EFFECTS OF LARGE ORGANIC MATERIAL ON CHANNEL FORM AND FLUVIAL PROCESSES

Small low gradient meandering streams may not have the competency to redistribute the debris. In larger streams flowing water may move large organic debris, concentrating it into distinct accumulations (debris jams). Organic debris may increase or decrease stability of stream banks; influence development of midchannel bars and short braided reaches; and facilitate development of meander cutoffs. In small to intermediate size mountain streams with steep valley walls and little or no floodplain or flat valley floor, large organic debris jams may locally accelerate or retard channel bed and bank erosion and/or deposition; create sites for significant sediment storage; and produce a stepped channel profile which provides for variable channel morphology and flow conditions. - from Authors