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Effects of flooding upon woody vegetation along parts of the Potomac River flood plain

Professional Paper 1206

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Abstract

A two-part study along the Potomac River flood plain near Washington, D.C., was undertaken to investigate the effects of flooding upon woody vegetation. Floods abrade bark, damage branches and canopies, and often uproot trees. The first study was of vegetation in five monumented flood-plain plots which differed in the frequency and severity of floodflow over a 10-year period. Basal area and survival of trees appears to be related to velocity of floodflow, which in turn is related to flood magnitude and channel shape. However, the effects of flooding also depend on the nature of the flood-plain surface and size and growth habit of vegetation. In the second study, a catastrophic flood after Hurricane Agnes in June 1972 was found to cause large-scale changes in the age, form, and species composition of flood-plain forest below Great Falls, Va. The impact of the flood depended primarily on the flow regime of the river; destruction was greatest in areas exposed to the maximum flood foce, and minimal at sheltered locations. Age determinations from dead trunks and surviving trees suggest that most trees in severely damaged areas started to grow since the last great flood, which occurred in 1952. Trees along sheltered reaches survived several previous catastrophic floods. In addition, species varied in ability to withstand damage from the Hurricane Agnes flood. Least likely to recover were species growing on infrequently flooded surfaces, which may explain, in part, their absence at lower flood-plain elevations. (USGS)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Effects of flooding upon woody vegetation along parts of the Potomac River flood plain
Series title:
Professional Paper
Series number:
1206
Edition:
-
Year Published:
1982
Language:
ENGLISH
Description:
21 p.