Water Resources Research Act Program

Details for Project ID 2011DE212B

Spatio-Temporal Hydrodynamic Variability in a Small Tidal Creek: DNERR St. Jones Reserve

Institute: Delaware
Year Established: 2010 Start Date: 2011-03-01 End Date: 2012-02-29
Total Federal Funds: $3,000 Total Non-Federal Funds: $6,000

Principal Investigators: Jack Puleo, Rebecca Aiken, Thomas McKenna

Abstract: Within the past two decades, the area of degraded wetlands in Delaware has increased from 25-54%. Tidal wetlands sustain high nutrient and biological activity and serve an important function in many ecosystems. They provide habitation and feeding grounds for wildlife, such as birds and fish. Furthermore, wetlands act as a filter for many sediment pollutants, limit the movement of heavy metals and toxins, and buffer storm activity. Largely as a result of sea level rise, these degraded wetlands are slowly converting into tidal flats, areas that do not support high levels of vegetation and wildlife. Without the plant-life to support the wetlands, erosion may occur at an increased rate. As a result of higher erosion rates, poorer water quality occurs due to fine-grained sediment transportation. The water may also be contaminated by higher quantities of carbon and pollutants. To date, limited studies have been conducted analyzing the hydrodynamics within small tidal creeks that cut across wetlands influencing sediment transport and wetland flooding. Our research is aimed at quantifying the spatio-temporal variability in surface and near-bed velocities and the vertical structure of nearbed flow as a function of tidal phase. These studies will focus on the bed stresses (the sediment mobilizing agent) and analyze nearbed energy dissipation. The results obtained from this research will allow better prediction of future morphological changes in marsh wetlands and potentially assist in implementing systems to maintain marsh stability.The goal of this study is to explore the effectiveness of in-situ measurements to quantify fundamental hydrologic characteristics necessary for comprehending and modeling shallow flow in tidal wetlands. This research specifically aims to identify: (1)the magnitude and variation in the turbulent kinetic energy and bed stress in secondary and tertiary tidal creeks and (2) the relationship between sediment suspension and tidal levels, bed stress and energy dissipation.