Yes I will be doing the work myself.

So for the excavation I will just deepen the current drain path(6" deep now)from the head to the creek(taking into account the fall from the head)? I am thinking this will give me surge/splash capacity when I am excavating the main pit as well as allowing for greater drain capacity. I would expect that the main excavation site will fill with water pretty quickly and will make removing material from the site a soupy mess if this is not done.

In your experience how long would it take for previously saturated soil like that to dry up? I know there is likely a good bit of variables that can affect it. Thanks for all of your help by the way.