POND: Determining maximum size

[livemusic]

I have my eye on some land on a creek. Does anyone know how one could determine the maximum potential size of a pond you could build? I have zero experience building a pond. I could get a topo map and outline a certain elevation contour, but I have no idea how big a dam would be required, and the potential cost. Is there any expert one could consult to have them calculate such a thing? I am talking about a large pond (probably dozens of acres) and I know it would be expensive because a lot of dirt would have to be moved for the dam, but I'd like to know the potential size because the location is prime. I think it would be called an 'embankment' pond, a drainage pond with a dam that fills from its watershed.

EDIT: I am 90% sure that the soil type in the location contains a lot of clay. Secondly, people build ponds around here all the time. It is definitely allowed. I would, of course, check with authorities. Lastly, I don't own the land (yet), so, I was hoping there is a way to estimate the potential size from topo maps before even approaching the landowner. Then again, the landowner may not sell. But it is a great spot for a large pond based on maps.

[H.O.D.]

most states have many restricktions on pond building..cant just dig a hole where you want anymore. It would need to be permited and enginerd I think..keeps you out of big trouble. Good luck.

[fishpharmer]

You should be able to get the info needed from your local NRCS office.

https://www.nrcs.usda.gov/wps/portal/nrcs/main/la/contact/local/

If they cannot directly help you they should know who can. 

Or try here
http://www.wlf.louisiana.gov/fishing/fisheries-contacts

http://www.lsuagcenter.com/portals/our_offices/regions/northwest

[fishpharmer]

There are general pond construction guidelines here

http://mdwfp.com/media/24904/mississippi_pond_mgmt_revised_feb_2016.pdf

[GAB]

The first thing you need to know is the soil type in the area.  If it is sandy or gravely it may not hold water.  If it is clay then you are golden.  If the permitting process is too much of a pain you could always drop off a bunch or group of beavers in the area you want it in and you may also have to supply them with the proper building material.  Please note that they may not put it in the same spot that you desire but they might build it and they do not get permits.
Just a thought.
Gerald

[IndyIan]

In Ontario, any flowing surface water is to be left alone.  It might be possible to get permissions to alter flow but I don't know anyone who's done it or ever seen a pond built using a surface stream, and one farmer I met who winged it, got a large fine and had to fill in the pond and restore the stream bed.
Ground water is fair game though, our pond is built without permits at all as it was just a damp spot where water was always just below the surface. 
Anyways, find out your local rules and then talk to excavators who specialize in ponds.  Anyone can dig a hole, but to create a pond that's an asset is tricky.  The fellow we chose took us to a half dozen he's done before and all but one were great. 

[pineywoods]

LM, daming a creek to make a pond generally not a good idea. Makes a nice pond initially, but silt and debris washed from upstream will gradually fill in the pond, then you have a marsh..Soil type is critical, bore some sample holes (post hole drill on a tractor). I built one by building a dam across a draw. Filled up nicely from the first rain, week later it was empty..

[livemusic]

LM, daming a creek to make a pond generally not a good idea. Makes a nice pond initially, but silt and debris washed from upstream will gradually fill in the pond, then you have a marsh..Soil type is critical, bore some sample holes (post hole drill on a tractor). I built one by building a dam across a draw. Filled up nicely from the first rain, week later it was empty..

I have read this very thing, that it might not be a good idea because of silt brought in from heavy rains. And we certainly have our share of gully washer rains. Yet, around here, ponds like this are built a lot and they seem to make great ponds. I fish several of them and they are decades old. It might happen but I have never seen such a pond silt in. All of these ponds are in hill land, gently rolling hills.

On land that I bought recently, such a pond was built before my birth, and I'm 63, and it's still in fine shape. So, I don't understand why people say this.

[Gearbox]

Who is down stream ? A farmer with cows that depends on the water . Some one with lots of money and a babeling brook through there back yard that no longer has water in it .

[livemusic]

Who is down stream ? A farmer with cows that depends on the water . Some one with lots of money and a babeling brook through there back yard that no longer has water in it .

Travel some. Come to Louisiana. There is no shortage of water. Farmer Brown is wishing he could get rid of it.

[DFILER2]

You would only stop the water for a while, once the pond filled the amount of water coming out would be the same as the water going in.

[nativewolf]

Lots of things to add here.  First, today the Corps of Army Engineers and other soil/water quality regulators frown on any attempt to dam a stream.  Reasons for this vary from safety to water quality to species/environmental issues.  Safety is the biggest one. 

Secondly there are well know metrics for how big a dam/pond can be and the local soil and water conservation office is where you want to start because they are experts at pond construction.  If you give them a topo of your land they can find the best place for you. 

Start with a topo map and look at the size of the pond, place a dam across a topographically good point.  Raise a dam height to X, determine how many acres of a pond that will be.  Then look at the surrounding area, the "watershed" should not be larger than 10-20 x the acreage of the pond.  So, for a pond of 2 acres  a watershed of 20-40 acres is the max you'd want.  The size of the watershed is really dependent on the local environment and your so in southeastern NC with sandy soils and little topography you might have a multiple of 20, in the mountains of NC it might be a multiple of 5.  A watershed could easily overwhelm a dam and cause the dam to fail and flood causing damage downstream.  The reason you don't want to dam a stream is that if you are damming a running stream you (almost surely) have a huge watershed and you need a really large pond and a really large pond dam failure is bad.

A dam is something that has to be able to survive our short lifespans and not fail as long as it is properly maintained.  Large ponds are dangerous and there is going to be a limit above which they can endanger life. 

So, in summary...start with your local soil and water office.  Good luck!