[Tim Fitzgerald]

I am brand new to this idea but am planning to build a probably 15 x 40 swimby pond. I live in louisiana and the lot I where I will be building is sandy content. Is there some way I can dig down to take a soil sample or pay someone to do it. Someone told me it had to have clay bottom. I know there is some clay on my lot because I have hit some digging fence poles. If not I supposse I would have to have some clay dirt trucked in... Also when I was digging at around 4 foot, the hole started to fill up with water. Would this mean that the water table is fairly shallow and there is potential for it to stay filled on its own??

How deep should I have them dig it?? Someone mentioned dig deep enough to prevent algae...?

How high should the banks be and what do I have to do to them to prevent silt runoff into the pond / erosion??

Also someone some where mentioned drilling a well to keep it filled in the summer, I think this is an excellent idea but what should I consider with this.

I know this is a dumb question but for the well, would I have to have elec / pumphouse?? or could it just be capped and free flow when needed.

The last thing I need is a mosquito breeding grounds / cotton mouth attractor...


What do I need for overflow...?

Just have a bunch of questions, anyone with experience pls chime in, thanks to all in advance..

 

[Brad]

Contact a Geo Technal engineer. It will cost you money, but he can answer all your quetions after a test. There is a type of clay that you can buy in balls and line it with, that swells up to several times its size, just cant think of the name right now
Here it usually cost around $2500 for Geo survey

 

[kkimmes]

Most of the times when you dig a pond, you can use the dirt you removed to elevate the areas you want around or near the pond. Many times, people will design a few different spots for the dog to mark from that is a bit elevated and works well for places to have the dog when you throw marks.

You can get a soil sample done by a geotechnical firm to find out the soil beneath the area you want to put the pond. Typically, you order a spilt spoon soil sample. The geotech firm will do tests to determine the size of the particles in your soil. When looking at the diameter, soils go from the largest diameter in rock, to sand, to silt, and finally clay having the smallest diameter. If you have to much rock, sand or silts, water will not stay in the pond and you will have to line the bottom. You can truck in clay from close by or you can buy bags of clay products.

The type of clay that swells a lot is bentonite clay. There is also a product called Pondseal that is small rocks with bentonite clay baked onto the rocks. One inch thick of pond seal will seal a pond the same as 1' of trucked in standard clay. Do a google search and you can find Pondseal. The bad thing about bentonite clay is it takes a long time to settle when disturbed and if it is a wavy day, the water will turn cloudy. You can take an extra step of placing 6" of sand on top of the bentonite clay to keep your pond clearer.

When you grade out the pond, keep the area just above your desired water elevation and just below that elevation very flat with only a slight grade change. Typically it is referred to as grades of 10:1 meaning for every 10 feet horizontal, you lower 1' vertically. If you do this, you will have a pond that is safe for puppies, kids, etc to enter without slipping on a steep cliff at the waters edge. This also eliminates erosion more.

If you want to spend the money on erosion prevention, check out turf reinforcement mats products like Pyramat or Landlok 300. They are a product made by Propex. They work in the areas above the water line. For areas at and below the water line, check out the product flexamat. It is a roll of concrete pyramids connected by a grid. Grass grows in around the pyramids and almost hides the concrete but the product eliminates erosion. You can google these product names to learn more. They are not cheap so depending on how much of a project you want to make this, you can decide on what you want.

After you are 1' deep in the pond, most people grade the pond at 3:1 grades to maximize pond volume.

Some developers I have had as clients insist on having consistent pond water levels and do have small point wells to keep them filled. You will need power to the well for a pump to run. You can have the well several hundred feet from the pond and pipe to the pond though, so keep that in mind.

Sorry for a long post, but I have designed many ponds and something I know a bit about.

Kevin

 

[Tim Fitzgerald]

Thanks Kevin, that was a wealth of information!

 

[jonathon27]

Hi there, I am a geologist and amateur trainer. There are a couple of things you need to know. What are the groundwater levels in your area (at what point below the surface in the local wells is there water)? With a sandy bottom if the groundwater is at a height where you could slope down and then dig your pond you will not need a sandy bottom. Your pond water height would flunctuate with the groundwater, but this will also be true if you have a clay (clay acts as an aquitard slowing water movement through the soil) just at a greater lag time. I would not pay for a geotechnical engineer to come out, what I would do is get the backhoe or whatever equipment out there that you plan to dig the pond with and do a couple test hole to see where the water is. If there is a creek that is evidence of the groundwater level. Any water at surface means the groundwater is at that level recharging the surface water, unless the water is being pumped in. If you plan to pump the water in you will definently want to clay line the bottom of the pond in an attempt to slow down the water drainage. I hope this helps and I can talk with you more on this if you have more questions.

Jonathon

 

[jonathon27]

I noticed you asked about a pump whether being electrically pumped or capped. This would depend on the particular aquifer your on top of. If the aquifer is under pressure then your well would be a free flowing or artesian well and the water would flow out to the "potentiometric" surface or basically the point of recharge or close to it. What is your area? I could look into your area a bit a have a better Idea.

 

[louisianadukdog]

I was told that the NRCS would come out and do a bore sample free of charge. That should tell you if it will hold water and at what depth you should quit digging to hold water.