Pond Boss Forums AERATION Systems questions Time it takes the Pond to stratify again

This thread is an example EXACTLY why the forum exists.
When I begin working with a client, they usually want to focus on the fish in the pond. But, from a pure science standpoint, managing a pond is much more than managing fish. On a daily basis, we deal with all the issues surrounding the behavior of water. In fact, the way water behaves is the most limiting factor of what can live in it.
Cody's explanation of stratification is at the core of what a pond will allow us to do.
His cliff dive into that topic must be in the next Pond Boss.
Great job, Bill Cody! Standing ovation from World Headquarters.
I think we'll use it in "Field Notes."

On a similar note, one of the lakes at Savannah Dhu, in upstate New York, had some amazing stratification behavior. This lake, fifteen minutes south of Lake Ontario in Wayne County, covers 105 acres. It is a long lake, shaped similar to a "Q" with a 60 acre island in the middle. So, it has long, narrow strips of water. There is very little water in or out. It is built above natural ground level and receives runoff from rainfall and snowmelt from surrounding drumlins (long, narrow, tall hills formed by glacial movement 10,000 years ago). This lake is 15 years old
I worked with them for two years to develop a world class fishing program, and saw that lake overflow one time, for about two days.
Much of the lake is 5-7 feet deep and there are two or three holes where the water is deeper. The deepest is 28 feet.
Here's the kicker. Each winter, this lake is the last one in the area to freeze. Consequently, every goose within miles roosts on this lake as it slowly closes.
Nutrient source....
The first summer I monitored the lake, in 2004, I was amazed at how volatile the plankton blooms were. I spent at least five days a month on site, sometimes as much as three weeks. The lake would shift from planktonic algae, a rich deep "pea soup" green to an olive color to a zooplankton bloom within three to five days. Then, it would start over and do it again, over and over.
We started measuring water temperature, oxygen, pH, and specific conductivity top to bottom at several locations.
I wanted this data for several reasons. First, we wanted to be able to provide the best water for fish. Second, we wanted to figure out the best way to aerate, if needed. Third, the owner of the property wanted to see the results of excellent water husbandry, beyond the obvious.
On April 15, water temp at the surface was 10.69C, dissolved oxygen was 11.74 ppm, pH was 8.13, sp cond was 255, secchi reading was 2.8 meters. At 5 meters, temp was 9.78C, DO was 10.28, pH 8.21 and sp cond was 257. At 9 meters, readings were similar.
May 4, surface was 11.14C, DO-10.33, pH 8.22, sp cond 228, secchi was 4.5 meters. At 5 meters, we had 10.61C, DO-8.22, pH of 8.03, sp cond 229. At 6 meters, we had .2C, DO 1.91, pH 7.42, sp cond of 231. At 9 meters we had 6.44C, DO-0.14, pH 7.4, sp cond 236.
May 18 was almost exactly the same as May 4.
June 3 was similar, too, except the temperature was rising faster.
In July, things began to happen much faster. Surface temp was 27.55C, DO was 8.81, pH 8.52, sp cond was 225, secchi at 4.3 meters. The thermocline was now at 3.5 meters where oxygen was 5.34 ppm. Another meter deeper and temps were 16C, and DO was less than 1.5. pH was 7.5, and specific conductivity continued to rise, up to 281.
By late August, the surface temp pushed 33C, DO at the surface was less than 7 ppm, and the thermocline was at 2 meters. Every living creature in the lake was trying to make a living in hot water, literally. Largemouth bass, smallmouth, black crappie, walleye, tiger musky, northern pike, hybrid stripers, yellow perch...all these fish with different habitat requirements were being forced into the top four to six feet of this lake.
At its peak, the thermocline sat at 1.2 meters deep, less than 6 feet.
So, at the beginning of the next year, we installed several Solarbee units into this lake and changed its behavior totally. We had consistent temperatures from top to bottom, good oxygen, and the plankton blooms stabilized and took several weeks to run their course.
Now, the lake continues to go through a "cleansing" phase during the summer, and the goose waste is composted much more quickly. This lake was a prime candidate for both summerkill and winterkill. But, with the bottom aeration, it has continued to thrive. Fish have responded with significant growth rate changes, their health is much improved and the lake seems to have moved to the next level.

Bill, that's great. I have printed it out, read it several times and made notes.

Can you tackle (or re tackle) another one? Several years ago, I posted the question regarding non oxygenated water coming from wells. I believe it was on the old Forum that got wiped out by a virus. You explained it in a way that got down on the stupid level where I live.

As I recall, I asked how well water that I understood as H2O could become H without 2 parts of O.

The question of using wells to fill ponds and the possible need to aerate through baffling or other means comes up pretty often. This would be another one for the archives.

Thanks,

Dave

Outstanding !!!

Guys note this that Bob said and Bill earlier said could happen. A warning about DOs and light.

"In July, things began to happen much faster. Surface temp was 27.55C, DO was 8.81, pH 8.52, sp cond was 225, secchi at 4.3 meters. The thermocline was now at 3.5 meters where oxygen was 5.34 ppm. Another meter deeper and temps were 16C, and DO was less than 1.5."

Note - light (at 4.3m)which is below the thermocline (at 3.5m) but very little O2.

You know, I was just reading this entertaining thread and I realized something.

What we had termed the "clarity line", which would be the water below the depth at which a Secchi Disk can be seen, might not be the "respiration line" at which plants respire. My point being that just because my eyes can't see below this point, doesn't mean that plants can't collect light.

Does that make sense?

Plants ability to collect light for photosynthesis may be better than my eyes ability to collect light.

Just adding a comment.

It makes perfect sense, Bruce. The clarity line (secchi depth) does NOT define the lowest penetration of light into the pond, it's just the farthest into the water Mark I eyeball can discern black vs. white.

Someone with a snorkel & facemask (or a desire to see if FA will grow in vitreous humor) can go underwater and prove this by observing light below the secchi depth. And plants could maybe get enough light for photosynthesis below the depth at which we can see light.

Bruce, you are correct about secchi depth and ability of plants to photosynthesize. The usual depth at which enough light penetrates to allow for photosynthesis is considered by some to be 1.5 times the secchi depth. Textbook definition of the zone for normal aquatic plant photosynthesis is the depth at which 1% of the incidient light can penetrate. This depth is called euphotic zone. Some specialized plants can survive and photosynthesize at even lower light levels than this. It all depends.