Consider a different material, like flexible schedule 40 PVC pipe for the intake. You can find it at suppliers who service the koi pond trade. Swimming pool plumbing also uses it. The dimensions allow it to be glued into sch 40 PVC fittings, and there are also some special ($$$) barbed fittings it can be clamped over. It is capable of enduring winter temperatures (after you drain the above-water portion)
I will look into that...