I'm building a retaining wall for a circular fire pit area in my backyard, which has some slope to it. I've stacked the stones along the front part of the fire pit to make a kind of retaining wall, but I haven't put mortar in-between the stones just yet. The plan is to eventually build up the backside of the fire pit area where we've dug into the hill. We'll set flagstone down eventually as the base of the circle. And just so you have a sense of scale, the diameter of the circle is roughly 14.5 feet and the maximum height of both the "uphill" and "downhill" retaining walls are roughly 1.5 feet (see photo below).
I'm a little unsure what to do about drainage for this thing. Should the circle be slightly angled downhill to allow for runoff? Or do I need to bury some piping behind either retaining wall to allow for drainage? And if I'm going to mortar the stones together (on both the "uphill" retaining wall and the "downhill" retaining wall), should I plan to leave holes in the mortar so water is allowed to seep through the retaining wall?
Thanks so much for the help, I'm a bit out over my skis on this one.