The Geomorphic Approach

The philosophy behind our projects is based on fluvial geomorphology, or naturally occurring landforms that have been shaped by moving water. A lot of important work has been done in this field by David Rosgen, Wildland Hydrology, Inc. The Rosgen stream classification system has been adopted by the U.S. Forest Service and most other federal and state land management agencies. It is based on factors that can be measured in the field such as floodplain accessibility, channel shape and other channel dimensions and patterns. It is important to understand what is governing the dynamic stability of the watercourse we are dealing with before going about making improvements. This way we can have confidence that our influence on the watercourse will be appropriate and coordinated with the natural forces that shape it. The following chart is in development to explicate the principles discussed above.

Bill Zeedyk is a locally famous stream restoration practitioner from New Mexico who has developed the technique of Induced Meandering. This is a subtle approach which helps an ailing watercourse fix itself by governing the patterns of sediment erosion and deposition that are caused by the hydraulic power of floodwaters. For this to work we must anticipate the natural meander pattern appropriate for our particular stream type and size and build structures designed to influence the flow of floodwaters to do the work of reshaping the impaired channel into one that is stable. A key factor here is the Meander Wavelength, which is the valley distance taken up by a pair of opposite curves or bends.

Van is a long-term student of both Rosgen and Zeedyk.