Last year were fortunate enough to have Water Explorers from Ireland assist us with fixing the gutters for our Jojo tanks. We have one 2500litre tank that was reconnected to the gutters and we also had a pump installed to help us access pressurised water. We then investigated how much water we could potentially harvest from our roof in one rainfall event of 30mm. This was an interesting excercise. All our Grd5, 6 and 7s combined forces to work this out.
We need to work out the area of all of our roof space (length x breadth). For the 3 building we have it worked out to be 465 square metres.
We then had to convert 30mm to metres = 0,03m
We then had to get our volume of water = Area x height = 465m2 x 0,03m = 13, 96m3 which doesnt sound like that much.
But remember we then had to convert metred cubed(m3) to litres, so, 1m3 =1000litres
Therefore our roof area could capture an amazing 13,96x1000 = 13 950litres!! Thats a lot of water for ONE rainfall event - thats nearly three 5000l jojos!
But we only have one 2500litre tank which is at least something, this made us realise how much water we could capture if we had more jojo tanks!! Our principal is now working hard to see what she can do about that!