MONITORING & EVALUATING STORMWATER NETWORK PERFORMANCE IN TĀMAKI MAKAURAU (AUCKLAND)
Stormwater Conference 2024
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Gemma Chuah, Vanessa Castro, Janet Kidd (Auckland Council Healthy Waters)
ABSTRACT
Understanding the performance of the stormwater network and its impact on the environment and community is under growing scrutiny, putting increased pressure on councils to account for service delivery. Stormwater is of particular focus due to recent weather events, together with aging infrastructure and longstanding community expectations. It is therefore imperative that the performance of the network is assessed and reported to provide accountability as well as stimulate continuous improvement and efficiency.
For Auckland, the region-wide stormwater network discharge consent (NDC) is founded around this need to assess and report on ongoing performance. A critical element is the development and implementation of a Monitoring and Evaluation Strategy, which establishes how data is collected and used to assess stormwater performance under the consent.
Understanding stormwater network effects is challenging due to connections with land use activities, overlapping responsibilities, and its open and diffuse nature. These complexities and challenges mean that a range of data sources and knowledge must be collated and analysed. Thus, the strategy framework comprises four core pillars:
This paper describes each pillar, the corresponding programs and how the data is used inform actions and prioritisation. The pillars reflect how results from state of the environment monitoring, watercourse assessments, and other more targeted sampling programs complement and feed into modelled results for fresh and coastal water quality, stream erosion, criticality and flood hazards. Together these provide spatial and temporal coverage of the region. The pillars also capture the impact and benefits of stormwater upgrade and improvement programmes, even where these are not quantifiable, as a means of demonstrating accountability.
The NDC includes a range of quantitative and qualitative targets for the assessment of progress towards achieving consent outcomes and objectives. The finding from the Strategy are used to demonstrate performance against the targets though the regular 6 year reviews of the NDC. These targets are also reviewed and updated to ensure the NDC remains relevant over time.
The first review of the NDC in 2022 highlighted the challenges of linking programme delivery to improvements on the ground. The next step for the Strategy is therefore to address this gap while also enabling efficient use of data sources and alignment of existing work programmes to provide multiple benefits. Other initiatives include ongoing improvements in modelling, targeted stormwater device monitoring, use of new technology, such as drones for surveys and AI, and ways of embedding cultural monitoring and citizen science.
Auckland is not alone in this challenge, with councils across the country spearheading such innovative thinking. The new government has foreshadowed that higher levels of transparency will be required of the water sector through information disclosures under economic regulation. This type of monitoring and reporting will be important for demonstrating the benefits of stormwater investments under this type of regime. However, the country's pool of technical experts and engineers in stormwater management is limited and day-to-day pressures mean they have little bandwidth to work strategically with other regions. It is imperative that institutions actively working in stormwater management lead the scoping and development of such measures, based on the ground learnings such as those outlined in this paper, ideally through a legislative framework or at minimum through a pan-region centre of excellence.