Chanlon,
Don't let anyone dissuade you from fishing the Donegal. It's not what it once was, but there are fish to be found. Focus your efforts in the stretch between Rt. 23 (Marietta Pike) and Rt. 772 (Anderson Ferry Rd.). Just recently, I saw "breeders" in that stretch and know that there are some nice fish still within its banks. Above and below that stretch is not productive water, although there may be a few fish scattered here and there. It suffers from poaching, lack of habitat, low water volume, farmland runoff, and bank erosion, just to name a few things.
As mentioned, stockings will be returning to the creek this spring. There are still wild browns to be found; although by PFBC numbers, nowhere close to Class A biomass. For someone local, it offers angling opportunities without having to drive far.
Here's a little bit of history (from 1996) on some work that was done as well as stream info: http://www.dep.state.pa.us/dep/deputate/watermgt/wqp/wqstandards/tmdl/DONEGAL.pdf
Also, if you have an interest in joining like-minded individuals, consider joining the DFCA (or at least checking out a low-key meeting). We aren't promising to save the Donegal, but do what we can and drink a beer or two along the way.
http://www.donegalfish.com/
Donegal is a straight up limestone spring creek. That being said, it has numerous forms of aquatic life typical of spring creeks. Turn some vegetation over sometime and you'll find an abundance of scuds and cress bugs.