Personally, I think I would PVC cement the connections on the intake side and if you ever need to remove it, just saw the pipe off leaving enough to reconnect with a rubber joint.
You could use two 22.5 degree elbows to form a "jiffy joint" and then you wouldn't have to dig as deep into your dam to bury the pipe.
It may also be wise to pour a decent sized chunk of concrete below where the outlet comes out of the ground then anchor the discharge to it to reduce the risk of the joints breaking over time.
