Collecting rainwater from the roof to water the garden is a common practice for homeowners in Delta.
At Sunnybay Greenhouses on Ladner Trunk Road, which grows 12 hectares of peppers, they are taking this practice to a whole new level.
"Basically our greenhouse is one large green roof system," states owner Jos Moerman.
The roof system is designed to capture water from both the inside and the outside of the roof. From the outside, rainwater is collected by aluminum gutters. From the inside, water transpired by the crop condenses on the glass.
"This water trickles down the inside surface of the glass roof into the gutter through specially designed slits," explains Moerman.
All the captured water is stored in a retention pond that can hold up to 20 million litres. When this water
is needed, it is taken and mixed with just the right amount of nutrients for healthy crop growth. Then using another water conserving measure, drip irrigation, it is applied to the roots of the plants.
Water is conserved again at this stage of the process when it is recaptured.
"The crop sits on slightly sloped gutters," describes Moerman. "These gutters collect the water and nutrients that drains out of the growing bag and gravity is used to feed it to a storage tank."
The recaptured water is mixed with the rainwater to get the nutrient balance right, before it is reapplied to the crop.
"The cycle is repeated endlessly with no water or nutrients leaving the system," says Moerman proudly.
To ensure the correct amount of nutrients are added each time, samples
of the recaptured water are collected once a week and sent to a laboratory for tests.
"The analysis we get back allows us to determine the ratio of rainwater water to recaptured water to use," explains Moerman. "It also lets us know the amount of nutrients to add to this water mix."
Before mixing the rain and recaptured water together and adding nutrients, the water goes through a pre-treatment process
where it is passed through a sand and gravel filter. This is to remove any particles that might plug the drip irrigation system.
During the dry summer months, when there is not enough rain to supply the greenhouse, the system is supplemented with city water.
Sunnybay Greenhouses manages to meet 60 per cent of the crop's water needs through its water conservation and recycling practices.
