Abstract/Description/Artist Statement
In recent years, saltwater marshes fringing the Lafayette River, a tributary of the Elizabeth River, have experienced degradation in response to increased inundation and ocean energy . These marshes provide critical ecological and economic benefits to the City of Norfolk, and prioritizing their long term health and sustainability is an important challenge. An emerging restoration tactic involves enhancing marsh elevation through the application of dredge material that would otherwise require disposal offshore (known as thin-layer placement or TLP). An important first step in TLP projects is characterizing the textural and geochemical properties of the existing marsh sediment. The goal of this study is to examine the existing conditions at several sites on the Lafayette River, including two that are unmodified and at risk of further degradation (Waynes Creek (WC) and behind Granby Elementary School (GE)), and one site that has been previously restored at the Ryan Resilience Lab (RRL). We collected sediment cores and surface samples at multiple locations within each marsh, which we later analyzed for particle size distribution and organic matter fraction. We observe that the sediments in the natural marshes (WC and GE) experience finer particle size than the restored marsh (median diameter 5-17 um vs. >100 um), and organic matter contents ranging from 20-60%. . Future work will examine the elevation of each marsh to consider the risk of prolonged inundation and further marsh deterioration.
Faculty Advisor/Mentor
Richard Hale
Faculty Advisor/Mentor Email
rphale@odu.edu
Faculty Advisor/Mentor Department
Ocean and Earth Sciences
College/School Affiliation
Other
Student Level Group
Undergraduate
Presentation Type
Poster
Included in
Living Shorelines as a Solution to Saltwater Marsh Erosion
In recent years, saltwater marshes fringing the Lafayette River, a tributary of the Elizabeth River, have experienced degradation in response to increased inundation and ocean energy . These marshes provide critical ecological and economic benefits to the City of Norfolk, and prioritizing their long term health and sustainability is an important challenge. An emerging restoration tactic involves enhancing marsh elevation through the application of dredge material that would otherwise require disposal offshore (known as thin-layer placement or TLP). An important first step in TLP projects is characterizing the textural and geochemical properties of the existing marsh sediment. The goal of this study is to examine the existing conditions at several sites on the Lafayette River, including two that are unmodified and at risk of further degradation (Waynes Creek (WC) and behind Granby Elementary School (GE)), and one site that has been previously restored at the Ryan Resilience Lab (RRL). We collected sediment cores and surface samples at multiple locations within each marsh, which we later analyzed for particle size distribution and organic matter fraction. We observe that the sediments in the natural marshes (WC and GE) experience finer particle size than the restored marsh (median diameter 5-17 um vs. >100 um), and organic matter contents ranging from 20-60%. . Future work will examine the elevation of each marsh to consider the risk of prolonged inundation and further marsh deterioration.