Extract

1 Introduction

The original Technical Publication 10, “Stormwater Treatment Devices Design Guideline Manual” (TP10), was developed in the early 1990s by the Auckland Regional Council (ARC) to assist stormwater treatment designers. It has been in use in the Auckland regional since October 1992 and recently has also been used as the design basis for a number of other New Zealand regions.

Many of the devices installed in Auckland in the mid-to-late 1990s and early 2000s either do not function correctly or are difficult to operate and maintain. As time has elapsed and experience in stormwater treatment devices improved, many practices in relation to the design and construction of treatment devices have changed and as a result stormwater treatment devices have improved.

TP10 has been subject to only one revision incorporating changes in the philosophy and approach in relation to stormwater treatment devices. The manual provides information on the operation and maintenance of these devices; however its focus was primarily on their design and has not tailored specifically on their construction. Consequently, the construction of stormwater devices required additional information of relevance to network managers, developers and construction contractors.

The objective of this report is to provide additional information on how to progress from the design of stormwater treatment devices through to construction. In particular it attempts to correct common construction issues, many evolving through poor design that has been common in the industry.

1.1 Objective

This report aims to provide information which allows designers to advance stormwater treatment device design through to the construction phase, and to ensure that these devices are constructed in a manner that produces a good quality, functioning device. 

The scope of this report is restricted to devices included in the current TP10, but excludes proprietary devices. The devices covered include:

• Stormwater ponds
• Wetlands
• Swales and filter strips
• Rain gardens
• Tree pits
• Sand filters
• Oil/water separators
• Rain tanks
• Permeable paving 
• Infiltration trenches and dry wells
• Living roofs

Auckland Regional Council technical report, TR2010/052