I walked around the Amalyn housing development today and notice that they are putting up more silt fences to control erosion. These fences usually go up shortly before they start work in an area, so there is likely going to be construction in this part of the former WMAL transmitter site. An area of underbrush has been cleared at the end of Derbyshire Lane, and a silt fence has been installed the entire frontage with Derbyshire. Fortunately, the fence is only two feet tall and you can step over it.
The fence continues to the dip in the field. There is still some fencing and equipment beyond it so it is possible they will continue the fence on the other side of the muddy area.
If you every walk around the field, you will probably recognize this part, it stays wet for longer than anywhere else and is a proto-stream. The silt fence stops just before it.