I capped off the spring by using a plastic food grade 30 gallon barrel. Cut top and bottom off. Cut down the side. Used it for a dam where the spring was coming out. Piked rocks on outside to hold it up. Put stones in it totally the void and kinda filter. Put 2 bulkhead fittings in it connected to a pvc pipe coming out of top. Pvc in stone has holes drilled in it. Plastic over top with dirt covered to hold it down. So shouldn't be any rainwater coming in. Bottom bulkhead fitting is outlet, top is overflow. Pvc out top is vent or if u want to put chlorine or something like that in.