Large Pond Hydro Attempt

[Pond Scum]

We started Last early spring working on this old pond .

First we put down a layer of old army sandbags and then put the 8 inch pvc pipe in over the spillway and then started building from there,

After putting in 76 army bags we started using bigger horse feed bags , and eventually huge seed bags

  Ill keep posting details and pics about our project and we need help on what type of hydro turbine we should use with that much drop and all, we have a very good flow too,   We welcome any comments,  thats my buddy Bobby in the pics , me and him did most of the work by ourself

[RUFUS]

You guys make quite a pair of beavers

Great job so far, looks like an excellent

location. what is the drop? looks like 10 or 12 foot

                                          RUFUS

[Titantornado]

Wow, lots of work there.  That one picture really shows the scale of what you're attempting.  I guess all the sand for them bags has come out of that ravine, eh?

There's only one thing that worries me.  I once did something very similar, but failed to take into account what happens to a dam during conditions when more water enters the pond, than can be removed under controlled conditions.  My failure occured when flood water spilled over the top.  Perhaps if I would have poured a concrete outwash apron it may have survived, but, like you, I didn't, and the overspill rapidly eroded away the base of damn, which eventually caused a breach.  From there, it didn't take long before it washed away most of the dam.

Be sure to find a way to control floodwaters from spilling over your dam. Even if it means digging a huge flood channel, it's still better than reconstructing your dam.

[Ungrounded Lightning Rod]

Be sure to find a way to control floodwaters from spilling over your dam. Even if it means digging a huge flood channel, it's still better than reconstructing your dam.

Not to mention everything downstream of it.  Floods are no fun.

[hiker]

nice pond......

 seems to me you would want to tap into all that water pressure and install that pipe

 at the base of your dam....add a valve-to controll your turbine and water level..

 looks like fun....what neck of the woods are you in?? cant be in alaska were still

 in the minus degrees here........

[Nando]

What I would like to know is the water volume and the head available, also what is the water volume feeding the pond.

This way a good definition of the possible available energy that can be harvested from the site in a continuous basis or even part time.

Make sure that the spill way is properly protected against erosion or you may have a breach, also that the spill way is sized for maximum incoming flow plus 100 % additional capacity, specially for those rare occasions that the incoming flow may surge to great levels.

Nando

[Ungrounded Lightning Rod]

seems to me you would want to tap into all that water pressure and install that pipe at the base of your dam....add a valve-to controll your turbine and water level..

Pressure depends on the difference in height between the pond's level and the outlet's level.  The height of the tap regulates what level the flow shuts off at (also what level the pond sits at when the inflow is no more than the penstock can handle.

So you don't need to cut into the lower part of the dam to tap it.  Tap it at the level where you want it to start generating and which you want to be the low point of the pond.

[Ungrounded Lightning Rod]

Note, though, that if the tap is high and the inflow is less than what the turbine wants your pipe won't necessarily be full and the head will be reduced.

But if the tap is low and the inflow is too low, the head will also drop as the pond empties out.

Seems to me the high tap is still preferable.  You can adjust your turbine's inlet jet to match the available flow.

[Pond Scum]

Thanks for the responses,   we just got back from working down there today and i took some new pics,   we have the pencock about 3 feet below the water line now and shes rising as much as we can stand,     We had one bad flood a couple monthes ago and lost a few big sandbags off the top but quickly rebuilt it  better stronger then before (the bionic dam)

   After we open back up the lower pencock again we will take some flow and drop measurments,  

   We currently are letting the tail water spill over the damn and have beefed the spilloway up right much as you can see from the pics.

  Yes we got all the material to fill the bags with out that revine and itts all top quality white clay.  We have moved 1000s of buckets of clay by hand to fill the bags.

  We are in central Virginia,  very near Patrick Henrys Grave.

  My grandfather built this pond with a bulldozer back in the 40s

We have 3 creeks feeding the pond and one comes from a spring on our land thats very bold.

Ill get yall more info soon.   its all coming togather great.

The Beavers moved in this winter and help us out, by packing mud and silt around the base of our damn and have greatly helped fill a low hole in the damn.

[Ungrounded Lightning Rod]

The Beavers moved in this winter and help us out, by packing mud and silt around the base of our damn and have greatly helped fill a low hole in the damn.

My wife says:  "Oh, yes.  That's what beavers do."

Beavers have a simple algorithm:

 - Find the sound of running water.

 - Weave sticks on top of it and patch the holes between them with mud.

You can get them to build a dam in the middle of a meadow - or in your backyard near the woodpile - by burying a loudspeaker and playing the sound of water running over rocks through it.

But of course in your case you want them doing exactly what they are already doing:  Reenfocing the dam and plugging any leaks.

Convenient, aren't they?  A totally natural 24/7 construction and repair crew.

[Titantornado]

Looks like you could still get another two or three feet up yet, eh? I can't tell from the pictures, but are you just bagging mostly vertical on the pond side of the dam?  I'd want a fairly shallow slope into the pond, like this:


else I'd be worried about a toppling hazard, especially since the dam isn't curved into the pond.

Also, that water spilling over still worries me a lot. (I reserve the right to a "I told ya so" for later)  That ravine was formed by that very action, and slowly moving upstream, and now your dam is the next thing in line.

Getting the water to the bottom of the ravine without it running over (eroding) the edge would be top priority in my playbook.