BY JUSTINE BENNETT, TECHNICAL DIRECTOR – ENVIRONMENT and WATER, AND JENNIFER COURT, GREEN INFRASTRUCTURE LEAD, GHD

As we have seen in recent months, traditional grey infrastructure approaches to stormwater management and typical urban development practices are not enabling us to protect our communities from severe weather events. Nor do they effectively respond to challenges in our aquatic environments, or enhance the wellbeing of our communities and natural environments.

The dominance of hard and impervious surfaces in urban areas modifies the hydrological cycle. The run-off from such surfaces is conveyed much quicker to our waterways, carrying pollutants, which leads to poor water quality and impoverished aquatic ecosystems. The paucity of green spaces and natural elements can also have a detrimental effect on the physical and mental health of our communities.

The use of blue-green infrastructure (BGI) solutions is an alternative approach that could help us achieve more resilient outcomes for our communities. It’s not a new idea – BGI has been around for decades, and while it is featured strongly in Auckland and the Waikato, it is still without widespread application.

The approach and its outcomes align well with aspirations for a more holistic and integrated water management landscape, which are being driven by the principles set out in the National Policy Statement for Freshwater Management, as well as core tenets of the New Zealand Water Reform process.

So, what is holding us back from more widespread use of these approaches? The potential challenges faced include:

• lack of national and regional leadership
• lack of knowledge, experience and capacity
• scarcity of trusted performance data
• cost and value uncertainty
• dispersed asset base
• multiple owners
• lack of proven asset management approaches.

These perceptions are common across Aotearoa New Zealand, and internationally. However, there are increasingly more success stories that others can learn from to overcome these challenges.

The City of Vancouver, in Canada, is a great example of a municipality that has taken proactive initiatives to promote and drive the uptake of BGI. In 2019, the City of Vancouver adopted the Rain City Strategy, which includes the aspirational vision of becoming a water-sensitive city, and treating rainwater as a resource to be embraced and valued. The strategy includes three key goals: improve water quality, increase resilience, and enhance livability by improving natural and urban ecosystems. Alongside these aspirational goals, the city has set measurable targets, committing to capturing and cleaning a minimum of 90 per cent of Vancouver’s average annual rainfall, and managing urban rainwater run-off from 40 per cent of impervious areas in the city by 2050. The city also established a plan to retrofit 10 per cent of all current impervious surfaces around the city to ensure that rainwater run-off is managed by BGI.

To achieve this goal, the city forecasts that it will need to scale up from 283 to 10,000 BGI assets by 2050. The Green Infrastructure Implementation Branch (GII Branch) was created to lead this initiative. It took on ownership for the existing assets (previously managed by nine branches), as well as the responsibility for new assets. This transition came with challenges, including the need to streamline the governance, operations and maintenance (including both the financial and human resources) of these legacy assets, while planning to invest in a significant number of new BGI assets.

To realise the benefits of BGI and to overcome the challenges associated with scaling such a program, the City of Vancouver developed a Strategic GI Asset Management Program. In particular, GHD worked with the GII Branch to gain a greater level of understanding about the legacy assets that it is now responsible for (including the life cycle costs associated with these assets), and supported the GII Branch in developing a living framework that can be sustainably scaled (considering both financial and human resources capacity).

This living framework included levels of service, a service delivery model, governance structures and a financial strategy. To accomplish this scope, GHD’s work included identifying the pressures and demands that will impact city BGI services, what services are required, how the services will be delivered, who is responsible and accountable for ensuring the services are provided, how to manage the short- and long-term costs associated with current and future assets, and what to track to ensure service performance. This process included data reviews, interviews and workshops with city staff and staff from comparable ‘peer cities,’ as well as financial modelling.

A key lesson learnt from this process was that BGI asset management is an emerging practice, particularly at the strategic level. Governance for BGI assets is often complex, with many different parties having a stake in funding and managing the deployment, operations and maintenance, and monitoring of assets. While some municipalities are doing well at operational asset management, none have implemented asset management at the strategic, decision‑making level.

BGI has many benefits, encompassing not just water management, but also the enhancement of community, social and cultural values, and health. The outcomes from the process undertaken by the City of Vancouver provide an example to other municipalities about how to plan strategically, set targets, fund and manage BGI assets in the long term, and enable others to fully realise the benefits that these assets deliver.