Water Resources Research Act Program

Details for Project ID 2012NC173B

Nutrient retention and floodplain connectivity in restored Piedmont streams

Institute: North Carolina
Year Established: 2012 Start Date: 2012-03-01 End Date: 2013-02-28
Total Federal Funds: $21,079 Total Non-Federal Funds: $51,368

Principal Investigators: Sara McMillan, Greg Jennings

Abstract: The objective of this proposed research is to quantify and predict sediment, nitrogen (N) and phosphorus (P) retention in the floodplains of restored streams. Floodplains and riparian zones are known to be important locations for sediment storage and nutrient transformations. While extensive research has been conducted on the capacity for riparian zones to buffer sediment and nutrient loads in natural systems, we know relatively little about the water quality function of floodplains in restored streams. Floodplain nutrient dynamics operate on long timescales through the build-up of organic matter in floodplain soils and on shorter timescales via episodic deposition of sediment, associated nutrients and dissolved inorganic and organic nutrients. By linking channel geomorphology, frequency of floodplain connectivity and metrics of nutrient and carbon fluxes, we will better understand and predict the effect of flooding on nutrient retention and subsequent water quality. Specifically, we will measure the degree of connectivity via detailed survey information and high frequency monitoring of stream stage and monthly nutrient/sediment loading to assess episodic effects. On longer time-scales, we will quantify the effects of soil development on potential rates of N and P mineralization and denitrification. Finally, these metrics will be combined to develop a predictive tool that relates hydrogeomorphic characteristics, discharge and coupled biogeochemical cycling to better understand the role of multiple floodplains in improving water quality. Through this proposed research, we will provide a useful design tool for stream restoration designers and practitioners: the quantitative, functional relationship between restored floodplain connectivity and nutrient and sediment retention processes.