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Islands of silt plague Charles

Hazard to boaters; calls for dredging

The sediment built up in the Charles is attributed to sand applied to roadways to keep cars from slipping. The sediment built up in the Charles is attributed to sand applied to roadways to keep cars from slipping. (Essdras M Suarez/Globe Staff)
By David Abel
Globe Staff / July 23, 2011

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Bruce Smith stepped off his boat into the copper currents of the Charles River and seemed to walk on water.

As he strolled about on what became clear was a large sandbar in what should be about 8 feet of water, he considered what could be done with this new landmass in the middle of one of the busiest recreational rivers in the country.

“We have a new island,’’ said Smith, executive director of Community Rowing in Newton. “If you were a real estate developer, it would be a great place to build a house.’’

But Smith said the sprawling stretch of sand is no marvel of nature and no joke. It has become a hazard for the 15,000 or so rowers and boaters who pass through the area on a typical day.

He and others said the massive hump in the waterway, across from the IHOP restaurant in Brighton, is the result of sand, applied to roadways to keep cars from slipping and washed into the river over the decades.

Runoff from a nearby storm drain is also a factor. The sandbar now often rises several inches out of the murky water, depending on the flow allowed through the Watertown Dam.

Boaters have watched the riverbed rise, limiting traffic to a narrow channel, but it became a more urgent concern in recent months after at least two rowing shells slammed into each other, Smith said.

Bob Zimmerman, executive director of the Charles River Watershed Association, compared the problem to what would happen on the Massachusetts Turnpike if traffic were limited to one lane for vehicles traveling in both directions.

“We have a crisis,’’ he said, pointing out that the silt has produced unnatural shallows along the river, most notably the 2 miles from the North Beacon Street Bridge to the Watertown Dam.

“The bottom line is that the storm-water infrastructure we built a century ago doesn’t work,’’ he said. “Something has to be done to fix this.’’

He and Smith have discussed rounding up volunteers to create a bucket brigade to dredge affected portions of the river.

But they realized there could be hazards, given the possibility of arsenic, oil, PCBs, and other pollutants in the muck.

“No one knows what’s in there,’’ Smith said. “We were worried about stirring up the sediment and creating more of a problem.’’

Smith and Zimmerman have begun trying to identify who would be responsible for dredging the river, but they said no local, state, of federal authority has volunteered to do the job, which could cost tens of millions of dollars if the sediment is found to be toxic.

Tim Dugan, a spokesman for the US Army Corps of Engineers in New England, said his agency would probably be responsible for issuing a permit for any dredging. But he said it was not the Corps’ job to dig that far from Boston Harbor, where it is responsible for maintaining sea lanes.

“We have been contacted about this, and that’s all we can say for now,’’ Dugan said.

S.J. Port - a spokeswoman for the state Department of Conservation and Recreation, which maintains land on both sides of the river - said officials are aware of the concerns.

She said the department plans to send engineering and water resource teams to the site next week to inspect the sandbar.

“Following that, we hope to engage the relevant parties to determine the extent of the problem and next steps,’’ she said. “Is it possible that this has been there for years, but that use patterns as well as increased use have highlighted the situation?’’

For now, the many rowers and boaters who cruise through the area daily will have to use caution as they navigate the shoals. A solar-powered buoy, which is lit at night, is the only signal to alert approaching traffic.

Aleks Zosuls, a director of the Charles River Alliance of Boaters, said a number of boats have run aground at the sandbar.

He said he is as worried about the ecology of the river, which has become much cleaner over the past decade, as about its future as a navigable waterway.

“Something has to be done, and done soon,’’ he said.

David Abel can be reached at dabel@globe.com. Follow him on Twitter @davabel.