If a pond is underlain almost entirely by heavy clay, is it inevitable that the fine sedimentary particles will cloud up the water without artificial intervention like alum? Or am I worrying too much?
My RES/SMB pond, thread here, is all red and grey clay bottom and it is way too clear. Too much bushy pond weed. My old refurbished pond right next door made of the same clay was turbid for a while. But it had BH pretty thick (which tend to stir up the bottom mucking around in it). Now about 5 years down the road the LMB have pretty much eliminated the BH and the water has cleared up. Still not as clear as the RES/SMB pond, but much less turbid than it was. I also have to add that when it was turbid I did add some ag lime and that seemed to help some. Probably what helped more was adding some 2-4" rock lining the north and south shores keeping the wave action at bay. If you are in a windy location (these ponds are) wave action along a bank will definitely stir up clay turbidity.
Usually not always a new pond with clay bottom has to form a biofilm "skin" layer on the bottom to help seal the loose sedimented colloidal clay on the bottom. First thing to check is do the jar sedimentation test to see if the clay particles will settle if left undisturbed. If the exposed clay dirt shoreline has wave action as noted by Snrub this keeps the colloidal clay in suspension. Snrub provides excellent advice of "Probably what helped more was adding some 2-4" rock lining the north and south shores keeping the wave action at bay. If you are in a windy location (these ponds are) wave action along a bank will definitely stir up clay turbidity." Notice one form of bio-growth in the link below that occurs among the rocks applied by Snrub. This eventually helps "seal" the clay from the overlying water and helps reduce currents from resuspending the surface layer of sedimented colloidal clay. Bank erosion and rock lining
Application of rock or broken concrete to the down wind shoreline should to a lot to reduce constant clay turbidity. However remember, wind always comes from all directions during a period of every 3-4 weeks.
Last edited by Bill Cody; 11/15/1910:57 AM.
aka Pond Doctor & Dr. Perca Read Pond Boss Magazine - America's Journal of Pond Management
An observation here based on my experience lining my entire shore this way.. I would recommend obtaining true "rock" if doing more than 25-30% of shoreline. Unless you need to raise pH some or increase alkalinity, in which case I found by using great amounts of chunk concrete, the high content of Calcium hydroxide (hydrated lime) in this concrete has shot me up from 7.3-7.4 to a constant 8-8.2 pH. Some waters need it, others don't. If you're not doing 50% +, it may not have the effect that mine did doing the entire shore, but as stated above and in snrub's threads, the sedimentation (suspended) has gone away as soon as rock was completed.
I had excellent results from adding gypsum. I purchase it in 50lb bags from my local farm fertilizer store $3 a bag. Its pelletized, I mix half a 5 gallon bucket with water to make a slurry, then toss it into the water. The gypsum acts as a colloidal. I add it in the spring. It clears up the suspended clay in about 2 weeks.
Most of my turbidity comes from my inlet. This is a pic I took after a rain. It tells the tale. My pond is 100% clay.
An observation here based on my experience lining my entire shore this way.. I would recommend obtaining true "rock" if doing more than 25-30% of shoreline. Unless you need to raise pH some or increase alkalinity, in which case I found by using great amounts of chunk concrete, the high content of Calcium hydroxide (hydrated lime) in this concrete has shot me up from 7.3-7.4 to a constant 8-8.2 pH. Some waters need it, others don't. If you're not doing 50% +, it may not have the effect that mine did doing the entire shore, but as stated above and in snrub's threads, the sedimentation (suspended) has gone away as soon as rock was completed.
In our area the soils are all acid. So crushed limestone is what I use to help lime the pond. The limestone does grow algae super well though, good or bad.
