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Direct and Indirect Effects of Forest Harvesting on Sediment Yield in Forested Watersheds of the United States
Author(s) -
McEachran Zachary P.,
Karwan Diana L.,
Slesak Robert A.
Publication year - 2021
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/1752-1688.12895
Subject(s) - environmental science , surface runoff , sediment , watershed , hydrology (agriculture) , sedimentation , erosion , forest management , water quality , watershed management , agroforestry , geology , ecology , computer science , geotechnical engineering , paleontology , machine learning , biology
Managed forests generally produce high water quality, but degradation is possible via sedimentation if proper management is not implemented during forest harvesting. To mitigate harvesting effects on total watershed sediment yield , it is necessary to understand all processes that contribute to these effects. Forest harvesting best management practices (BMPs) focus almost exclusively on overland sediment sources, whereas in‐and‐near stream sources go unaddressed although they can contribute substantially to sediment yield. Thus, we propose a new framework to classify forest harvesting effects on stream sediment yield according to their direct and indirect processes. Direct effects are those caused by erosion and sediment delivery to surface water from overland sources (e.g., forest roads). Indirect effects are those caused by a shift in hydrologic processes due to tree removal that accounts for increases in subsurface and surface flows to the stream such that alterations in water quality are not predicated upon overland sediment delivery to the stream, but rather in‐stream processes. Although the direct/indirect distinction is often implicit in forest hydrology studies, we have formalized it as a conceptual model to help identify primary drivers of sediment yield after forest harvesting in different landscapes. Based on a literature review, we identify drivers of these effects in five regions of the United States, discuss current forest management BMPs, and identify research needs.