The Environmental Flow Needs (EFN) Project is a collaborative project between ONA, Ministry of Forest, Land, and Natural Resource Operations (FLNRO) and the Okanagan Basin Water Board (OBWB). The goal of the project is to develop Environmental Flow Needs (EFNs) (“target flows”) and Critical Flows (“minimum flows”) for water management in Okanagan streams. A list of 19 priority streams was developed collaboratively at the beginning of the project.
Phase I of the project consisted of developing methods for EFN setting, and included a literature review of EFN methodology and historical information gathering for Okanagan streams. A report with proposed methods has been distributed, consisting of two components:
- a desktop effort identifies EFNs via historic streamflow records, information on naturalized flows, and a known (from literature) proportion of the mean annual flow that a range of fish species and life stages need.
- a more intensive field-based effort where the change in suitable fish habitat is measured in relation to streamflows to develop a stream specific relationship between flows and habitat. Habitat features to be measured include depth, velocity and temperature in high-value habitats (and macroinvertebrate production, pending funding).
Phase II of the project is consists of implementation of the methods, including field data collection and development of EFNs for Okanagan streams based on the methods developed in Phase I. All 19 streams will be assessed via method (1) (desktop exercise) but since there is not sufficient funding to do a full field study on all streams, 11 streams were prioritized using a ranking system for assessment under method (2) based on the following criteria:
- Fish habitat value
- Known low flow issues resulting from water use
- Likelihood of new licenses being issued (some systems are “closed” to new licensing)
- First Nations value and use
- Data and/or Water Use Plans already available from previous studies
The streams that are measured in Phase II of this project include:
- Coldstream Creek
- Lower Vernon Creek
- Equesis Creek
- Nashwito Creek
- Whiteman Creek
- McDougall Creek
- Mission Creek
- Inkaneep Creek
- Shingle Creek
- Shuttleworth Creek
- Vaseux Creek
Phase II of the project is mainly conducted and delivered by ONA with support from the bands. Fish Habitat Transect sites were established in all 11 streams between July and August 2016. Study sites include up to 10 transects per stream, including riffles and glides. In addition, a total of approximately 24 hydrometric stations, including 2 real-time stations, were installed and will be maintained at least throughout the life of the project.
It is anticipated that EFNs and critical flows to be used in water licensing and drought management decisions by FLNRO will be developed in a workshop or series of workshops following completion of Phase II. This process has been identified as Phase III of this project.
- Install and maintain hydrometric stations throughout the basin
- Measure appropriate habitat parameters to calculate Weighted Useable Width (WUW) values for all glide transects
- Establish Environmental Flows Needs and Critical Flow Needs based on WUW values at varying flows for Okanagan Streams