Anacostia Watershed Society
Stream Corridor Assessment
Eastern Headwaters
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Anacostia Watershed Society
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The following information was provided by Masaya Maeda of the Anacostia Watershed Society.
AWS has decided to conduct a SCA (Stream Corridor Assessment) survey on the Northwest Branch and has already conducted it on a small portion of the stream. We would like to identify environmental problems such as eroding stream banks, inadequate stream buffers, exposed pipes, altered stream channels, fish migration barriers, pipe outfalls, in-stream construction sites and trash dumping locations along the branch. The major findings will be reported appropriately. The data will be also used to raise people's awareness of stream problems and eventually it will be incorporated into WRAS project by State Government.
Approximate length: 264 ft Approximate height: 5 ft
This erosion site is on a side stream to the NW Branch.
Evidence of "head-cutting"
The main NW Branch has been scoured (down-cutting) due to the increased peak stream flows on rainy days. Then, tributaries to the main branch also start to down-cut to adjust the heights of riverbeds between the main branch and the tributaries. This site (237103-3) shows an active down-cutting point at a tributary to the main NW Branch. It is called "Nickpoint." The nickpoint moves upstream as down-cutting proceeds. The process of moving upstream is called "head-cutting." This tributary would be a gully in the future discharging tons of sediment downstream.
Approximate length: 633 ft Approximate height: 5 ft
 
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A downstream portion from the culvert in the picture was channelized probably in association with the culvert installation. Channelized portion does not get scouring but the earthen bank after the channel gets scouring once the flow is released from the channel. Then the riprap (A facing layer (protective cover) of stones placed to prevent erosion or the sloughing off of a structure or embankment) could be a fish barrier.
Or these rocks might have been placed to be a fish barrier.
Approximate length: 240 ft Approximate height: 4 ft
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Approximate length: 378 ft Approximate height: 6 ft
Approximate length: 298 ft Approximate height: 5 ft
Approximate length: 150 ft Approximate height: 4 ft
One might say, "What is a problem with this pipe outfall?"
See the diagrammatic explanation shown below the picture 240110.
There is the evidence that large volume and strong velocity on rainy days eroded/scoured streambed downstream.
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