Green Infrastructure

13 – LESSONS FROM THE PAST INFORM THE FUTURE IN METRO VANCOUVER: Water Balance Accounting Pillar addresses Changes in Hydrology

November 26, 2024 - Posted in Chronicle of Green Infrastructure Innovation in Metro Vancouver (1994-2024), Extracts from the Synopsis

Note to Reader:

In November 2024, the Partnership for Water Sustainability in British Columbia released THE SYNOPSIS for the Chronicle of Green Infrastructure Innovation in Metro Vancouver. The Chronicle is a sweeping narrative of the 30-year period from 1994 through 2024. The Chronicle is a layered package comprising four documents: the Chronicle of the Journey, Stories Within the Story, Synopsis and Executive Summary. The target audience for each layer is different.

The Synopsis is the third layer in the cascade. It is oriented to senior managers who have limited time to absorb what they need to know to make informed decisions. The Synopsis is visual and so can easily be skimmed in 20 minutes or less! This extract is from pages S22 and S23.

Reinventing Urban Hydrology in BC

“In the mid-1990s, the research program initiated by local governments in Puget Sound and led by Richard Horner and Chris May at the University of Washington shook conventional stormwater management wisdom to its foundation. Their findings inspired development of the Water Balance approach in British Columbia,” wrote Kim Stephens, Synopsis author and Partnership Executive Director.

“With publication of Stormwater Planning: A Guidebook for British Columbia in 2002, British Columbia adopted the Water Balance Methodology and led the way in North America. The methodology is the foundation piece for setting Performance Targets to reduce runoff volume and mimic the flow-duration relationship.”

What matters is the flow-duration relationship in streams

The next two images illustrate core concepts that underpin the Water Balance approach

Why has British Columbia fallen behind?

“Practitioners of Rainwater Management in BC fallen behind the West Coast states in protecting streams and reducing risk. Why is that? How did this happen? The needs of BC communities closely align with the other west coast areas that suffer from adverse stream flows rather than the degradation of water quality which is the case on the east coast,” states Jim Dumont, technical advisor to the Partnership.

“California, Washington, and the Oregon DOT require that stormwater management systems maintain stream flow duration to protect against stream erosion and flooding.”

To learn more, download a copy of Living Water Smart in British Columbia: A window into the green infrastructure journey in the Metro Vancouver region.

The edition of Waterbucket eNews published on October 3, 2023 featured the clear thinking and innovation of Jim Dumont in evolving the Water Balance Methodology to the point where it underpins a risk reduction approach to protecting streams in a changing climate.