Gross pollutant traps as a stormwater management practice. Literature review

Bridget Fitzgerald, Warren S Bird
Auckland Council Research, Investigations and Monitoring Unit, RIMU
Publication date:

The current design guidelines (TP10) provide limited information with regard to the definition of gross pollutants and Gross Pollutant Traps (GPTs), therefore the scope of this project has been to bridge these knowledge gaps and address the following:

  • Identify the various types of devices currently available, with performance achievements, benefits and limitations outlined
  • Carry out a literature review of design factors, methodologies low flow and high flow bypass systems for various devices
  • Confirm key device selection considerations and criteria
  • Outline specific maintenance requirements for the Auckland region

By examining local and international research and design guidelines to establish best practice, this report aims to develop improved selection criteria for GPTs in the Auckland region. This report presents aspects of GPT implementation including appropriate selection and design considerations, construction, maintenance and operation.

This report does not attempt to set an Auckland region wide gross pollutant treatment objective. Therefore the implementation of GPTs will continue to occur in selected catchments on a site specific basis. Requirements need to be considered on a catchment by catchment basis, and this report details key selection, design, construction and operational monitoring and maintenance aspects to consider once the need for a GPT has been established.

This report discusses the GPT types available on the market, along with their benefits and limitations. Whilst this report may name companies and/or products, the Auckland Council does not endorse any particular product or company. The naming of a product or company is purely to discuss the current methods available in the market for GPTs. It is acknowledged that other products may be available (or have become available since the time of writing).

Auckland Council technical report TR2011/006

Last updated: 2018-07-09