Daylighting Rivers

by Sally Cole

Daylighting:  A Global Trend Transforming Cities in the 21st Century

Waterways were once the lungs and arteries of urbanization.  Yet, most of the world’s cities have buried their founding streams under concrete or incorporated them into sewer networks under roads and expressways and housing and industrial developments.  Burying rivers has degraded habitats and increased pollution and the costs of water treatment and waste management.  It has also increased flooding and damages due to flooding that are increasing with climate warming.

What is Daylighting?

Daylighting is the process of removing concrete and culverts that are covering and obstructing original rivers, creeks and drainage paths and of revitalizing original wetlands and drainage flow.  Daylighting is part of a larger flood management and water treatment strategy and an attempt to redress the thoughtless neglect of cities that continue to pollute their rivers.

Why Daylight?

Bringing back lost urban rivers by removing culverts and integrating flowing rivers into cities again –daylighting – is part of a global movement to rediscover urban rivers in cities worldwide.  In the 21st century, forward-thinking cities and citizens – in London, New York, Seoul, Zurich, Berkeley – are daylighting their historic rivers in a bid to halt pollution end environmental degradation, and increase the liveability and future viability of their cities.

These cities report that their daylighting projects have:

– reduced water treatment costs

– aided flood management

– increased property values

– revitalized natural habitats with the return of indigenous plants, trees, fish, birds    and other wildlife

– added greenbelts, bike routes and walking paths that have produced connectivity within and between neighbourhoods

– increased social health and volunteer citizen engagement;

– created tourism and related business opportunities.

Montreal has an opportunity to join this progressive urban trend and invest in the future of our city by daylighting our historic St. Pierre River, the river on which our city was founded.

The Lachine Canal bike path crosses where the bed of the St. Pierre used to be.

Models of Successful Daylighting in Cities Around the World

Since 2009, London has opened up more than 17kms of waterways.  Throughout the U.K. – where daylighting is known as deculverting — municipal governments have incorporated deculverting into legislation on water and flood management.

Zurich, which has undertaken more daylighting than any other city in the world, has tracked, documented and analyzed the combined social, environmental and economic benefits.  The city has found the economic rewards of daylighting in reduced wastewater treatment costs.  Channeling clean water out of sewers and back into original rivers and streams reduces the volume of water that flows to sewage waste management facilities for treatment.  Zurich also reports an increase in public desire and civic engagement to recapture lost spaces and to improve the quality of life in the city.

The daylighted Cheonggyecheon Stream in Seoul, South Korea, transformed a polluted, urban, crime-ridden wasteland into a major flood relief channel and a 10.9km public downtown recreation space that has revived the city centre and attracts more than 60,000 visitors each day.  Restoration of two historic bridges over the restored river, along with managed changes in the downtown traffic system, has reduced by 2.3% the volume of cars entering downtown Seoul each day and increased bus and subway use.  Along with reducing air pollution, daylighting the Cheonggyecheon has created an environment with clean water and natural habitats that also helps to cool temperatures in the downtown area to 3.6 C lower than other parts of Seoul.

Daylighting the Sawmill River in Yonkers, New York, has created a vibrant green corridor in the city and revitalized the downtown.

In an effort to reduce future flood risk, after hundreds of basements flooded in a 1999 storm, the city of Dubuque, Iowa invested in an engineering study.  The key recommendation of the study was to restore, through daylighting, a one-mile section of the buried Bee Creek that flows under the city centre.

To manage frequent flooding in the downtown area of Kalamazoo, Michigan, city engineers found that it was cheaper to daylight the buried Arcadia Creek than to rebuild and expand the century-old culvert system.

Friends of Meadowbrook Are Daylighting the St Pierre River!

The first step in daylighting is to map the route and extent of a buried river under the city.  The route of the St Pierre River is well known — from its source on Mont Royal through its various tributaries and down to its original outlet into the St. Lawrence River at Pointe-à-Callière.

The St. Pierre River in 1834. source: carte de l’ile de Montreal, 1834, by A. Jobin, BAnQ

The next step in daylighting is called cultural restoration of the river.  Cultural restoration celebrates a buried river through markers, public art and activities to inform the public of its historic path and ecological role, and to raise awareness of the environmental issues and economic costs that have been created over time.

In the case of Montreal, the city has buried the St Pierre River and channelled it into its sewage system until only 200 metres of the original river remain above ground today – in the Meadowbrook golf course.  And those 200 metres are severely polluted through the continued crossing of sewage and floodwater pipes.  Members of Friends of Meadowbrook have begun the work of cultural restoration of the St Pierre River by organizing an annual bike ride along the river’s route from Meadowbrook to Pointe-à-Callière.

The ultimate goal of daylighting is natural restoration: to revitalize some or all of a river to recreate its original ecology and habitats and its rightful place as the centrepiece – the lungs and heart — of a community.

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