound watershed planning. In particular, the relationships between P and SRP and specific suspended particle size classes remain largely uncharacterized. This study was initiated to develop an empirical relationship between P, SRP and suspended solid concentrations and particle size (mg/L and μm, respectively) in a representative Appalachian mixed-land-use watershed. Event-based water samples (n = 128) were collected from agricultural, urban and forested reaches in West Run Watershed, located in Morgantown, WV, USA. Preliminary analyses show average P and SRP concentrations of 0.4 and 0.31 mg/L for P and SRP, respectively, while minimum and maximum concentrations ranged from 0.0 - 5.03 mg/L (P) and 0.0 - 4.56 mg/L (SRP). Average, minimum, maximum and standard deviation (SD) values of turbidity were 27.82, 0.46, 621 and 74.35 NTU, respectively. Mean, minimum, maximum and SD values of total suspended solids (TSS) were 25.3, 0.0, 402.0, 26.6 mg/L respectively. On average, 93 %, 33 %, and 0.0 % of particle size classes for all samples were below or equal to 62.23 µm, 5.5 µm and 0.072 µm, respectively. Preliminary analyses further indicate that highest P and SRP concentrations corresponded to particle size classes below 62.23 µm and above 0.072 µm. Ongoing analyses will include elucidation of which particle size classes corresponded most significantly (α = 0.05) with P and SRP. This work is timely given that phosphorus has been identified as a principal driver of degraded aquatic health in fresh water. Results will provide quantitative information that will advance the ability of land managers and policy makers to target specific practices that may reduce particle size class transport and remediate the fate of total and reactive phosphorus.