Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Pond Muck Question

Jeff - the muck covering the hard pond bottom is partly due to what others suggested. Depending on the amount of external inputs the addition the muck can easily be mostly due to nutrients in the pond growing the internal food chain consisting of all sorts of plants from microscopic algae (phytoplankton) to fish that eventually die and sink to the bottom. Think of it in terms of you collecting all the grass clippings from your fertile lawn each year and what the amount of this clipped / mowed grass biomass would be if it was not able to be decomposed and then it would lay as an accumulating dead annual layer on your lawn. This is basically what happened in your pond. The pond each year grows lots of plant material, most of it dies, sinks and is not able to decompose quickly due to lack of oxygen on the bottom. Lack of oxygen in the sediment results in black smelly muck.

Lack on oxygen( anaerobic ) on the bottom sediments causes very slow, I call it "dirty' decomposition that allows the muck to relatively quickly accumulate on the bottom. In a normal pond this muck accumulation can easily increase at 1" or more per year. This equates to your example observed in your pond 18" of muck in 15 years.

The previous video shows that bottom aeration can help keep oxygen on the bottom of the pond where oxygenated sediments (aerobic) will decompose relatively quickly and cleanly and the recycled nutrients will tend to keep the food chain active and growing. With proper active bottom aeration the muck buildup is minimized and the life of the pond is a lot longer before it needs to be rebuilt or dug out.