SAFE NETWORKS: A COLLABORATIVE PROGRAMME FOR MITIGATING WASTEWATER CONTAMINATION IN STORMWATER RUNOFF

A. Schollum & M. Neale (Puhoi Stour Ltd), H. Foreman & N. Brown (Auckland Council Healthy Waters)

ABSTRACT

In July 2021, Healthy Waters’ Safeswim programme was cited as an exemplar of global best practice by the World Health Organisation in its updated guidance on recreational water quality monitoring and communication. From February to October 2017, after picking up responsibility for Auckland Council’s recreational water quality monitoring programme, Healthy Waters completely redesigned recreational water quality assessment in Auckland by:

1. discontinuing weekly monitoring in favour of targeted sampling to build and validate the predictions of water quality models,
2. collaborating with Watercare to integrate continuous monitors on the wastewater network to enable automatic real time warnings of sewage overflows, and
3. providing for manual alerts to be uploaded as required by network managers, public health experts, and surf life saving professionals.

Following significant upgrades in the lead-up to the 2022/23 swimming season, Safeswim now provides a fully integrated system for water quality and beach safety monitoring, management, and communication from Cape Reinga to Port Waikato, and has been adopted by Surf Life Saving New Zealand as the preferred platform for public safety communication at all lifeguarded beaches around New Zealand.

This paper provides an overview of the Safeswim system, explains the scientific and methodological framework that underpins its approach to water quality assessment, describes the predictive models and digital architecture that underpin the system, and presents the results of independent investigations into the accuracy and performance of the system undertaken throughout the programme’s history – including by Audit New Zealand in 2020, 2021, and 2022.

The limitations of recreational water quality monitoring programmes based on weekly monitoring were illustrated across New Zealand this summer with beaches ‘closed’ due to ‘out of date’ monitoring results that no longer represented actual conditions. Conversely, in the United Kingdom people routinely swim unawares in water contaminated by overflows from wastewater networks.

As the ‘Three Waters’ policy programme stands poised to transform New Zealand’s institutional arrangements for water management, Safeswim’s accurate, transparent, user-focused, and world-leading approach provides an alternative to current monitoring programmes to find and fix the causes of contamination and to tell swimmers what they want to know – is it safe to swim now?

A review of the Safeswim system conducted by NIWA for the Regional Council Sector in 2017 recommended the sector should adopt the approach to recreational water quality monitoring and communication pioneered by Safeswim. This paper compares Safeswim with the recreational water quality monitoring and communication programmes operated outside of Northland and Auckland, and identifies what steps might lie ahead in the evolution of the Safeswim programme.