Plant bermuda next spring. Your pond is small enough you can weedeat it in less than an hour.
If you choose not to plant anything, Mother Nature will do it for you...and you may not like what shows up.
45 degrees is tough to mow with a riding mower, but landscaping companies use push mowers for that small an area, and on steeper slopes they tie a rope on the lawnmower handle and pull it up and down with the rope, while standing atop the levee. Seems weird to me.
The best idea, overall, is to make the slope 3 or 4 to one, making it mowable, and to fill the pond within two feet of the top of the dam.
On the backside slope, if you want to mow, make it 4 to 1.
