I'm a new member to TFP and have been getting acquainted with the site and the methodology. Currently working through a variety of issues with pool chemistry but have discovered a non-chemistry issue which I need help with. The area I live in has water restrictions so I haven't water the lawn for some time. Noticed a "green oasis" of grass in my backyard and started to dig and found a leaking +/- 2" PVC pipe which appeared to be previously repaired. It's the pipe on the left in the below pic.
I believe its a secondary return to the spa which is active when the main pool water is being circulated. I want to repair it but have two questions: 1) How do I cut off supply so I don't have water gushing out and 2) Does my assumption that it's a return to the spa make sense.
Below is a picture of my system, I believe it is the L-shaped connection to the return on the left.
Thank you for any assistance or guidance you can provide.