Fluvial Geomorphology

In 2005 and 2006, erosion surveys were done by the Scott Soil and Water Conservation District (SWCD) on the major streams in the County. Thirty-seven miles of erosion were found, and – unfortunately -- the cost of fixing those areas would have been virtually cost prohibitive using traditional approaches. However, the Scott Watershed Management Organization (WMO) hired a consultant, Inter-Fluve, Inc., to perform a “geomorphic assessment” of the streams and develop a plan of how to best address the problem rather than to continue to simply react to it. The science of “fluvial geomorphology” (literally translated, is the study of landforms, including their origin and evolution, and the water and erosive processes that shape them), provides a foundation for managing river systems in concert with natural processes rather than against them.

Inter-Fluve fluvial geomorphologists performed a walk-through reconnaissance survey of over 100 miles of stream channel on Credit River, Sand Creek, and their tributaries. During the fieldwork portion of this project, data was gathered about infrastructure, stream condition, stream stability, and potential stream improvement areas. As a result of this effort, potential restoration projects will be prioritized using such factors as environmental impact, cost, and infrastructure risk.

The Fluvial Geomorphic Assessment develops a strategy for repairing and restoring eroded stream banks on Sand Creek and Credit River. A fluvial geomorphic assessment does this by evaluating how the streams were formed, how they change, and how they transport both sediment and water. By understanding these influences, we can develop cost-effective strategies that work with the natural processes of the stream rather than against them. All too often, erosion management merely reacted to the existing situation, focusing on armoring the banks with rock. This approach not only fails to address why the problem is occurring in the first place, but it can often cause additional erosion in adjoining reaches of the stream. Understanding fluvial geomorphology allows management to focus on the relevant causes and effects, allowing us to be proactive in addressing this problem. Finally, this effort will allow us to better target Scott WMO cost-share funds and deal with the basic underlying problems that are causing the stream bank erosion in these areas.

Disclaimer

Credit River Fluvial Geomorphology Report 3/5/08

Sand Creek Fluvial Geomorphology Report 6/23/08