Heavier, more frequent rains.
This is what residents in the Lower Mainland could expect over the coming decades due to climate change, based on a report.
Lillian Zaremba, a senior project engineer with Metro Vancouver’s liquid waste services, has prepared a report regarding a study by the regional government on the impacts of climate change on local precipitation.
Rainfall will be 20 percent to 45 percent more intense by 2050, according to Zaremba’s report.
By 2100, rainfall intensity will increase by 40 percent to 75 percent, the report also stated.
“These increases are averaged over the entire region and averaged over different types of storm events with durations ranging from 5 minutes to 24 hours,” Zaremba wrote.
Rainfall intensity is a measure of the amount of rain over a given time.
Warming temperatures increase water evaporation, causing more rains.
Zaremba also noted that study likewise “suggests that intense rainfall events will more occur more frequently”.
Zaremba explained that the current one-in-100-year event of a “large rainstorm” has a one percent probability of happening in any year.
A rainstorm of the same size could become either a one-in-12-year or a one-in-six-year event by the end of this century.
“Infrastructure upgrades are required to maintain current levels of service for stormwater management and local flood protection in the future climate,” Zaremba stated in the report included in the agenda Thursday (February 7) of Metro Vancouver’s waste water committee.