When the Hofmann Dam removal project was being planned, much time, effort and money was spent on dealing with the contaminated sediment that has accumulated above the various dams.
Dozens of pages of each subsequent plan were given over to listing this data and the contaminants, estimating their volume and describing various methods for their removal and safe disposal.
When the village board finally met to grant the easements for the project, the plan they based their decision on stated that there were 21,000 cubic yards of sediment above the dam containing dozens of toxics.
It called out the removal, dewatering and hauling away to an approved site 3,000 cubic yards of sediment – 15 percent of the total – and, as mandated by the EPA, the covering over of approximately 8.8 acres of newly exposed sediments with 9 inches of clean fill.
Now, miraculously, the Army Corps says there are no toxic sediments that need to be removed. How can that be? Where did they go?
Similarly, the Corps engineers argued for years that the reductions in the depth and width of the river above the dam, once it is “notched”, would not materially affect the quality of life for the residents.
But the IEPA report says the backup from the dam extends 6.5 miles upriver and creates a surface area of 12 acres. It warns that the removal of 150 feet of the dam and the resulting lowering of the surface of the river … when the opening is removed to bedrock will cause the upstream river to be reduced by half – and much more at low water levels.
This condition will prevail far beyond the Corps work limits and far beyond Riverside.
The Army Corps scoffed at my predictions, saying the river rarely got to such low levels, then eventually came close and in some cases exceeded what I had forecast for what the new river depth and width will be after removal.
But they still conclude that their estimates of low water would rarely, if ever, be reached. They even provided charts to that effect which are posted on the village web site.
Well, gentlemen, today, April 9, 2012, the river gage at Riverside operated by the USGS is stating that the river is 2.36 ft. deep (near Millbridge Road) and is running at a flow of 127 cfs.
The river has been hovering around this level for a few weeks now, and over the years I have seen similar readings in every month from April to November. Today we have the 7Q10 flow they said we almost never get. And it is only April.
Let me be clear. If this project goes forward, on a day like today with the dam removed, we will experience drastic changes in the depth and width of the river above the dam. I confidently predict:
From the railroad bridge down river to Salt Creek, the river will be 2.5 to 3.5 feet shallower and 75 feet narrower than it is now. From Salt Creek to the dam it will be up to four feet shallower and 70 to 200 feet narrower than it is now.
In some places where today there is broad water it will be less than 50 feet wide and there will be acres of odorous mud and debris exposed all along both sides of the river, both within their work zone and far above it.
If you want to see what it is going to look like, take a look at the land that is already exposed right above the dam on the Fairbank shoreline, or look down into the water from the Lyons side or from the bridge. You can see all manner of trash and debris now, and much, much more will be exposed when the surface of the water at the dam will be 10 to 11 feet lower than it is now. Cleaning and removal is not in the project.
I was not able to place markers north of the railroad bridge because of private property, but I expect that on a day when the river is flowing as it is today, the river walls of the homes along Maplewood will be 40 to 50 feet from the water.
In between will be mud and debris that has been tossed there over the last 100 years. All along the river, in the First Division, along West and Maplewood, up in North Riverside and at the Golf Club and far beyond, significant changes are going to cause a vastly different riverscape and views.
This thing is almost here. They are starting to fence the staging area. Don’t say nobody warned you.