Shannon & Mangaore

The Shannon wastewater scheme was installed between 1969 & 1971 to replace the septic tank system, and Mangaore Village in 1975 for the same reason. Both consist primarily of 150mm dia. pipe with some larger pipes up to 300mm. Shannon was mainly AC (asbestos cement) while Mangaore is GEW (glazed earthenware). Sewage from Mangaore Village was connected into the Shannon reticulation in 1990 from a pump-station located at the site of the abandoned Imhoff tank. This transfers the raw sewage some 3.5km along a 50 dia. rising main into Shannon. The records for the reticulation being of relatively recent construction are quite comprehensive and accurate.

The discharge consent has expired and an application has been made for renewal. Although the renewed consent has not yet been issued, draft conditions have been provided and council is working to those conditions. Essentially there needs to be an upgrade of the system and a working party of local people has been reviewing the system and looking at options since 2003. The working party is to report in 2005.

The operational parameters of the Shannon scheme are:

Population Served: 1,400
Connections: 562

The operational parameters of the Mangaore scheme are:

Population Served: 100
Connections: 32 

The key issues relating to the scheme are:

• The likely need to upgrade the treatment capacity so that the effluent complies with relevant water quality standards. The Council has expressed a preference for land disposal of the effluent.
• The reticulation being all of the same age is likely to require replacement over a short time frame late in, and beyond, the planning period.
• There is an infiltration problem which needs addressing.
• Affordability for the small number of ratepayers contributing towards this scheme.