Ok guys, Thanks for all your help. We have determined we will be installing a bottom draw pipe with a standpipe on the backside of the dam.It will be 8inch schedule 40 pvc.A t for the upright and a valve for draining if ever needed. What kind of valve will work the best on sch. 40 pvc and where can I get one. Also I will be using a 24 inch plastic culvert for my emergency overflow pipe.

8" valve? Oh my. There's some money. I found an industrial ball valve but it's about $2k.

http://www.spearsmfg.com/
Specific price list here..
http://63.156.201.111/SMCPDF/VALVES_BV-1.pdf

Tis rated for 150 psi. Be sure you protect it very well. If a vehicle hits that and cracks it, you'll lose a lot of water very fast.

PS: Slice gate valve.. not sure I'd really want that, but it's cheaper.. only $975.
Only rated 10 psi.. I'd be scared to use it with any notable depth pond.
http://www.americangranby.com/Products.a...lNHVjgwMFNMOw==

A knife blade valve from Valterra will work fine, as will any PVC ball valve. The PSI is pretty low...A 40 foot deep pond will only have about 17.31psi.

Bury the valve in the backside of the dam in an access tube to protect it in case of freezing weather or being hit.

Contact the guys at http://ponddampiping.com/ for several choices....

I'd much rather see you have a emergency spillway vs a 2nd pipe for an emergency spillway.

How big is the pond going to be, and how many acres of watershed do you have?

The pond is going to be 2 acres. I think a spillway may be the way to go. Do I just need to pour concrete? I would like to be able to drive over the spillway. What do you think? I am getting very frustrated with the idea of a stand up pipe at all. I plan to bottom aireate the pond so I am thinking of using plastic culverts now or just dig a spillway out and use no pipe at all. Its wearing me down guys.

Flame

I'm new to this game also. I looked at a stand pipe but the cost was more than I wanted to pay with the idea that it can clog up for whatever reason and if it does you're ------ so I went with the spillway approach . I'm puting slag in it to keep erosion down and you can drive over it just fine. With beavers in the area they can plug a pretty good leak. I just put my bucks into the lake not the overflow. It's important by I liked the spillway better than the other options


Pat W

If you need a 8" valve, Rex is right on - I also installed a Valterra 8" knife valve and it has worked reliably for two years. 9' depth very little head pressure has handled it without issue. I recommend the product, cost was around $500 IIRC.

Pat, Help me understand the concept of the spillway. Is the spillway area for keeping your pond at the level you want and then also have a emergency overflow? Or is the spillway the emergency overflow and I would maybe use a culvert for a drain somewhere else to keep the pond at normal pool? Anyone please help explain. Thanks Pond is 2 acres and costing more to dig than I thought. I am going to bottom aireate and have acess to a 6 inch water pump any time I need to draw the pond down for some reason.So I did not want to put a lot of money in the pipe system.

The overflow pipe is what sets the normal full pool level of your pond. That would be your bottom draw standpipe.

The emergency spillway comes into play when the water level rises above the capacity of the overflow pipe but below the top of the dam. It is an emergency way to get rid of a whole bunch more water in the event of a 50 yr rain or such.

Look at the link here:
VT Ponds

Figure 15.1 shows a top view and side view. They call the overflow a riser. You can see the emergency spillway is at a higher level and off to the side of the dam.

Flame, when you sit on your bank, admiring your place, the cost will never enter your mind! Skimping on drains of fish are 2 of the most common, and COSTLY mistakes that can be made!!! How expensive do you think it is when a heavy rain blows out your dam and floods out your downstream neighbors or, God Forbid, injures someone??? A half acre pond, 10 feet deep that blows out a dam will send a wall of water a long way down stream!!

Flame in my area of Texas my pond may never get to pool. With that being said I went with a spillway in stead of the piping system. The spillway system is very common in my area. In fact no lake around me has anything but a spillway and has functioned that way for 30 years. Mine is probably 5-6' below the top of the dam and 20' wide. Your lake builder should know how to install as not to erode the dam if the overflow is in use. I just have rock in it to drive over in a high water situation. I saved about 3k$ this way and don't think there will be an issue. With all the beavers up in our area even a culvert can be risky.

Pat W

Thanks everyone. We will be making a decision soon.