Year Established: 2014 Start Date: 2014-03-01 End Date: 2015-02-28
Total Federal Funds: $18,878 Total Non-Federal Funds: $37,756
Principal Investigators: Anne Jefferson
Abstract: Stream restoration is a multi-million dollar industry in Ohio, with major goals of improving water quality and habitat degraded by urban and agricultural runoff. Yet restoration often falls short of significant improvements in water quality and biodiversity. Given this, an important question is how to improve the theory and practice of stream restoration in order to achieve greater benefits from the investments being made in it, yet there is limited data and understanding of the physical and microbial responses to restoration that constrain the potential for water quality and ecological improvements. Hyporheic exchange, the exchange of water into and out of the streambed, is an important stream process that serves critical roles in naturally functioning streams. Hyporheic flowpaths allow for stream water to participate with the substrate in biogeochemical cycling of nutrients and pollutants, buffering of stream water temperature, and supporting benthic microhabitats important to river ecosystem integrity. Hyporheic flowpaths can be altered by the transport of fine sediment through the stream bed and are thus susceptible to changes in sediment regime and hydraulics. If stream restoration is to be successful it is important that these flowpaths are generated by the constructed form and sediments and maintained in the face of stormflows and sediment inputs post-construction. The goal of our research is to determine the effectiveness of restoration in enhancing hyporheic flow and associated biogeochemical processes to improve water quality. We plan to measure physiochemical and biological parameters in three streams, one restored each summer 2012-2014. Hyporheic exchange will be assessed using an array of piezometers at each stream and hydraulic conductivity will be measured by pressure transducers during slug tests in the piezometers. These data will then be interpolated between points to assess reach-scale hyporheic fluxes. Microbial abundance will be evaluated by collecting samples from hyporheic sediment, filtering, staining with DAPI, and measuring bacterial biomass under epifluorescent microscopy. Diel oxygen dynamics at upstream and downstream ends of a reach will determine metabolic activity in a stream and plateau injections will be sampled throughout each reach to establish nutrient uptake lengths. This set of stream metrics will be measured and sampled in April and October at the streams restored in 2012 and 2013. The stream restored in 2014 will be sampled immediately after construction is completed as well one week, two weeks, and one, two, three, six, and nine months after. By collecting these temporal data we can determine how magnitudes of hyporheic exchange and associated microbial communities and biogeochemical cycling evolve as the stream equilibrates to the constructed form. Understanding the interaction and trajectory of these processes in a post-restoration stream will help practitioners and managers plan projects that will achieve more effective results on streams in Ohio.