ICAN Practical Water Solutions
by Jan Brettnacher

Heading into the fifth year of the Rainwater Harvesting Program on Quadra, we would like to introduce you to two community members who have set up a workable system with IBC tanks. 

The food grade plastic 1,000 litre IBC tanks were brought onto the island and distributed at cost as part of a volunteer effort to service and educate concerned water users. Hundreds of tanks have been distributed to enable islander’s systems, including some on Cortes and Sonora.

Kathryn Manry and Mark Zimmerman were kind enough to share a tour of their system and explain how it was installed and utilized. About four years ago they started with six tanks and have since installed seven more for a total of thirteen. Three of the 1,000 litre tanks fill from their carport roof and are used with an attached hose to hand water their orchard via gravity feed. Six of the tanks are placed at a low point on their 1 1/2 acre, sloping property and four are placed on the highest point. The house roof gutter drainage system was diverted from the discharge point and into a pipe running under their driveway and down to the six lower tanks.

Standard white 4 inch PVC drainage pipe was used and a moveable arm was positioned above the tanks to allow Mark to move it from tank to tank for filling. When the lower tanks are full he can then use a small fire fighting pump to move the water to the upper tanks so that the lower tanks can refill.

To utilize the water from the upper tanks to water their large vegetable garden they have attached a 3/4 inch black poly pipe to the valves near the bottom of the tanks. This pipe runs downhill bordering the gardens and culminates at the bottom of the lower garden and just above the driveway. The pipe has several outlets along the length for water access for hand watering and a final valve at the end that serves as both an outlet for draining the system and an access for pumping the water uphill from the lower tanks. This is accomplished by closing all drain valves on the upper tanks and attaching the hose from the lower tank fire pump to the last valve on the black 3/4” pipe at the bottom of the garden and pumping the water uphill to refill the upper tanks.

The first year the system was filled and ready to use was a rainy June and they didn’t start using the collected water until July.  This allowed them to water their extensive gardens for the remainder of the gardening season with no water from their well. On years when they started use of the collected water in spring and with no measurable summer rain, they had to supplement with well water by August to finish the season. With all the tanks full going into the gardening season it is approximately 13,000 litres (plus any additional rains that occurs for refill) of water they are able to not draw from their well during the dry summers.

All of the tanks are wrapped in 10’ X 12’ dark tarps to inhibit growth in the tanks and prevent degrading of the plastic. The gutters on their house have gutter guards and there are no inline filters. It is important that all tanks are levelled. They empty the tanks in the winter to avoid freezing and begin filling them as the temperatures warm in late winter or early spring.

Kathryn and Mark estimate that with the tanks, pipes, hoses and pump they have invested approximately $3,000 to $3,500 in the system.

Do you have rainwater harvesting system information you would like to share with the community? If so please email the ICAN Practical Water Solutions Team at quadraicansociety@gmail.com