Opening PLENARY JUNE 18 1:45 - 2:30 PM

Designing Sustainable Restoration Projects in the Reality of Watershed Extremes

Dave Rosgen, PhD, PH
Wildland Hydrology
Fort Collins, CO

In the face of climate change and the numerous hydrological impacts from land uses, extreme floods and droughts must be anticipated. How does a restoration practitioner prepare for such extremes? First, understanding the functioning (geomorphic & ecological) of natural stable reference reaches is critical; these systems are self-formed and self-maintained, reflecting their ability to absorb past extreme events. Reference reaches are selected in restoration using stream succession to understand how impaired streams respond to disturbance and the stages that streams undergo to recover. Impaired systems can then be compared to appropriate reference reaches to analyze departure. Second, restoration must incorporate a multi-stage river system to accommodate a range of streamflows, including periods of extreme flooding and droughts, by incorporating well-developed floodplain and low flow features. The low flow channel provides adequate depths for fish habitat during low flow periods and also increases sediment transport capacity. The multi-stage river system also allows for a functioning riparian ecosystem and a great diversity and complexity of aquatic and terrestrial habitats by ensuring that the stream channel is interconnected with its floodplain. This presentation will discuss these important concepts for designing sustainable restoration projects.