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Recovery of sediment characteristics in moraine, headwater streams of Northern Minnesota after forest harvest

Journal of the American Water Resources Association

By:
, , , , ,
DOI: 10.1111/j.1752-1688.2010.00445.x

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Abstract

We investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of unstable banks, surficial fine substrates, residual pool depth, and streambed depth of refusal as response variables. Basin-scale year effects were significant (p < 0.001) for all responses when evaluated by repeated-measures ANOVAs. Throughout the study area, unstable banks increased for several years postharvest, coinciding with an increase in windthrow and fine sediment. Increased unstable banks may have been caused by forest harvest equipment, increased windthrow and exposure of rootwads, or increased discharge and bank scour. Fine sediment in the channels did not recover by summer 2007, even though canopy cover and unstable banks had returned to 1997 levels. After several storm events in fall 2007, 10 years after the initial sediment input, fine sediment was flushed from the channels and returned to 1997 levels. Although our study design did not discern the source of the initial sediment inputs (e.g., forest harvest, road crossings, other natural causes), we have shown that moraine, headwater streams can require an extended period (up to 10 years) and enabling event (e.g., high storm flows) to recover from large inputs of fine sediment. ?? 2010 American Water Resources Association.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Recovery of sediment characteristics in moraine, headwater streams of Northern Minnesota after forest harvest
Series title:
Journal of the American Water Resources Association
DOI:
10.1111/j.1752-1688.2010.00445.x
Volume
46
Issue:
4
Year Published:
2010
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
733
Last page:
743
Number of Pages:
11