Hydrologic Events and Water Quality in the Pigeon River, Ottawa County, Michigan

Researchers conducting water quality tests in the lower Pigeon River The Pigeon River drains a 16, 765-ha agricultural watershed in western Ottawa County, Michigan and discharges into south-central Lake Michigan. Extensive areas of wetlands in the upperwatershed were drained in the 1920s, causing significantly altered hydrology character-izedby flashy dischargesduring storms and periods of snowmelt. We studied stream chemistry and hydrology for a four-year period between September, 1996, and October, 2000, to determine water quality status, to estimate annual nutrient exports, and to evaluate the effects of different seasonal flow types. Results of our study confirmed that the upper reaches of the Pigeon River experience chronically degraded water quality, with contributions from both nonpoint and point sources. As a result, the watershed has highannual rates of nutrient export (approximately 10.8 kg ha-1 inorganic N and 0.25 kg ha-1 P04,P). With the influx of groundwater, change in land use to forest, and development of natural stream channe