Intake from canal needs replacing - broke in the water

[SidTheKid]

Im new to this and trying to figure it out. I have a new intake ready to go but where it broke is under water. I cut it flush and tried using a compression fitting but it was too much weight due to the rise and distance. The intake goes into my seawall and is cemented around it and the water level is above it or always touching it.. I cant glue because its wet. My only other thought is I need to break out the seawall and cut the pipe 'on land' where its dry. My other thought is how to prevent this from happening again if the valve goes bad? Can i just add some threaded pieces around intake and unscrew it to replace it? Should the pipe that is going into the canal be threaded only and not glued in case something like this happens? We get a lot of boat traffic and they occasionally hit it i think.

 

[Valveman]

That is a lot of coupling on a short piece of pipe. A union would be hard to make the correct length. You maybe be able to use the compression coupling if you chain or cable the pipe as well. Most compression coupling need the pipe chained to keep it from slipping out of the compression coupling anyway. There is also some hot glue that will work underwater. It would also be good to add a Cycle Stop Valve to the pump, as that makes the pump stop while pumping only 1 GPM instead of full pump flow. The check/foot valve is only open the thickness of a piece of paper at 1 GPM when the pump shuts off. This eliminates water hammer and makes check/foot valves last much longer.

 

[wpns]

When you say "seawall" I assume it's into fresh water? Is the water depth directly below where the pipe goes through the wall sufficient? I'd put the foot valve as close to the wall as possible, straight down from where the pipe goes through the wall. I'd also think about using the existing pipe through the wall as a sleeve for a smaller pipe (at least for that distance), which would make future repairs easier. Why does the water level vary, is it tidal or seasonal or (???) Maybe there's a tine when it's dry enough to cut it off close to the wall and glue on a union...