"BC Ministry of Transportation and Infrastructure is aligned with Beyond the Guidebook 2010," reports Kim Stephens
Note to Reader:
In May, the second in the 2011 Comox Valley Seminar Series addressed urban watershed protection and restoration issues. The focus of Seminar #2 was on a ‘design with nature’ approach to green infrastructure that integrates rainwater management and drought management.
The article below was prompted by the discussion regarding alignment of efforts at a watershed scale to achieved desired outcomes, in particular protection of property and stream health. The article deals with the role of the Ministry of Transportation and Infrastructure as the approving authority for land development in general, and drainage design in particular, in electoral areas within regional districts.
The article is structured in three parts. First, the enabling powers and responsibilities of local governments are introduced. Then the Ministry’s requirements for land development drainage design in electoral areas are summarized. Finally, the Beyond the Gudebook initiative is explained. The key message is that the Ministry’s requirements mirror the objectives that provide the technical foundation for Beyond the Guidebook.
Enabling Powers for Local Government
In British Columbia, the term ‘local government’ encompasses municipalities and regional districts. The distinction is noteworthy because municipalities and regional districts are governed by the Community Charter and Local Government Act, respectively.
The Community Charter empowers municipalities with extensive and very specific tools to proactively manage the complete spectrum of rainfall events. These tools enable them to achieve watershed goals and objectives.
Although the Local Government Act provides regional districts with similar enabling powers to establish a drainage function within a service area boundary, regional districts that do not have such a service do not have the same regulatory powers as municipalities. The Ministry of Transportation and Infrastructure has historically regulated drainage in electoral areas.
Drainage Responsibility
British Columbia case law makes clear the responsibility of municipalities to manage runoff volume to prevent downstream impacts.
“An increasingly important corollary to that responsibility is the need to work from the regional down to the site scale, to maintain and advance watershed health to ensure that both water quantity and quality will be sustained to meet both ecosystem and human health needs,” states Kim Stephens, Executive Director of the Partnership for Water Sustainability in British Columbia
“While a municipality has control over HOW rainwater runoff is generated and managed within its residential, commercial and industrial land uses, it does not have the same ability to regulate watershed activities that are taking place upstream and outside its municipal boundaries.”
Provincial Guidance Framework
“Fortunately, the Ministry of Transportation and Infrastructure has adopted drainage requirements for land development that are aligned with the desired outcomes for the Province’s Living Water Smart and Green Communities initiatives. Both are about adaptation to a changing climate. Both encourage shared responsibility.”
Ministry Requirements for Drainage Design in Electoral Areas
“In June 2007, the Ministry released the BC Supplement to TAC Geometric Design Guide 2007 Edition. From a local government perspective, Chapter 10 is the key. It outlines the requirements for drainage designs. Of paramount significance, Chapter 10 makes a distinction between highway drainage design and land development drainage design. This distinction provides the Ministry with the capability to align its efforts with municipalities and support a consistent watershed-based approach to rainwater management,” reports Kim Stephens.
Alignment with Municipal Rainwater Management
“The BC Supplement references both Stormwater Planning: A Guidebook for British Columbia and the Water Balance Model for British Columbia. These provide the policy and technical foundation for contemporary rainwater management in BC. This foundation is keyed to an understanding of the integrated strategy for managing the rainfall spectrum (refer to image above), ranging from light showers to extreme storms.”
“Released in 2002, the Guidebook was a catalyst for action to implement a ‘design with nature’ approach to rainwater management and green infrastructure. The Water Balance Model was developed as an extension of the Guidebook.”
Beyond the Guidebook
“In June 2007, Beyond the Guidebook: Context for Rainwater Management and Green Infrastructure in British Columbia was released. By then, practitioners were becoming comfortable with what ‘rainfall capture’ meant in practice. So, it was time to focus attention on how to truly protect and/or restore stream health in urban watersheds,” continues Kim Stephens.
“Beyond the Guidebook initiated the paradigm-shift from the single-function view of traditional ‘stormwater management’ to the integrated and holistic perspective that is captured by the term ‘RAINwater Management’. This also set the stage for defining water sustainability as an outcome` of green infrastructure policies and practices.”
“Stream health protection is a driver for Beyond the Guidebook. Stream health is a function of flow duration, and therefore correlates with stream erosion. Flow duration is something that we can measure and verify. We can also assess the potential for erosion or sediment accumulation within a watershed.”
Beyond the Guidebook 2010
“Released in June 2010, Beyond the Guidebook 2010: Implementing a New Culture for Urban Watershed Protection and Restoration in British Columbia provides guidance for aligning local actions with provincial and regional goals to ‘design with nature’ so that British Columbians can create greener communities, live water smart and prepare for climate change,” states Kim Stephens.
“On this matter of alignment, the language in Chapter 10 of the Ministry’s BC Supplement mirrors the objectives in Beyond the Guidebook 2010. In particular, Chapter 10 states that flows must be managed to ensure that no increase in flooding and stream erosion occur as a result of development storm drainage.”
To Learn More:
To download a copy of the complete Chapter 10, click here. The relevant information is contained on the second and third pages in the sub-sections titled Discharge Rates for Land Development and Detention Storage and Run-off Controls, respectively.
Re-Establish the Connection to the Stream
At Seminar #2 in the 2011 Comox Valley Series, Jim Dumont presented a short course on rainwater management in a watershed context. He is the Engineering Applications Authority for the Water Balance Model Partnership. His “course within a seminar” encompassed History-Science-Tools.
Jim Dumont explained the Beyond the Guidebook methodology and how to apply the Water Balance Model to achieve science-based performance targets for rainfall capture and runoff control.
“The goal of the water balance methodology is to re-establish the connection to the stream, recognizing that we will not able to provide a direct connection to the soil…..because that is what has been lost, unfortunately,” stated Jim Dumont.
“The first construction with urban development will destroy the interflow system. The reality is that it’s gone when we build a road or install services. We are trying to build something to mimic that natural operation.”
To Learn More:
Click on Rainwater Management in a Watershed Context: “Do More With Less & Achieve Stream Health Benefits”
