It can leak through the holes in the lining, it can come from aerial sources such as rain or a. We didn't receive a huge amount, but it was difficult for a while. There is water under the liner and the liner is floating upwards. Some of the rocks are floating as if they were in a water bed.
If we take the water out from under the liner and finish adding the rest of the rocks in the pond, will that keep the liner down? What else can we do to keep the liner in place? I thought about pins, but then realized that I would only make holes in the lining. How can we prevent water from going under the bag? A very common source is water that flows or seeps below the ground on a hillside or in a slope situation. In the latter case, the pond well crosses the slope, opening the groundwater to the sky. When a pond liner is installed in the well, it acts as a barrier to water movement.
Unfortunately, it is a weak and flexible prey. Many, if not most, people have a clay soil base beneath their landscape. When a hole is dug in the clay, a naturally (mostly) airtight basin forms. Water pressure from uphill areas of the watershed can seep into the clay-lined hole under the liner.
The water inside the pond liner cannot withstand the pressurized water coming from below, and the liner will move. Even heavy rocks and rock retaining walls cannot contain the water that pushes against the entire facing wall on which the stones are seated. When there is water under a liner in a clay hole, no amount of water on top of the liner will rapidly push water under the liner through the clay. Sometimes water under a liner slowly seeps out on its own.
This is especially true for rare accidental additions of additional water to the landscape. No additional work is required in this case. The finished rock work will likely keep the liner in place because of these rare occurrences of extra water. When installing a pond in a low-lying or water-holding area, it may be necessary to treat the water problem under the liner on an ongoing basis.
In the same way that a concrete-lined pit in the ground, called a basement, forms a container that can be surrounded by moist soil, a pond liner lines a hole in the ground and can be surrounded by moist soil. In any case, it is necessary to remove water from the ground. In cases where the terrain is sloped, drainage tiles or gravel-filled trenches that start below the siding and that move water downhill to an above-ground location can sometimes be used. A sump pump style well can be installed next to a pond such that water accumulates in the well and is pumped to another location away from the clay lined well of the pond.
There is no need to install a pump in the sump pump well unless water accumulates continuously. In some landscapes, the pump will be a little-used convenience, provided the well has been previously installed as part of the pond well and with trenches or pipes moving groundwater to the well. When the pond is located on a slope or built on a hillside, water will want to keep moving through the hole location. Drain pipes installed around the hole or under the liner can move water sufficiently from the uphill side of the liner around the pond to allow water to continue on its way underground downhill.
Otherwise, pipes or trenches that open to the air at the ends or wells of the sump pump can be used to remove water. Finally, spring loaded lids can be installed on watertight bulkhead fittings in the pond liner. Lids open when water pressure pushes hard enough. Open lid allows groundwater to travel through liner to pond water.
This water may be pure or contaminated, and its temperature may not be close to the temperature of the pond water. Cold, contaminated water may not be good for fish health. If the pond has gravel near the lid, the gravel can move when the lid is opened and fall through the opening so that it cannot be closed, thus creating a leak when the water pressure reverses and is lower from the outside. You're lucky; it's best to find out there's a potential groundwater problem before the pond is finished.
The best solution allows groundwater to move on its own through pipes or trenches to a lower location. The second best solution is to rely on pumps to keep this water away. The solution of last resort is to rely on pressure relief valve covers. If you lift the pond with a berm around the surrounding ground, any water above the water table will act as a weight on the liner.
Pvc drain is a good idea only if the outlet is below the final pond water level, and a berm high enough could achieve this. Rocks would help, but they may not fully solve the problem on their own. The water is under the lining caused by the groundwater level higher than the pond water level. The easiest way to fix this is to lift the pond.
If you have excess lining, you can flip the lining on top of the rocks you have and put more stones on top of it. Fill with soil for a berm area. It contains the berm with rocks, plants, landscape borders, etc. Here's a picture of my pond today.
If there were no raised berm, the liner would be floating. It can be disconcerting to see your lining rise like a blister from the bottom of your pond, perhaps even taking with you the rocks of your river. Stones shouldn't float, so what's the matter? Your first consideration could be if there is a leak in the liner itself. If water penetrates the soil under the coating, it can begin to accumulate, especially if you have soil with a high clay content.
Once there is enough water below and above the liner, the liner will start to float. While I wish I had gone deeper, but had never planned to fish anyway, I simply drained my pond for cleaning in the fall (drained it through an overflow to the same system) and left it empty for a few days, no worries. When I rebuilt my pond a couple of months ago, I removed the liner and dug a trench under the %26 liner at the back of the pond. I was fortunate to have an existing drain for the municipal stormwater system and chose to drain the pond location with a buried pipe system.
This limited the depth of my pond (2 feet) because the existing drain was quite shallow and I still had to make 75 foot trenches to bring the drain pipe and existing pipe to the same levels for flow. It can leak through holes in the liner, it can come from aerial sources, such as rain or a hose that runs through the landscape, or it can come from a nearby pond or stream that overflows. Another works when there is a lot of pressure against the liner, but has prior knowledge of hippos when the pond is built. In that case, you could eventually face a situation where anaerobic bacteria take hold and your pond starts to emit an occasional sulfur odor.
If all else fails, dig a test pit that is deeper than your pond will be and watch for moisture to leak from below. The goal is to ensure that your pond is located well above the existing water table; if that is impossible, consider building an above ground pond. . .