Leaking fibreglass waterfall and stream units
Q. My water garden has a fibreglass waterfall and stream installed. It seems to be leaking but I cannot find where the leak is. It must be the waterfall because the water level does not drop unless the waterfall has been running. Are there any clues as to how to spot where it might leak and how do I cure it?
A. Check around the lips of the individual units and make sure there is no water travelling back to the soil along the edges.
Check there is no water overflowing over the back of the unit or out over the side. Tell tale signs are dampness in a dry spell weather-wise. This is a particular problem with very flexible, plastic waterfall sections. As the soil beneath consolidates or an ingress of rainwater below the units washes away the sand bed the units rest on, then the support for the units is undermined and they tip and crumple. As they do this, the problem is exacerbated as water spills out, undermining the units even more. If no leaks are apparent when you first turn it on, leave it running for at least an hour and come back to it
Check the outlet pipe that comes to the head of the stream is not letting drips flow backwards. Drips can be a problem.
Check that the water is flowing from the units properly. They may be badly positioned or have moved. If they have moved, nestle them back into their beds with more support from the back. Sand can be washed away easily and soil can sink or be eroded by ants. Well-placed rocks lend more dependable support.
Try to gain some more permanent support from a foundation of stone and nestle the unit in a bed of semi-dry cement and sand or mortar mix. Make sure that there are strategic barriers of rock and stone to prevent the new bed from washing into the pool before it has 'gone off'.
If the water still runs backwards towards the rockery from the front lip of the unit despite repositioning then it is time for the knife or hack saw. Cut away a bit at a time along where the water drips travel until the water flows forward. (When using a sharp knife, like a Stanley knife, always cut away from you).
If you still cannot find the fault, check the hose from pump to the outlet at the top of the stream. Some bright spark might have put a fork or spade through it. But in all my years of water gardening I have only known this happen once and it was me that did it.