Thoughts on the Moutere Water Catchment

TDC Hydrologist Joseph Thomas recently made a presentation on water issues in the 200 kmĀ² Moutere Catchment at a recent meeting of the Mapua and District Community Association. Here is a summary of the scientific and technical aspects touched upon:

The Moutere is typically a dry catchment with 3 zones: Eastern, Western and Southern, which is
where Mapua sits. The entire catchment is full of Moutere Gravels of varying depths down to the granite base at about 200 m.

There are up to three levels of water which is very old and is recharged very slowly from the hills to the South. Council has tight rules for drilling bores but these were created originally for irrigation purposes (in dry seasons). The yield from these bores is low, typically around 5 cubic meters/hour.

Use has changed since to include household use with 365 day draw-down. Private bores are allowed without permit, are typically around 80 m deep and allow 5000 l/day. Council is worried that year-round draw-down could deplete the aquifer and allow salt water intrusion.

Subdivisions in Mapua are deferred until water is available but existing water rights can be used although the
conditions around use are very tight. This has created a problem for Mapua which currently receives its water through a narrow pipe from the Waimea Catchment. This catchment is limited so there is no point in installing bigger pipes. The Motueka Plan for providing water to Mapua was rejected by the Environment Court, so future
increases in water use are predicated on the Lee Valley Dam (Waimea Community Dam) proceeding.

Cr Brian Ensor who was also at the meeting advised that Council has just passed a requirement for new builds in subdivisions with low water flows to have 25,000 l storage tanks.

Excerpt from the MDCA meeting minutes with kind permission.

Editor's Note: The new storage tank requirements mentioned will affect all users on schemes with restrictors such as the Dovedale Water Scheme. Be sure to check out the new storage requirements outlined in the full bylaw text. Storage requirements must be complied with by 1 November 2018.

In short, this will be:

  • a 25,000 L tank if you receive 1-3 cubic meters per day
  • 7,000 L storage for every cubic meter supplied if you receive more than that