Questions raised about Black River sediment, diversion

Wednesday, December 28, 2005

Officials involved in the cleanup of the Taum Sauk reservoir collapse are now worried about the health of Black River.

The failure on Dec. 13 caused the river to divert approximately 200 yards to the east. Furthermore, the sediment carried into the river may have affected the river's wildlife.

The concerns come on the heels of the state's third emergency declaration on Friday by Gov. Matt Blunt. The state is laying out a cleanup plan at the hydro-electric reservoir site near Lesterville which is owned by Ameren UE.

Ameren UE is responsible for conducting the cleanup, but Missouri's Department of Natural Resources (DNR) oversees its planning and implementation.

To date, Ameren has concentrated on the most practical aspects of the cleanup. This has meant plugging up the gash in the side of the reservoir with a temporary wall, clearing away rock debris on the hillside and chipping and hauling away trees.

The new plan calls for more attention to the Black River. The billion gallons of water that gushed down the reservoir wall caused the river to divert approximately two football fields east below the lower reservoir said DNR deputy director Kurt Schaefer.

"We've got to look at the prudence of letting the river stay there in this much older channel," he said. "Our priority is stabilizing the river."

Experts must determine whether diverting the river back to its original course will cause more ecological damage than has already occurred.

Also of concern is a 6 1/2- acre pool or "scour hole" that has formed in the same area at the east fork of the river. The DNR is concerned that a heavy rain could cause both the scour hole and the river to flood onto the campground area below.

Schaefer says DNR is collecting data and may recommend that Ameren drains the hole and erects a rock structure to the west of the river and in front of the campground.

The torrent of water also brought with it a lot of sediment.

"The Black River is normally exceptionally clear; it's great for swimming and floating," said Schaefer. "Now, beyond the east fork, below the lower reservoir, it is very muddy. It has what we call a lot of turbidity. This is a concern not only for swimmers, but also for a lot of aquatic species."

Schaefer said the water upstream from the confluence has taken on a bluish tint which indicates a smaller concentration of sedimentary particles.

Officials worry that a heavy rain could cause more sediment to wash down the drainage canal into the river. To combat this, Ameren will blanket the sloping area with stone extracted locally. DNR further asks that Ameren construct two small barriers called check dams in the drainage canal.

DNR director Doyle Charles hopes some services to Johnson's Shut-Ins State Park will be restored by this summer, but he cautions patience. "We first have to get the debris removed and determine what water quality impacts the Black River has suffered," he said. "We are working quickly but carefully."

Ameren has been "extremely cooperative," said Schaefer.

tgreaney@semissourian.com

335-6611, extension 245

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