Principles of stormwater management

The principles of stormwater management cover the philosophy and design principles necessary to implement best practice. Principles can include items such as treatment at source, requiring community values to be incorporated, hydrological neutrality, etc.

Some of these principles are applicable internationally, but there are also important national, regional and local differentiations. Links to key source documents are given below.

Local guidance and examples

Waterways, Wetlands and Drainage Guide (WWDG)
Section A of the Waterways, Wetland and Drainage Guide sets out the “principles and background information for inter-disciplinary planning and management” of stormwater. Although not updated since 2003, it is still a good source document for stormwater management within Canterbury, while being focussed on Christchurch.

Codes of Practice (COP)
Codes of practice set out the design requirements for subdivision, and usually include a section on stormwater management. COPs provide the guidance for understanding the local application of regional, national or international principles.

Cultural principles

Te Rūnanga o Ngāi Tahu is the statutory authority representing iwi members and includes ten local rūnanga within Canterbury, known as Papatipu Rūnanga. Cultural principles for management of stormwater are included in both region-wide documents as well as iwi management plans for specific areas.

Ngāi Tahu Freshwater Policy
The Ngāi Tahu Freshwater Policy includes the environmental outcomes in freshwater sought by Ngāi Tahu, and the principles by which Ngāi Tahu expect freshwater to be managed.

Iwi Management Plans
Iwi management plans (IMPs) are important in assisting with the identification of Ngāi Tahu cultural values. Each IMP covers a different area, and there is advice on the Environment Canterbury website for which IMP applies to which area.

National guidance and examples

National Policy Statement for Freshwater Management
The Freshwater NPS outlines some of the environmental and social bottom lines for the management of freshwater. This policy statement is key for understanding the importance of managing stormwater discharges into freshwater.

Auckland Council guidance and examples
Auckland Council has developed guidance on what it has termed ‘water sensitive design’ (WSD). The Auckland Design Manual is a web-based manual which includes guidance and examples. There is also a guideline document available for download.