Pond Boss Forums INTRO Questions & Observations Question from a Rookie

Will Rain add oxygen to a pond?

You're darn tootin' it does. Not only are the raindrops probably saturated with O2 themselves, the mechanical action of their impacting the pond adds even more.

But it's depth of effectiveness is limited is it not?

Yep. The heavier the rain, the deeper the O2 goes. High wind with heavy rain would add more O2 and mix it deeper.

I would think that rainwater is often colder than the pond water which would result in mixing and carry the O2 down. Maybe.

I agree GW. You have to also keep in mind that a heavy cold rain with cloudy skies (especially if coupled with run-off)in summer can greatly reduce the plankton bloom and result in an O2 crash.

I don't understand the factors involved in that...

The heavy cold rain can dump enough cold, dense water on top of the pond to cause a mid-Summer turnover (or just thorough mixing). If the lower water layers of the pond are devoid of oxygen, the top or entirety of the pond can suddenly have low oxygen. Add overcast, windless days which hamper photosynthesis and don't add O2 through wave action, and not much O2 is added to the pond after the rain event.

Destratification during the Summer via aeration is probably the best defense against this possibility, by keeping the whole volume of the pond better oxygenated.

I'm not sure I completely understand that either. But after several extremely dry years towards the middle and end of July our area received unusually heavy rains for the season with overflows in my pond and I lost my bloom. For a few days the water turned a redish brown but it wasnt muddy and almost overnight it turned back to its normal unfertilized tanic/black very clear (visiblilty 3' or a little more). I acutually fertilized again around the first of August this year to get a bloom back.

Last year during the drought when the pond dropped so low and the water area was greatly reduced I was afraid to feed with so many fish concentrated in just a little over half the normal surface area of the pond. The water color stayed a nice green and I never saw dead fish.

This year after the heavy July rains I havent received much rain at all. As the pool level dropped I kept my bloom and visibility of about 18"'s but green color had a darker not as nice to look at color. Yesterday we received only about a half of inch of rain but the look of the water was a much nicer cleaner color of green and the visiblility increased to around 2'. But 1/2 inch of new water with no run off wasnt enough new water to dilute the pond. And although the rain water may have been cooler the actual morning tempature that resulted from the front that moved through was warmer than the previous several mornings by probably around 10 degrees F.

Anyone have any ideas on how all this is affecting the DO level?

And since equipment that can measure DO is so expensive is there a cheap way for us poor folk to estimate DO levels in our ponds since weather events can have such a rapid and dramtic effect on DO levels?

Great info...thanks guys!!!!

We need more discussions on water quality.

Theo is the Commissioner of the Better Water Quality League. He only sanctions one water - good aerated water - no skunky water allowed. The Comish is wise -- amen !!

The 2 biggest sources of O2 for a pond are plant/plankton respiration and surface-air interface mixing. If the warm water plankton community's respiration is greatly reduced by cold water and cloudy skies and you get the mixing of low O2 water (cold water sinks until it reaches its greatest density at 39F) the Comish described you may end up with the deadly 15 mins. of reduced DO noted by Bruce.

A heavy summer hail storm can be deadly to a small pond. I see the problem as the rate of change of change.