By Phil Jackson
When designing and building natural ponds, contractors often hear their clients say, “I want it to be spectacular.” That said, while every contractor prides themselves in his/her ability to create something unique on every job that will exceed their client’s expectations, sometimes the scope of the project does not allow for much creativity. Therefore, when a project does materialize that gives a natural pond design/build firm the opportunity to let their creativity shine, the crew’s excitement and energy levels get much higher. This was the case for this particular project in Guelph, Ont.
After the client told their landscape maintenance company they wanted to have a pond built, the homeowners were referred to Jackson Pond in Burlington, Ont.
Despite the scope of the project, the initial consultation with the client was surprisingly brief. They knew what they wanted, where it was going to be installed, and that a substantial budget would be required. After some subsequent meetings, a couple of proposals were presented, and a final design and budget were agreed upon.
Let the digging begin
Digging the 1.8-m (6-ft) deep, 18.3- x 30.5-m (60 x 100-ft) pond proved to be a challenge, however. Typically, the excavation procedure involves digging the pond to its various depths with neatly cut shelves at the appropriate levels, which in this case was every 0.6 m (2 ft). However, due to the geographic location of the property, it was known the area is synonymous for its even mix of soil and stone.
With every scoop of soil and rock that was excavated, the edges caved in due to the lack of compaction in the soil and rock mix. As a result, the typical procedures for the build process had to be changed. That said, during the initial dig, the pond was excavated and shaped as much as possible, but backfilling was necessary for each level as the dig progressed.
Once the rough shape of the pond was complete, the geotextile and ethylene propylene diene monomer (EPDM) pond liner was installed. Due to the size of the pond, three pieces of EPDM had to be seamed together. This procedure was performed on-site, within the excavation, using special primers, glues, and tapes.
Let the rocking begin
To make the pond appear natural, the liner had to be completely covered in rock. One by one, hand-selected large boulders were slung into the pond and lowered into position. To safely pull out the rock straps after each boulder was lowered in place, on top of a geotextile permeable fabric, sheets of Styrofoam insulation were also positioned under the boulders. Because of the overall size of the water feature, the excavator had to be driven closer to the centre of the pond so the large boulders could be swung into place.
The heavy liner was rolled up along the edges of the pond’s bottom shelf to provide safe access towards the centre. Soil ramps were created within the excavation to allow access for the machinery. Due to the soil conditions mentioned earlier, once the pond’s bottom ring was completely ‘rocked in,’ the heavy equipment had to be moved out of the excavation to unroll the liner. The entire liner was then folded into the centre of the excavation so the pond walls could be backfilled using clean soil against the newly installed rocks. This procedure re-established the edges of the pond shelf.
Once this was complete, the liner was unfolded and the same process was followed to complete the next shelf up. Layer by layer, the entire pond was rocked in using more than 150 tons of granite boulders. Once all of the boulders were installed, river stone was placed on all of the pond’s flat surfaces, as well as between any cracks and crevices. The objective was not to see any of the liner, geotextile, or Styrofoam insulation.
A 1.8-m (6-ft) long, 305-mm (12-in.) diameter pipe was installed along the bottom of the pond to create a fish cave. Once covered in rock, it not only provided an area for the fish to hide, but also a place where they can overwinter. A gentle sloped area (beach entry) was created at one end of the pond to allow the family’s two dogs to easily enter and exit the water during their mid-summer swims.
Five skimmers were installed around the edge of the pond to help maintain the water by drawing in surface water and debris. Pumps are installed within the skimmers to circulate water into various areas of the pond. Ensuring all skimmers were installed at the same elevation can be challenging, as is determining the specific water level. Creating proper circulation within the pond is critical to water quality; therefore, skimmer and pump placement is important during the design stage.