Environmental flow needs

Last updated on June 6, 2024

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 (PDF, 1.2MB) has been developed to guide the review of applications in their consideration of environmental flow needs.

Blueberry River First Nations Implementation Agreement - pilot operational policy

As of November 28, 2023, new Pilot EFN Operational Guidance policy (PDF, 477.9 KB) replaces the Interim policy and provides a quantitative EFN methodology to support water authorization decisions under Water Sustainability Act s.9 and s.10 in the Blueberry River, Upper Beatton River, and Lower Sikanni Chief River water management basins (Pilot area).

The Interim policy applies to applications received between April 1 and November 28, 2023.

Pilot Water Allocation Tool (PWAT)

The operational policy is accompanied by a new decision support tool. The Pilot Water Allocation Tool (PWAT) quantifies diversion thresholds established to protect EFNs and generates diversion schedules based on weekly estimates of streamflow variability. Learn more in the PWAT User Guide (PDF, 596.7 KB).

PWAT training videos

An online video PWAT Training Series is available. The series offers training on the following PWAT modules:

Streamflow measure guide

To support the recommendation that authorization holders measure streamflow, a A User’s Guide to Measure Streamflow (PDF, 1.5 MB) has also been developed.

Implementation agreement

The pilot operational policy and decision support tool were developed in partnership between Blueberry River First Nations, the BC Energy Regulator, and the Ministry of Water, Land, and Resource Stewardship, per Schedule P of the BRFN Implementation Agreement (PDF, 51MB). Parties intend to provide a collaborative review of the pilot operational policy and decision support tool before the end of 2024.

Interim policy and tool

Applications received between April 1, 2023 and November 27 2023 inclusive will be subject to evaluation and decisions according to the Interim approach (PDF, 273KB) and Interim User's Guide (PDF, 1.2MB) that was in place during this period.


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

The following exemptions are defined in the WSR:

  • 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 WSA ss. 26, 27 or 31 (amendments to authorizations) 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.