Environmental Flow Needs

The environmental flow needs (EFN) of a stream are defined as the volume and timing of water flow required for proper functioning of the aquatic ecosystem.

The Water Manager must consider environmental flow needs when deciding a water licence or use approval application on a stream or on an aquifer that is hydraulically connected to a stream.

A provincial EFN policy has been developed to guide the review of applications in their consideration of environmental flow needs.


Application types that typically will not have an effect on environmental flow needs are exempted from the mandatory requirement to consider EFN under Section 16 of the Water Sustainability Regulation. However, the Water Manager has the discretion to consider EFNs in any application.

The following exemptions are defined in the Water Sustainability Regulation:

  • An application for a new authorization for a domestic purpose
  • An application for a change approval
  • An application for a drilling authorization on an aquifer that is not hydraulically connected to a stream
  • Existing groundwater users applying for authorization within the transition period
  • An application under sections 26, 27 or 31 (amendments to authorizations) of the Water Sustainability Act, but only if granting the application would not cause a change in the point of diversion, an increase in the rate of diversion or a change in the timing of water use
  • An application for a final licence

Assessments and Reporting

You may be required to support your application for a licence or use approval with additional information, which may include reports or assessments that detail the stream's aquatic ecosystem needs. Reports and assessments must be carried out by people with the qualifications specified by the Water Manager.