Canada: Water Issues In Sustainable Developments: Stormwater Management, Sewage Management And Green Roofs



Clean drinking water is a precious resource. Maximizing water efficiency is one of the most effective strategies in building sustainable communities. The following three approaches all contribute to this goal:

  • reducing quantity of, and improving quality of stormwater runoff being released to municipal drainage systems;
  • reclaiming rainwater collected on-site to be used for non-potable purposes; and
  • using green roofs to retain stormwater.

Urbanization leads to increased amounts of stormwater runoff, as development increases the surface area impervious to rainwater.1 Rainwater rolls off cement surfaces such as roofs and roads and enters the municipal sewer system, becoming stormwater and gathering sediment particles as it travels. Sedimentation and stormwater runoff pose continual risks to ecosystems: the runoff containing sedimentation and contaminants eventually enters lakes, rivers and other water bodies, threatening the environment, downstream aquatic life and recreational resources.

On-site sewage treatment systems reduce the volume of water released to municipal sewer systems as well as potable water consumed by residents. The treated water is not potable, but could be used for irrigation, water features and flushing toilets.


Both Dockside Green and UniverCity, award-winning communities in Victoria and Burnaby respectively, feature many water conservation designs and treatments in their communities. The technologies used in both communities are similar in nature. However, the legal framework is quite different with Dockside Green having established a site-wide regime and UniverCity employing site-specific solutions.

1. Dockside Green

In Victoria, the City of Victoria ("COV") entered into a Master Development Agreement (the "MDA") with the developer of Dockside Green Limited Partnership ("DGLP"). The MDA set out the blueprint as to the manner in which Dockside Green would be developed. Under the MDA, DGLP was obliged to, inter alia:

  • comply with design guidelines;
  • building to certain LEED standards; and
  • construct and provide a sewage treatment plant (the "DG Sewage Plant").

DGLP subdivided the original lands into a number of different lots. The MDA was registered as a section 219 covenant in favour of COV on title to all of the Dockside Green lots. The lots to be used for multi-family residential purpose are or will be further stratified. DGLP is the developer of all of the subdivided lots, and is therefore responsible for constructing and marketing the development and selling the units to purchasers directly.

2. UniverCity

UniverCity is a large urban community with a projected population of 10,000 residents located on Burnaby Mountain adjacent to the Simon Fraser University campus. "Environment" is one of the four Cornerstones of Sustainability on which the community is founded.

SFU Community Trust (the "Trust") is the master developer of UniverCity. The Trust causes the leasehold interest in the subdivided lots to be transferred to third party developers, who are therefore responsible for constructing and marketing the development and selling the units to purchasers.


To better understand the effects of sedimentation and stormwater runoff, the following are their definitions:

Sedimentation: "[T]he settling out of soil particles transported by water. ... Sedimentation occurs when the velocity of water in which soil particles are suspended is slowed for a sufficient time to allow particles to settle out. Heavier particles, such as sand and gravel, settle more rapidly than fine particles such as clay and silt."2

Stormwater: "That portion of rainfall and snowmelt runoff that does not naturally percolate into the ground or evaporate, but flows via overland flow, interflow, pipes and other features of a stormwater drainage system."3 Stormwater carries sediment to areas incorporated into the stormwater drainage system, contributing to sedimentation in those areas.



1. How it Works

In Dockside Green, stormwater management is integrated into design features. A system of naturalized creeks and ponds (collectively, the "Ponds") collects stormwater which would otherwise be conveyed into the municipal stormwater system. Rainwater is collected from the roofs and off the grounds, funnelled into deep underground pools and released into the Ponds where it is processed with the assistance of plants and aquatic life native to the environment, which effectively clean the water without the use of chemicals.

2. Legal Mechanism

(a) The Society

Dockside Green (Victoria) Society (formerly Dockside Green Community Association and hereafter the "Society") was formed with the mandate to, inter alia, maintain and operate various common amenities and facilities.

The members of the Society are the registered owners of the unstratified lots within Dockside Green (other than the Society or Dockside Green Power Ltd.) and, after the stratification of each lot, the strata corporations created thereby. The Society was designated under section 219(3)(c) to accept Section 219 Covenants and under section 218(11)(d) of the Land Title Act (British Columbia) to accept statutory rights of way.

(b) Legal Instruments

Two site-wide instruments, a reciprocal easement burdening and benefiting all of the subdivided lots and a statutory right of way in favour of the Society, were registered on title to establish a regime for the access to and use of common roadways, utilities, amenities and facilities including the DG Sewage Plant (collectively, the "DG Common Facilities") by all Dockside Green occupants.

The Society has the mandate to operate and maintain the DG Common Facilities as set out in its bylaws. The easement grants the owners rights to access other owners' lands to carry out maintenance in case the Society fails to do so. The intent is that the Society will maintain and repair the DG Common Facilities, so that the owner of a dominant tenement may not exercise its rights unless the Society ceases to carry out its responsibilities, and even then, such owner may not exercise its rights except in respect of works that benefit its lands exclusively.

A Section 219 Covenant is granted in favour of the Society to ensure that the lands are used as intended by the reciprocal easement and that the owners and strata corporations may not modify or discharge the reciprocal easement without the Society's consent.

A statutory right of way and rent charge (the "Rent Charge") have been granted in favour of the Society to operate and maintain the DG Common Facilities.

(c) Cost Sharing

As required by the Statutory Right of Way, the Society's directors prepare an annual budget which includes the maintenance costs for the Common Utilities. The proportionate share attributable to each lot is based on a fraction which has:

(i) as its numerator the area in square feet of all residential, commercial and industrial premises located on such lot; and

(ii) as its denominator the total area in square feet of all residential, commercial and industrial premises located on all of the lots.

The Rent Charge secures the obligation of each owner or strata corporation to pay its proportionate share of the maintenance costs. As each lot is subdivided by a strata plan, the maintenance costs allocated to that lot will be included in that strata corporation's annual budget. In turn, the owner of each strata lot will pay for his or her share of such maintenance costs based on the applicable unit entitlement.


1. How it Works

The approval of the City of Burnaby ("COB") of an acceptable stormwater management plan is one of conditions of Preliminary Plan Approval ("PPA") for UniverCity projects. The typical plan entails the developer installing an infiltration facility (the "SWM Facility") which stores stormwater and releases the water to the natural soil in the lot rather than the municipal stormwater system.

The SWM Facility could be in the form of a cistern or pools, which could be incorporated as a design element in the development.

2. Legal Mechanism

A section 219 covenant is granted in favour of COB setting out the obligation to install and maintain the SWM Facility. As with many green technologies, it is important that proper maintenance and inspections are carried out on a regular basis to ensure that the SWM Facility functions as intended. Therefore, the covenant contains an obligation to have annual testing and reporting done by a qualified professional for the first three years following installation of the SWM Facility. This obligation will be assumed by the strata corporation created upon filing of the strata plan in respect of that lot.



Developers who intend to create onsite wastewater treatment facilities must comply with the Environmental Management Act Municipal Sewage Regulation ("MSR")4. The MSR applies to flows over 22,700 litres a day and provides authorization for the reuse of wastewater, replacing the need to obtain site specific permits for discharge of treated wastewater into the environment or its reuse5.

One of the MSR's stated goals is to "encourage the use of innovative technologies to provide an alternative for the "big pipe", improved source control, water conservation, water reuse and reduced discharge of treated effluent to the receiving environment."6 The MSR permits communities to avoid connection with the municipal sewer system, as well as allowing treated wastewater to be reused for specified purposes.


1. How it Works

The DG Sewage Plant treats all the wastewater produced in the Dockside Green development. The plant is located in one of the subdivided lots, which is owned by the Society. The water, once treated, is released into the Ponds, like the stormwater, where it is then used for irrigation and other non-drinking purposes.

2. Legal Mechanism

Since the DG Sewage Plant is located on a lot owned by the Society, the Society is responsible for the DG Sewage Plant. Although responsible for maintaining the Sewage Plant, the Society has contracted with an operator experienced in designing, building and operating waste water collection and treatment infrastructure to carry out this function. Accordingly, the Society entered into an Operation and Maintenance Agreement (the "O&M Agreement") with DGLP and Corix Utilities Inc. ("Corix").

Under the O&M Agreement, Corix is responsible for the operation and maintenance of the DG Sewage Plant. In the event of an emergency, if it is necessary to use COV's sanitary sewer system to dispose of sewage and waste water, the Society would be responsible for paying to the City its disposal rates for such use, unless the emergency is due to negligence by Corix.

Sewer charges are payable by all the strata corporations to offset the fee charged by Corix.


1. How it Works

Rather than a site-wide treatment plant, the Trust is employing its water reduction strategy in one building for the time being.

The Trust has constructed a childcare centre designed to meet the Living Building Challenge. To meet the challenge, a building must address seven performance areas or "Petals": Site, Water, Health, Materials, Equity and Beauty. The childcare centre will satisfy all seven Petals. 100% of the childcare centre's non-potable water will come from an on-site closed loop system. Water collected from the roof plane and a blackwater treatment system (the "Blackwater Plant") form part of the net zero water strategy.

2. Legal Mechanism

The section 219 covenant required by COB with respect to the Blackwater Plant provides that the operation and maintenance manual (the "O&M Manual") for the Blackwater Plant must be approved by COB prior to issuance of PPA. After its initial installation, the Blackwater Plant must be maintained, serviced and sampled regularly to ensure it is operating in accordance with the design criteria set out in the O&M Manual.

Effluent releases will be sampled and tested for a period of three years from the date the Blackwater Plant is commissioned for operation. If the Blackwater Plant fails to meet the requirements set out in the O&M Manual for three consecutive tests, the Blackwater Plant must be abandoned and a direct connection to the municipal stormwater system constructed.


Green roofs are an innovative method of managing stormwater and, in turn, controlling sediment.


Green Roofs for Healthy Cities defines green roofs as "an extension of the existing roof which involves a water proofing and root repellent system, a drainage system, filter cloth, a lightweight growing medium and plants."7 In effect, green roofs reduce the amount of impervious surface area in urban environments by reintegrating vegetation. As rain hits green roofs, the vegetation absorbs the water and gradually returns it to the atmosphere.

The efficacy of any green roof will depend on the depth of the growing medium, the amount of water already retained, and the slope of the roof; but "an average four inch roof can usually retain most of a one inch rain during the summer if the last rain was at least a week ago."8 Even during heavy rainfall events in colder months, a green roof can reduce and delay runoff.9 Consequently, green roofs are an effective stormwater management and sediment control system year round. The Metro Vancouver Stormwater Inter-Governmental Liaison Group has identified green roofs as a best management practice for stormwater source control.


1. Insurance

Notwithstanding their environmental benefits, green roofs can and have encountered hurdles. Circa 2008, a number of local governments in BC proposed making green roofs mandatory in new construction, including residential construction.10 The Homeowner Protection Office ("HPO") was quick to point out that such a bylaw may conflict with requirements in the Homeowners Protection Act ("HPA").11 The HPA, enacted in the wake of BC's leaky condo crisis, requires new home buyers to purchase home warranty insurance.12 At the time, only one of the four main home warranty providers was prepared to insure a residential building with a green roof "and then only under very special circumstances – the right project, the right site, the right designer, the right installer and plenty of financial security for the insurer."13 Metro Vancouver acknowledged in a 2009 publication that "insurance for strata-owned residential structures with green roofs has been virtually impossible to obtain."14 The perception of insurance companies was that green roofs would significantly increase the potential for leakage/water damage. However, this hurdle may be gradually subsiding thanks to increases in awareness and green roof research. BCIT has developed a Green Roof Research Facility which has been used to create design guidelines,15 the BC Landscape and Nursery Association has developed a "BC Standard for Extensive Green Roofs" to improve implementation, and LEED is "raising the profile of green roofs" across North America.16 Significantly, the green-roofed Millennium Water project was able to obtain insurance from a major insurer for its post-Olympic, residential use. This represented an important initial success over this obstacle for the region.

2. Maintenance/Access

Typically, a green roof is located in one building, owned by one owner or is part of the common property of a strata corporation. In the latter case the bylaws may reflect usage of the green roof in terms of restricting the nature or species of plants which could be grown, and regulating use and access by the residents. Any maintenance expense would be incorporated in the strata corporation's budget.

The green roof at the Cornerstone building in UniverCity spans two vertically adjacent properties. The building consists of residential strata lots within an airspace parcel (the "AP") and commercial units within the remainder (the "Remainder") of the lot. Consequently, a reciprocal easement between the owners of the AP and the Remainder was entered into to facilitate the access and maintenance of the green roof. The green roof is, in effect, on top of the Remainder but the space above the roof belongs to the AP. Therefore, a landscaped area is planted by the AP owner on the green roof to be used and enjoyed by the residents in the AP. The Remainder owner granted an easement in favour of the AP to permit encroachment of the green roof into the Remainder. In return the AP owner granted the Remainder owner an easement over the AP for the purpose of installing, repairing, maintaining and inspecting the green roof. As the Remainder was the only property at risk from green roof failure (i.e. leakage), it was logical for the Remainder owner to be responsible for installation and upkeep. In addition, a restrictive covenant provides that the AP owner may not do anything which may damage the roof including the roof membrane. An equitable charge secures the amounts owing by the AP owner to the Remainder owner.


1 Nicholas D Van Woert, "Green Roof Stormwater Retention: Effects of Roof Surface, Slope, and Media Depth" (2005) 34 J Env Quality 1036

2 "Best Management Practices Guide for Stormwater – Appendix H: Construction Site Erosion and Sediment Control Guide," Greater Vancouver Sewerage and Drainage District (October 1999) at 2-3, online: Metro Vancouver [Best Management

3 "Aggregate Operators Best Management Practices Handbook for British Columbia Volume I: Introduction and Planning," British Columbia Ministry of Energy and Mines (April 2002) at 122, online: Ministry of Energy and Mines .

4 B.C. Reg. 129/99

5 Light House Sustainable Building Centre, "BC Green Building Code Background Research: Greywater Recycling" October 2007, pp. 38-42

6 B.C. Reg. 129/99, supra at note 17

7 "About Green Roofs," Green Roofs for Health Cities (8 December 2009) online: Green Roofs .

8 Center for Green Roof Research, "Storm Water Quantity Research," Department of Horticulture, Pennsylvania State University, online: Pennsylvania State University .

9 Ibid.

10 Ken Cameron, "Green Roofs and Homeowner Protection in British Columbia: Balancing Benefits and Risks" (2008) 50:1 Planning West 1 at 2.

11 SBC 1998, c 31.

12 Ibid, s 22(1).

13 Cameron, supra note 11.

14 Implementation of Green Roofs, supra note 1. at 2-4

15 Gail Lawlor, et al, "Green Roofs: A Resource Manual for Municipal Policy Makers" (Canada Mortgage and Housing Corporation, 2006) at 35, online

16 Gail Lawlor, et al, "Green Roofs: A Resource Manual for Municipal Policy Makers" (Canada Mortgage and Housing Corporation, 2006) at 14, online:

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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