Excellent article. Restoring floodplains would be a critical step in not only preserving salmon habitat and improving the health of Puget Sound, but would also serve to remove property holders now before a major catastrophe happens. I know New Orleans is an extreme example, but the controlling of the Mississippi along it's delta has, of course, disastrous effects not just on the health of the river and Gulf, but of the inhabitants too.

Mitigation, in this instance, is cheaper and more thoughtful than avoidance.

I run the blog for the state insurance commissioner's office in Olympia. We put up a blog post yesterday that includes some suggestions for homeowners and businesses in the area. Please see http://wainsurance.blogspot.com/2009/09/businesses-in-s-king-county-scrambling.html

Rich Roesler

Dayton, Ohio, and the surrounding areas dealt with this problem back in the 1920s by setting up the Little Miami conservancy District. In this district numerous properties were purchased and set aside to fill with water and allow controlled discharge and runoff when major rain events occur. Most of the areas are leased to adjoining farmers for use as pasturage. I believe Arthur Morgan, who superintended the project, has written an excellent book on the principles of conservancy and how they were implemented.

It is not necessary to allow all of the land in the lower reaches to flood. Reducing the amount that flows into the river upstream reduces the amount of flooding downstream. Reducing the peak flow of the river reduces all the costs of dealing with it at the downstream end.

Unfortunately, the Corps of Engineers is institutionally unable to learn. Over the past 20 years we have seen repeated disasters as their philosophy has failed, to the point where if your home is "protected" by Corps of Engineers structures, you might as well just move to high ground now and get on with your life. But even today, the Corps' idea of 'solving' the flooding problem is to canalize the river upstream from the Howard Hansen Dam, causing more water to flow faster into the impoundment area.

We, as a society, have shown so little aptitude for problem solving that the best solution for the individual is probably to move to a hill, and not be a part of any taxing district that embraces commercial development in the floodplain.

Reading fast I possibly missed your estimation of where best to apply the lever to pry open the buy-back option. Elaboration, in any case, would be helpful. Please?

When the price of oil returns to its steady uptick, local production of all kinds of things will become competitive enough to encourage reconsideration of the wastage of once productive flood plains. Possibly the hardest to deal with in the valley in question is how much the flood plains between Seattle and Mt Rainier have become the refuge for those priced out of their normal inner city neighborhoods.

Re' the buy-back idea, and where those businesses might relocate -- and to 're-green' the Valley back to when occasional flooding would fertilize the crops - why not allow the low-land businesses/land owners at risk to take their industry/zoning to the higher surrounding elevations. Rebuilding on the surrounding "glacial toil", encouraging landowners in the Valley to re-green would be a net environmental gain.

This flooding issue can be used to modify the Growth-Management Act to redress past rural/urban zoning mistakes.

The flood threat facing the Green River valley cities is only the latest and most spectacular of many examples--the list would include North Bend, Snoqualmie, Carnation and Chehalis--of the Growth Management Act's schizophrenic mandate to identify critical areas including floodplains and grow, grow, grow your boat in spite of these critical areas. In this regard the GMA is a blunt instrument that begs the question of whether flood-challenged cities should ever have been incorporated in the first place, let alone be encouraged to continue to grow in spite of floodplain constraints.

One of my favorite books is "The Control of Nature" by John McPhee, a staff writer for the New Yorker. Published in 1990, it is an account of places in the world where people have engaged in all-out battles with nature. McPhee describes how in Louisiana the Corps has since the early 60s thrashed with the lower Mississippi in order to prevent it from changing course and flowing into the Gulf of Mexico through the Atchafalaya River, thereby turning New Orleans and Baton Rouge into an island. Katrina and its aftermath can be seen as a sequel to this chapter of the book in which things don't seem to be going all that well for the Corps. Another chapter describes how Icelanders have conducted heroic efforts to use massive fire hoses to quick-freeze red hot lava into quick-frozen pyroclastic levees intended to divert hot lava away from a crucial harbor. In Los Angeles, enormous catch basins, each of which is equipped with enormous track racks that trap devastating debris flows from the San Gabriel Mountains, and can stop boulders the size of Volkswagens that occasionally pop out of ravine walls from barrelling through homes and blowing out roads in movie star inhabited neighborhoods such as Topanga and Laurel Canyons.

McPhee details the thought processes of experts whose careers are focused on controlling nature. Some of the people are eccentric foolhardy to an extreme, but many are dedicated public servants who learn these skills in engineering school, never seriously believing that some day they might be up against a situation like the one we are facing on the lower Green River. McPhee's message is that nature is complex and extremely powerful, and though humans can win tactically, we may be doomed in many of our efforts to defeat nature over the long haul.

Will Howard Hanson Dam’s structural problems become grist for a gruesome new chapter in our ongoing battle to control nature? Will the Green River valley become Seattle’s “Little New Orleans?” Or will we emerge from this debacle relatively unscathed because of the fortuitous arrival of an El Niño weather pattern and installation of structures that prove effective in temporarily raising 40 miles of levees. Locally, El Niños are usually associated with warmer, dryer weather, and are not conducive to formation of large snowpacks that melt during intense, very warm “Pineapple Express” events that trigger major flooding of river vallies. Only time will tell, and it will be interesting to watch events unfold as decision-makers grapple with this situation.

Undoubtedly some of the Green River levees will be get severely damaged during some of the storms that will arrive in the next few winters. These levees will need to be repaired. The real question is whether after all the mud has settled we will resume business as usual and build bigger, higher, more deeply rock-blanketed, even more expensive levees, or change course and improve our efforts to work with nature instead of opposing it. We will soon have at least a theoretical opportunity to do things differently. We could for example choose to spend some of the recovery money buying land and buildings that now line the river so we can rebuild the levees further back from the river so that the next time something like this happens (and remember folks, sinkholes in the exact same part of the dam, the right abutment, were also found and repaired in 1962 and 1996) the river has more breathing room and can better store and convey floodwaters. Taking this kinder, gentler approach would also be consistent with Puget Sound salmon recovery efforts on which we will ultimately spend $$$ billions, as well as the "green cities" movement that calls for re-creation of tree canopies to help counter the heat island effect in densely urbanized areas that are now hot seas of pavement and other impervious surfaces.

Because of landowners who want to max out profits on every last square inch of their land and the craven politicians who cater to them, the odds are better than even that local efforts to control nature will will out. Again. Regardless of what happens in the short term, I have a hunch that future generations will for other reasons, including disappearance of water and desertification in the California's Central Valley, which produces half of the US food supply, someday remove malls and tilt-up warehouses and restore the Green River valley to farmland so future Seattle area inhabitants will continue to have a reliable food supply.

It’s good that the over development of our regions flood plains is finally getting some attention. I’m sure that many readers will be interested to learn that the Legislature amended the GMA this year to prohibit the expansion of Urban Growth Areas into flood plains. While this does nothing to rectify the flood plain development which has already occurred, it does signal a positive change in the thinking about flood plain management (at least at the state level). Given the extremely high costs associated with mitigating the damage caused by flooding and the multitude of environmental benefits resulting from maintaining flood plains in a natural state I am hopeful that the public will demand change at the highest levels.

I am amazed at how the obvious is often overlooked... After seeing how all involved parties are dealing with the current issue, I hopefully will not have to see how everyone responds when (WHEN, not IF) Mt. Rainier has it's next major eruption. I suspect the Lahar Escape Route signs may not prove to be enough...

Anyone selling Lahar Insurance?

Nice article, my only question is the levels that the "experts" quote as to level of flood damage. Having lived here for all my life, I can remember driving with my parents the West Valley Highway using bamboo stakes to keep on the road. The Kent Justice Center was built on a 10 foot lift of fill dirt. It may get close, but I bet the Justice Center will not flood. When you look at all the railroad tracks in the Valley, in a major flood, they were all 10 to 15 feet above the water. I do believe there is some Chicken Little going on here, but, the true damage will be to all the residents whose home and apartments were never built on large lifts of dirt like most commercial buildings were. It is still a disaster waiting and the Corp of Engineers should be fessing up.