thumbnail

The effect of channelization on floodplain sediment deposition and subsidence along the Pocomoke River, Maryland

Journal of the American Water Resources Association

By:
and
DOI: 10.1111/j.1752-1688.2010.00440.x

Links

Abstract

The nontidal Pocomoke River was intensively ditched and channelized by the mid-1900s. In response to channelization; channel incision, head-cut erosion, and spoil bank perforation have occurred in this previously nonalluvial system. Six sites were selected for study of floodplain sediment dynamics in relation to channel condition. Short- and long-term sediment deposition/subsidence rates and composition were determined. Short-term rates (four years) ranged from 0.6 to 3.6 mm/year. Long-term rates (15-100+ years) ranged from -11.9 to 1.7 mm/year. 137Cs rates (43 years) indicate rates of 0.24 to 7.4 mm/year depending on channel condition. Channelization has limited contact between streamflow and the floodplain, resulting in little or no sediment retention in channelized reaches. Along unchannelized reaches, extended contact and depth of river water on the floodplain resulted in high deposition rates. Drainage of floodplains exposed organic sediments to oxygen resulting in subsidence and releasing stored carbon. Channelization increased sediment deposition in downstream reaches relative to the presettlement system. The sediment storage function of this river has been dramatically altered by channelization. Results indicate that perforation of spoil banks along channelized reaches may help to alleviate some of these issues. ?? 2010 American Water Resources Association. No claim to original U.S. government works.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The effect of channelization on floodplain sediment deposition and subsidence along the Pocomoke River, Maryland
Series title:
Journal of the American Water Resources Association
DOI:
10.1111/j.1752-1688.2010.00440.x
Volume
46
Issue:
4
Year Published:
2010
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of the American Water Resources Association
First page:
686
Last page:
699
Number of Pages:
14