Okanagan Basin Water Board. (2014). Okanagan Water Allocation Tool. Kelowna: Okanagan Basin Water Board.
The Okanagan Basin Water Board, in partnership with B.C. Ministry of Forests, Lands and Natural Resource Operations (MFLNRO), commissioned this report to develop a plan for an Okanagan water allocation tool, known as the OWAT. The primary purpose of the tool is to support water licence decisions made by MFLNRO. Decisions regarding licence approval (with or without conditions) or licence refusal are currently made using guidelines and policies that were last updated in the 1990s. The new Water Sustainability Act legislation and continued the pressure on water resources in the valley fuel the need for a more sophisticated, scientifically based and transparent decision support tool.
The overall objective of this project was to review existing Okanagan data and models to determine how they can best be used to create an effective decision support tool for water licensing in the Okanagan, and to identify tasks required to develop the tool.
The project engaged key knowledge holders and end users and included the following steps:
- Review of existing Okanagan Basin studies, specifically, the hydrologic and water accounting models completed for the Water Supply and Demand Project, as well as a review of Environmental Flow Needs (a.k.a., In-stream Flow Needs or EFNs) information;
- Consultations with MFLNRO water allocation staff and other knowledge holders to advise on OWAT objectives and a framework;
- Preparation of a draft OWAT plan and vetting of the plan at a Kelowna workshop attended by knowledge holders and end-users; and
- Completing a final OWAT plan report documenting the process, information gaps and questions to be addressed and recommended approach for plan development.
The focus of this project was to evaluate the potential applicability of two platforms to house the OWAT:
- The Northeast Water Tool (NEWT) adapted to the Okanagan; and
- The Okanagan Water Evaluation and Planning (WEAP) platform, which served as the framework for the existing Okanagan Hydrologic Connectivity Model (OHCM).
Outcomes of Consultations and Existing Model/Information Review
MFLNRO staff provided current licence evaluation criteria that have been in use for a number of years. These criteria use different risk of water shortage tolerances based on types of uses (e.g., domestic, small or large waterworks, or irrigation). The evaluation criteria require varying degrees of spatial and temporal data, in the extreme case, daily stream flows for intakes on tributaries. One issue with existing licences was that there is currently no central database that associates water licences and points-of-diversion with estimates and/or records of water use; moreover, the provincial E-licence database does not report all licence conditions so work is needed to converge the various databases (both electronic and hard copy) into a comprehensive format to support new licence decisions. The reports, models and model platforms reviewed for this study included component technical studies and databases for Okanagan water supply and demand, including the MikeSHE hydrology model, the Okanagan Water Demand Model, the OHCM, EFN calculation methods, the NEWT user interface and a similar interface being developed for Northwest B.C. (NWWT). The capabilities of the various technical approaches, models and model platforms were evaluated against OWAT objectives and the user needs expressed by MFLNRO staff.
The outcome of this review is that none of the existing models, in current form, can be used as water licence decision making tools without significant technical expertise, but that both WEAP and NEWT platforms have considerable potential for use in the Okanagan. Also, as conditions change and new licences are issued, it will be necessary to have a convenient system to update data and risk model scenarios. Similarly, while there are a number of potentially applicable approaches to determining EFNs, there is no consistent methodology for the Okanagan. Examples do exist from prior water use plans (WUPs) in the Mission and Trout Creek watersheds that could potentially be applied in other local drainages. It was a consensus of the group that where EFNs are established as a component of existing supply, they must be operationally attainable given the existing state of water management in the basin.
Recommended OWAT Plan Approach
Any modeling approach will have its own advantages, constraints and disadvantages, and this held true in our evaluation of the WEAP and NEWT/NWWT platforms as possible stand-alone tools developed for the OWAT. Based on discussions held during the project, including a March 2014 workshop in Kelowna, a consensus emerged favouring a hybrid approach incorporating a new hydrologic supply and demand model using the WEAP platform, coupled with a NEWT-like user interface. However, MFLNRO is apparently considering developing a NEWT-like water allocation tool for the entire Thompson–Okanagan region, which includes but extends considerably beyond the boundaries of the Okanagan Basin.
Should two tools covering portions of the same area be developed (OWAT for the Okanagan, and a NEWT-like tool for Thompson-Okanagan) it would be better if one approach can complement the other, and the appropriate decision support tool could be chosen based on the location and the available data. Covering the same spatial domain with two models raises issues such as how to resolve inconsistencies (if both were used). A strong consensus was that having a similar user interface as the NEWT and the NWWT for the Okanagan would help foster consistency across the province. To take advantage of the detailed hydrologic and water supply information that is available, development of a new tool using a new WEAP-based model and a NEWT-based user interface is recommended for the Okanagan basin. OWAT development must continue to involve end users and key stakeholders and prior to implementation should be pilot tested on typical licence application scenarios (e.g. intake on stream, lake intake, storage, etc.), as requested by Ministry staff.
Summary of Key Gaps and Questions to be addressed
Based on the outcomes of this project and the consultations (which should continue in the next phase with key stakeholders and end-users), we identified a number of issues that need further deliberation and questions that must be answered. The table below summarizes the major gaps and questions (not necessarily in priority order) that must be answered as the OWAT project moves forward toward the development and implementation stage. Detailed discussion of each of the major issues, and other lesser but still important ones, may be found within the main body of the report.