While waiting to start construction on my new pond I'm stockpiling materials to use for structure when the time comes. So far I have things like pallets, lumber, brush, old bricks, cinder blocks, stone...

This got me wondering: Are there any materials that I should stay away from that could adversely affect the water quality or poison the fish? Specifically, is it ok to use treated lumber to build underwater structure? How about painted wooden pallets?

I won't use treated lumber in a pond itself, although I certainly have enough of it (fenceposts, mostly) in the watersheds.

There a lot of folks who use old metal items in their ponds for structure, but I personally would shy away from them only because they rust and I just don't like the idea of a sharp, rusted T-post sticking up somewhere in my pond...du

Dave Davison had a bad experience with green oak tree tannin if I recall correctly.

Bad experience is an understatement.

Ack, when I first built the pond, I had a big pile of freshly knocked down oak trees pushed down into the bowl. It sounded like a good idea. When it rained about 3 or 4 days later, the tannins came out of the green oaks and turned the water black. I bought some fish and they all died within a couple of hours. It was lethal. I tried just about everything, mostly chlorine, to clear it but fish kept dieing. Into the one acre pond, I added enough chlorine to kill all of the nasties in 50 Olympic sized swimming pools. Finally, I pumped it out and let the Texas summer dry out everything.

Wow! I'm glad you guys mentioned the green oak trees. We have a tree nursery nearby and part of my structure plan was to hit them up for dead 5-20 foot trees. I wonder how long trees have to sit out before they're safe to put in a pond in large numbers?

Personally, I think a year would be safe.

My high falutin scientific test: Get a wheel barrow or maybe even a bucket of the pond water. Cut a piece of the oak tree in question; the trunk area, not a limb. Put it into the water and see if it changes the water. After about 2 weeks, toss in a couple of 2 to 3 inch bluegills and see if they die.

So I have a cotton wood tree I was thinking of cutting down and letting fall into my pond? Is that ok? Is this just a Oak thing?

Thanks,

Cottonwood is fine to add. There are differences in oaks and people's opinions on how much of a problem tannins are. DD1 had serious problems and I have added lots of oaks and never had a problem.

Yep, lots of difference in adding some oaks to an existing BOW and doing it at impounding time. Lusk once posted about regional differences regarding soils. In some areas it might not be a problem. I just don't know and can't remember which areas that is. That's why I recommend the bucket test.

I agree and suggest if your alkalinity is less than 25 that you add ag lime before you add much oak. It offsets the tannic acid.

Thanks guys I apprecaite the info!!! That Cotton Wood is coming down! It's about 5 feet from shore and it's about 35 feet tall so it will make a good piece of structure for my fish.

It will also suck up an unbelievable amount of water.

I've heard when guys fell large, live Cottonwoods they literally bleed hundreds of gallons of water...that's what my engineer told me [city boy] anyhow. He went on to say that the cottonwood is notorious for soaking up tons of water around one's pond...more than any other cultivar of tree. Again...may have been a story. Can anyone verify?

TJ, I can't verify but have an interesting observation. As I drive rural roads, I often notice clumps of cottonwood and willows. I often stop, climb the fence and look. Almost everytime, I find a dry or almost dry, silted up stock tank/pond/pool. The late Harrel Arms once told me that having willows and cottonwoods around the pond is like having a 2 inch pump running full time.

Ive also been told they suck up huge amounts of water.I cut down every one I had when I bought my property.

My dad was told that if he wanted to dry up a wet area of the yard that he should plant a few weeping willows. That's why I was concerned about the willow on the island in the pond. I think it'd be a good time to research how much water they will suck up.

Wow! I did not know that??? I will be cutting that thing down ASAP now!!! Thanks for the great info. I only have one of them ubt it's pretty darn big.

I did some searching this morning on how much water trees transpire or use, but couldn't find any concrete info. that was substantiated. It all depends (of course) on the weather, type of tree, size, etc. I found figures from very little to over 500 gallons per day.

Looks like my engineer wasn't just pulling my leg...I love Cottonwoods but their thirsty nature makes one consider their place on the pond.

Just curious as to using old concrete rubble or cinder blocks if the concrete agent causes any problems when submerged?? I know my local watershed will no longer allow any concrete to be used as Rip Rap but they couldnt site me specifics. They will only used freshly cut limestone chunks which causes another problem but we wont go into that.

Thanks,
Salmonid

If the pond will be used for swimming also, any sharp objects should be avoided nearby to where folks will swim.

Someone once mentioned a danger of someone getting their foot caught in a wooden pallet.