Reflections on the Flood

Date Line: March 8, 1996

It is now 30 days out from the great floods of 1996. Some perspective is possible. We have the following report published by the Bonneville Power Administration.

"The Corps reported that changes in Columbia and Willamette hydro system operations reduced the water level by seven feet at the Portland, Ore., Seawall. The Willamette River crested two inches below the top of the seawall. . . . . Along the Columbia, the water level at Vancouver, WA was Seven feet lower."

Ultimately, only a few levees on the lower Columbia River failed or were overtopped, and the total number of houses and farms flooded on the Columbia were modest in number. This was bad enough, but swamping the seawall at Portland (saved by 2 inches) would have flooded downtown Portland, and a few more feet on the Willamette at Salem would have collapsed or overtopped levees protecting thousands of people. The flood protection on the main stem rivers did its job and a major regional calamity was reduced to a mere disaster with flooding involving a few hundreds of families instead of several thousands.

That is the good news. The situation is not so pretty in Vernonia. Vernonia is not on the Willamette or Columbia, but is located in a narrow valley along a coastal river known as the Nehalem. In normal times the Nehalem will scarcely float a kid on an intertube, and the question of whether it would be classed as 'navigable' in the legal sense is debatable.

Vernonia is no more than 20 miles from the Nehalem's source. Forty feet wide and a foot deep would describe its normal flow. The immediate banks of the river are typically 20 feet high, and extending out from that is flat ground which we now clearly understand to be flood plain which here and there is only slightly wider than the river to areas where it is half a mile wide. Beyond the flat river bottom land the lands move up steeply, sometimes almost vertically. Soil type is a fairly unstable yellow clay of marine deposit origin which develops the consistency of applesauce when saturated with water.

As noted elsewhere, this valley loops through Northwestern Oregon and the vast majority of all West Oregon members live along perhaps 50 miles of the valley floor. Presumably, in a broad sense, it makes sense to expect that a valley floor in a long narrow valley will flood from time to time, but community memories are not that long. Native Americans did not permanently reside in the Nehalem Valley, preferring instead to use it for hunting grounds while living along the more hospitable Columbia. The non-navigability of the waterway discouraged early settlers, and the Nehalem Valley did not begin to see settlers until the later 1860's.

The earliest recorded flood level in the Vernonia area was marked by the Sword family in 1894. A weather pattern similar to the one of 1996 put the Columbia and the Willamette to the highest levels which are reasonably documented, and set a flood benchmark in the Vernonia area as well. The 1894 flood levels on the Columbia has long been the base for calculating flood levels on the lower Columbia. While there are historical reports of a tremendous flood on the Willamette during the 1860's, its levels are not documented, and the '94 flood is the benchmark for the Columbia. In Vernonia, the Sword family identified the 1894 flood level with an ax mark and then built their home which still stands today, on the banks of the Nehalem with the floor 2 feet above the 1894 flood marker. Their house took 18" of water this year, and the West Oregon Electric just across the river from the Sword house took about 39" of water implying that the WOEC office was built just marginally above the highest recorded flood level in the short history of the area.

While such flood levels are preferable to the situation nearby where the Vernonia High School football field had water to the cross bar of the goal posts, it is still pretty much a wipe out level. The rogue's gallery of past and present directors is about the only thing that didn't get wet. Substantial portions of the building itself are made of masonry and structural problems to the building are minimal. Concrete floors and brick and concrete walls hold up pretty well in flood conditions. The furniture and veneer partitions were not so fortunate. We have also conclusively demonstrated that computers and flood waters are not compatible.

Will this level of flooding reoccur? Common sense says yes. When? Who knows! There is no one alive now in the community who has a first hand memory of the next highest flood which hit the area 102 years ago. In the mean time floods have been rare but not of any regular pattern. Apparently the interim flood years were 1937, 1964 and 1968 on the Nehalem. Two of the '50 year ' floods hit 4 years apart. There has been nary a field drown out since 1968 in the Vernonia area which has provided plenty of time for everyone to forget, and those levels were below the 1894 level easily lulling one to believe that the 1894 flood was the 'worst case' scenario. Well, not quite.

Will the area recover? People forget about floods fairly quickly and new comers are common. It was interesting to watch the TV interviews of people in the worst flooded areas taken during the flood. The most common comment the camera crews would extract from someone was "I've lived here 6 months and never seen anything like this before!" While living in a flood zone is not a preferred idea, the Nehalem Valley folks have little choice. The Valley walls rise abruptly, and besides being too steep and often prone to slides, they are mostly in corporate timber plantation ownership, leaving the effective choice of living on the valley floor which becomes uninhabitable every 100 years or so, (and in some of the lower areas every 25 years or so) or moving out of Northwest Oregon completely. Considering the statistical odds that no one now living will see flood waters that high again, most people are likely to eventually dig out, rebuild and go on with life, with this being just one more trial in their life.

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robert@vannattabros.com