Balancing Wetland Functions in an Urban Setting -- Water-Quality Improvement and Habitat Preservation, Ellison Park Wetland, Monroe County, New York

The Ellison Park wetland, a 423-acre, predominantly cattail marsh at the mouth of Irondequoit Creek in Monroe County near Rochester, N.Y., was evaluated for its potential role to decrease phosphorus loads that are derived from a 151-square-mile largely urbanized area and that ultimately enter and exacerbate efforts to ameliorate the eutrophic conditions in Irondequoit Bay. Monroe County's water-quality management plan included (1) modification of flow patterns upstream from and within the wetland by diverting storm runoff into backwater areas of the wetland, and (2) construction of a flow-control structure midway through the wetland that would cause short-term rises in water levels and increased dispersion of runoff through the wetland. An ecological-monitoring program was implemented to assess the effects that the hydrologic modifications might have on the plant, fish, bird, and benthic-macroinvertebrate communities, and on sedimentation rates and sediment quality. Streamflow and phosphorus concentrations in water samples were measured and used to calculate phosphorus loads entering and leaving the wetland.

An 11-year study, which generated a long-term and multi-disciplined database that has advanced the understanding of hydrologic processes in palustrine marshes along the shores of the Great Lakes, was conducted in cooperation with the Monroe County Department of Health. Study results that compared the 1990-96 pre-control conditions with the 1997-2001 post-control conditions indicated that the flow modifications (1) had no discernible effects on wetland biota or their habitats; (2) caused an apparent increase in sedimentation rates upstream from the control structure; and (3) brought about a 17-percent decrease in phosphorus loads. These results, which were published in a USGS Water-Resources Investigations Report (WRIR 03-4224), can be used locally by county planners to manage their water resources, as well as by others to manage cattail marshes in similar climatic and geographical settings.

Monitoring of water quality and sedimentation rates is ongoing to ensure that the control structure continues to have water-quality benefits without causing any adverse effects on the wetland.

Monroe County, NY