bz, Here goes:
But why more ground water now than any other time? Is it because of snow melt soaking into the ground? I suppose the ground water level rises somewhat this time of year?
A small amount of the additional water comes from snow melt and rain runoff directly, but most of it comes indirectly from the Rock River that runs adjacent to the pond. The river has no direct connection to the pond. As the river rises from runoff it creates hydrostatic pressure on the ground water table. This pressure forces the ground water to follow the path of least resistance for relief. Since the pond is close by and it is a gateway into the groundwater table the pressure is relieved most easily by the water rising in the pond. You may want to refer to this
thread for more information.
Does that level the DO reading because of mixing?
There appears to be a process that causes groundwater that moves through sand and gravel under pressure to have increased DO levels. This is only conjecture on my part, but I have been monitoring DO concentrations for a long time and every time the water table rises significantly there is a corresponding increase in DO.
(Note to Dave) Someone should do a research paper on the high DO levels that seem to be typical in ponds that are dug down into the ground water table (pit type ponds).
