Yep, I was just trying to add some "out of the box" additional options for you.

If you cannot divert water to some adjacent areas with gentle, grassy slopes, then I agree that your pond plan is the best solution.

Erosion by water is strongly controlled by the "base level" of that moving water. Your new pond will greatly elevate the local base level of the water running down your draw above the pond. You will be reducing erosion in the watershed above the pond location, merely by constructing the pond.

If you have some other erosion problems in that draw further down the slope, you could even build a second small pond (while you have construction equipment on site).

That pond wouldn't even need a liner. All you have to do is create a "still" pool to reduce erosion. If the water leaks outs over 1-2 weeks, there would still be plenty of critters that would benefit.

Good luck on your project!