Historical temporal trends in monthly, seasonal, and annual mean, minimum, and maximum streamflows from the Okanagan River watershed in south-central British Columbia, Canada

Abstract

Historical trends in monthly, seasonal, and annual mean streamflows, as well as minimum and maximum monthly streamflows, were investigated at nine hydrometric stations in the Okanagan River watershed from south-central British Columbia, Canada. Overall, mean annual streamflows in the Okanagan River watershed are not exhibiting any significant time trends. No consistent declines in monthly minimum streamflows are evident at any point during the hydrologic year. Mean monthly and monthly maximum streamflows in tributary streams to the mainstem system appear to be significantly increasing over time during the spring snowmelt period of March and April. Any temporal changes in flow patterns at the mainstem Okanagan River stations likely reflect alterations in water management strategies over time at the respective upstream dams.