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Rainwater Management

Download British Columbia guidance documents. Learn about the guiding philosophy and tools for implementing ‘sustainable watershed systems, through asset management’. Be inspired by success stories. Understand why it is necessary to manage the complete spectrum of ‘rainfall days’ in a year, preserve or replicate the pathways by which water reaches streams, and so mimic flow-duration distribution. The emphasis herein is on the drainage runoff side of the Water Balance distribution.

Latest Posts

DOWNLOAD: Stormwater Planning: A Guidebook for British Columbia


“Released in 2002, the Guidebook provides a framework for effective rainwater management throughout the province. This tool for local governments presents a methodology for moving from planning to action that focuses on implementing early action where it is most needed,” states Laura Maclean. “The Guidebook approach is designed to eliminate the root cause of negative ecological and property impacts of rainwater runoff by addressing the complete spectrum of rainfall events. The Guidebook approach contrasts with conventional ‘flows-and-pipes’ stormwater management.”

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Water Balance Model – On Tour!


“Have a look at some of the Water Balance Model slideshow presentations that have been made to industry and government groups starting in 2001. This includes some of the early presentations on the Water Balance Methodology that helped pave the way for the paradigm-shift from 'peak flow thinking' to 'volume-based thinking'. The many presentations created awareness and influenced expectations,” stated Ted van der Gulik.

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Primer on the Ecological Accounting Process (EAP) – A Methodology for Valuing the ‘Water Balance Services’ Provided by Nature (released January 2019)


“The concept of natural capital and natural assets can be a challenge to integrate effectively into asset management practices. EAP deals with a basic question: what is a creekshed WORTH, now and in future, to the community and various intervenors? We landed on the notion of the ‘natural commons’ as the starting point for calculating the financial value of a stream bed and riparian corridor. The EAP valuation methodology yields an asset value for the stream corridor that can then be used for budget purposes,” stated Tim Pringle.

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SUSTAINABLE WATERSHED SYSTEMS: Every urban creekshed comprises a ‘constructed commons’ and a ‘natural commons’, and each is a system – this way-of-thinking is foundational to the Ecological Accounting Process (EAP) which looks at the value of the lands that underlie the natural commons


Professor John Henneberry in the United Kingdom and the Partnership for Water Sustainability in BC have identified the same methodological problems – that is, natural systems do not dissect conveniently in order to be quantified and given financial value. ”Quantifying and valuing nature are complex tasks. Undertaking them alters our conception of nature. As a result of it, nature appears more fragmented because we have to slice it into categories and dice those categories into bits before we can value bits of those bits,” states John Henneberry.

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LIFE AFTER CARBON: “The emerging idea inverts the modern-city hierarchy, restoring nature, instead of the city, as the dominant context,” wrote Peter Pastrik and John Cleveland in their book about cities that are reinventing themselves to combat climate change (published in 2018)


“Part of urban renaturing is a restorative exercise, a way to reinstate balance and sustainability to the city’s relationship with nature,” wrote Peter Pastrik. “When cities renature themselves, they pursue three distinct, interrelated applications of the idea. They expand the use of green infrastructure. They protect and enhance ecosystems and biodiversity. And they provide people with ways to immerse in nature. Each of these methods involves innovative practices used at multiple urban scales.”

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HOW CITIES CAN MAKE ROOM FOR WATER: “Understanding the water cycle is an opportunity to generate a positive relationship between natural processes, plants and people,” stated Elisa Palazzo


“Innovative strategies understand flood as a natural process to work with, rather than resist. Non-structural, soft and nature-based solutions to flood adaptation are replacing centralised and engineered technologies. These projects use climate change positively to provide multiple added benefits,” wrote Elisa Palazzo. “Looking at how cities are designed and performing in Australia, there is plenty to learn from the international experience. We have a lot to do to adjust this knowledge to the local context.”

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BUILDING RESILIENT BMP TOOLKITS: “Resiliency is not about just bouncing back, but bouncing back in better shape than before,” wrote Jacob Dorman


“Jurisdictions are struggling to make their infrastructure more resilient in light of challenges such as recurrent flooding, higher intensity and longer duration rainfall events, aging conveyance systems, and the lack of financial resources, to name just a few issues,” wrote Jacob Dorman. “Before you can solve the problem of providing resilient BMPs, you must first understand what resiliency is all about in the first place. It’s an immense undertaking at the community scale and requires a seismic shift from historical thinking.”

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GREEN CITY, CLEAN WATERS PROGRAM: City + University Partnership Pioneers Application of Real-Time Data to Help Philadelphia Improve Green Design for Rainwater Capture


“A partnership between the Philadelphia Water Department and Drexel University’s Sustainable Water Resource Engineering Lab uses sensors on green infrastructure in order to utilize city storm water more efficiently,” reports Ben Levine. It just so happens that Drexel’s campus has a variety of green infrastructure project types that make it a good test bed for developing new and more efficient approaches to monitoring and using new technology and networks. They have developed low-cost and low-power sensor networks to collect environmental data from green infrastructure in real time.

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LOS ANGELES COUNTY’S BOLD PLAN FOR RAINWATER CAPTURE: “Measure W gives Los Angeles County and its 88 cities the chance to transform urban hardscapes into more nature-based, green infrastructure,” wrote UCLA’s Mark Gold in an op-ed published in the Los Angeles Times


The county is developing a plan to supply 20% of annual water demand from rainwater capture. “Going forward, every street improvement initiative should be viewed as an opportunity for greener streets that facilitate water absorption and ensure that remaining runoff is treated. New park projects should include ways of capturing runoff on site for local irrigation or to augment groundwater supplies. With funding from Measure W to supplement existing funds, these goals now seem possible,” wrote Mark Gold.

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URBAN TREE CANOPY: “What the economy really needs is more trees” – Ross Gittins, the Sydney Morning Herald’s economics editor


“Planting trees in parks, gardens or streets has many benefits, helping to cool cities, slowing stormwater run-off, filtering air pollution, providing habitat for some animals, making people happier and encouraging walking,” wrote Ross Gittins. “Shading from strategically placed street trees can lower surrounding temperatures by up to 6 degrees – or up to 20 degrees over roads. Green roofs and walls can naturally cool buildings, substantially lowering demand for air-conditioning.”

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USE OF ‘MACHINE LEARNING’ TO DISTINGUISH BETWEEN TREE CANOPY AND TREES: “Trees are pretty hard to map. So, what’s the solution if we want to map tree canopies in places with complex geographies? How do we fill in the gaps between official street tree census and trees in parks and on private property?” – Tim Wallace, geographer for the New York Times


“(Tree) surveys are expensive to conduct, difficult to maintain, and provide an incomplete picture of the entire extent of the urban tree canopy. Both the San Francisco inventory and the New York City TreesCount! do an impeccable job mapping the location, size and health of street trees, but exclude large chunks within the cities, like parks,” wrote Tim Wallace. “This data gap is neither accidental nor purposeful. The trees they mapped were a product of bureaucratic choices and limitations.”

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BEYOND THE GUIDEBOOK PRIMER SERIES: “The purpose of the Primer is to connect the dots and disseminate information on the ‘science-based understanding’ that underpins the vision for Sustainable Watershed Systems,” stated Peter Law, formerly with the BC Ministry of Environment, when the Partnership for Water Sustainability released the Primer on Application of Ecosystem-based Understanding in the Georgia Basin (September 2016)


“An interface is needed to translate the complex products of science into achievable goals and implementable solution for practical resource management. This interface is what we now call a science-based understanding,” stated Peter Law. “Understanding how land development impacts watershed hydrology and the functions of aquatic ecosystems provides a solid basis for making decisions to guide action where and when it is most needed. This understanding will help multiple audiences ask the right questions so that communities make informed decisions.”

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