Invasive Riparian Species Management: Loss of Sediment Storage and Potential Impacts on Transportation Infrastructure

摘要

River management efforts in the 20th Century included the stabilization of channelreaches using non-native plant species including Tamarisk species (salt cedars). Although theintroduction of species often had the intended effect of stabilizing the channel, the establishmentinvasive species also were accompanied by many unintended and undesirable consequencesincluding channel incision, extirpation of native species, and reduction in ecosystem services.Large-scale removal of introduced plant species is now a priority of several managementagencies. Local eradication efforts have revealed that stream system can respond dramaticallyfrom the removal of invasive salt cedars, which have acted to stabilize channels and storesediments over the past several decades. Studies have shown that channels rapidly widen andlarge volumes of sediment can be transported downstream following large storm events. Morerecently, a newly introduced species, the salt cedar leaf beetle, has proven to be an effectivemethod for removal of salt cedars over a much greater geographic extent. This species has thepotential to rapidly reshape the characteristics of stream channels as salt cedars are reduced orremoved. The drastic increase in sediment loads in these systems could pose a major risk todownstream transportation structures such as bridges and culverts. Our research is focused onestimating sediment and debris loads from salt cedar removal and the consequences of theincreased sediment loads on downstream road crossings.