Tayport water
Tayport Community Garden, established in 2015 with initial support from the Scottish Government’s Climate Challenge Fund, has always focused on tackling climate change by reducing carbon emissions and waste while growing more food locally.
“Practically and philosophically, people like to see something they are getting for free from the sky and knowing it’s better for the plants they are growing…”
Will, a long-term garden volunteer, recounts how Tayport’s water catchment system has been “years in the making” as the garden has evolved and learned over time.
“To begin with, we were just collecting water from our lock-up shed in a really simple way, using industrial bulk containers (IBC’s) raised off the ground. It was a very basic system that only scratched the surface of what we really needed to grow food. We didn’t have mains water on site originally, and we quickly realised just how much water we were going to need.”
Over time, the garden has expanded its growing infrastructure to include a large tunnel, various sheds, and a polycrub. All this infrastructure presents an opportunity to capture more rainwater, which is now stored in nine recycled black industrial bulk containers (IBCs) across the site, with a total capacity of 8,000 litres. Tayport’s approach is simple: don’t water unless you have to, and only water when necessary, focusing irrigation where it is most needed. The general rule is to avoid watering the outdoor garden unless absolutely necessary, instead prioritising efforts to build moisture-retentive soil. The garden now has a metered mains water supply for occasional use, and if required, the IBCs can be refilled from the mains. However, as part of a larger organisation, the garden is not eligible for the Scottish Water Charitable Exemption Scheme so every free drop collected makes a difference. Will reflected on Tayport’s water catchment strategies, highlighting the trial-and-error approach used to refine their system over time. For more detailed technical information keep scrolling.
“It’s all been a matter of trial and error and common sense, really. The trickiest part has been testing and improving our solar pump and drizzler system, but we now have a simple setup that all our volunteers feel confident using.”
Our main polytunnel has by far the largest surface area and is therefore the primary rainwater collection source. For each mm of rainfall you can harvest 1 litre of water per square meter of collection surface. We collect water in 9 reconditioned IBC’s prefering black over the ranslucent ones to reduce algal growth but this does make it difficult to visually gauge how much water you have.
IBC lids are higher than the guttering on the polytunnel so slots cut into the side of the tanks allow direct transfer of the rainwater from the gutters into the storage system. A scrubbing brushed trimmed to match the gutter profile and a mesh bag at the gutter end (inside the tank) prevents leaves and debris entering the IBC’s.
The gap between guttering and polytunnel skin is bridged using polytunnel repair tape to channel the water into the gutter. This tapes needs to be replaced every 2 to 3 years as it gradually peels off.
The drizzler irrigation system ensures water is directed to the plants where and when it is needed, thus reducing wastage. This type of drizzler was chosen because it can be unscrewed and flushed out if it gets blocked by any debris in the rainwater. Also, given that in warm conditions, irrigation systems may harbour the Legionella bacterium, we reasoned that the use of drizzlers mitigated the risks associated with aerosol droplets used in mist systems.
We use an 12v diaphragm pump to force the water through a hosepipe connected to the drizzlers. The pump and drizzlers are protected from any debris that may have entered to water in the IBC supply by two sequential in-line filters (coarse and stainless steel mesh-regularly cleaned). We don’t have mains electricity so power comes from a 12v battery charged from a solar panel. The pump can deliver 14 litres perminute which covers a supply network of up to 30 drizzlers at full capacity. We have 5 of these networks set up to water all the beds in the polytunnel. The pumped supply can be conntected to each of them in turn by attaching them to the pump with simple Hozelock fittings (other brands equally good!) Depending on the crop and external weather, we find that a 5 or 10 minute window of irrigation per network is enough (70-140 litres), so watering everything in the polytunnel can be completed in under an hour. During the active growing season we irrigate every second or third day. Volunteers connect the supply to each system for each raised bed, this is not too labour intensive and allows them to do something else whilst the pump is working. We prefer daytime watering just so that any potential system failure can be spotted and corrected. With an automated system there is always the worry that if something goes wrong all our carefully stored water is pumped out and the pump is damaged.
This is our original collection system (two IBC’s with a total capacity of 1800L). The drainage pipe catches water off the tool shed roof and the water runs through a filter into the top of one of the tanks. When that tank is full, the collection pipe can be swung around to fill the adjacent IBC. These tanks are not connected to the pumped irrigation and are used to fill watering cans. When necessary, they can be drained into the polytunnel collection tanks if the pump supply runs low on water.
Our main water collection system that feeds the pumped irrigation comprises four IBC’s at the back of the polytunnel with a total capacity 3200L. These tanks are interconnected, so that water that runs from the polytunnel gutters into the two outer tanks accumulates in all four IBC’s . During winter, when these tanks are full, the pump can be used to transfer water up into a supernumerary IBC stacked above the collecting tanks. Water from this tank can be used in summer when the collection tanks are running low. We only have one supernumerary tank, but plan to acquire more when funds are available.
More recently, we have extended our indoor growing space by the addition of a ‘Polycrub’ (clad with insulated polycarbonate sheets rather than polythene, so much warmer). Collecting rainwater from the Polycrub will be more complicated because the guttering can only be fixed quite low down (only 40 cm above ground level). The plan is to drain the guttering into a below-ground sump from where it will be transferred into raised IBC tanks by a 12v bilge pump (with a float valve). We hope that this will provide sufficient water to run a separate irrigation system in the Polycrub but only time will tell…
If you’d like to visit, see and learn from the Tayport team at first hand you might be able to apply for The Community Learning Exchange. Contact us for more details.