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Definition and calculation of freshwater quantity over-allocation

Publication date:  March 2018
Publication reference number:  CR 305

This working paper produced by NIWA for the Ministry for the Environment in 2016 proposes a methodology for calculating over-allocation of fresh water.

The National Policy Statement for Freshwater Management (as amended 2017) requires limits for water quantity to be set in regional plans to manage the cumulative impacts of abstraction. Defining abstraction limits is important for establishing a level of environmental protection and clarifying availability of the water resource to users.

Comparing the limits against actual water use from active consents and permitted activities characterises the status of water allocation (under or over-allocated). This is important because the NPS provides direction to councils to avoid over-allocation. However, there are considerable and practical difficulties in defining water resource use limits and subsequently calculating over-allocation.  This working paper may help councils to undertake this task.