The Waimea Community Dam

lee river

The Waimea Community Dam will use nature's delivery system - rivers - to increase water to the aquifers that supply our community.

When the Waimea Community Dam is operational along the Lee River, it will work like this: when it rains in wet months, the Lee River will run higher and the Dam system will capture those higher flows and store the water in a reservoir that is being built in the Lee Valley. During drier months when the Lee and downstream Waimea and Wairoa systems are running below desired flow levels, the Dam will release some of the stored water (slowly!) down the river, increasing their flows and naturally adding water to the aquifers.

Everyone living in Richmond, Brightwater, Mapua, and other urban areas along the Waimea Plains relies on these aquifers for their water supply, including for drinking. Where other dams function with lots of piping to extend the water supply to urban areas, we are using nature as the piping system. Topping up the river flows naturally will refresh and resupply groundwater aquifer levels.

Importantly, a higher minimum flow throughout the Lee, Waimea, and Wairoa River system means improved river health, which benefits 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 will provide access to water for 100 years for residential, industrial and commercial needs across the region. 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) will have water security for ongoing residential and commercial needs. The Dam can also be a third water source for Nelson.

Dam structure and safety

The Dam will be a concrete-face rock fill dam. A rock fill dam is a very stable structure, as compared to earth dams. The Waimea Community Dam will be approximately 53m high, 220m long and 6m wide at the crest. About 430,000m3 of rock will be used to build the dam or be recycled on site. The reservoir lake created by the dam will contain approximately 13.4 million cubic metres of water.

The Waimea Community Dam is designed to the latest international design standards under the NZ Dam Safety Guidelines and has been and continues to be peer reviewed by technical experts.

Regional economic drivers
The Waimea Plains

The Waimea Plains holds some of the most fertile productive land in the South Island, producing fruit, vegetables and boutique crops such as hops and grapes. It is of national strategic importance and its loss of productive capacity would be significant.

The value of New Zealand’s horticultural products exceeds $8.8 billion, including $5.1 billion of exports. These exports command a premium overseas and Nelson Tasman fruit has proven highly valued: the Envy™ apple, for example, is grown locally and was recently crowned 'favourite apple' by US consumers. Although wine, kiwifruit and apples dominate horticultural exports, Nelson Tasman is the only region growing boysenberries and one of two growing blackcurrants, unique additions to NZ's export success. For apple orchard owners, their value has increased by 70% since 2015 due to success in international markets.

Security of water with the Dam will mean continued growth in higher value crops and, therefore, increased economic activity and value to everyone who lives in the region.

Significant contribution to regional economy

Several independent organisations, including the NZ Institute of Economic Research (NZIER), Northington Partners, and the Nelson Regional Development Agency (NRDA) analysed the data and concluded there are major economic arguments in favour of water storage.

The Nelson Tasman region will see tremendous benefit in terms of jobs, general health and well-being, and future economic development. These benefits are substantial: with the Dam, the region could see GDP increase by as much as $923 million in the next 25 years, almost $37 million each year. In the first year alone, Dam construction will bring high paying jobs to the region and household incomes and consumption could rise by $27 million.

We can't discount the supporting industries - it's not irrigators alone who will realise greater economic growth. According to the NRDA, our regional horticulture sector supports 21 other industries including business support, technology, research, and others. Today’s horticulture sector directly contributes 53 percent of the GDP from those industry sectors. It supports 41 percent of the total employment of those industries, which equates to thousands of people. The jobs in these 21 sectors pay a median wage that is 10 percent higher than the Nelson Tasman average.

Read these reports in full on our Documents page under the heading "Economic Analyses."