Taming the Hungry Beast: the effectiveness of engineered log jams in an incising gravel-bed river

摘要: A recent focus in river management has encouraged the reintroduction of large woody debris (LWD) into streams, implementing geomorphic and ecological principles to rehabilitate stream channels. Practice outpaced scientific assessment, with few scientifically constrained LWD programmes Australia. No assessment yet been undertaken regarding effectiveness constraining active channel destabilisation. This study assessed responses construction engineered log jams (ELJs) a 3 km reach lower Wilson River on mid-north coast New South Wales (NSW). ELJ was prevent further bed incision bank erosion associated upstream migrating Eight floods significance have occurred since structures installed including flood record February 2009, 48 year recurrence interval (1845 m3s-1). comparison repeated surveys throughout period remediation, from 2004 2012, conducted capacity available most authorities. Reach sub-reach changes were using ANOVA statistics GIS analysis, as pool-riffle wavelength amplitude. largely performed design objectives predominantly remained stable under high energy conditions, though some are considerable risk failure. Despite these risks, no detectable magnitude variability, amplitude or wavelength. Riffle elevations however increased many areas not occurred. demonstrates ELJs can provide successful mechanism managing destabilisation, this must be framed within context long term riparian rehabilitation.