29 November 2018
As specialists in the water environment, Kingcombe are often contracted by private clients for maintenance and restoration works, including the design and installation of many waterfalls and cascades of various sizes.
An example is a project we completed in Dorset. We were originally contracted to line the existing lake on the estate, for it to be completely restored to an exceptionally high standard after many years of neglect. The project saw some significant challenges, especially where modern drainage culverts had been installed underneath the lake area.
The natural look of the lake was maintained by installing a Firestone EPDM 1.02mm, Pondgard membrane, covered with a 300mm layer of subsoil to provide a suitable planting medium for the aquatic plants. Due to the low flow into the lake and to maintain the water quality, we recommended that the water was recirculated, preferably over a cascade to entrain more dissolved oxygen into the water.
The client decided that this should provide a spectacle that was visible to their visitors coming up the drive to the house. Alongside the lake was a disused sandstone quarry, that had provided local stone for many of the buildings and walls on the estate. This offered a unique opportunity to create an impressive 6m high natural cascade feature, fed by water pumped up to a header pond from the lake, where it emerges as if it was from a spring head, before flowing back down over the quarry wall to the lake below. The new challenge was to create a natural stone waterfall to look as if it was an integral part of the original stone wall of the quarry.
The face of the quarry was lined with the same Firestone material, draped down over several steps in the stone to ensure no loss of water from the system. A new hard stone face was constructed on top of the liner, built in layers using large stone pieces up to one tonne in weight to simulate the rock seams running through the quarry. The waterfall cascades down to a stilling pool, from where it flows down a further set of small rock pools and a stream back into the lake, all lined with Pondgard material that was completely concealed under the new stone facing.
The water recirculation was achieved by installing a pump chamber at the other end of the lake, connected through a 150mm balance pipe. Silent running, efficient and easy to maintain duty/standby submersible pumps are housed in this below ground chamber. The automatic top-up is sourced from a local borehole on the estate.
The cascade has created an impressive feature, visible from the drive and the house. The lake is now well oxygenated and the water well mixed.