Pond Boss
Posted By: B Relan Help! Input Desparately Needed! - 08/30/07 11:32 PM
I have a site 15-20 acres in beautiful rolling wooded hills that I am trying to dam up. I have civil and soil engineers and NRCS help. I have done an intensive soil survey. Result: Everyone agrees the dam will hold. The NRCS says that due to the sandy nature of some of the sides of the pond that the water will just escape there. Does anyone have similar experiences that they have worked out? The dam itself would be 25ft high with a 20ft water depth which just increases any expense dramatically. The size of the lake itself would be 15-20 acres. There is a large knoll at the top of the site which would be excavated to build the dam, and get the lake to this size. This material is solid clay, perfect for the dam. In areas around the site theres good silty clay with places of clayey sandy gravel. The land itself is in Louisiana. There is an 8, 30, and 190 acre lake between 1 and 5 miles away. I am looking for a minimum of 15 acres because of what I've read about needing this surface area to get a healthy population of bass and crappie(sac a lait). I have put alot of time and $ into this and I feel like I am no closer. ALL input would be GREATLY APPRECIATED! THANKS.
Posted By: GW Re: Help! Input Desparately Needed! - 08/31/07 01:29 AM
Hi there B Relan.

Your situation sounds very similar to the pond my girlfriend is building now. I'll get back to you when I have a little more time.

Welcome to the forum!
Posted By: B Relan Re: Help! Input Desparately Needed! - 08/31/07 04:29 AM
Thanks, I'll look forward to your response. Thanks everyone for such a great welcome to this forum. I am pulling my hair out trying to decide what to do. This is a project I have been looking forward to for years and I fear it's in jeopardy. Thanks again!
Posted By: Rick Mathis Re: Help! Input Desparately Needed! - 09/03/07 05:33 AM
Hello B Relan.

As you probably know, there are many factors to consider in building a pond or small lake. I don't know what type of help you have received from NRCS or from a civil engineer, but hopefully they explained most of the basics to you. It sounds as if you may have a good site, soil-wise. What about drainage area, spillway feasibility, impact on adjoining property, utility easement considerations, and other critical factors which must be evaluated? Has someone looked at your site and discussed these specific factors with you?
Posted By: Rick Mathis Re: Help! Input Desparately Needed! - 09/03/07 08:37 AM
B Relan, I may have jumped the gun with my first reply. I now have looked at all of your previous posts and I see you have had an engineer out to the site. Let me just say that engineers (as well as NRCS technicians) are not generally comfortable with making guarantees about whether a particular site will hold water. This is one of those CYA situations for them.

I have looked at and evaluated hundreds of pond and lake sites in the past twenty-seven years, and I can tell you that it would be very unlikely that a site with good clay in the bottom and which extends high up in the sides, such as in the knoll you describe, is going to lose it's water through what sounds like pockets of sandy material on the sides. If the parent soil material at your site is clay, as it seems from your description, then I would say the sandy material up on the sides is of no particular concern except where it may underlay the embankment. That material will be taken care of through the standard site preparation and/or coring as appropriate for construction of the embankment.

If I were you, I would be very encouraged by the existence of the several other good lakes in close proximity to your site, since that is always one of the better indicators for a feasible pond or lake site. I seriously doubt that any of those other lakes in the vicinity were clay-lined as a seperate construction procedure since that is such a cost-prohibitive factor for a lake of any appreciable size.

My suggestion would be to get someone who knows what they are doing in terms of designing and staking out the embankment, spillway, and water impoundment areas. Then find a reputable local dirt contractor with pond or lake building experience to do the work, according to prepared drawings and construction specifications.

Good Luck
Posted By: Dave Davidson1 Re: Help! Input Desparately Needed! - 09/03/07 10:29 AM
A small pocket of sand is one thing. A seam can be a whole different animal. Before I committed the bucks, I would want to know just how far the sand went. Also, just how much sand/gravel is mixed with the clayey stuff? Neither sand nor gravel can be packed. Does the Engineer agree or disagree with the NRCS guys?
Posted By: B Relan Re: Help! Input Desparately Needed! - 09/04/07 12:49 AM
Thanks guys! I believe the engineer disagreees with the NRCS. He is as optimistic as I am, but it comes down to the amount of sand and gravel in the side. About 3 months ago I had the engineers assistant go in and dig a couple of holes with the backhoe. I havn't really kept an eye on them this summer, but I checked them yesterday and today and to my surprise one was holding around 18" and another 8". My son and I played with the material that had come out of the holes, and the material in one was like modeling clay. In another, the material was a grittier, but was still able to shape. As Rick questioned, there are no easements and no real worry about adjoining property. The soil engineer who did the analysis was really surprised by the NRCS. He really thinks the site can work. His analysis included dam design as far as slopes, clay keyway, 300' clay blanket, etc. The civil engineer has designed the spillway. Plus, I've had the trees that need to come out marked by a forestry manager. I don't know if I should do more backhoe holes to get a better visual, have a driller come in???????? It just seems so close. Noone will probably give a guarantee, but I have to have something more in my heart before dumping out $$$$$$$$.
Posted By: Rick Mathis Re: Help! Input Desparately Needed! - 09/10/07 06:45 AM
Hi B Relan,

I would get a few more test holes. They are cheap compared to the total cost you are thinking about investing in the site. Try to get them strategically located within the area to be innundated by water so you can get an overall indication of suitability, and hopefully locate any problem areas if they do exist. I would also investigate what appears to be the worst-looking sand or gravel area with the backhoe just to see exactly what it amounts to and whether it is a closed pocket. I believe your optimism is well founded. Locate your site on a soil survey and read up on the soil descriptions for all of the soils involved, paying particular attention to the subsoil classifications. Good luck and keep us posted.
Posted By: B Relan Re: Help! Input Desparately Needed! - 09/14/07 04:08 PM
Thanks everyone. Lately I've contacted Seepage Control, Inc. about lining the lake area with ESS-13. They have agreed it will work in my lake and would guarantee it. That's very promising, but the process is not cheap by any means, especially in a 15-20 acre pond. Has anyone had an experience where the lake bottom, dam, and one side was impervious to water, but then lost water to a weak side??? I guess I am going to try and move forward with contacting a contractor and get ready to build the dam. If it comes down to it, I will have to get Seepage Control involved. Anyone have any experience with them? I guess I am happy that I can do the project, although at a price. I think I might do some more holes throughout the area and check the results. I have looked at topos of my area and there are plenty of lakes and ponds. Why me???
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