Review of Swale Design for the Auckland Region

The Auckland Council is in the process of updating Technical Publication 10 ‘Stormwater Management Devices: Design Guidelines (TP 10). This paper provides a summary of a technical report prepared to inform the review of the TP 10 swale chapter. The report documents the developments in stormwater management swale research that have occurred since the publication of TP 10 in 2003, and uses that to provide a revised design methodology, including new design parameters.

The literature review identified a range of new research that provided additional information on the water quality treatment performance of swales, and the particular mechanisms which affected the performance of the swales in those studies. Limited research on the water quantity management performance of swales was found.

One of the primary objectives of the TP 10 review was to assess the existing design procedure and parameters, and update this where appropriate. The technical report provides guidance for recommended applications of swales, site constraints that will affect the suitability of swales, and details on the principles and processes by which swales provide stormwater management benefits. This paper provides an overview of the key findings and recommendations of the report.