The Waimea Community Dam

lee river

The Waimea Community Dam will use nature's delivery system - rivers - to secure to the region’s water supply for 100 years.

It does this by

  • capturing Lee River flows,
  • storing the water in a reservoir in the Lee Valley, and then
  • allowing controlled release of stored water into the river system during periods of high water demand and/or low natural river flows.

Water from the Lee River flows into the Wairoa / Waimea River system, recharging the groundwater aquifers that everyone living in urban areas and on the Waimea Plains relies on for their water supply. At periods of low-flow in the Waimea River, the Dam can release water into the river systems that perform the natural function of refreshing and resupplying groundwater aquifer levels. A higher minimum flow means improved river health, which benefits instream fish and other aquatic life, recreational pursuits, and environmental amenity values.

Regional water security

Access to water affects every person in Nelson Tasman. The Dam provides access to water for 100 years for residential, industrial and commercial needs across the region. The Dam will maintain groundwater aquifer levels during periods of drought, resulting in improved water security for water users in Richmond, Brightwater, Mapua and Wakefield (Wakefield currently has a sufficient supply of water for the next 30 years with the Wai-iti Dam at Kainui), as well as providing a third water source for Nelson residents.

Dam structure

The proposed dam is a concrete-face rock fill dam. It will be approximately 53m high, 220m long and 6m wide at the crest and will have a total reservoir storage volume of approximately 13.4 million cubic metres. The dam is designed to the highest safety standards applicable for dams in New Zealand. It is expected that it will take about 30 months to complete construction.

The best solution

The Waimea Community Dam:

  • is the most cost-effective solution for ratepayers and funders
  • has the lowest capital cost for ratepayers
  • has the lowest overall risk of any alternative
  • has the highest compliance of any alternative
  • already holds all the necessary resource and other legal consents required for such a structure
  • meets the Waimea River’s health requirements for minimum flow
  • is the only solution that leverages private and central government investment and is not 100% Council funded