Challenge

Hydro International partnered with Hynds and LDE - Engineers & Scientists to deliver a robust, high-efficiency stormwater treatment system for a car park extension in Auckland, built around the Up-Flo® Filter.

Urban development across New Zealand continues to place pressure on local waterways, especially during heavy rainfall events when stormwater runoff carries fine sediments, hydrocarbons, heavy metals and organic contaminants into receiving environments. Meeting regional stormwater regulations requires high-performing and resilient treatment solutions.

The project required a solution capable of removing:

  • Fine sediments

  • Heavy metals

  • Hydrocarbons

  • Organics and organic-bound bacteria

  • General stormwater contaminants

The treatment system needed to integrate seamlessly into a constrained urban site while meeting Auckland’s strict stormwater quality requirements.

Solution

A 15-module Up-Flo® Filter was selected to meet the project’s treatment criteria, and installed within a Hynds precast concrete chamber.

The filter combines:

  • A patented upwards flow path for maximum media contact

  • A unique drain-down system to prevent standing water

  • High pollutant removal efficiency across variable flow rates

  • A compact footprint ideal for space-constrained urban environments

Stormwater enters the manhole sump, passes upward through the filter media bags, and is treated before discharging into the stormwater network.

Installation

Working closely with Hynds, LDE and contractor Elite, the project team delivered a smooth installation. Hynds supplied a 2550mm-diameter manhole fitted with 15 Up-Flo® Filter modules, providing a durable, accessible and long-lasting treatment structure.

The installation was completed in under an hour — a testament to the efficiency of the design and the coordination between all partners.

Key benefits of the Up-Flo® Filter

  • Removes fine sediments, nutrients, heavy metals, hydrocarbons and organics

  • Customisable to suit site-specific treatment requirements

  • Consistent performance even under fluctuating flow conditions

  • Compact footprint ideal for urban sites

  • Simple, cost-effective maintenance with easy access to filter bags

  • Durable construction for long service life

  • Supports compliance with regional water-quality regulations