In 2015 West Hants hired CBCL, a company of consulting engineers, to develop a Storm Water Management Plan for the growth area of Falmouth. It has become increasingly evident that with more frequent and severe rainfall events, flooding continues to be a problem in the built up areas of Falmouth. The best plan of action is to first gather the facts– what is causing the flooding, where are the problem areas – and then figure out the best way to deal with it.
One of the action items in the Municipal Climate Change Action Plan (MCCAP) was to "complete a Storm Water Master Plan and ensure the plan assesses the effects of climate change on rainfall intensity and presents a solution to the drainage bottlenecks in growth centres." The CBCL study completes that action item and provides us with the facts – and they are not what some might have thought!
"The flooding in Falmouth is mainly caused by the insufficient drainage capacity and the flat landscapes within the community." (p. 25)
"... it indicates that the culverts themselves are not the primary cause of flooding..." (p. 26)
"...the flood extents of most areas are natural phenomenon that have likely been occurring since before the land was developed." (p. 26)
Municipal staff, with the support of the Municipal Climate Change Action Plan Committee, are now tackling the challenge of finding the best way to address flooding in Falmouth. The Storm Water Management Plan outlines a number of options such as educating residents about the benefit of Low Impact Development, and perhaps developing best management practice guidelines. We will also be working with Nova Scotia Transportation and Infrastructure Renewal so that they have the information about existing culverts and flood areas.
So – what does "1 in 100 year" REALLY mean???
As part of the Falmouth Storm Water Management Plan, CBCL prepared a computer model of what a "1 in 100 year" flood might look like in Falmouth (see YouTube video). Here's something to keep in mind – the phrase "1 in 100" does not mean that something will only happen every 100 years, it's just one way of expressing probability. Put another way, over the course of a 30 year mortgage, there is a 26% chance that you may be flooded by a "1 in 100" year storm as shown on the model. But it could happen this year – and next – or never. What we do know is that climate change is changing the numbers, and changing them faster than we originally thought.
Take a look at the Falmouth Storm Water Management Plan, and if you have any questions, we encourage you to call or email us – we welcome your input!