From the Foreword:
"Although Okanagan Lake provides the region with a large natural reservoir, replenishment of water is irregular owing to extreme variations in runoff from snowmelt and rainfall from year to year. As demands for the consumption of water for agricultural and municipal uses increase, particularly in tributary basins, the available supplies for non-consumptive uses in recreation, aesthetics and fisheries decrease. Added to the uncertainty concerning water supplies is the gradual deterioration of the quality of the valley's major lakes, indicated by an abundant growth of weeds around the shorelines and occasional algae blooms during the hot summer months."
See the "Main Report" page at EcoCat. Note: EcoCat page also includes appendices and maps document.