Developing a plan to mitigate adverse impacts of contamination in stormwater

Wellington Stormwater Monitoring Plan

Stormwater doesn’t only consist of the rain that falls, but also the debris and chemicals it picks up after flowing across rooftops, industrial sites, roads, car parks, fertilized lawns, and overflows from the wastewater network. With a need to better manage and monitor stormwater flowing into Porirua and Wellington harbors, a Stage 1 consent was initiated for the Wellington region to develop a stormwater monitoring plan (SMP). The SMP assists with the assessment of stormwater-related environmental effects and any acute effects on human health. 

With one main client, Wellington Water, the project concerned multiple districts and agencies across a wide area. To develop a framework for preparing the SMP, we formed a technical reference group consisting of five water quality scientists and one resource management planner. The reference group conducted workshops with stakeholders as part of the plan’s development process. The final SMP proposed refining and re-purposing several existing monitoring programs conducted by the local authorities, Wellington Water, and the Greater Wellington Regional Council.

With implementation of the SMP, for the first time in the Wellington region, a comprehensive approach has been adopted to identify and mitigate the effects of stormwater discharges. The SMP and subsequent management responses will help deliver a range of benefits to the region’s communities including reduced effects on human health, improved water quality, and improved ecological health.