Friday, February 13, 2015

The Levee Hook at Deming

I've posted before about the Deming levee (nooksack-levee-at-deming). The image below shows what is being protected and points out the hook at the downstream, west end of the levee.

The hook at the west, downstream end is taking the brunt of the river of late and has been progressively eroded. The only purpose of the hook is to prevent the river from entering into an area of bottom land with forest and old river channels. The hook was built by the Army Corps of Engineers after a flood event a few years ago and the local diking district would like this section of levee to extend down river to another set of levees.

The forest land behind the hook is all low flood prone land with former river channels so permitting and justifying the costs of a levee along this river reach would likely be problematic as it would narrow the flood plain, cut off habitat areas, and be very expensive way to protect private land. The land is private so it is understandable that the owner would like to see a levee and a hard pill when watching your timber get eroded away. But then again it is a hard pill to have tax payers pay for a massive levee project to protect private land. A geologic argument could be made that the hook is causing property damage on the other side of the river as it is deflecting the river towards the opposite bank. Eventually I suspect this reach of river will be purchased and turned into a habitat project perhaps as off set for the confinement and habitat loss of the river elsewhere. 

What can be said is that the levee upstream where it was designed to protect Deming, the school and the Nooksack facilities including sewer systems for both has held up well despite some hard testing of the river aimed directly at the structure in 2007.

The hook is marked on the DEM below:

A careful look shows how the hook is blocking and directing the river away from the old channel area downstream behind the hook.

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