Dangers Still Lurk Beneath Mississippi’s Surface : Environment: Historic flood filled the waterway with hazardous new twists and turns. Some officials say the time has come to rethink life on the river.

The Mississippi River may be a subdued beast once more, but a recent spate of storms and rising water has reminded returning flood exiles that the river remains unharnessed.

Stretches of high and low water have turned the river into an aquatic obstacle course. The passage is treacherous for helmsmen piloting scores of towboats on the main channel and for researchers plying the Mississippi’s contours in survey boats to study the flood’s impact.

Two months after the flood’s official end, much of the waterway is still wild, endangered by swift current traps and floating debris. In the northern realms of the Mississippi, sandbars butt into the main navigation channel. They can be removed only by a massive dredging operation that will proceed 350 miles from Wisconsin to the southeast tip of Missouri.

“It’s like a whole new river. You really have to be on your toes,” said Capt. Walt Morgan during a recent run of his tow, the Floyd M. Blaske, through blinding fog near Dubuque, Iowa.

Even when the most pressing dangers finally subside, river experts say, the flood may leave a permanent stamp on the Mississippi after public officials hash out new stances on regulating flood relief, monitoring pollution and managing lowlands along river banks.

“This is the best chance we’ve ever had to rethink our relationship with the Mississippi,” said Bruce Hannon, a University of Illinois geographer who studies the river. “The flood was our alarm bell.”

For river people who have only recently returned to the Mississippi after fleeing during the flood, it is still too early to rethink life on the river. They are still trying to regain a semblance of normalcy.

That process has been hampered by recent rains, which forced residents to sandbag again near Kimmswick, Mo., and prodded St. Louis officials to lock 21 floodgates in place along the downtown flood barrier last week as the river rose more than four feet to 39 feet, nine feet over flood stage.

Buoys and markers were set adrift like corks by the rising water, a nightmare for veteran river pilots who rely on the visual aids. Tree limbs and riverborne trash mass under bridges, creating traps for oncoming boats. The clinging debris stirs up currents, snagging tow lines and snapping barges loose from their moorings.

One 15-barge towboat, the Brimstone, recently lost control in swirling currents as it approached a railroad trestle near Louisiana, Mo., and was pinioned into the bridge. Most of its barges broke loose and were not tethered for three days, said Coast Guard Cmdr. Alan Peek. A similar barge accident is being blamed for the recent Amtrak train wreck that killed 47 people in Alabama.

“There’s so much velocity in the current,” Morgan said. “Everything’s moving anywhere between three and eight miles faster than it usually does. And this is as you’re pushing something two city blocks long and heavy as a small skyscraper. One miscalculation can hurt you bad.”

The Blaske began slowly plowing north toward St. Paul, Minn., after Morgan was given the green light on Aug. 23 to ship out of Hennepin, Ill. The vessel had sat there for 48 days, marooned by the flood. Striated with rust scars and algae, the 650-ton vessel shepherded 22,000 tons of cargo--salt, coal, caustic soda, iron pipe, ethyl alcohol, steel coil, molasses and fertilizer.

In the wheelhouse one recent morning, Morgan guzzled coffee and kept a steady hand on the tow’s steering lever, peering through a fly-specked windshield as he maneuvered his 15 barges into a lock near Belleville, 25 miles south of Dubuque. The barges clattered and shrieked as the tow slipped into the lock, just inches from a concrete wall.

Bill Vaughn, the U.S. Army Corps of Engineers lock operator at Belleville, was dumbfounded when he saw the Blaske materialize out of the fog. He had known the tow was downriver, but he had expected Morgan to drop anchor south of the lock until the mist burned off.

“You take your life in your hands when you move in weather like this,” Vaughn muttered. He added: “I can’t blame them, though. They have a lot of catching up to do.”

The Blaske--one of 20 tows on the upper Mississippi operated by American Commercial Barge Lines--was among more than 70 boats and 3,000 barges stranded by the July floods.

Most are on the river again, moving in smaller clusters and at speeds reduced by a third, on Coast Guard orders, to lessen boat wake that could breach sodden levees.

Estimates are that the river traffic industry lost more than $100 million because of the flood, and most tows are laden to capacity to make up for lost time.

“The push now is getting cement and coal northbound to the Twin Cities and grain (wheat and soy beans) down to New Orleans,” said Norbert Whitlock, American Commercial’s president.

New hazards loom to the north. Between LaCrosse, Wis., and St. Paul, the river dropped so quickly after the flood that it had no time to scour away tons of sand that had collected in high water. Sections of the shipping lane are now studded with giant sandbars. One shoal found near Wabasha, Minn., spanned 2,800 feet.

Sand deposits have reduced the Mississippi’s standard nine-foot-deep channel by as much as four feet, prompting the Coast Guard to insist that tow loads be lightened so that barges do not risk dragging in shallow water.

Despite the order, 10 tows have run aground in recent weeks on new shoal formations near LaCrosse, forcing the Corps of Engineers to make that section of the river a dredging priority.

“The deposits are more severe than anything we’ve dealt with in a routine year,” said Dan Krumholz, chief of navigation for the Corps of Engineers’ St. Paul District. “We have channel maintenance people who’ve been out on the river 30 years saying this is the worst they’ve ever seen.”

The Corps of Engineers brought in two extra dredges to augment the hydraulic dredges already on hand in Wisconsin. In a normal year, Krumholz said, no more than 20 trouble spots may require dredging after high water. This fall, the Corps of Engineers is racing to thin out between 30 and 50 areas before the river’s northernmost stretch ices over, as it does every November.

The dredging operation--which will be repeated all the way to Cairo, Ill.--aims to return the river’s main channel to its nine-foot depth. But Corps of Engineers crews routinely pare the river bottom up to 15 feet deep “to give us a decent cushion of time before we have to dredge again,” said Gary Dyhouse, chief hydrologist for the Corps of Engineers’ St. Louis District.

Environmentalists criticize the extra dredging as dangerous to marine invertebrates living on the river bottom. “It’s just another subsidy to the barge industry,” said Brent Blackwelder, vice president for Friends of the Earth. Corps of Engineers officials respond that the flooding has already stirred up marine habitats.

To find shoals that require the most immediate dredging, seven Corps of Engineers survey vessels have sailed onto the upper Mississippi, using sonar and surveying instruments to rechart the waterway. One of them is the Sweatt, a snub-nosed aluminum boat named for an Army crane operator killed in a 1986 mishap.

Plying the waters between Balltown, Iowa, and Dubuque during a recent pass, the Sweatt’s three-man crew spent a day charting a hook in the river known as Finley’s Landing--”one of the worst spots on the upper Mississippi,” according to Kenny Brenner, a Corps of Engineers riverman piloting the boat.

Finley’s Landing has a history of snaring towboats, catching them in sand deposits that regularly build at a point where the Mississippi doglegs to the west, Brenner said. As the Sweatt tacked back and forth along the river, its crew members spotted a new shoal that had formed near the landing--a formation that caused a spike on the boat’s electronic mapping system.

Moments later, the boat itself jolted as it sideswiped the sandbar.

“A bar like this can really sucker in a boat’s bottom,” Brenner said. A veteran riverman who lives in Rock Island, Ill., and often motors on the Mississippi to fish, Brenner said “only a fool would go out on the river now. You hit one of these shoals and you can really damage your boat.”

Yet all day long, as the Sweatt poked back and forth in the syrupy river, powerful cruisers roared by--sometimes veering dangerously close to the sandbars. Downstream, the Silver Eagle, a gambling boat from East Dubuque, Ill., wallowed near an island still sunken in high water. Knots of elderly gamblers pressed up against the boat’s windows, ignoring the slot machines for a brief interlude to gawk at submerged cottonwoods and burr oaks.

Up and down the river, researchers are keeping their wary distance from pleasure craft as they survey the river’s new realities. Bridge inspectors are checking the Mississippi’s 60 river spans for weakened bridge supports but have found little evidence of major scouring.

Surveyors from the U.S. Geological Survey were stunned recently when they detected high traces of farm pesticides in the river. Federal officials had expected the tremendous flood flows to dilute any excessive runoff of pollution.

Instead, researchers found that levels of atrazine, a widely used farm pesticide, matched the same peak traces recorded in past summers. Water experts say that in high concentrations, the chemical can kill river insects such as midge and fly larvae--crucial links in the river’s food chain.

Because the river flow was so much higher during the flood, researchers concluded that atrazine levels found in recent weeks were 50% higher than amounts recorded in previous annual measurements.

A separate survey by University of Iowa researchers found that more atrazine flowed into the Gulf of Mexico during the flood’s five-week duration than was dumped into the sea during all of 1992.

In a single day, geologists found 12,000 pounds of atrazine gushing past the town of Thebes, Ill.

“We’re extremely concerned about any impact on life on the river beds,” said Kevin Oberg, a USGS hydrologist.

Federal officials say the high chemical levels will likely force them to monitor pollution runoff much more closely in future floods--and could prod them to take preventive action.

Philip Cohen, the USGS’s chief hydrologist, said his agency already plans much closer monitoring of pesticide levels in the river.

Scientists have also found evidence that the river altered its flow at several points along the Mississippi shelf--indications that the river’s contours could change.

One well-publicized diversion came just north of St. Louis, where the Mississippi and the Missouri River flowed together 10 miles north of their usual meeting place near the town of Portage des Sioux, Mo. The twin flow has since largely abated, Corps of Engineers officials say.

In 1986, when the two rivers last flowed together, the local levee district rebuilt a single horseshoe-shaped breach in its flood wall. This time there are at least three major breaks in the levee--ruptures that can only be repaired with local funding.

Corps of Engineers officials acknowledge that if the area’s levee district is unable to pay for flood wall repairs, the engineers will have to take action to keep the Mississippi straitjacketed--most likely using a line of rock revetments to keep the two channels independent of one another.

But even that process would still allow some overflow from high water, the Corps of Engineers’ Dyhouse acknowledges. “Without a repaired levee, all we could do there is keep the channel intact and prevent further deterioration,” he said. “We wouldn’t be able to stop the water anymore. Living in the flood plain would get pretty impractical.”

Across the river, south of Thebes, geologists have found another diversion at a junction known as Dogtooth Bend. A levee break there allowed a fifth of the Mississippi’s flow to divert south and east, spewing nearly 200,000 cubic feet a second--nearly three times the normal flow of the Illinois River--into adjacent farm fields during the height of the flood.

The flow has since dropped significantly, but scientists studying the cutoff say that if the breached levee is not repaired--a real possibility because federal funds are not available--future floods might divert more water through the area and threaten to cut a new channel.

Civil engineer William Klingner suspects a third diversion may have occurred near the town of Meyer, Ill., just north of Quincy, Ill. Klingner, who has years of familiarity with Quincy area levees, said he fears that the Mississippi may now be flowing east of Meyer instead of west of the town, where the Lima Lake levee broke.

Scientists are skeptical about a new cutoff forming at Meyer. But the other diversions, they say, are sure signs that the river is trying to throw off its yoke of dams and levees and alter course.

“If nothing is done in these cutoffs,” said Bob Dalton, a planner for the Illinois State Water Resources Department who has surveyed Dogtooth Bend, “the river will lend itself to more frequent flooding and would start reshaping the land, making it more hospitable for larger diversions.”

Corps of Engineers officials insist there is no likelihood that the Mississippi’s navigational channel will be left to nature. Still, a recent memo sent to the Corps of Engineers by Katie McGinley, director of the White House Office on Environmental Policy, cautions the agency to consider “other alternatives to levee restoration.”

Scott Faber, director of flood plains programs for the American Rivers conservation group, said the memo was a “revolutionary” new step for the federal government, one that could ultimately lead to the purchase of farmlands for use as natural flood plains.

“If we get real serious about returning wetlands to the river, you could see real changes in the river’s shape over time,” Faber said.

Other environmentalists, like Corps of Engineers officials, are less sanguine about the government taking a new direction.

“Unless they clamp down at the White House, it’s going to be business as usual,” said Hannon, a former Corps of Engineers official who expects most levees to be repaired with either federal or local funding.

Still, if even a minority of levees are left breached, they are likely to become regular depositories for high water in future floods--a process that will reshape the river, even if in small increments.

“When you realize how much we’ve altered the Mississippi over the years and controlled its course,” Hannon said, “even a little change would be an incredible victory for nature.”

Times researcher Tracy Shryer in Chicago contributed to this story.