The Evolution of Rainwater Management

When it rains, the water falling from the sky runs down the roofs of our houses, across our lawns and yards, across sidewalks and down streets to disappear into the little grates that dot the roads and parking lots of our towns and cities. What happens after that may be a mystery to most, but, as a civil engineer, managing that rainfall run off properly is one of the main focuses of my career.

For most of the modern age, urban and sub-urban rainwater management has consisted of capturing and channeling rainwater to catch basins to keep our homes, business, streets and sidewalks free from flooding. After the water enters the catch basins, it flows into pipes that increase in size as more areas are connected until, eventually, the rain water discharges into a natural watercourse. The pipes were sized to contain storms up to a certain size, with the water from larger storms intended to run overland to the nearest watercourse.

While the above methodology sounds reasonable, it has some inherent flaws. For example, when you take an area of land that was originally forested, and build roads, houses and sidewalks on it, you greatly reduce the amount of rainfall that was naturally absorbed by the landscape. This can lead to flooding and erosion issues at the point of discharge of the stormwater system. For comparison, a forested area will absorb 80% of all rain that falls, whereas a residential development might absorb 20% of the rainfall.

Furthermore, when rain falls on a forest, or vegetated area, it tends to stay spread out in sheet flow or small rivulets. The traditional stormwater system concentrates the flow, and the pollutants that end up on our sidewalks, parking lots and streets get washed off into the stormwater system.

Fortunately, new techniques, standards and legislation are being developed and implemented all the time to remedy this situation. For example, detention and retention of a certain amount of rainfall on a developed site has become common practice in much of North America. Oil-water separators are more or less a standard requirement, and the technology available improves all the time. While these measures can increase the up front costs to develop land, the will help ensure a more sustainable future for everyone.

Andrew Gower is a partner and Courtenay branch manager of Wedler Engineering. He volunteers with several local non-profits and is passionate about the Comox Valley’s sustainable future. He can be reached at 250.334.3263 or www.wedler.com.

Andrew Gower

Wedler Engineering

Who pays for roads?

A common theme of debate when discussing bike lane and pedestrian construction projects is the question of who pays for roads in the first place. Detractors of those who wish to walk, take transit, or ride bikes to transport themselves often claim that only those who own and drive cars pay for roads. The idea that cyclists should be licensed and insured is brought up also. So, just how are road projects funded?

One of the more common ways municipal roads are funded is via new developments. A developer building a subdivision has to construct the roads for the new lots, and has to pay “Development Cost Charges” (DCC) to the municipality they are in for future road works. The money to fund this road construction and pay the development cost charges is passed on to those who buy the new lots. Thus, homeowners are paying for these roads. If the houses are rented, or the new project is multi-family including rentals, then renters are paying for these roads. Whether any of these people have cars or ride bikes is immaterial – the cost of the infrastructure is included in the new home / apartment price.

Road expansion projects in municipalities in BC are typically funded by a combination of municipal funds (drawn from taxes and DCCs), Provincial grant funds and Federal grant funds. The largest share of Federal revenue in Canada is personal income tax at 48.1 % of all revenue. A fund that is often cited as paying for roads is the Federal Gas tax, however this makes up less than 5% of all Federal revenue, and totals only $2 billion per year of Federal Revenue. It is estimated that road maintenance costs in Canada, including expansion projects, total some $12 billion dollars per year.

Who pays for the roads? The answer is everyone pays for the roads, and if the revenue derived strictly from vehicle related taxes were to become the only source of funds used for roadworks, we would have a lot less roads and bridges to drive on.

Andrew Gower is a partner and Courtenay branch manager of Wedler Engineering. He volunteers with several local non-profits and is passionate about the Comox Valley’s sustainable future. He can be reached at 250.334.3263 or www.wedler.com.

Andrew Gower

Wedler Engineering

Climate Change Debate?

We see the debate on climate change play out at all levels of politics and government. From the federal level with a now required carbon taxation program opposed by some, to the provincial level where BC has had a carbon tax for some time now, to even our local municipal level, where it gets discussed at local council meetings with some heated debate about its reality. Despite all of the rhetoric and opinions that counter whether or not climate change is happening and how severe it may be, the debate, for what it was worth, is actually over.

As a practicing civil engineer working in BC since 2005 now, almost all projects I have worked on in all of the various municipalities that they have happened in have been governed by regulations and standards that have incorporated mitigating measures to climate change. From predicting how much potable water can be supplied from certain watersheds, to designing stormwater infrastructure to safely convey rain water away from our homes and streets, climate change has been factored in to the very basis of the calculations and data used for over a decade now.

Locally, all four municipal governments in the Comox Valley signed on to the Climate Action Charter “pledging to take action to significantly cut both corporate and community-wide greenhouse gas emissions”. The City of Courtenay amended their Engineering Design Standard and Specifications in 2002 to increase the required amount of rainfall analyzed for stormwater systems to account for climate change.

A lot of the policy and design standards that have responded to climate change have been written and championed by engineers. Across Canada, professional engineering associations have been very clear on the need to mitigate and adapt to climate change, and that its cause is from human produced emissions. Why, you may ask, have engineers both individually and cooperatively signed accepted and taken action on this? It’s simple: ample scientific evidence exists, and it is the duty and ethical obligation of engineers to take action that is in the best interests of society.

Andrew Gower is a partner and Courtenay branch manager of Wedler Engineering. He volunteers with several local non-profits and is passionate about the Comox Valley’s sustainable future. He can be reached at 250.334.3263 or www.wedler.com. Andrew Gower

Wedler Engineering