central iowa, 1.5 acre pond, 12' at the deepest, avg 7.5 when full

i am in a drought, pond is down 2'

i aerate via windmill year round, deep in summer shallow in winter, always have an open hole all winter

my question and fear is that the drought will break and put two foot of unoxygenated rain runoff in my pond right before winter without enough sun to really hold a good algae bloom, the water is clarifying quickly here, pre winter as the water is cooling off

is there any precautions i can take a head of time, or be ready to take in case of a influx of rain water?

I would suspect your water temps are low, maybe in the 50s? Your water oxygen is going to be very high, probably near max even without windmill due to wind action and water temps.
I would not see lack of algae as a problem. If you DID have a good bloom going I would worry more about a sudden temp change from a big rain runoff event causing all the algae to die and a big oxygen crash. But with no algae I can't see a worry related to algae.

If water temp in pond is 50 and a rain event happens the rain water is probably air temp or maybe 55-60? Not sure where in Iowa you are. I would think there would not be a big temp difference even with a big run off.

What I"m not certain on, and would like input from others... Is rain water really un-oxygenated? I would think pumping ground water from depth and putting in your pond would add poorly oxygenated water but I have not heard on this forum that rain that falls through the air and then runs over the ground into the pond is without oxygen. anyone?

I know the fish that died in my pond during a huge run off event during a heavy rain probably died from chemicals that ran off the roads into the pond plus the temperature shift. I can't rule out that the stratified water with warm water on top and cooler on bottom didn't also break up and mix with the big surge of new water. It was only my largest fish and the warm intolerant fish that died.

adam,

Not an expert on this topic, but rainwater should be very well oxygenated.

I believe you may be thinking of a different method where a big fall rain event can lead to a fish kill.

In the fall when your pond water is still relatively warm, but the rain storms are being caused by relatively low temperature cold fronts, a big rain event can cause a pond to "turn over". (As canyoncreek mentioned above.)

Basically, the cold rainwater at the surface of the pond is denser than the warm water underneath. If this cold water rapidly sinks into the deep, low spots of the pond, then it displaces all of that water into the main column of water where the fish live.

In a poorly-aerated pond, that water that comes off the bottom may be so oxygen deficient that it leads to a fish kill. Further, if it stirs up a significant amount of organic matter, that material will start to consume oxygen itself as part of the decomposition process.

If your pond is well aerated down into most of your deeper portions, then I don't think you should have a huge worry about a big rain filling your pond back up to normal pool level.

You are correct that there will definitely be some stress on your fish - rapid temperature change, muddy water, water chemistry change, etc.

It actually might be safer to also have your algal bloom starting to die off for the winter already. If it all died off at once, then that actually consumes oxygen.

My non-expert advice would be to keep running your aeration system.

Do you have any means to partially divert the water coming into your pond? If so, and you see lots of rain in the forecast, then maybe let your pond re-fill over 2-3 rains instead of just one?

Good luck on getting your pond back into optimum condition.

thank you fishinrod and canyon creek for your thoughts, they make perfect sense to me, and after pondering your thoughts i am much less concerned, no rain in the forseeable future, i am amazed they are enduring as well as they are

Healthy fish are pretty darn tough.

Sounds like you are doing a good job of keeping yours healthy. That should allow them to handle a little adversity.

We are in a drought here also. One pond is down almost 4 feet, the other about two feet.

Only 2 feet? I put fish in my pond and where I had the pickup truck parked, if the pond would have been at full pool the whole truck up to the windows would have been submerged in the pond.... My pond is down 6' vertically......... The island? Where the tree branches hang down? That is where the water level should be or even 6" up into the leaves.



The gangplank should be horizontal. Take a look at the green grass on the other side of the end of the pier. That is where the top of the pier should be. The top of the pipe nearest to the camera at the end of the pier should be flush with the decking on the pier. The cinderblock that has the white pipe running through it on the far left of the picture should have roughly 18"-24" over the top of it..... To give you a size reference on the pier, the skirting going around the pier are 2"x12's.

Mine is down ~3'. Dock sections align when the pond is full. We need a toad strangler here in the middle of Misery.

We have been pretty lucky where my pond is at in Randolph county, my pond is only down about 8 to 10" at the most.

Down near 6 foot here in deep east Texas!! we have had ONLY 18 inches of rain ALL YEAR!! Record low!!

Down at least 5 foot in Central OK. I will see if I can get some pictures soon.

For those of you that might be interested. Now that my 2 acre pond is near 6 foot low. My stacks of wooden pallets that I have 5 high are completely high and dry. I must say I am VERY impressed that they still look almost like when I put them in OVER 7 YEARS AGO!!!! So, those of you wondering how long wooden pallets last?? There you have it!!

Did the fish use the pallets much? Any particular species that really liked it?

I know the fhm used it. I regularly saw schools of fry around them. Though I believe a lot of times it was cnbg fry. Algae did grow on them some and you could see tiny fish feeding off that. Also I regularly could catch at least small lmb around them. I know a few times lmb spawned next to them. Also my pond is so low I can see a complete empty colony of cnbg beds out in front of them. So in my opinion it was one of the best things I did for my pond! Now I just need rain!!

Flame,

Thanks for all of the feedback on the pallets! That is some cheap structure that is readily available to almost everyone on the forum.

Maybe with your water down, you could add some brushpiles sized for larger LMB adjacent to your pallets? Who knows what a productive "micro environment" that could create?