Wetland Innovation

(The following is the first two pages of a 15 page Report.)

An Investigation into a combined Greywater and Septic Tank discharge via constructed Wetlands to ground.

The site for which this investigation is concerned is contained in a Rural residential section at 263 Hillhead Road, St Clair, Dunedin.

Legal description Lot 2. DP379741

Researched and written by S.A.K. Pivac

Tall Tree Company

RD 32 Opunake.

Ph: 06 761 7269

[email protected]

Tall Tree Company is a Taranaki based forestry Company involved in all issues relating to forestry and farming in Taranaki.

Involvement with water management includes a number of matters involving consents relating to both water use and waste discharge. This has included community based issues around both water supply and domestic and industrial discharge. Protection of wetlands and the use of plantation trees and other vegetation to mitigate the effects of farming and forestry multi-point runoff is a key part of Tall Tree Company business.

Mr S.Pivac is also a director of privately run 'Cold Creek Community Water Supply Ltd' and completed a Public Health Risk Management Plan, filed with MoHealth in 2007 for the Company.

The investigation that follows is the result of a query by Jack Pivac as to the potential for innovative means of dealing with domestic waste issues around the building of a residential building on a Rural Residential section of 2.02Ha in St. Clair, Dunedin.


The use of wetlands to decontaminate or modify industrial or farming discharges is now a well established simple technology. It is receiving widespread recognition as a more 'natural' system to treat waste discharges. Perhaps because of this it has a perception in the public domain as being a preferred option for mitigating potentially harmful effects.

Constructed wetlands have significant ancillary amenity values which include both aesthetics in areas where landscapes have become bare, and habitat enhancement.

An inspection of the site for which this investigation is being considered appears to suit any preliminary planning. It is sloping away from the house site so that no pumping is necessary for waste flows; and it is well away from any natural watercourse.


Legislation relevant to this investigation includes but is not limited to the Resource Management Act 1991, Building Act 2004, Health Act 1956, and relevant Building Codes and Standards.

Regarding this Investigation:

1.Building Code G13 protects other property from loss of amenity values (due to accumulation of offensive matter, safeguards people in general from illness and protects other properties from the effects of discharges from the proposed site; and that on-site disposal of foul water shall be appropriately provided.

2.AS/NZS1547:2000 demands minimum performance standards which include a treated discharge having a:

Maximum oxygen demand in five days (BOD5) of 20mg/L(20g/m3)

Maximum suspended solids (SS) of 30mg/L .

Loading rate onto ground in any disposal field must not exceed 3.5mm/d (3.5L/m2/day).

1.The consenting authority may accept an alternative solution as a reasonable means of compliance.

2.The Local Government Act 2002 requires a sustainable development approach to authority jurisdiction.An Investigation into a combined Greywater and Septic Tank discharge via constructed Wetlands to ground.


Further information on request