Thursday, October 2, 2008

Anacostia River looking good

FONA (Friends of the National Arboretum), and the American Bonsai Association jointly sponsored a boat trip/lunch today for employees of the Arboretum. We cruised up and downriver with narration by representatives of the Anacostia Watershed Society. I think we were all amazed at how free of debris the river was. It's not free of sediment though. We learned that the channel to Bladensburg approached 40'!!??!! in depth in the 18th century. Land clearing and the inevitable erosion resulted in the deposition of a lot of silt. We were on the river at high tide and in the channel and the depthfinder read 7'! Wow.

As development has overwhelmed the river almost all of the tidal marshes have been lost to draining and filling. These marshes are a critical part of a healthy tidal river. They support a tremendous quantity of plant growth that provides the food energy that supports the entire system. The growing plants also use up dissolved nutrients and absorb and lock up or break down a variety of otherwise unpleasant chemicals that find their way into the river.The Society is working to restore/replace those areas where they can. We passed several newly contoured and planted areas, One is visible in the background of this picture.

Partly into the trip we were treated to the sight of a pair of bald eagles harassing another raptor, possibly a marsh hawk. Very cool. I often see egrets and herons from the bridge over New York Avenue in the evenings. All the bird-life isn't welcome though; the resident geese pose a huge problem with marsh restoration as they voraciously gobble up much of the newly planted material.

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