Exploring the St-Clair-Detroit River System Watershed using the SWAT model

Session: 35. - Watershed Modeling across all Scales from Small to Large

Awoke Dagnew, University of Michigan, [email protected]
Rebecca Muenich, Arizona State University, [email protected]
Yu-Chen Wang, University of Michigan, [email protected]
Colleen Long, University of Michigan, [email protected]
Margaret Kalcic, Ohio State University, [email protected]
Donald Scavia, University of Michigan, [email protected]

Abstract

The St.Clair-Detroit-River system watershed is one of the major watersheds that feed nutrients from agricultural and urban areas into Lake Erie. A SWAT (Soil and Water Assessment Tool) watershed model was developed to evaluate nutrient load reduction strategies, specifically for phosphorus. In this study, the smallest modeling units in SWAT, hydrologic response units, were constructed to capture agricultural fields so that agricultural management scenario analysis could be performed at a detailed level. The model was calibrated and validated at six major tributary outlets for flow, total phosphorous, dissolved reactive phosphorous, total nitrogen, nitrate, and total suspended sediment. Calibration statistics for flow indicated mainly very-good performance at a monthly time step. Simulated monthly and annual water quality trends and values were also representative of observed nutrient and sediment loads; however, at the daily time step the model captured observed sample water quality values inadequately due mainly to a lack of frequent observed data in the watershed. Preliminary agricultural management scenario analysis, such as implementation of fertilizer-reduction, controlled tile drainage, filter-strips, and wetlands, indicated opportunities for nutrient reductions. Hence, combined nutrient reduction management strategies should be simulated as a next step to identify optimum approaches for sufficient load reductions from the watershed.

1. Keyword
watersheds

2. Keyword
water quality

3. Keyword
modeling

4. Additional Keyword
SWAT

5. Additional Keyword
Hydrology

6. Additional Keyword
Great Lakes