Re: Kenneth Brown..could you open this please
OK, rang the Engineer and these are the reasons for the failure of my Dam.<br />You were correct....it came down to poor construction. <br />The dam wall was constructed and compacted correctly, but it needed to have a layer of topsoil over it, and it was to be planted out with a mat-type grass (kikuya) and not a tuft-type grass. <br />This was not done as there is no topsoil in our area, and the grass I planted died in the drought. <br />The highly expansive clay has dried and cracked allowing what I think he termed 'pensils' which when water came back in to the dam, it allowed water to flow into the dam wall. <br />These extended over the years of the drought, giving me a steady loss of water to a specific level.<br /><br />Solution. Drain the dam, remove all silt and organic matter, allow to dry, then rebuild a watertight layer. <br />Problems: <br />the batter of the slope is steep and needs heavy equipment. <br />Access could be a problem...going over all my concrete drives at 4" thick. <br />Result...no guarantee the dam will not do similar in another drought.<br /><br />Other solution. <br />Drain, dry, smooth out with bobcat the bottom and part way (as far as is safe)up wall. Do rest of wall by hand...not actually a problem, or with mini excavator <br />Then use a membrane liner at $2.94 sq M (black polyethelene UV stabalized, .3mm thick). <br />Over the areas of the liner that are likely to get a lot of sun, cover it with a material not unlike a weed-matt, secured at top in a trench with a seam sewn in bottom to slip galv pipes through to hold the material down the bottom. Idea: to keep sun off liner, to extend liners life.<br />Have recieved sample of the liner today, and at first it appears cheaper to line dam with poly liner that carry out earthworks.<br />The poly liner will be waterproof to, and even if it needs redoing in 10-15yrs who cares.<br />Keep in mind, our drought must be in to its 6th year. I have stopped counting and don't really care to know. It has wiped out one part of my business completely.<br />Was told I am one on many dams like this at the moment.<br />Anyway, thank you for the discussion; i have learnt a lot (as I hope others have) and now have a definite plan to ponder.<br />Cheers<br />Phillip
Quite generally in that part of Taxes man made ponds are referred to as "tanks" the terms are really interchangeable except to the purist. Sorry I can't be of any help Mr Phil.
