Abstract: Closing Plenary Session 9:30 am (BACK)
Integrated Stream and Wetland Design in Urban Settings: A Watershed Approach to Restoring Ecosystem Functions and Services on the Landscape
Authors: C. Richardson , N. Flanagan and M. Ho , Duke University Wetland Center, Durham, NC, 27708
At Duke University an 10-ha (24 acre) Stream and Wetland Assessment Management Park (SWAMP) was created over the past 13 years to assess the cumulative effect of restoring multiple portions of stream and former adjacent wetlands, with specific goals of quantifying water quality improvements, and increasing ecosystem functions and services. SWAMP has become a key part of Duke Universities plan to “blue” the campus, provide flood control and water quality improvements, and importantly act as a student outdoor teaching and research laboratory. To accomplish these goals a five-phase stream/riparian floodplain restoration (> 2000 m), storm water reservoir/wetland complex (1.6 ha) along with a surface flow treatment wetland (0.5 ha), a stormwater wetland BMP and a novel anabranching wetland complex was ecologically designed to improve water quality by increasing the stream wetland connection, and restoring groundwater wetland hydrology. The multi-phased restoration of Sandy Creek and adjacent wetlands resulted in functioning riparian hydrology, which reduced downstream water pulses, nutrients, coliform bacteria, sediment, and stream erosion. Storm water event nutrient budgets indicated a substantial attenuation of N and P within the SWAMP project. Most notably, N and P and TSS loads were reduced significantly under both base flow and storm events. Sediment retention in the storm water reservoir and riparian wetlands showed accretion rates of 1.8 cm yr-1 and 1.1 cm yr-1, respectively. Nearly 500 metric tons of sediment were retained in the wetland/water reservoir complex each year. In addition to improved water quality services (> 50% reductions in some nutrients) the diversity of newly created wetland and stream habitats have resulted in a doubling or tripling of stream macroinvertebrates, bird and plant species.