I have just purchased a piece of property that is 10 acres in size. It has a pond on it that is about 1/2 to 3/4 of and acre. The pond was built about 15 years ago. The dam has no drain pipe in it at all, and the water level stays the same(within about 3-4 inches) pretty much all of the time. It has a small creek going into it, but it stays dry unless it rains. I figure it is mostly a drainage pond. The pond is pretty much the low spot of the surrounding 25+ acres. My house sits about 20 feet above the water line. My question is how can I find out for sure if there is a spring or not feeding the pond? My wife and I want to make the pond bigger to about 1 acre, and were wondering if the pond would fill up if we dug it out. Thanks for any information that you can give me.

Hey fishfinder...welcome!
I've been hangin out on this outstanding forum for about 6 months as I execute my pond plan. I came with some book smarts (some dumb stuff, too), and followed the pro's here to know this much...
With 25 Ac of drainage, you are in v good shape. Dependent on your average precip, this number is v likely strong. Based on your description, it sounds like a classic "run-off to a low spot that channels it off"...quick, put up a dam and back 'er up. Unless you live in an arid climate (highly doubtful anywhere in NC hosts cacti), 25 Ac of drainage will serve a 1 ac pond v well. WRT the possibility of a spring, there are a number of questions that arise, but assuming my above analysis is reasonably accurate, you will likely rather one does not exist. You should not need it, unless your plan includes fish stock that requires the constant cooler water. There are threads on the forum that address the pros and cons of springs, but the cons tend to win. What a spring giveth, a spring can taketh away. Maybe one of the resident PB experts can lend help, but I know of no other way to determine if there is a spring other than to see a water level rise during drought or emptying it.
It will be an interesting project. Keep us up on your decisions and progress. I am sure my mentors will kick in and tune up my spiel as required.

Hey Brettski,
Thanks for the info, I can use as much as I can get. I have fished all of my life, but have never taken on a project like this. I think it will be fun, and I will try to get some pics of before, during, and after. The first thing I plan on doing is to build another dam about thirty yards further downstream, and get rid of the old non-protected dam. Thanks again for info.

I just peeked at a precip map in Pub. 590 for your zone...you have PLENTY of juice. So much so that if your estimate of 25 Ac of drainage is close, you will want to seriously consider installation of a some type of mechanical primary spillway. With that kind of in-feed, even a simple pipe spillway may be an intelligent decision in the new dam. Poke around with the search function; alot of this stuff has been discussed. The one obvious note will prevail: think smart now, cuz it's tuff to change later.

fishfinder,

You're getting good advice from Brettski's "spiel" but I was just wondering about the comment "non-protected dam". Does that mean it has no natural spillways? Does the water go over the dam? I suspect maybe you mean it has no pipe through the dam?

Building another dam as you mentioned may be a good approach, especially if there is some kind of damage to the old dam. However, if the old dam is solid and fully intact and protected by functioning natural spillways, which have protected it for the lifetime of the pond, then consideration should be given to just raising and expanding that dam to accomplish your desired water volume.

In addition to that decision, you will have to make another decision on what to do with the "muck" that is in the existing pond. It can not be used for any part of the construction and must be dealt with. Most folks remove it, haul it off somewhere, and spread it. I've renovated two ponds in which I developed/used and alternate approach. This approach will also provide you great structure for your fish. The approach is to create an underwater island out of the muck. With the dozer, pick up clay around the edge and push the muck into as tight a circle as you can forming an island that will eventually be covered with x feet of water. You need the clay ring to keep the muck in place for years and years in the future. You will not read about this technique anywhere and as far as I know I am the only person who has ever done it.

I have used it in two pond rennovations so far and it has worked beautifully. The fish love it, I love it because of all the work and money it saved, and others love not having to see all that muck piled up or spread out somewhere on the property. In both cases, it took me only a matter of a few hours seat time to build these islands...whereas removal would have involved track-hoe, dump trucks, and dozer and possibly even a loader. It saved me a lot of money and time and turned a liability into an asset....but you won't find it in 590 and you probably will not find anyone else who has done this approach...works for me.

Meadowlark,
What I meant when I said non-protected was that the dam does infact have no drain pipe, and the normal flow of water goes over the dam, It has a 8 inch channel grooved into it about 5 inches deep. It does seem to have a secodary spill way though. If there is any extra rain and the pond level rises it runs over the bank into what I consider a low area that actualy stays wet (for the most part) year round. This low area is next to the dam. I figure this area is what has kept this dam intact. Thanks for all the good info. you all are giving me some good considerations to think about. I'm sure there will plenty more questions to come.