Comments on: Western Washington Sees Pattern of Severe Flooding

By: Lucien Beauley

Lucien Beauley — Tue, 17 Mar 2009 23:42:45 +0000

Almost every year, many parts of the country are plagued with flooding from heavy rains in the early Spring, but this unfortunate episode can be eased and possibly totally prevented by taking some very basic precautions in the previous years. Admittedly,

Some Sure Ways of Preventing Local Flooding

By: Michael Ricciardi

Michael Ricciardi — Sat, 31 Jan 2009 20:41:36 +0000

I agree with the general conclusions of the study, but, these “conclusions” are constantly being modified as new data (and theory) appear. I know of no study that is definitive on this topic.

The blog post speaks plainly of a confluence of factors, only one of which is clear-cutting (and it clearly mentions over-development in/near rivers and streams, hence the photo). But you’ll note that the trees in the background are quite tall, at least 30-40 years old or more. Flooding tends to rot and kill trees that come in contact with excessive water on a regular basis. Point being: it’s been a long while since flooding hit this particular area of Chehalis, WA.

Regarding clear-cutting’s impact on flooding, granted, this is difficult to determine precisely (and its effects are indirect), but this is because the practice occurs in various topologies, and to different degrees. Clear-cutting along mountain sides has demonstrably led to siltation of streams, which, in time, fills the stream and prevents the stream from doing its job (channeling water to a river, and providing shallow water habitat for spawning salmon). Also, clear-cutting of forested mountains promotes loss of vegetation and erosion, and this demonstrably leads to landslides (one of the co-effects of flood-producing storms).

I recognize the tendency of web media to distort information for increase traffic (not much different than print) and I strive for balanced writing (note the last paragraph). Blog posts, due to their brevity, tend to simplify.

Regards, M.R.

By: Peter Heide

Peter Heide — Fri, 16 Jan 2009 20:05:16 +0000

A rusty pickup in the middle of a flooded field is an interesting photo, but not evidence of increased flooding. It is symptom of the real problem: that is people and development moving into floodplains. The flood plain is the area where water goes when it rains hard like it of the does on the west side of he Cascades and has for millions of years. The snow melting lowland winter storms makes for more water. That is why we have these great deltas along the margins of Puget Sound. Those deltas were for the fish, but now they have become the preferred place to develop. Weather happens it always has. If you look real science you will see that forest management, including clearcuts, have very little to do with the impact of flooding in these big events. Read “Effects of Forest Practices on Peak Flows and Consequent Channel Response: A State-of-Science Report for Western Oregon and Washington” Gordon Grant et.al. Pacific Northwest Research Station General Technical Report PNW-GTR-760. May 2008.

What you will find in this the “state-of-the-science synthesis of the effects of forest harvest activities on peak flows and channel morphology in the Pacific Northwest.” The conclusion is “The magnitude of effects of forest harvest on peak flows in the Pacific Northwest, as represented by the data reported here, are relatively minor in comparison to other anthropogenic changes to streams and watersheds.”

What this means is that flooding is worse because of damming, diking, dredging, filling and building in flood plains not clearcutting. The real environmental issue in the western Washington is loss forest. Managed, productive, lumber producing forest included. The loss is not from harvesting and growing more trees, but from development that permanently removes trees and replaces them with roof tops and pavement.