Precipitation-Driven Watershed Response Factor “C” - A New Tool for the Prediction of Hydraulic Geometry Relationships
David Bidelspach, PE
5 Smooth Stones Restoration, PLLC
Livermore, CO
Engineers have been looking for patterns in which to classify streams and predict their natural form and size for as long as anthropogenic influences have been degrading the landscape and its waterways. Regional relationships have been developed extensively since the 1950s to predict channel dimensions based on independent variables of drainage area or discharge for a given region of similar physiographic characteristics. Although regional curves can show large error at times with much inconsistency in data collection and improperly identifying bankfull stage, engineers continue to use these curves to estimate design dimensions for natural channel design of stream restoration projects. To increase efficiency, we propose to replace regional curves with a method that predicts channel cross-sectional area with the same degree of accuracy as existing regional curves. We have analyzed years of published hydraulic geometry data to develop a “Watershed Response Factor” that uses drainage area and average annual precipitation to predict bankfull cross-sectional area with minimal resources. Although it is not the intend to predict final design dimensions with the watershed response factor, it will be an invaluable tool for initial design, especially in areas lacking developed hydraulic geometry relationships. It will also be a great tool to help locate bankfull features in the field where regional curves have yet to be developed. Additionally, regulators will now have a quick and consistent way to validate restoration projects before approval and implementation.
About David Bidelspach
David (Hebrew) = “Beloved”
Bidelspach (Beutsbacher -German) = “One who works from a bag by the streams”
David has been “Beloved” since 1977 and desires on the good days to share this love with others. He has worked and played in streams since 2002, when he was drafted by Greg Jennings at NCSU. Nomadically, his family has lived from bags, while traveling to distant lands to work with streams and rivers. David’s community desire is to train others, to share the gift of ecosystem restoration and to be in wonderment and awe of nature. Mr. Bidelspach wants to encourage others to spring up among the ordinary green grass, like willows by flowing streams.