I'm now trying figure out what is best plan of action for erosion control. Wondering if I should try putting a type of seed down now if not too late.
Silt fencing is cheap and easy to install. That would give you some immediate help.
Get vegetative cover going ASAP also. Always good to meet your local NRCS agent as noted above. The agent can give advice on the best grass seed blend for your area and soil (if you are going with grass). They may even have seed for sale or a cost share program for erosion control.
Yes, it is a little late to plant because some of your grass will not be well-established when you get hot, dry, 100+ Oklahoma days this summer. So you will almost certainly need to overseed later. However, all of that eroded material is stealing depth from your pond! Any less than perfect vegetation you get going now is still an excellent "pond investment". You should be able to get some rye grass to sprout up quickly during May and help very soon.
Finally, pumping from the creek would be an excellent idea from an "engineering only" perspective. Better for you to find out sooner rather than later whether your pond holds water or needs more work.
The legal perspective is a little more dicey. There are both federal laws and state laws regarding pulling water from a creek. In Kansas, I could do it as a result of some exemptions that are granted within the legal framework. Don't know about OK. Might be another good question to ask your NRCS agent. You might also call the water regulatory body for the state and see if you get a knowledgeable person on the phone.
