Subject: Repairing Nisqually "Damage"
Date: Feb 13 18:21:17 1996
From: "Jon. Anderson and Marty Chaney" - festuca at olywa.net
Tweets,
I appreciated Steve Herman's perspective on the historical efforts to =
establish some sort of tidal flow south of the dikes at Nisqually.
I think there is little doubt that the area is in that ugly stage of =
vegetation succession between farm pastures and alder thicket. From a =
avian habitat diversity standpoint, and from the standpoint of enlarging =
the estuarine habitat for juvenile salmonids - as well as all other salt =
marsh species - it is *very* desirable to re-establish tidal flow behind =
the dike! As Steve noted, there is a fair amount of upland farm field =
habitat in the area, and darned little estuary remaining in Puget Sound.
This flood destroyed nothing except the pitiful efforts of man to keep =
the river and the Sound out of its own. Now might just be the time to =
interject our perspective into the "Repair" process that USF&WS will be =
going through in the wake of the '96 Flood.
If the dike is breached in a number of places, so much the better. =
Culverts should be installed, rather than tide gates. The culverts in =
the dike should be large enough to pass water without causing further =
erosion of the dike. I'm no engineer, but I am quite aware that culvert =
sizes can be determined to pass the water through. In a flood like last =
week's, mind you, no culvert can handle the flows. But, in a 'normal' =
50-year flood (that we get every year or so, anymore), the waters would =
come in the upper end and flow out the lower end. The sloughs south of =
the dike at Nisqually are obviously vestigal channels from when the =
Nisqually flowed 'free'.
Just re-building the dike, repairing the breaches, will do nothing for =
the ecological integrity of the area. I'd much rather be put off from =
walking the dike trail for several months (years?) until they got =
culverts in than have them rush the job, filling in the holes with rocks =
and dirt, just so they can be able to drive and walk around the doggone =
place! If they just re-build the dike, it'll just blow out again in the =
next big flood. What a waste of resources!
Anyway, if folks think this (Culverts instead of Dikes) might be an =
approach worth discussing with the Refuge Manager of Nisqually NWR, =
let's talk about it and set down some options for the gentleman. Maybe =
we could include some Black Hills and Tahoma Audubon conservation =
committee types?
Jon. - Visualize Estuary - Anderson
Olympia, Washington
festuca at olywa.net