How to Stop Water Loss in a Pond
So things have been going along fine with your pond for some time. One day, you notice an unusual drop in the water level. In warm weather, maybe a half-inch per day water loss is normal, but what do you do if you notice 1.5 to 2 inches per day of water loss from your pond? Check the easiest things first.
For starters, we will assume that your pond is well-designed and that you have built a good water-tight waterfall. Also, if your pond is small, hopefully you have limited the amount of dramatic splash your waterfall provides. Get too much of that splashing and dancing off rocks effect, and your water will disappear in a hurry.
OK, so you’ve covered basic things well. What’s next?
The most likely cause of water loss from your pond is simple evaporation caused by changes in your waterfall. Your waterfall most likely has covering plants, taro, and rush, and eventually they are going to take off — not necessarily in the first couple of years. But when they do, watch out. Also, rocks can shift in your waterfall.
Take a look at the water flow down your rocks. Does their positioning allow for free flow downward? You may need to set some smaller rocks at strategic places to better channel the water stream.
Notice where your taro or rush are. Do big specimens grow in places that dam up water? Remove them.
Most importantly, check the bottom of your waterfall. As covering plants thrive, their roots can grow into a mat. This has an effect like a sponge — it soaks up water and doesn’t allow it to escape down the lip. The plants can also grow past the edge of your waterfall. Cut and prune them.
Remove string algae if that is a problem, and prune enough of the plants so that you start to see water channeling off the edge. Cat tails growing near the bottom of your waterfall can also act as a wick, so you may want to prune those too.
If you have a pond that is only a few years old, the probability is very high that the above ideas on pruning plants and moving rocks will solve your water loss problem.
If you’ve a problem with aquatic snails, you’ll know it. You will see them in your waterfall and in your pond. They are hard to get rid of. But did you know that four or five tiny snails can get sucked into some pumps, and restrict the flow of water through the pump?
When the snails restrict water flow through the pump, you’ll see the water flow at the top of your waterfall slow down fairly dramatically. And the waterfall sound will be a lot quieter. The restricted water flow won’t contribute greatly to water loss, but every little measure helps to keep water moving.
With some pumps, you can dislodge those tiny snails fairly easily. Just unplug the pump, remove it from the pond, unscrew the base, and examine the impeller shaft. Take a small bamboo stake or crochet needle and poke it around the shaft to remove any snails. Put the impeller back in position, screw everything back together, and submerse your pump again. You’ll notice much better water flow through the falls.
If you’ve re-positioned rocks in your waterfall, pruned plants, and taken care of your pump and you’re still losing water, it’s possible you have a tear or hole in your pond liner.
You can tell this by not replacing any lost water. If it’s practical, let your pond drop to the level where the hole is, and you will see it. Then determine the next step. This could mean doing a patch or maybe replacing the liner if it’s an old one.
If you have a concrete or gunite construction pond, it may be more difficult to determine where a hole or crack might be. You may eventually decide that, rather than patch it, you will simply drop a liner in your pond. That’s the simplest way to stop a leak.
Unfortunately, sometimes rats will make their home under your waterfall. They slip in through the side of your vinyl liner and live there for a while. Eventually, they may get bored and chew a hole in your liner! This happened very recently to my waterfall. It was the source of the leak, and the diagnosis led to a suspicion of a rat chew.
If you have a dog with an acute nose (especially a terrier), you may notice your dog going over to the waterfall, pawing at it frantically, and sniffing. This happened with my miniature schnauzer, and she went precisely to the side of the waterfall where the rats were hiding out. So, if you have a dog, pay attention to their behavior around your waterfall, because that will give you the best idea of where the hole in the liner will be. It will save you a lot of time when you try dismantling your waterfall!
Fortunately for me, the hole in my waterfall could be patched, and I didn't have to replace my vinyl liner.
Leaks From the Ground Settling
Unfortunately, the ground can also shift and cause water to be diverted in a direction you don't want.
In very dry weather, the ground may shift under your waterfall. The rocks that make up your waterfall may settle, and cause water to be displaced.
Just recently, during our awful drought, this happened to my waterfall. I was having a loss of 6" of water per day (or more). About halfway down the waterfall, I finally moved a big rock and noted that there was a steady trickle of water off the liner edge.
You only have so much liner edge to work with, unfortunately. To fix this problem, I simply removed the three nice-looking rocks that were in the sidestream channel, which were now too heavy for the channel. That stopped the water from trickling out. Simple!
Please note that simple evaporation will contribute to some water loss. And evaporation will increase with brisk dry winds (in summer or winter), or in hot weather. Just keep an eye on your pond, and over time, you’ll learn what is normal evaporation.
If you do have to deal with a rip or tear causing a leak, it’s not the end of the world. Eventually it will happen, and some pond liners just need to be replaced.
Keep water loss to a minimum, and you won’t have to worry about constant maintenance and checking on your pond.