I'm doing a short wall, no more than 18 inches high at it's highest point. I do plan on running drainage behind the wall for good measure. My problem is that I have a downspout to contend with. I want to do a pop-up under the base for the downspout. My question is, can I tie the drainage for the wall into the downspout drainage or should I keep the two separate? I'm trying to minimize having multiple pop-ups or multiple holes in the wall for the pipes to drain. Thanks.