The pond is now pretty much drained. Due to the size of the dam we decided to pump it out with a large PTO driven pump � just a tad left to finish with a 3" pump. As you may have guessed, no obvious leak holes jumped out. Several test holes were dug in the area around the pond to look at the dirt. Basically it is just OK, not great and not terrible. The local pond guru calls it adequate but the equipment guy is skeptical about its quality for a good seal.

I have some recommendations on methods to seal the pond from the local pond guru. One is to use the local dirt and line the bottom of the pond with 4 6� lifts each packed with a sheepsfoot. The remaining sides should be disked up and packed with the sheepsfoot.

An additional recommendation would be to add soda ash at 15 lbs/100 sq ft to each lift on the bottom of the pond. This would end up to 5-6 tons of soda ash mixed in. I was not informed of pricing or a source of soda ash but was told it would leave the water very cloudy for several years.

A final option to seal the pond was to use fly ash at 2 tons per acre. There is a coal burning power plant close by that could be a source for this but I have no idea about the cost or whether this is a good idea. I assume there may be some toxins in the fly ash.

So now I am asking for additional comments on my situation. One thing I have to keep in mind when making my decision is cost. I know there are no guarantees, but I�d like to give myself the best chance of getting a good seal for less than $5K. One thought I had was to use the soda ash or bentonite in the area we suspect it to be leaking. This would be the area around the pond where it usually stops leaking (about where the water line usually is). I would still do some work on the other areas, but focus the addition of soil amendments in this area.

Any comments on price, source or experience using soda ash or fly ash?
Would the addition of bentonite be a better option?
What would you do with my budget and the options provided?