A nifty way to handle a pump that may need to be removed, is cut holes and slots in a bucket (big enough for the poop to get through) and then place the bucket where you want the pump, fill in your rocks and stuff around it, then just plop the pump in the bucket, you can even cut a slot in the lid (for the cord) and put the lid back on the bucket to keep duck feet from getting down in there with the pump. You can simply pop the lid off and fish the pump back out if needed.
If you are SURE that you won't be moving the pond, it would actually be a neat idea to put your bucket in and pour the concrete around the bucket with a slight slope going towards the bucket, then the pump will actually be set down below the level of the rest of the pond and all of the water will run over there on it's own.
You can also make a solids filter to get all of the solids out and then put plants in there to make it more natural for her. They will enjoy the dissolved nitrogen in the water from her waste and help keep the water clean as well.