The Sedimentology of Pecausett Pond: A Case Study for Sediment and Contaminants Sotrage in FloodPlain Tidal Ponds on the Lower Connecticut River

Elzidani, Emhmed Z

Publication:
The Sedimentology of Pecausett Pond: A Case Study for Sediment and Contaminants Sotrage in FloodPlain Tidal Ponds on the Lower Connecticut River

dc.contributor.advisor	Jonathan D Woodruff
dc.contributor.author	Elzidani, Emhmed Z
dc.contributor.department	University of Massachusetts Amherst
dc.contributor.department	Geosciences
dc.date	2023-09-23T03:37:10.000
dc.date.accessioned	2024-04-26T21:12:27Z
dc.date.available	2011-04-12T00:00:00Z
dc.date.issued	2011-01-01
dc.date.submitted	May
dc.description.abstract	In this study I assess spatial and temporal patterns of sediment deposition in Pecausett Pond, located along the tidal extent of the Connecticut River, in order to assess the role of tides in the transport and storage of sediment and associated contaminants within floodplain tidal ponds. Findings reveal that tidal ponds have significantly higher rates of sedimentation compared to neighboring marshes due to the fact that these ponds have more accommodation space and receive uninterrupted tidal exchange with the main river. Tidal tie channels introduce a pulse of suspended sediment and contaminants from the main river into these ponds each flood tide, with sedimentation rates fast enough to allow settling before the subsequent ebb tide can transport these sediments back to the main river (i.e. tidal pumping). Some studies performed on the tidal floodplain of the Connecticut River show high deposition rates and have attributed periods of high accumulation to anomalously high river discharge events. However, this project shows that tides are more likely the major mechanism responsible for transporting and storing sediment and associated contaminants at backwater sites located along the tidal floodplain. Deposition rates in this 3-4 m deep pond exceed 2 cm/yr. These rates are far too high to maintain equilibrium morphology for much longer. However, ground penetrating radar surveys from the study site reveal truncated stratigraphy common to erosional unconformities, which suggest that mechanisms for sediment remobilization and removal may exist. Periods of episodic erosion therefore may be helping to maintain the morphology in this shallow environment, and allow for the high rates of short-term deposition. Further, a sudden increase in percent inorganic potentially associated with the opening or clearance of the tie-channel is observed at a sediment depth approximately between 1.9 to 2.2 m. A radiocarbon date obtained below this transition is consistent with a significant drop in sedimentation prior to this tie-channel development. High rates of sedimentation in Pecausett Pond are therefore likely relatively recent phenomena, transpiring over the last few centuries following early colonization.
dc.description.degree	Master of Science (M.S.)
dc.identifier.doi	https://doi.org/10.7275/1936021
dc.identifier.uri	https://hdl.handle.net/20.500.14394/47507
dc.relation.url	https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1692&context=theses&unstamped=1
dc.source.status	published
dc.subject	Spatial and temaprat patterns
dc.subject	Floodplain tidal Ponds
dc.subject	Flood tide
dc.subject	Fine-grained sediments
dc.subject	Associated contaminants
dc.subject	Deposition rates
dc.subject	tidal pumping
dc.subject	Truncated stratigraphy.
dc.subject	Geology
dc.title	The Sedimentology of Pecausett Pond: A Case Study for Sediment and Contaminants Sotrage in FloodPlain Tidal Ponds on the Lower Connecticut River
dc.type	campus
dc.type	article
dc.type	thesis
digcom.contributor.author	isAuthorOfPublication\|email:emhmed@geo.umass.edu\|institution:University of Massachusetts Amherst\|Elzidani, Emhmed Z
digcom.date.embargo	2011-04-12T00:00:00-07:00
digcom.identifier	theses/605
digcom.identifier.contextkey	1936021
digcom.identifier.submissionpath	theses/605
dspace.entity.type	Publication