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Date of Graduation
Master of Science (MS)
Department of Biology
Christine L. May
Stream restoration is gaining popularity in the Mid - Atlantic region to offset impacts from urbanization. Increased levels of impervious surfaces, decreased vegetation along banks, and changes in water flow patterns make urban stream ecosystems flashy and result in high erosion rates, increasing the amount of nutrients entering the Chesapeake Bay. Different restoration practices can play a large role in the amount of nutrients and organic matter leaving a stream and the amount of habitat that is present in-stream.
Due to the recent interest in stream restoration as a tool to help the health of the Chesapeake Bay, this study was undertaken to evaluate the in-stream effectiveness of two restoration practices: conveyance channels and material processing channels. Ten streams, five of each restoration practice, were evaluated in terms of organic retention and macroinvertebrates. The upper and lower reaches of each stream were sampled with transects to measure organic retention percent cover and sampled with two methods for macroinvertebrates.
Despite each site being evaluated only once during the summer of 2018, which was the highest rainfall on record in Maryland, trends were still apparent. Material processing channels had significantly higher organic retention compared to conveyance channels, as they had a larger average hydraulic radius and a greater presence of woody debris. Focusing on macroinvertebrate sampling methods, traditional kick-net sampling and habitube sampling collected similar richness. Abundance varied greatly, though habitubes collected higher average abundance compared to traditional sampling in conveyance channels.
Results from this study suggest that urban stream restoration practices can impact the amount of organic retention within streams as well as the ability to provide the best habitat for in-stream biota. When designing streams to reduce impacts to downstream waterbodies, material processing channels should be considered as they retain more organic matter and work to provide greater habitat potential, without an artificial substrate. Due to similar richness collections across all reaches, habitubes have the potential to be a valid future sampling technique. This or a similar study should be continued over multiple years through different seasons to see if the trends persist or get stronger as the site ages.
Berg, Madeline, "Urban stream restoration: An evaluation of material processing and conveyance channels" (2019). Masters Theses. 625.