Stream D: Stormwater Issues


4.1 Nicomekl and Serpentine Sea Dams:  Preparing for Earthquakes and Sea Level Rise in Surrey

4.2 Erosion and sediment control: Preventing stormwater pollution one project at a time

4.3 An integrated approach to urban infrastructure: Richmond’s No. 1 Road drainage pump station

4.4 Combining green and gray infrastructure: Restoring the John Matthews Creek Ravine

4.5 OGS ETV verification and performance – Key design variables

4.6 “Dry weather flow”... What's that? Wastewater collection system upgrades at the City of Prince Rupert’s Hays Creek Area



4.1 Nicomekl and Serpentine Sea Dams:  Preparing for Earthquakes and Sea Level Rise in Surrey

Presented By: Matt Osler, City of Surrey; & Adrian Corlett, Parsons
Time: Monday, 2:00 - 2:30 PM


The City of Surrey maintains extensive flood protection infrastructure, including approximately 10 kilometres of sea dykes, 100 kilometres of river dykes, 20 spillways, 2 sea dams, 30 drainage pump stations, and over 170 flood boxes. Without major changes to the current flood control system, a range of municipal infrastructure will be impacted by a changing climate, including over a dozen bridges becoming either partially or completely submerged, based on sea level rise predictions by the year 2100. 

Two sea dams are over 100 years old and situated in the tidal portions of the Serpentine and Nicomekl Rivers. These critical structures protect the rivers from high tide and storm events, and allow the rivers to passively discharge during low tide periods and will need to upgraded or replaced to accommodate both rising sea levels and today’s seismic design criteria. A large seismic event will one day strike the coast, most likely caused by the Cascadia Subduction Zone off Vancouver Island. It is critical that these structures do not fail during this event, which could lead to inundation of the floodplain.

The City and Delcan are developing preliminary designs to achieve these goals. The designs will be integrated with Surrey’s phased approach to Climate Change Adaptation Planning, allowing structures to be adjusted as actual sea level rise is observed. The project also explores the conversion of the existing passive gravity outfall systems to an active pumped systems to mitigate the inland impacts of sea level rise.

pdf icon Presentation PDF


4.2 Erosion and sediment control: Preventing stormwater pollution one project at a time

Presented By: James Kay, Focus Corporation / Erosion & Sediment Control Association of BC.
Time: Monday, 2:30 - 3:00 PM

Stormwater protection is gaining recognition and priority amongst municipalities across British Columbia. The impact of construction sites on stormwater is an enormous contributor to the stormwater pollution impacting our watercourses and aquatic habitats. Erosion & Sediment Control can be designed and implemented effectively and efficiently, yielding enormous benefits for our natural environment.

ESC is a recognized and familiar challenge. However, practices throughout BC have evolved very rapidly in the last few years. With clear performance objectives, increased enforcement, and innovative practices and products, many sites are finally achieving and maintaining compliance. Designers, reviewers, monitors, contractors and approving agencies alike are working together to devise and implement plans that work. These plans need not be any more expensive, they simply use the resources more effectively.

However, there is increasing disparity between those areas aggressively enforcing ESC compliance, and those still doing "business as usual". This presentation will focus on:

- Introducing new approaches, practices, and methodologies to ensure compliance

- Reviewing the fundamental processes that impact ESC performance

- Understanding the regulatory regime and performance criteria for ESC

 pdf icon Presentation PDF


4.3 An integrated approach to urban infrastructure: Richmond's No. 1 Road drainage pump station

Presented By: Simon Kras, Opus DaytonKnight
Time: Monday, 3:00 - 3:30 PM.

As space in cities becomes increasingly prized, mixed land use will become more common in infrastructure projects. The City of Richmond adopted a mixed land use approach for the No. 1 Road Drainage Pump Station, which serves two purposes: as critical drainage infrastructure, and as a pedestrian node along the City's extensive dike trail.

The City requested a design, which would consider the lines of sight of the adjacent properties, provide public space along the dike trail, enhance the aesthetics appeal of the station, and provide increased flood protection and post disaster performance. The station and surrounding dike were required to resist a 2,475-year return period earthquake. Coordination of architectural, landscape, mechanical, electrical, structural, civil, environmental, and geotechnical disciplines was required to meet the above objectives.

To preserve the lines of sight, the building floor was lowered below the adjacent road grade. All venting was done through gratings on the building roof. On the roof was a plaza with benches, serving as public space for pedestrians along the dike trail. The building was sealed from water ingress up to an elevation of 3.0 m above mean sea level (1.0 m above the adjacent road elevation). Marine hatch style doors were used for access to the rooms, and all conduits into the rooms were sealed.

The project required efficient coordination and fast-tracking measures to meet a tight design and construction timeline.

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4.4 Combining green and gray infrastructure: Restoring the John Matthews Creek Ravine

Presented By: Michael MacLatchy, Associated Engineering.
Time: Monday, 3:45 - 4:15 PM

Many watersheds in Metro Vancouver were developed before current practices in rainwater management, including John Matthews Creek in the City of Burnaby. This watershed was developed in the 1970s, with the then common practice of pipe and convey. The current Integrated Watershed Management Plan encompassing John Matthews Creek includes the introduction of more advanced rainwater management approaches as redevelopment occurs. However, this is not enough to reverse some active erosion sites in the ravine.

During large storm events in 2010, a significant channel instability developed in the John Matthews Creek ravine, downstream of the urbanized watershed. Naturally erosion resistant glacial tills, which had controlled the rate of channel erosion, were breached, exposing underlying sand layers and resulting in massive downcutting. Sediment was transported and deposited downstream of the ravine in fish bearing reaches, culverts were blocked and lowland channel capacity was reduced. A deep vertical incision formed, exceeding 10 metres in depth at the upstream end, requiring immediate action to prevent slope stability issues and address the damage to the creek ravine.

A combined approach of providing a peak flow diversion incorporated in the channel invert, with reconstruction of a naturalized step-pool channel in the disturbed ravine simultaneously addressed erosion issues, restored slope stability, and provided improved habitat. Resident cutthroat trout have returned to the restored channel reach, which was previously inaccessible to fish. This project represents a successful approach to mitigating historical development driven changes to watershed hydrology, while restoring a degraded and unstable reach of creek.

 pdf icon Presentation PDF


4.5 OGS ETV verification and performance – Key design variables

Presented By: Scott Perry, Imbrium Systems.
Time: Monday, 4:15 - 4:45 PM

The use of Oil Grit Separators (OGS) for stormwater treatment has existed for over two decades in North America. When adequately designed, these treatment devices can mitigate the adverse impacts of urban runoff. Economic pressures and the demand for stormwater treatment have increased the various methods for designing OGS systems. The typical professional engineer could spend countless hours trying to decipher various performance claims, marketing information, design methodologies, and true benefits of a technology. The majority of Provincial and local municipalities have not yet established clear performance or design criteria for OGS devices. This lends to variable performance, as engineers often rely on manufacturers' recommendations, and contractors end up making decisions after the designing has occurred. Unfortunately, limited knowledge of the key design parameters, real world stormwater pollutant attributes, fierce competition, and contractors driving the buying process can result in very low performance and water quality benefit from the installation of significantly undersized or designed OGS units. Establishing clear performance metrics, using verification programs such as ETV, and setting clear associated design criteria creates a level playing field for implementing OGS units. This paper explores the fundamental unit processes that govern OGS units, expected outcomes from the new OGS ETV verification program and the key critical design parameters necessary to achieve a net positive environmental benefit. Examples of common design assumptions and stormwater research are presented in a manner that allows the audience to make informed decisions regarding OGS design, performance verifications, and device selection to protect the environment.

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4.6 "Dry weather flow"... What's that? Wastewater collection system upgrades at the City of Prince Rupert's Hays Creek Area

Presented By: Arash Masbough, Associated Engineering.
Time: Monday, 4:45 - 5:15 PM

Hays Creek Sewer (HCS) collects and conveys a significant portion of the City of Prince Rupert's wastewater. It runs the length of the riparian zone of the Creek in McClymont Park. This is a fish-bearing creek that flows into Prince Rupert Harbour. Along the length of the creek, the century-old HCS is either below grade, surface-laid, submerged, or on concrete pedestals. In many locations, HCS actually runs within the creek for a significant distance, often exposed. In the past, sewer line breaks have occurred due to a combination of mudslides and downed trees. Infiltration and Inflow (I&I) factors of 40 to 200 fold have also compounded the issues related to wastewater management.

Due to the sensitivity of the of the creek and the fact that HCS is operating many years past its design life expectancy, the City of Prince Rupert decided to reduce or eliminate this risks by upgrading the system and relocating some infrastructure. The ultimate goal for the project is to enable the sanitary sewer system to operate in a safe and environmentally sustainable manner while enhancing, where possible, the local environmental habitat. The City has undertaken a three-phase project that includes installation of two new pumping stations and a number of new sewer lines. The I&I issue has turned out to be the single most challenging aspect of the upgrades.

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