I have a familiarity with designing raised beds and a working knowledge of construction techniques. What I'm lacking though, is knowledge about irrigation and drainage, so I'm seeking out advice from the internet. Here's the situation, my new backyard is slightly sloped towards the house with a raised car parking spot (see attached photo) and I want to design/construct a raised bed around the drainage pipes from the raised spot. What I need to decide is whether or not I should try to incorporate the drainage pipes into the raised bed irrigation or just divert a new drainage pipe(s) through the bed and create small rain garden to absorb excess rainwater? I'm planning on growing vegetables in the bed(s) and rotating them in succession with the seasons and leaving it dormant in the winter only. I've attached some sketches to this post as well to give you all an understanding of the idea I originally conceived. I'd love to hear how some things work vs. better ways to accomplish my goal. Additionally, I'll try to answer any questions about the environment/site, plans for veggie selection and/or design implementation. I hope to start construction in March 2019, so I still have a decent amount of time to figure out all of the details.
Thanks in advance for any feedback!