Pond Boss Forums INTRO Questions & Observations should you always compact the soil?

I found a contractor, to do my 1/3 acre pond in North Texas. His quote was $5700.That will include extensive mounding work. When i ask him about compacting the soil, he said that most of the ponds in this area don't need it, and that we should be able to see if it needs it after the pond is built. There does seem to be heavy clay beneath the topsoil. I have a small dugout area about 4' deep.It does not seep at all when it fills up with rain, so maybe he is right about this. What would be you'alls advice on this matter? Would you compact it even if it looks like it did not need it?And how much should it cost?

I really appreciate the help i'm getting from this board, as i'm starting to get my pond off the ground.

regards,
rory howard

Not compacting a pond basin, even if the soil consists of good clay, is gambling. What if there is even a small area (12 in sq) or zone of lose soil anywhere in the basin? Leakage will occur in that spot. You want to do as much as possible prevent any leakage. This way the only water you will be loosing will be primarily due to evaporation and your pond will remain as full as possible considering rainfall and runoff it receives. It is betrer to have it too full and overflowing than leaking.

The extra cost of compacting is good money spent as leakage insurance. The only way I would not compact the basin is if the contractor guarantees in WRITING no leakage and he will come back and fix it free. If your pond does not leak you should not loose any more water per day than the pan evaporation rates for your area. In the summer it is hard to keep a pond full just due to evaporation losses alone. You don't want to have leakage adding to those losses. Fixing a leaky pond is much more expensive than doing the job properly in first time.

Compacting costs are monies well spent in the long run.

Always compact clay in a new dam. Always. It always needs it. My favorite comparison came from a liner salesman. He asked, "What device holds water better than anything on the planet?" Answer? A bathtub...except for that little-bitty hole at one end. All you need is one little bitty fracture or "hole" in the clay and you have a bathtub.

I can't add to BC's & Bob's comments on the importatnance of compacting.
However I will offer advise relative to his statement. I learned over the years to key on comments & actions of new aquaintances in predicting future dealings with them. His statement above sends up red flags.
My advise: find another contractor.

OK..I think i get it..So how much should compaction add to the cost of the job? I'm really not familiar with how that part of the job is done.
thanks again for all the input,
rory howard

It won't add any cost. It should be part of the process of "processing" soils and moving them where they go. If the soils need to be moved, compacting them as moved is not hard. It should be automatic.

Just to be clear, this will be an excavated pond, with no dam. So any compaction will be to the sides and bottom only.

As he pushes dirt out of the pit and shapes the pond, the final product will have a clay liner. That clay liner should be compacted, all the way around the pond, top to bottom. It should be part of the process of building and molding the pond. I know the area where you are excavating, and there is good clay. But, there are also fractures of sand and gravel in different places. Be aware of those. Anywhere clay is placed, it should be compacted, just as a matter of the business of building the pond. I know you have had a hard time finding a contractor, so I would simply communicate to him what you expect, and then hold him to it. Even though a bulldozer isn't the best tool for compaction, it will be adequate for the heavy clay soils you have near Pilot Point.

Thanks Bob,
Your right, finding a contractor to do this job has been ridiculouly hard. I think that basically many simply don't want the job, because of it's small size.I got this contractor from the NRCS list, and he is has built many ponds in this area, so i would really like to use him. We will be discussing this compaction issue again,before he begins the job.

My experience with earth movers is that we depend on them to know what we want them to do. Rather, they should depend on us to make sure we communicate what we want. The more we depend on them to be our knowledge base, the greater the margin for missing our goals. I'm not necessarily telling you to tell them HOW to do the job as much as to precisely and specifically describe WHAT you want done and what you expect. Compaction is one of those things I have learned to expect.

I must be missing something here. If it's a dug out pond, then the un-desterbed soil is already compacted. Running heavy equipment over it will just be a waste of fuel with no added benifit.

If he's digging out the bottom and putting clay in to fill an area that wasn't clay,then yes, he needs to compact that soil, as does any soil that is used for structual purposes.

Is the dirt that's being dug out of the pond being used for anything on the pond? If it's being hauled off, or spread out all over the place, than there's no need to compact that material.

I guess I just don't know how you'd compact soil that's already compacted from millions of years of sitting there?

Eddie

Very carefully

Eddie,
The soil being removed is going to be used for cosmetic mounding around the pond. But will have nothing to do with the pond itself. So, i guess your question would be, " can you improve the degree of compaction on heavy clay-content soil that has already been naturally compacted with all the overburden,and would it be significant to a potential leak issue?"I would think so, but to what degree would best be answered by someone else.

I believe you're looking for 95% compaction. Undesturbed soil is not compacted to that extent & will not be uniform in it's compaction throug out the pond basin. As Bob said it's easy to do while digging the pond. Take it from me it can be a heart breaker when not done properly. Even in good clay look at it as an insurance policy.

just a final wrap-up on this topic. The pond has been full for about a month now. Using only the bulldozer for compaction, it holds water like a bathtub