Has engineered stormwater doomed BC’s waterways?

Has engineered stormwater doomed BC’s waterways?

by | May 1, 2019

Courtenay Councillor Wendy Morin (left) and Comox Councillor Stephanie McGowan listen to Tim Ennis speak about Kus Kus Sum / George Le Masurier photo

Has engineered stormwater doomed BC’s waterways?

By

As population growth continues unrestrained and subsequent urban development expands the dimension of impervious surfaces, an increasing volume of polluted stormwater runoff will poison British Columbia’s waters, local species and natural ecosystems.

It sounds like a doomsday prediction, and according to the keynote speaker at a recent provincial conference on water stewardship it’s going to take a major change in local government thinking to avert this disaster.

Bill Derry, one of the Pacific Northwest’s best known experts on stormwater management, delivered this keynote message recently to an audience of more than 200 British Columbia streamkeepers, local government engineers and elected officials and others. Derry spoke April 3 at the second Vancouver Island Symposium on water stewardship organized by The Partnership for Water Sustainability in B.C.

“Put the forest back”

Before any development occurred in B.C., soils and natural vegetation in forests soaked up rainwater, filtered it and slowly released it into streams that flow into larger bodies of water. But in cities, where nature has been covered with impermeable surfaces, rainwater flows along streets where it picks up toxic chemicals and carries them unfiltered into water systems through gutters and underground pipes.

To protect or restore water quality in developed areas is a complicated problem, but Derry said the solution is quite simple: “Put the forest back.”

That’s impossible, of course, yet alternatives do exist.

Fifty years ago, Scottish landscape architect Ian McHarg proposed using natural systems in urban planning. His 1969 book Design With Nature was a guide toward what we call green infrastructure today; the use of rain gardens and infiltration galleries.

Getting local government engineers to implement green infrastructure that protects or restores water quality in developed areas will take massive and relentless public pressure on local governments.

“Tweaking current systems and practices isn’t enough,” he said. “Major change is required, and governments can’t do it. They won’t do it unless we push them.”

Derry said government engineers and elected officials are reluctant to shift from managing stormwater with curbs and gutters toward source control — managing rain where it falls — out of fear of lawsuits and insurance liabilities.

And local governments don’t believe people will maintain rain gardens or other green infrastructure on their properties, he said.

“So we have to challenge old ideas at chamber forums and talk to decision-makers,” he said. “Change will only and always comes when motivated people talk to other people.”

Derry was one of several speakers at the conference who spoke of the benefits of designing municipal systems that attempt to mimic nature. Others spoke of studies that show green spaces and urban streams improve people’s mental health, and are aesthetically pleasing.

Jody Watson, supervisor of environmental planning and initiatives for the Capital Regional District, echoed Derry’s message that public pressure can effect change. Watson is also the past chair of the Bowker Creek Initiative, a successful restoration of a major waterway running through three municipalities in the Victoria area.

Because local governments had given up on Bowker Creek, more and more of it was being buried and channelized.

But widespread community pressure raised the creek to the regional district’s No. 3 priority. Consultants had to convince local engineers of the value of restoring and daylighting the creek. Some staff engineers had rigidly opposed daylighting the creek.

“Sometimes you have to just wait for somebody to retire,” Watson said.

Derry urged conference attendees to champion better stormwater practices on several fronts.

— No expansion of urban growth boundaries. Increase urban density and “save the best of the rest,” he said.

— Require government agencies to preserve forests, not just slow down development. “There should be no net loss of forest cover,” he said.

— Ban toxins such as zinc on vehicle tires, copper on brakes, phosphorous and the micro-plastics from single-use bags and water bottles at the local, provincial and federal level.

Deery cautioned his audience not to expect instant results.

“This isn’t something that will happen overnight,” he said. “But we need to amp up the seriousness of the discussions.”

 

 

 

 

 

 

COMOX LAKE, CONSERVATION PARTNERSHIPS AND BROOKLYN CREEK

Comox Valley Regional District Senior Engineer Marc Rutten spoke to the conference about the Comox Lake Watershed Protection Plan. It’s a wide-ranging effort that involves multiple landowners and will address issues of turbidity and hydrological changes from logging activities. The watershed is the only source of drinking water for 50,000 residents.

Tim Ennis, the executive director of the Comox Valley Land Trust, spoke about the Comox Valley Conservation Partnership, one of six such groups in the province. The partnership has a unique focus on local government, and speaks with one voice on conservation issues, growth and urban forest strategies. Ennis also talked about the Kus-Kus-Sum project, which he said is more about reconciliation than restoration. “Ten acres of steel and concrete is a daunting” restoration project. But he called the recovery of the K’omoks Estuary a “fantastic model for success.”

Al Fraser and Marvin Kamenz of the Town of Comox, and Christine Hodgson of the Brooklyn Creek Watershed Society, spoke about the relationship between the town and the streamkeepers. Hodgson said over the last 13 years, the streamkeepers have raised about $300,000 ($100,000 in-kind) for in-stream work to improve fish habitat. The town has roughly matched the group’s fundraising. The streamkeepers also do annual smolt counts and public education for neighboring residents.

 

 

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Stormwater systems shift slowly toward green infrastructure

Stormwater systems shift slowly toward green infrastructure

by | Dec 19, 2018

Director of Engineering Services Ryan O’Grady at Courtenay City Hall   |  Photo by George Le Masurier

Stormwater systems shift slowly toward green infrastructure

By

This is the fourth in a series exploring the adverse effects on our waterways from how municipalities have traditionally managed stormwater runoff, and the slow shift to mimic natural through green infrastructure. This week we look at how Comox Valley municipalities are addressing the issues. Next week: what other communities are doing.

 

Stormwater management plans in the Comox Valley have historically treated rainwater as waste, something to be collected and disposed of quickly, usually into previously clean streams or directly into the ocean.

Our local governments have commonly relied on hard engineering solutions that employ expensive infrastructure, such as storm drains, catch basins, pipes and ponds.

That approach has removed and altered the source of groundwater that used to recharge our aquifers. And it has left us with polluted streams incapable of supporting aquatic life, shellfish harvesting bans, eroded private and public property, the loss of attractive natural environments and a long-term financial burden we cannot afford.

Shellfish bans to all of the K’omoks Estuary

Comox Valley governments already have more than roughly $400 million in unfunded infrastructure liabilities (even more if the calculation was based on replacement cost), and stormwater systems account for a significant portion of that staggering total. The Town of Comox alone had $160 million in 2012.

And each new regional housing development ultimately adds more to the total because builders pay development cost charges that cover only the costs of installing infrastructure. They pay nothing for ongoing repairs, maintenance and replacment. Taxpayers are saddled with that burden, forever.

Clearly, a new approach is needed.

Forward-thinking municipalities have shifted toward source control, managing rain where it falls through infiltration, evapotranspiration and rainwater harvesting, techniques known as green infrastructure. This improves water quality, reduces flooding and erosion and costs taxpayers less.

To fund this fundamental transformation in stormwater systems, some municipalities have introduced new fees based on the percentage of impervious surfaces on a property, along with corresponding financial incentives to install green infrastructure.

So, given the benefits and cost savings of going green, are Comox Valley municipalities and other local governments rushing to implement green infrastructure? Not exactly.

A 2017 study conducted by the Canadian Freshwater Alliance and Green Communities Canada, which included data from the Comox Valley, found that most municipalities were moving slowly.

“Most communities surveyed are not far advanced in adapting urban landscapes to manage rain where it falls,” according to a Green Communities summary of the study. “Communities appear to be making moderate commitments … in community plans.”

So, what exactly are Comox Valley municipalities doing?

City of Courtenay

Ryan O’Grady, the city’s director of engineering services, will lead the development of an Integrated Stormwater Management Plan (ISMP) in 2019. The plan will encompass strategies for flood mitigation in the downtown core, how to replace traditional engineered infrastructure with green solutions and will, he says, look through a broad lens at regional solutions.

“The ISMP will have an educational component, too, about stormwater systems,” O’Grady told Decafnation. “These will be challenging conversations, but there is a collective desire to change.”

Water and sewer issues have gotten most of every municipalities’ attention up until now, he said. Stormwater is one of the last service areas to focus on.

Rain gardens on Courtenay’s new ‘complete’ Fifth Street

“Our city has prioritized stormwater lower in the past to deal with drinking water,” O’Grady said. “All staff are looking forward to working on stormwater.”

The city has also shifted its approach to management of assets from reactive to proactive, a move he said came from Chief Administrative Officer David Allen (see separate story).

For example, the city is currently doing a culvert assessment where streams pass under roadways to see they are working properly. Good working culverts are important for fish passage. And the recently renovated upper portion of Fifth Street was designed with rain gardens to test how well they work and the ongoing cost to maintain them.

“We’re learning how to integrate green infrastructure and low-impact development going forward,” he said.

O’Grady intends for the stormwater plan to take a regional view, including discussions about Brooklyn Creek, which originates in Courtenay, flows through regional Area B and empties into Comox Bay.

“There’s a collective desire to collaborate … it would be great to work together,” he said.

The stormwater management plan project is part of a national pilot project to improve Courtenay’s resilience to climate change. The city is one of 72 across Canada chosen to participate.

O’Grady told Decafnation he has already begun contacting representatives from the development community, regional technical staff, stakeholders, elected officials, regulatory agencies, creek and stream stewardship groups and the K’omoks First Nations. The planning will get underway in early 2019.

The city has set aside $110,000 to develop the plan, and will get additional funding assistance from the Municipal Natural Asset Initiative (MNAI), a collective that supports municipalities to better understand, value and manage its natural assets onan equivalent basis with its other infrastructure.

“I look forward to facilitating that conversation with the bigger group,” he said.

Town of Comox

Comox does not have a town-wide stormwater management plan, but has created detailed plans for specific developments, such as the North East neighbourhood..

On paper, the North East neighbourhood stormwater management plan looks to be the most progressive for a subdivision in the Comox Valley.

However, the green infrastructure recommended in a plan commissioned by the area’s land owners and developers from McElhanney Consulting Services Ltd., has not been adopted by the town into bylaws that fund and manage their long-term operation.

So, it is unknown at this point whether these green infrastructure policies will actually be implemented, or enforced.

Town of Comox Municipal Engineer Shelley Ashfield refused to meet with Decafnation to discuss the town’s plans. Instead she answered some email questions and referred us to links on the town’s website.

Vegetated property cleared for condos near the Comox Golf Club. Town says no source control on rainwater will apply

If fully enacted, the McElhanney report recommends a variety of source control measures for eventual North East homeowners. These include rainwater harvesting, disconnecting downspouts from stormwater pipes, rock pits (infiltration pits), green roofs, amended soil for rain gardens and permeable pavement for driveways.

The report also recommends the town require narrow streets for less impervious surface, town-owned rain gardens in roundabouts and boulevards, and infiltration galleries.

McElhanney expressed concern in its report about the possibility that homeowners and the town would not maintain or protect the green infrastructure features, which could result in their failure and cause flooding and other problems.

“Given the potential difficulties in enforcing the ongoing maintenance and upkeep … it has been decided that the water balance benefit derived from the use of these features ought to be significantly discounted, to ensure the long-term performance of the overall stormwater management system,” the report says.

To hedge against that possibility, the report suggests, “It may be prudent to approach the shift to greater reliance on Low Impact Development tentatively, by designing a few subdivisions on the basis of redundant capacity, and then monitoring for compliance with clearly worded and well-publicized operation and maintenance regulations.”

It appears the neighbourhood will get traditional stormwater conveyance in addition to requirements for green infrastructure

The engineers are recommending the creation of series of dry detention ponds connected by infiltration trenches that all ultimately flow into the Queens Ditch, which is a low-sloped ditch leading to the Strait of Georgia at the Point Holmes boat ramp.

And they recommend copious informational signs reminding homeowners of their responsibilities for managing rainwater on their property and not to damage town-owned green infrastructure.

Ashfield said the town is currently updating its Subdivision and Development Services Bylaw and she hopes to have it finalized by next spring. But she would not say whether all or some of the North East Comox stormwater recommendations would be included in the town-wide bylaw.

Asked via email whether the town asked for green infrastructure features in the redevelopment of the Comox mall, or in the development of new multi-family projects at the Comox Golf Course or on Anderton Road, Ashfield said it did not.

“These sites are per the town’s current Official Community Plan and as such are currently modeled with the town’s 2013 storm study,” Ashfield wrote.

She also said bioswales or other infiltration features were considered for the recent Robb Road renovation, but were rejected because of the installation and maintenance cost premium and soil condition.

Ashfield said the town would be an active participant in the Courtenay Integrated Stormwater Management Plan process.

“Anything upstream of the town drains into Brooklyn Creek and so is very important that all jurisdictions within any watershed work together …” she said.

Village of Cumberland

The majority of Cumberland’s rainwater is collected and is either combined with the sanitary sewer system or, where it is separated, directed to one of three wetland areas around the village.

Manager of Operations Rob Crisfield said the village does have some storm drainage systems where rainwater is collected into a bioswale and soaks away into the ground.

One of several rain gardens in the boulevards entering the Village of Cumberland

“This method is used in the new ditches that were established on Cumberland and Bedan roads as part of a (renovation) project in 2016-2017,” he told Decafnation. “Of course, this doesn’t always work, depending on soil conditions.”

The village also requires ground recharge infiltration methods in appropriate subdivisions to allow water to soak back into the ground without runoff. And it is looking at a man-made pond in the Carlisle Lane development as a retention pond.

“We are also looking at including the potential of rain gardens in our downtown enhancement plan when it is updated in the near future,” he said.

Comox Valley Regional District

Marc Rutten, the general manager of the regional district’s engineering services branch, says the CVRD has no stormwater infrastructure to manage.

But the regional district is responsible for land use planning in the rural areas and uses the development permit too to reduce natural hazards (steep slopes) and protect the natural environment (streams). The CVRD has mapped the entire district to identify steep ravines and slopes, and streams, with the goal of ensuring no adverse effects from water flows.

The CVRD also dictates that water flows before and after a property is developed remain equal, so that streams neither flood nor run dry. But the CVRD shifts responsibility to the landower to employ green infrastructure — minimizing impervious surfaces, ponds, rock pits, pervious pavers, etc. — to achieve that goal.

How a street-side rain garden functions

However, stormwater runoff from Courtenay and Comox does affect the CVRD wastewater treatment plant on Brent Road.

Inflow volumes at the treatment plant increase by 3.5 times during the rainy winter months, an indication that stormwater is leaking into the sanitary sewer system.

Rutten said current municipal bylaws don’t allow stormwater to be tied into sewer lines, but there are legacy connections, which were common 70 years ago. Courtenay and Comox have separated sewer and stormwater lines over the last 40 years.

But because sewer and stormwater pipes are usually buried side-by-side, stormwater can leak into a gravity sewage system, such as the Courtenay-Comox sewer lines.

A gravity sewer systems runs under atmospheric pressure and the pipes are generally 25 percent to 75 percent full and flowing downhill. There is generally not enough pressure inside the system to force sewage out of the pipe, but groundwater enters because when groundwater levels rise, static pressure is created to force the water into the sewer pipe through worn out gaskets in pipe section joints.

Darry Montieth, the CVRD’s manager of liquid waste planning, said the Ministry of Highways has some subdivision approval authority in rural areas, and maintains all rural ditches.

But in the developments where the CVRD does have approval authority, Montieth says the district stresses 30 metre riparian setbacks and steep slope guidelines and can require a stormwater drainage plan through the development permit process.

The future

“Stormwater runoff is one of the largest water pollution issues facing the U.S. today,” says Larry Levine, a senior attorney with the National Resource Defense Council, an international environmental advocacy group.

And the challenge for Canadian municipalities is to wholeheartedly embrace green infrastructure as the only affordable and effective long-term solution to how rainwater is managed.

Next: how other communities on Vancouver Island and around the world are meeting this challenge.

 

 

 

 

 

 

READ MORE

North East Comox Stormwater Management Plan

Green Communities Canada

Canadian Fresh Water Alliance

 

 

A SHORT GLOSSARY OF STORMWATER TERMS

Bioswales — A stormwater conveyance system similar, but larger than a rain garden (see below).

Evaporation — As water is heated by the sun, surface molecules become sufficiently energized to break free of the attractive force binding them together, and then evaporate and rise as invisible vapour in the atmosphere.

Green infrastructure — Any natural or built system that provides ecological benefits and help to maintain pre-development hydrology. It encompasses natural features like streams, wetlands, forests and parks, as well as engineered systems that manage urban runoff.

Groundwater — Subterranean water is held in crack and pore spaces. Depending on the geology, the groundwater can flow to support streams. It can also be tapped by wells. Some groundwater is very old and may have been there for thousands of years.

Hydrologic cycle — The endless circulation of water. From the beginning of time when water first appeared, it has been constant in quantity and continuously in motions. The same water molecules have been transferred time and time again from the oceans and the land into the atmosphere by evaporation, dropped on the land as precipitation and transferred back to the sea by rivers and ground water.

Low-impact development (LID) — The systems and practices that use or mimic natural processes that result in the infiltration, evapotranspiration or use of stormwater in order to protect water quality and associated aquatic habitat.

Precipitation — Rain, snow or hail from clouds. Clouds move around the world, propelled by air currents. For instance, when they rise over a mountain range, they cool, becoming so saturated with water that water begins to fall as, snow or hail, depending on the temperature of the surrounding air.

Rain garden — A miniature wetland in a residential setting, lower than the adjacent grade to collect rainwater from roofs, driveways or streets, thus allowing infiltration into the ground.

Runoff — Excessive rain or snowmelt can produce overland flow to creeks and ditches. Runoff is visible flow of water in rivers, creeks and lakes as the water stored in the basin drains out.

Transpiration — Water vapour is also emitted from plant leaves by a process called transpiration. Ever day an actively growing plant transpires five to 10 times as much water as it can hold at once.

 

 

 

 

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Can green innovations stop polluted stormwater from killing our waters?

Can green innovations stop polluted stormwater from killing our waters?

by | Nov 29, 2018

Grasses ready to plant in the rain gardens that line Courtenay’s Fifth Street renovation. George Le Masurier photo

Can green innovations stop polluted stormwater from killing our waters?

By

First in a series

The Department of Fisheries and Oceans slapped a ban on both personal and commercial shellfish harvesting throughout Baynes Sound this week because Sunday’s heavy rainfall, which came “after a prolonged dry spell,” will “adversely affect marine water quality.”

It’s a regular notice the DFO issues around most urbanized regions of Vancouver Island this time of year, and it usually lasts for more than a few days.

Why? Because every time it rains after a dry period, it’s as if a giant toilet flushes animal feces, fertilizers, pesticides, oils, road salts, heavy metals and other contaminants into our municipal stormwater systems, which in turn send torrents of polluted water directly into our watersheds, killing fish, eroding property and making our waters unsafe for shellfish harvesting.

This is not a new problem. For the past 100 years, urban development has replaced natural vegetated land with impervious surfaces like roads and parking lots. This has diminished the amount of rainwater absorbed into the ground and reduced the dispersal of precipitation back into the atmosphere from trees, which do the heavy lifting, and other plants, via a process called evapotranspiration.

As a result, surface runoff has become the primary means of rainwater drainage.

To control flooding, Comox Valley municipalities, like other local governments around the world, invested millions of dollars over time in underground infrastructure to channel rainwater runoff into rivers or streams. This not only polluted these waterways and killed wildlife, but the increased volume and speed of the moving water caused erosion and other flooding risks by altering the natural hydrologic cycle.

Even today, when streams get in the way of development, they are often diverted into pipes and buried beneath buildings and parking lots, which greatly increases the flow rate of stormwater and is more likely to cause erosion in a stream’s natural sections.

Comox’s Golf Creek is a prime example. Eighty-six percent of the once flourishing natural stream flowing into Comox Harbor has been buried beneath residential streets, the Comox Mall and the Berwick Retirement Community. It’s polluted after heavy rains and a downstream property owner is currently suing the town over erosion caused by the creek’s sudden fast flows and large volumes.

Former Comox Department of Fisheries and Oceans Officer Chris Hilliar says the problem with stormwater runoff is just the story of urban development gone wrong.

“Humans have an order to their development process: first we log it, then we farm it, then we pave it,” he told Decafnation. “Fish can get along with forestry, if it’s done right; they can get along with farming, if it’s done right; but, concrete and pavement are killers, a death knell to streams and the aquatic life within them.”

The list of problems caused by contaminated stormwater runoff goes beyond erosion and flooding.

Stormwater runoff is the main reason why many urban streams are devoid of fish or linger on aquatic life-support, and why these streams can pose a public health risk for children who play in them.

Stormwater runoff is the top non-point source of oil from human activity into North America’s oceans, according to the National Research Council. And it has been identified as the source of polychlorinated biphenyls (PCBs) that are harming British Columbia’s killer whale population, according to another NRC paper.

“It’s an iterative process. Every municipality is on a continuum of change; modernizing, moving forward with advances in knowledge” — Ryan O’Grady

It sounds like an irreversible situation whose remedy is too expensive to undertake. In a 2012 meeting with the Comox Valley Conservation Partnership, Town of Comox Public Works Superintendent Glenn Westendorp said the municipality was facing about $160 million in unfunded infrastructure liabilities that include fixing and replacing stormwater pipes.

“We know the bill is coming to us down the road and we don’t see the means of paying for it,” Westendorp was quoted as saying in the society’s newsletter.

But a shift in thinking about traditional methods of handling stormwater began to occur during the 1980s and 1990s toward constructing wetlands and ponds to detain rainwater long enough for contaminates to settle out and allow some water to infiltrate back into the ground. This gave hope there was a means of cleaning our streams and extending the life of municipal infrastructure.

Today, there’s been a further shift toward a recognition that nature itself cleans and controls rainwater better than any engineered solution. This new emphasis attempts to imitate nature with pervious surfaces, downspout disconnection, rain gardens, bioswales, green roofs and rainwater harvesting. And the prospects have excited many municipal engineers and environmentalists.

But the wheels of change turn slowly.

“Any change in regulations, such as we’re seeing for stormwater, does not go from 0 to 100 miles per hour,” Ryan O’Grady, Courtenay’s director of engineering services told Decafnation. “It’s an iterative process. Every municipality is on a continuum of change; modernizing, moving forward with advances in knowledge.”

And change also requires elected officials to pass new policies and update bylaws that give municipal staff the authority to require LID and green infrastructure. Without legal regulations, not all developers and property owners will embrace the movement, because these rainwater features take up space that some are loathe to forfeit.

Local governments have made progress

Almost all BC communities now follow a method that measures its organizational capacity for maintaining infrastructure to ensure sustainable service delivery. It’s a framework that Courtenay Chief Administration Officer David Allen helped create in his role as Co-Chair of Asset Management BC.

And Courtenay has launched a pilot project with the Municipal Natural Assets Initiative, which attempts to value a municipalities’ natural assets and is working with the Public Sector Accounting Board to change accounting methods to allow for this approach.

“We are using these methods to develop ways to use a combination of engineered assets and natural assets to replace our existing stormwater and flood management systems,” Allen told Decafnation.

In its recently completed renovation of Fifth Street, the City of Courtenay narrowed the roadway (reducing impervious surface area) and added rain gardens to capture runoff and encourage infiltration. The city plans to develop its first Integrated Stormwater Management Plan in 2019 that could set a new, greener standard for stormwater management in the municipality.

The Town of Comox has developed a Stormwater Management Plan for the North East Comox Neighbourhood — lands near the Comox Airport — that incorporates the latest best practices for low-impact development (LID) and green infrastructure regulations, although these have not yet been made into enforceable bylaws.

Cumberland added bioswales along Bevan and Cumberland roads when they were renovated in 2017, and may include rain gardens in its upcoming downtown redevelopment plan.

Other communities have taken big leaps forward

The City Victoria has created a new utility tax to fund its future cost of maintaining stormwater infrastructure and to encourage residents and developers to adopt green infrastructure and low-impact development designs. In most communities, stormwater infrastructure costs are paid out of general revenue.

Victoria residents are now taxed separately for the stormwater that leaves their property. In other words, the more impervious surfaces  and the fewer onsite mitigations you have, such as rain gardens and rock pits, the more you will pay.

Victoria joined Richmond, BC, and hundreds of other cities across Canada and the world that now expect residents and developers to manage their own rainwater, lessening the burden on municipalities.

It’s the theory behind Chinese landscape architect Kongjian Yu’s “sponge cities” concept, a way to describe the capacity of an urban landscape to absorb rainwater naturally. Major world cities have jumped on the idea. Berlin, Germany, adopted a city-wide Sponge City Strategy in 2017.

Since 2009, Toronto, Ont. has required buildings over 2,000 square metres to have green roofs, which use several layers of soil to grow plants that capture and release rainwater, slowing the rush of water through the city’s stormwater pipes.

The list and variety of innovations for managing stormwater through green infrastructure is long and growing.

Municipalities in the Comox Valley and elsewhere have focused heavily on drinking water and wastewater treatment in the past. But now their attention has turned sharply toward improving how we manage stormwater.

The change may seem to be coming too late for streams, like Golf Creek in Comox, that are almost entirely buried and channelized. But challenging initiatives like the 100-year plan to restore Bowker Creek in Victoria and the campaign to save the Morrision Creek headwaters between Courtenay and Cumberland may someday restore fish in our streams and keep our waters open to shellfish harvesting.

 

GLOSSARY OF STORMWATER TERMS

 

Bioswales — A stormwater conveyance system similar, but larger than a rain garden (see below).

Evaporation — As water is heated by the sun, surface molecules become sufficiently energized to break free of the attractive force binding them together, and then evaporate and rise as invisible vapour in the atmosphere.

Green infrastructure — Any natural or built system that provides ecological benefits and help to maintain pre-development hydrology. It encompasses natural features like streams, wetlands, forests and parks, as well as engineered systems that manage urban runoff.

Groundwater — Subterranean water is held in crack and pore spaces. Depending on the geology, the groundwater can flow to support streams. It can also be tapped by wells. Some groundwater is very old and may have been there for thousands of years.

Hydrologic cycle — The endless circulation of water. From the beginning of time when water first appeared, it has been constant in quantity and continuously in motions. The same water molecules have been transferred time and time again from the oceans and the land into the atmosphere by evaporation, dropped on the land as precipitation and transferred back to the sea by rivers and ground water.

Low-impact development (LID) — The systems and practices that use or mimic natural processes that result in the infiltration, evapotranspiration or use of stormwater in order to protect water quality and associated aquatic habitat.

Percolation — Some of the precipitation and snow melt moves downwards, percolates or infiltrates through cracks, joints and pores in soil and rocks until it reaches the water table where it becomes groundwater.

Precipitation — Rain, snow or hail from clouds. Clouds move around the world, propelled by air currents. For instance, when they rise over a mountain range, they cool, becoming so saturated with water that water begins to fall as, snow or hail, depending on the temperature of the surrounding air.

Rain garden — A miniature wetland in a residential setting, lower than the adjacent grade to collect rainwater from roofs, driveways or streets, thus allowing infiltration into the ground.

Runoff — Excessive rain or snowmelt can produce overland flow to creeks and ditches. Runoff is visible flow of water in rivers, creeks and lakes as the water stored in the basin drains out.

Transpiration — Water vapour is also emitted from plant leaves by a process called transpiration. Ever day an actively growing plant transpires five to 10 times as much water as it can hold at once.

Water table — The level at which water stands in a shallow well.