In January of 2001 we started making a (cienega) wetland that I thought would be wonderful for birds. I figured it we lined it heavily with bentonite to where it couldn't leak that for most of the year we could keep a shallow layer of water in it. Sweet Sherwood wanted whatever made me happy. We worked really hard on it and it held water pretty good at first. But I wanted willows, reeds, and cattails in it.
We enjoyed it for several years, and I have hopes of enjoying it again during rainy years.
Now it's starting to look like an oasis. The tanks are all full when this next photo was taken, probably in the summer of 2001. In the foreground is the cienega, which is currently abandoned for lack of water. Once I let vegetation grow in it, it no longer held water. Without vegetation I didn't really want to waste precious water on it. Actually, didn't have it to waste. At best, it leaked moderately. Bentonite works better in less gravelly soil, I suspect.
Around about that same year we decided to concrete the Permalon tank. We hired help for that one, knowing we were in over our heads (no pun intended) that time. I had to cut the stretchy Permalon all the way around. Otherwise, the concrete wouldn't weigh enough to hold it down. We couldn't have big air pockets under the plastic because the concrete would have cracked horribly with the weight of water. The weight of it full of water stretched it out, but the concrete wasn't heavy enough. I sure hated doing that, but the tank has never leaked. The other option would have been to remove all the rocks (9,999) on top that were holding the Permalon taut. I think that would have been the better option but I just didn't have it in me to do. It was May when we were concreting the tank. As it was, it took the whole month. It could have rained any time, too. It did rain, but just small showers that put tiny puddles in the tank. We used it to mix concrete with. You can see a small puddle in this photo.
Here is the newly concreted tank at last.