Mary Battiata ["Silent Streams," Magazine, Nov. 27] correctly identified the surge runoff from pavement after rains as a major threat to local streams. This surge erodes the banks and carries the resulting silt downstream.

The C&O Canal, at several points above Swains Lock, is almost filled in by silt that has been carried down hillside streams by such surges. This recent damage to the historic canal is obviously due to the failure of some developers along River Road to properly install catchment ponds to contain the runoff from the pavements that they have constructed.

There has been much ado about some tree cutting and replanting along the canal, none of which has harmed the canal. The National Park Service and Montgomery County should act immediately to correct the source of real damage and require proper catchment ponds.

L.C. KRAVITZ

Rockville

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I live in the Spout Run watershed, play next door in Donaldson Run watershed and work for watershed restoration across the country at the Environmental Protection Agency. "Silent Streams" was a timely call for grass-roots action to monitor and protect against storm water pollution.

This week the EPA is issuing national guidance to help control urban and suburban runoff in treasured but threatened watersheds. Low-impact development can slow the flow of pollution and keep the fauna flourishing, the streams healthy and the drinking water pure. In this area, local, upstream efforts also will help speed the cleanup and repair of the Chesapeake Bay. More information is available at www.epa.gov/owow.

BENJAMIN H. GRUMBLES

Assistant Administrator

Office of Water

Environmental Protection Agency

Washington