New-school techniques to minimize flooding at Mount Rainier and elsewhere
As a region, we haven't had a particularly good track record of taking care of our watersheds and rivers over the past hundred years, writes guest columnist Phil Eidenberg-Noppe. "Old-school" techniques, such as dredging and levees have not served the region well.
Special to The Times
A RECENT Seattle Times article presented compelling science about the effects of Mount Rainier's shrinking glaciers but failed to adequately examine our broader role in causing flooding problems and our inadequate response to solving the problems ["Rainier's rocks are filling riverbeds," Jan. 3, Page A1].
As a region, we haven't had a particularly good track record of taking care of our watersheds and rivers over the past hundred years.
We need to understand that: 1) watersheds are the bodies that determine the health of the circulatory system that is our rivers, and 2) our aquatic veins and arteries can only take so many stents or balloon angioplasties before they systemically fail.
It is time that we as a region come to terms with the fact that dredging, levees and other hard-engineering approaches are "old-school" techniques that have not served us well. We need to start funding shovel-ready projects that involve more logs, root-wads, fir and cedar trees and less concrete, riprap and dredging.
When the floodgates of post-flood recovery funding open, we need to be ready to take actions that provide permanent flood protection in line with sound ecological principles. The first course of action must be for us to remove ourselves from the hazard, even if it means relocation that may be costly in the short term.
I served as an emergency hire hydrologist at Mount Rainier late last year, focusing on flood history, response and new solutions for problems on the Road to Paradise. This critical link to the park is repetitively damaged but repetitively rebuilt in the same place with the same limited flood-control facilities.
All too often, the answer at the park has been more rock riprap bank protection and channel dredging, with in-kind replacement or reconstruction of undersized culverts. To be fair, managers and scientists at the park face challenging circumstances, including limited funding, Wilderness Act restrictions and archaeological concerns.
At the same time, with National Park Service geologist Paul Kennard's guidance, the park has recently started to consider a shift to newer bioengineered approaches, including engineered log jams strategically placed in the Nisqually River to control river flows and sediment movement.
Beyond the park, it seems we are still learning about the repercussions of our past actions. Many counties in Western Washington have had active gravel-mining and levee-construction programs for years. Most of the dredging, levee construction and lining of stream banks with rock riprap in lowland rivers was done in response to lowland floodplain draining and development, and uncontrolled clear-cutting and logging-road failures in headwaters areas.
Turn-of-the-century replumbing of major forks of some river systems simply set the stage for a series of unmitigated insults. The Skokomish River, typically the first to flood, is the poster child.
More recently we've come to understand the implications of our early actions on the Green-Duwamish River. However unlikely it is that the Puget Sound warehouse district that is now the Green River floodplain will be returned to anywhere near natural conditions, it is still critical that we as a region understand what we give up when we decide to permanently alter the landscape.
Paving of the Skagit River Valley floodplain looms as a threat in the distance.
The Pacific Northwest has always been in the forefront when it comes to natural science. Let's set an example for a world that is now struggling to find answers to global climate change. We can do this by using the expertise and insight provided by our renowned local scientists to implement policies, provide adequate funding, and take actions now based on sound ecological principles. No further time is needed for study, off-the shelf designs are shovel ready.Phil Eidenberg-Noppe is a hydrologist with more than 20 years experience in stormwater and floodplain management in Western Washington.