Building a tranquil pond

by jason_cramp | March 28, 2017 12:00 pm

By Phil Jackson

[1]

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.

[2]

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.

[3]

However, due to the sheer size of the pond, additional filtration was needed beyond skimmers and waterfalls to ensure its appearance remained natural. Therefore, a bog filter was installed to help maintain the water. This area was dedicated for the dense planting of water-loving marginal or bog plants. It is a smaller, supplementary pond that is typically 10 to 20 per cent of the size of the main water feature. A bog filter can be located inside or adjacent to the main pond. For this project, it was installed within the main pond.

Water was pulled from one of the skimmers at the opposite end of the pond and pumped into the bottom of the bog area. The slow flowing water then rises up through the roots of the plants where natural biological filtration takes place before the water flows back into the pond. The bog not only provides this required filtration, but also ensures incredible beauty when all of the plants are in bloom.

To ensure the proper movement of water within the pond, underwater jets were also added. These jets pull water from one skimmer and push it into the bottom of the pond, forcing water to circulate in the deepest point of the pond to avoid water stagnation from occurring.

Next step, waterfall building

This design called for a main waterfall to be built 3.6 m (12 ft) wide by approximately 2.4 m (8 ft) high. The waterfall needed to be dramatic in appearance and sound, bearing in mind this was a residential project.

Further, the scale had to be such that it was in keeping with the pond’s size, but not too big that it detracted from the feature’s natural appearance. The first step involved using clean soil to create the rough shape and drop points of the waterfall. Geotextile was placed on the soil followed by the waterfall liner. Starting from the pond elevation and working up, the waterfall was built in levels. The bottom drop, where the water cascades into the pond, needed to be constructed at the right level; therefore, knowing exactly where the water level was going to rest in the pond was a must.

[4]

More than 80 tons of boulders were slung into position one by one and, like the pond, once the first waterfall level was built, the liner was folded up to allow clean soil to be placed underneath. Then, the liner was folded back in place before building the next level.

Constructing the waterfall of varying drop heights and cascades gave it a natural appearance, but more importantly it achieved the soothing sounds of moving water the client was expecting. On the opposite side of the main waterfall, a secondary waterfall was built. The purpose of this waterfall was not only to provide additional filtration for the pond, but also to enhance the view of the feature from other areas of the property. This waterfall was smaller in size, but incorporated a 3-m (10-ft) long stream. More than 113,562 L (30,000 gal) of water pours over the waterfalls every hour.

A pond at night is an awesome sight

Pond and waterfall lighting is a must for a water feature of this scale. As such, light-emitting diode (LED) lights were added at varying depths within the pond, which transforms its appearance during the evening hours. The waterfall and stream lighting creates a dramatic look as the water ripples past the lights. Finally, underwater lights also accent the strategic placement of a stump and log placed within the bog. (The stump and log were removed during the excavation and it seemed appropriate to reuse them in the finished feature).

Within the pond is an array of aquatic plants. Water lilies flourish within the deeper portions of the pond, while shallow water plants grow with the edge rocks. Their colour and beauty not only help to soften the appearance of the large-scale feature, but also provide an additional area for wildlife to flourish. Carefully selected terrestrial plants were placed around the perimeter of the pond and waterfall to complete the natural setting and to co-ordinate the water feature with the existing landscape.

Bring on the water

The pond holds more than 302,833 L (80,000 gal) of water and several water trucks were required to fill it. All in all, the six-week project was completed on time and on budget, and exceeded the homeowner’s full expectations.

[5]Phil Jackson is president of Jackson Pond and has worked in the water feature industry for 25 years. From their design centre and retail store in Burlington, Ont., Jackson Pond builds and maintains award-winning water features across North America. He can be reached via e-mail at phil@jacksonpond.com[6].

Source URL: https://www.poolspamarketing.com/trade/building-a-tranquil-pond/

---