BCWWA – Okanagan Basin Water Supply and Demand Project

This collaborative project is to provide a platform for science and sustainable water management in the Okanagan – right across the watershed, through three regional districts. The objective is to update knowledge of water supply and needs; and to evaluate alternatives and future climate effects. The project is underway and ongoing with a total budget of $2.1M.


  • 1974 Okanagan Basin study – was considered groundbreaking at the time – but population has increased beyond the predictions made in those days. – and growth continues.
  • Need to appreciate growth on First Nations lands
  • Need to have a whole basin approach
  • Extremely variable annual rainfall – may precipitate water shortages
  • climate change will have innumerable effects
  • longer, hotter, dryer summers
  • highly agricultural water use in the basin

2004-5 – Phase 1 – Compile existing data, gap analysis and strategy
2007-9 – Phase 2 – Model components of land, water and climate against supply and demand.


  • State of the Basin Report
  • Hydrologic Models for surface and groundwater as well as instream flows
  • GIS Basin Irrigation Demand Model
  • Comprehensive Water Report
  • Water Database Library

WUAM: Water Use Analysis Model
watershed water balance model suitable for this type of basin with multiple sources and types of users as well as forecast scenarios involving changing use patterns, population and climate change.

The watershed was broken up into 18 nodes in a weekly time series for 11 years (1996-2006) to build the model.

Component Studies:
Existing knowledge and ongoing research on all of these components to develop models that represent current and future supply and demand:
– Supply

  • Groundwater
  • Hydrology
  • Lake Evaporation
  • Climate Scenarios

– Demand

  • Actual Water
  • Irrigation Demand
  • Instream Flow Needs
  • Climate Scenarios

Beyond phase 2:

  • moving to a public consultation to assist in local and provincial decision making and directing policy.
  • continual updating of the model with more localized data
  • supporting a basin-wide water management plan

Published by Mike Thomas

Mike Thomas P.Eng. ENV SP, is the author of UrbanWorkbench.com and Director of Engineering at the City of Revelstoke in the Interior of British Columbia, Canada.