Irrigation Operation details
Guidelines for the Operation of the Waimakariri Irrigation Scheme
The Waimakariri Irrigation Scheme, like most irrigation schemes, resembles an arterial system in that race sizes get smaller as side races are fed and water supplies are made. All of the races have been designed to carry the volumes required to supply the shares they service.
In total, the scheme has nearly 250 kilometres of irrigation race and it takes up to 48 hours for water from the Waimakariri River to reach those shareholders furthest from the intake. As a consequence, requests for water, or to cease supplying water, must take this lag time into account.
Water is only available to properties that have been formally identified by the shareholders and at a flow rate that matches their share allocations. All races have been designed for specific volumes and shareholders must take their ordered water entitlements from the designated location.
At least 24 hours notice is required from Shareholders who wish to take, or cease taking water. This is required because it takes that amount of time for the water to travel through the system and reach all shareholders’ properties. Shorter notice periods are possible in some cases with due regard being given to the lag times involved.