Wetland Resource Group Meeting November 13 1992

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f WETLANDS FIELD TRIP DNR WETLANDS RESOURCE GROUP November 13, 1992 MASSEY DRAW (C -470) - Field Stop 1 Background: Construction of C -470 resulted in the filling of 18 acres of wetland in Massey Draw. Wetland Type: Existing wetland that was filled was a wet meadow /shallow marsh dominated by rushes, sedges, redtop grass, and prairie cordgrass. Hydrologic Regime: The wetlands at Massey Draw are supported by a high groundwater table, scattered springs, and surface flood irrigation. Mitigation: "Live topsoil" (soil containing roots, seeds, rhizomes, and entire plants) was removed from the Massey Draw wetlands and used for the construction of replacement wetlands at Chatfield Arboretum (Stop 2). CHATFIELD ARBORETUM - Field Stop 2 Background: The Chatfield Arboretum wetlands were designed to occupy 4 landscape depressions (Figure 1) with a goal of creating 18 acres of wetlands similar in wetland type to the Massey Draw wetlands. The wetlands were created during the fall and winter of 1986 -1987. Wetland Type: The created wetlands have undergone substantial succession during the last 5 years. In the early years of succession the wetlands were dominated by species typically associated with aquatic and fluctuating inundated environments such as cattail, bulrush, knotweed, spikerush, and coontail. Over the last 2 years, the sedges, rushes, and grasses have become well - established. Hydrologic Regime: First designed to be supported by high groundwater levels similar to Massey draw, however, no preconstruction groundwater studies were done. The wetlands are supported by a diversion of Deer Creek at Pond 1. The water from Deer Creek and soils from Massey Draw have helped to create a series of perched wetlands. Results: Eleven acres of wetlands have been created (not 18 as planned). The wetlands provide an important resource to the area, but are not the same as the Massey Draw wetlands that they replaced. Costs: $600,000 or $54,545 /acre (land was donated, costs are solely for design, construction, and monitoring). Remedial Actions: Following the first year of monitoring (1987) there were approximately 3 acres of open water and 4 acres of wetlands. Recommendations were made for changes -in pond water levels. Water Quality: The wetlands are removing at least 50% of the total phosphorous load of Deer Creek, which translates to a 4.5% reduction in the total phosphorous load to Chatfield Reservoir.