darnold,

I hate to see a good overflow go to waste.

What is the size of the riser and drain pipe?

Can you manipulate a pvc pipe enough to glue an elbo? If not, you may have to use threaded steel pipe. When I was much younger I drilled water wells (using a spudder rig). You should be able to find a local driller that can install steel piping and elbos in any hole.

Perhaps try lowering a short riser steel pipe with a pre-installed elbo to the drain pipe level and then thread into the elbo from the the drain pipe area.

With either pvc or steel, I would put a riser on the elbo to at least 18 inches above the break and fill the void with mortar to about 15 inches, leaving a 3 inch lip.

Before pouring the mortar, you may want to have some stuffing on hand to pack around the drain pipe exit if mortar finds its way that far which is not likely.

After pouring the mortar, pack it as best you can, let it dry an hour and then fill the lip with clean water and keep water on the fresh cement for at least a week. Cement cures best under a layer of water. If possible, I would then dry it and fill the three inch lip with a sealer, perhaps hot tar, perhaps some new stuff that may be available.

If this does not work, cement the sucker, fill almost full and keep a four foot deep pit in the stand pipe to keep a supply of minnows on hand.

Here in Oklahoma, I would be very concerned that a 350 ac. water shed going to an 8 ac. lake is going to flood big time after every rain. You need a method to drain down the lake.

The reason a drain down is a good ideal is to keep a reserve available to catch large rains in your area. Fish farmers generally recommend a three to six inch reservoir depending on the amount of rain expected in the immediate future. A drain down is also good for draining down in winter to kill off shallow weed growth ( if you get a freeze that far south).

I like the ideal of installing a syphon system for drain down. It does not have to be really large and I would not let it extend much below six or eight inches below overflow level just in case you forget it is open or something goes wrong with any level control you have on it.

Due to the large water shed, be sure you have a proper emergency overflow area spread evenly over at least a fifty foot grassy area with a gentle slope. You may want to fence the emergency overflow to keep your fish in the lake.

By the way, sorry you got hooked. You may want to get a second job to support this new habit, I mean hobby.

Good luck.

Dennis