Kevin Mawson
Introduction
Why did we consider a rainwater harvesting system at Kingsthorpe Bowling Club?
With a changing climate, we are told we will be having warmer wetter winters and hotter and dryer summers. The dryer summers are bad news for the outdoor greens and it is likely that they will need more irrigation each year. The mains water supply used to irrigate the greens will see the cost of water, like other utilities, continue to rise along with the likelihood of watering bans creating a double problem.
Current Situation
Currently, the greens are irrigated using water from a 5,000-litre storage tank that is “slow” fed from the mains water supply. The irrigation sprinkler system, used during dry periods, consumes a great deal of water. Although 1mm of water per two minutes of run time doesn’t sound like much, spread over the area of the greens it amounts to between 2,500 and 3,000 litres each time.
The Project
To safeguard the greens from drought and reduce the cost of irrigation the plan is to buy 12 reconditioned Intermediate Bulk Containers (IBC) each of 1,000 litres. With 12,000 litres of rainwater storage, the greens could be irrigated four times before any “paid for” mains water has to be used. These are high-density plastic bottles inside a steel cage and on a steel pallet. This will enable the IBC units to be double-stacked behind the existing storage tank and linked to the existing storage tank outlet by a 50mm or 75mm pipe and so connect to the current irrigation sprinklers.
Rainwater Harvesting Operation
Collected/Filtered rainwater fed from the building roof Downpipe A to the top IBC container that will have a high-level float switch to enable excess water to be diverted back to Downpipe A. As the roof gutter is continuous Downpipe B and Downpipe C can also be used to harvest additional rainwater if the single feed does not fill the IBC tanks quickly enough. Only if the water level in the main storage tank and the IBC tanks is insufficient to meet demand will a valve activate to switch on the mains water for infill into the main storage tank only.
The combined IBC and existing storage tank will give us a total capacity of 17,000 litres – enough for 5 to 6 irrigation uses.
Feb 2023 - Project Update
Finally, the weather is warming up and I can get back to the project so here’s what’s been going on since the last update together with some more photos:
- Delivery of the IBC containers to the car park & moving them up the ramp alongside the green.
- IBCs weigh a total of 65 Kilos (plastic tub = 15, cage = 50) – so had to
remove the plastic tub from the cage before maneuvering up and over the fence - Then the metal cages were lifted up and over the fence using ladders and scaffolding planks
- Put the plastic tubs back into the cages and wrapped the whole cage in BLACK cling film (this stops sunlight from causing algae growth).
- Positioned and stacked the units two high
- Started plumbing all the units together so infill water will eventually fill into one top IBC container and then equalize across all IBCs and the main storage tank as well.
- Started clearing trees that overhang the guttering with a chainsaw.
April 2023 – Project Complete
Final photos and work completed were undertaken to bring the rainwater harvesting project live.
- plumbing was undertaken to join up all the IBC units, and then to connect the IBCs to the main storage tank.
This job meant me getting inside the main storage tank using a makeshift ladder to tighten up the nuts on the plastic compression pipes while Geoff Hayter was on the outside holding the fitting. Let’s just say that getting in was a lot easier than getting out! I was stuck inside for about 10 minutes before managing to climb out – and yes it was all around the club within an hour! - Stuart Coll (the plumber for the original club guttering and downpipes) and I then linked up the Filter/Diverter to the corner downpipe and the IBC top unit as input feed.
- The last bit of plumbing was to make sure that the overflow from the main tank was output back into the corner downpipe. I also included a hose outlet to a tap to use for washing down machinery and flower bed watering.
Finally – Friday 7th April I replaced the blind insert on the Diverter with the actual filter and waited for rain which we had on Monday 10th April, and all the connections were checked & worked OK – After 2 hours of off-and-on rain the gauges showed as 800 litres tanked – not much but it’s a start.
Kevin.
“The Directors and Management Teams would like to extend their gratitude and appreciation to project leader Kevin Mawson for his remarkable work to deliver, virtually single-handed, our rainwater harvesting project on time and under budget. We appreciate the time and commitment it has taken to understand the concepts of this project and deliver a solution that delivers significant benefits and savings by reducing our mains water usage.”
