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Where are they now? Natural assets prove unexpectedly valuable in Oakville’s stormwater management

Second in a series of posts on activities of the 5 original community pilots since completing formal involvement with MNAI in December 2018

The starting place: 

As an original MNAI pilot, the Town of Oakville, ON assessed stormwater services provided by a ~240 meter section of stream located in an older part of Town undergoing substantial redevelopment. This demonstrated that:

  • the stream provides stormwater services equivalent to an engineered asset
  • one segment alone would cost $1.24-$1.44 million to replace
  • the value increases in intensified development scenarios because it can adapt to changes in climate and development pressures.

The unexpectedly high value from a short section of stream provided impetus for investigating the value of, and options, for, other streams, ditches, and swales in the Town.

The Oakville MNAI pilot culminated in the presentation to Council of a report outlining the details and outcomes of the project.

Since MNAI:

Beginning during the pilot phase,  the Oakville Stormwater Master Plan Phase 2 integrated pilot findings to ensure natural assets and their value in providing municipal stormwater services are represented.   The Town expects that natural asset solutions will be incorporated into the final Master Plan recommendations, due in 2019.

The cross-departmental team responsible for the pilot also facilitated knowledge transfer to departments including Development Engineering, Environmental Policy, Financial Operations/Asset Management, Financial Planning, Parks and Open Space, and Roads and Works Operations.

Participation in the MNAI pilot represented an important step in moving not just the town, but municipal practice forward in addressing the value of natural assets and green infrastructure. This is increasingly important in light of a rapidly changing environment due to variables such as climate change and redevelopment.

– From the staff report to Council

Looking ahead

Oakville continues to place high value on natural assets and this is expected to continue as a Council – and therefore staff – priority during the Council term 2018-2022.

Practically, the MNAI pilot will:

  • be leveraged to develop stormwater management policy, including a planning context that reflects stormwater management needs and the value of natural assets in providing stormwater management services;
  • support policy development that recognizes natural asset services and benefits and how these services can be better supported though monitoring, maintenance and potentially protection and enhancement to ensure services are not compromised, degraded or lost;
  • support the integration of natural assets into the Town’s asset management system, and work to determine the best ways to do so given the current constraints in Canada’s accounting system;

Furthermore, staff are monitoring Public Sector Accounting Board’s deliberations on natural assets to inform and enhance Oakville’s asset management plan [see here for a related post].


Anticipated challenges include determining how to regulate the loss of natural assets on private land. The Town faces instances of community pressures to remove natural assets [e.g. swales, streams and ditches] and install instead engineered assets [e.g. culverts] to channel stormwater.

This challenge will be addressed in part using data on the unexpectedly high value of the creek, and, accordingly, the costs to taxpayers of replacing services with engineered options.

Before this pilot work, there was an incomplete understanding of the potential significance of [natural assets] to provide municipal stormwater services. There is now a better comprehension of the benefits [they] can provide in mitigating threats such as redevelopment, private landowner actions, and the shift from rural to urban road cross sections.

– From the staff report to Council

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