Presenter/s: Janine Castro
Symposium Session: 2022 - 00- Invited Speaker
Topics covered: lessons learned
RRNW is 20 — and hindsight is 20/20! This retrospective will cover where we’ve been, where we are, and where we might be going with stream restoration in the Pacific Northwest.
When River Restoration Northwest convened for the first time over 20 years ago, most restoration projects were channel-centric and large wood focused. “Channel Reconstruction” projects were designed to maintain sediment transport through a comparatively stable, single-thread channel that connected to its floodplain during relatively infrequent flows. We thought about large wood in terms of pieces per mile and habitat units in terms of multiples of channel width. During the early years of RRNW, restoration work was longitudinal in nature and metrics tended to be in feet and miles.
Jump ahead 20 years and the river restoration world has laterally expanded into two dimensions. There is broad recognition by the scientific community that increased floodplain connectivity is correlated to increased habitat complexity through fully integrated wetland-floodplain-channel systems. “Floodplain Reconnection” projects are now more often designed to connect at very frequent flow events and inundate the floodplain for weeks or even months each year. While there may still be a main channel, there are often multiple, interconnected channels. We now think about large wood in terms of total wood loads across the floodplain. Restoration work is both longitudinal and lateral in nature and metrics are often reported in acres rather than feet.
That bring us back to the future. Where will we be 20 years from now? Will we be restoring river-wetland corridors in 3 dimensions, fully embracing the vertical components in restoration design? In the same way that Lidar opened our eyes to floodplain microtopography, perhaps ground-penetrating radar will help us more fully understand, and then restore, the river corridor that flows beneath our feet.