|Citation||Abrahamson, BT. 2010. Probably Maximum Flood Estimator for British Columbia. Prepared for Agriculture and Agri-Foods Canada, Agri-Environment Services Branch.|
|Abstract/Description or Keywords||Water Resource Consultants Ltd. (WRC) was engaged by Agriculture and Agri-Food Canada
(AAFC) to develop a protocol to estimate probable maximum flood (PMF) peak flows and
runoff volumes based on past studies of PMFs. The results will be useful for preliminary
estimates of PMF’s or as rough checks on detailed PMF analyses to compare the magnitude
and volume of the estimated flood with other PMFs.
British Columbia has a long history of PMF development by the public and private sector
primarily for the design and protection of dams for water supplies and hydro-electric
development. Information on PMF studies was gathered from government agencies and
hydro-electric authorities in British Columbia and from adjacent watersheds in Montana,
Idaho and Washington. This study assembled the results from the detailed PMF studies for
these projects and correlated the flood peaks and volumes to the drainage area to develop
equations that can be used to estimate the PMF potential at other sites.
Because of the diverse topography and hydrological characteristics within the province the
PMFs were divided into regional groupings. These were Vancouver Island, British Columbia
Coastal, Columbia Basin, British Columbia Interior, and one region comprising the Okanagan
and Bridge River Basins. This last falls within Zones 12B and 15 in the British Columbia
Streamflow Inventory. The equation for the British Columbia Interior was developed from
data that included the Columbia River Basin. Zone 12B and 15 peaks for areas less than 8,320
km² are estimated using the equation developed for data within the two zones. It is
recommended that the overall provincial equation be used for areas greater than 8,320 km². Envelope curves were also developed for volumes, however, the scarcity of data will limit their usefulness.
|Sub-watershed if known|