CONOWINGO, Md. (AP) — A federal scientist says the Conowingo Dam in northeastern Maryland is not trapping as much sediment and nutrient pollution as it has in years past — possibly endangering the Chesapeake Bay.

The dam on the Susquehanna River prevents millions of tons of sediment and nutrient pollution from reaching the bay.

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The Susquehanna is the bay’s largest tributary, and for years, two-thirds of the mud washed downstream has been settling behind the dam.

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But Robert Hirsch, a research hydrologist with the U.S. Geological Survey in Reston, Va., tells The Baltimore Sun that things have changed. Hirsch has been reassessing the dam’s trapping ability in the wake of last summer’s Tropical Storm Lee.

Hirsch says he can’t provide details yet but will be briefing policy makers in a matter of weeks.

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