Nutrient loading and processing at Old Woman Creek in Ohio

Session: Great Lakes Tributaries: Connecting Land and Lakes (1)

Laura Johnson, Heidelberg University, National Ctr for Water Quality Res., [email protected]
Lauren Kinsman-Costello, Kent State University, [email protected]
Bree Richardson, Kent State University, [email protected]
Kristin Arend, Old Woman Creek Reserve, ODNR, [email protected]

Abstract

Old Woman Creek drains a primarily agricultural watershed (70%) that flows through a coastal wetland prior to reaching the central basin of Lake Erie. In 2015, we restarted high-frequency nutrient monitoring at the inflow and outflow of the wetland to compare with monitoring in 1989-1990. Annual flow-weighted mean concentrations (FWMCs) from 2016-2018 of particulate P (0.27 mg/L) and total Kjeldahl N (TKN; 1.5 mg/L) were similar to 1989-1990 and to other watersheds in Lake Erie. Dissolved P FWMCs (0.04 mg/L) were higher than 1989-1990 (0.02 mg/L), but remained low compared to other western basin watersheds. Nitrate-N FWMCs (3.3 mg/L) have decreased since 1989-1990 (6.4 mg/L). Suspended solid FWMC was among the highest we’ve measured (193 mg/L) reflecting the high erosive capacity in OWC. Annual time-weighted mean concentrations of dissolved P and nitrate-N were higher entering (0.022, 2.32 mg/L) compared to leaving (0.011, 1.14 mg/L) the wetland suggesting substantial N and P retention. Particulate P and TKN were higher leaving (0.12, 1.0 mg/L) the wetland compared to entering (0.075, 0.82 mg/L) indicating N and P was also transformed. This study highlights the effectiveness of coastal wetlands at attenuating agricultural nutrient loads prior to delivery to Lake Erie.

Twitter handle of presenter
@laura261