I went with the Access Vanish roll up. Cheap, easy to clamp on, and doesn't leak... much. A drip or two when I blast it with a high pressure nozzle and it gets under the flap.
https://www.accesscover.com/vanish/
I'll likely get a couple of years out of it, but next up will be a tri fold.
https://www.accesscover.com/vanish/
I'll likely get a couple of years out of it, but next up will be a tri fold.