Dunfarmin Blog

I suppose I have a fascination with water and having dug a pond last year I thought a 'stream' running through the garden would be appealing.

The original plan was to have a small stream about 16m long with a drop of 1.8m running at approximately 18,000lt/hr. The form of the bed was dug with 3 main 'falls' and a slower flowing part at the lower end. A 1,000lt IBC (intermediate bulk container) was buried at the lower end, wrapped in plastic sheet and back-filled with type 1 sub-base. A concrete cover was cast over this to avoid any buoyancy problems. A sheathed cable was run underground from an outbuilding and a 50mm hose was laid in a conduit to the top of the stream.

The bed was lined with sharp sand and a 0.75mm EPDM liner laid on top and adjusted to ensure no water could leak away. Unfortunately we had 96mm of rain in a few hours which washed all the sand down to the bottom. After rectifying this stones of various sizes were laid to form a bed. Rounded local stone was used as it is mainly a quartzite with attractive red or white colouration. Larger, more rugged stones were used for the margins. In the meantime our dogs had decided there were mice (or similar) under the liner and shredded about 3.5m at the top. As I had to order more liner I decided to buy enough to make a small pond about 3.0m x 4.5m and have the stream flow out of this.

River cobbles of 80mm to 100mm size were laid over the larger stones and then pebbles of 30mm to 50mm were spread on top. It required about 800kg of each from the local quarry. Pockets were left and filled with a homemade compost for planting later.

Things were left for about 10 days so that the stones could settle in place. 'Touch 'n Foam' Black Expanding Foam was then used to ensure water flowed over the stones and not under. Then where appropriate a sharp sand mortar was used to prevent movement of stones and hold soil back.

The pond was then filled and minor adjustments to the soil at water level made. Medium sized stones were used as the pond edge with several places for animals to escape from the water and beds for planting incorporated.

The pump, an Evolution Aqua VariPump 30000, was wired up and lowered into the IBC. After switching on several adjustments had to be made where stones caused water to flow in an unexpected manner. Once everything appeared to be OK, various water and marginal plants were introduced. The desired effect will not be apparent until next summer.