Bottom of the pond water - 09/02/14 03:09 PM
My pond has been running full for several weeks with frequent small flows thru the overflow pipe that draws off the top. Downstream of the dam I have 4 small settling pools. They drop out any sediments (mostly non-pond runoffs) and sometimes dry out between rains. When fed normal surface water, the pools take on a green hue and sometimes get a thin green scum when slow/stagnant.
This weekend, pond was full and more rain coming so I opened the drain line. It draws from 8-15' down. One can posit that it's under the thermocline- it's cool. Running the drain, overflow stopped. After a day the settling pools had all black water. It developed an orange foam downstream of the first rocky drop where oxygen might be added. After I closed the drain, the first pool had a shiny film on it that looked almost like oil. There is a distinct unpleasant odor, perhaps a sulfide? I was in the creek and the dark water and odor was observed quite a way downstream from where the branch dumps into the creek.
Is this typical anoxic water? For now I only have forage fish, but seeing all that doesn't breed confidence that large fish would want to be there in the future.
This weekend, pond was full and more rain coming so I opened the drain line. It draws from 8-15' down. One can posit that it's under the thermocline- it's cool. Running the drain, overflow stopped. After a day the settling pools had all black water. It developed an orange foam downstream of the first rocky drop where oxygen might be added. After I closed the drain, the first pool had a shiny film on it that looked almost like oil. There is a distinct unpleasant odor, perhaps a sulfide? I was in the creek and the dark water and odor was observed quite a way downstream from where the branch dumps into the creek.
Is this typical anoxic water? For now I only have forage fish, but seeing all that doesn't breed confidence that large fish would want to be there in the future.