Landscape level planning in alluvial riparian floodplain ecosystems: Using geomorphic modeling to avoid conflicts between human infrastructure and habitat conservation

Abstract

River channel movement processes necessary to maintain the natural heterogeneity in wildlife-dependent riparian ecosystems often conflict with the need to protect adjacent human infrastructure (e.g. towns, bridges, water pumps). This conflict can be avoided through long-term planning efforts which use process-based geomorphic simulation modeling to forecast potential long-term (>50 years) landscape-level effects of water management decisions on river meander migration. We describe two management conflicts from the Sacramento River, California, USA, and analyze alternative management scenarios using results from a meander migration and cutoff simulation model. The first example shows that the existing rock revetment upstream from Woodson Bridge State Recreation Area alters the river meandering and causes erosion problems. Removing the revetment would relocate the channel and create a natural meander-neck chute cutoff, reducing erosion at the park while providing ecosystem benefits. The second example suggests that although a bank revetment is needed to prevent the river from moving away from a major water pump, removing an upstream bank revetment would provide habitat benefits without causing pump facility problems. These examples demonstrate the benefits of taking a long-term, landscape-level view when implementing infrastructure projects in dynamic landscapes.