Observations on Natural Channel Design Approaches: Where Can we Improve?
Karl Koller
Minnesota Department of Natural Resources
Grand Rapids, MN
Authors: Karl Koller, Ann Thompson, Tim Beaster, Ben Nicklay, Nick Proulx
Natural Channel Design (NCD) has its share of detractors, with critiques ranging from generic tropes about the ‘cookie-cutter” nature and perceived focus on form to observations of individual projects that sometimes expose incomplete application of NCD or legitimate improvement opportunities. Some of the latter types of critiques can offer insight into the value of examining projects from different perspectives. Continuing to adapt and refine restoration techniques to improve resiliency and ecological function should be a goal for all stream restoration practitioners, especially given the cost of restoration and the more volatile nature of hydrologic events in recent years. Working on many aspects of channel restorations, from permit and plan review, design and construction oversite, and especially project monitoring, has offered an opportunity to examine and adapt approaches. In this talk I will share observations that have shaped the way my approach to channel restoration review and design has evolved. One area of focus will be on lessons learned from monitoring a restoration that required repairs following a large flood. Some of the learning just reinforced the importance of oversite on channel dimension or structure construction but it also changed design approaches including steering our designs to focus more attention of floodplain form. In addition, looking at engineer-designed projects through a fisheries biologists (and anglers) eyes has led me to examine how well we are mimicking natural variability in restoration design and to recognize how reliance on some tools has created some of the issues pointed out by critics. This talk will contain information that can help both the stream restoration practitioner early in their career learn from some of my missteps and observations and can help the seasoned practitioner examine where there is still room for improvement and encourage innovation in future designs. Restoring stream channels, their floodplains and riparian areas is a complex undertaking and the more we can share what we have learned from successes, and more importantly failures, the better off our field will be.
About Karl Koller
Karl Koller currently works for the Minnesota Department of Natural Resources as a Regional Clean Water Legacy Specialist. His primary focus is on stream assessment, restoration, mitigation and monitoring as well as road/stream crossings. He began his career with the agency 30 years ago as a fisheries biologist where he was the lead stream worker and first received his introduction to stream habitat and restoration projects. His interest in streams began in childhood as a fly fisherman, and that has carried on through his studies and into his career. He enjoys revisiting streams to observe how fluvial processes shape both natural and constructed channels.