Dam completed just in time
The long-awaited Waimea Community Dam may be two years late and over budget, but its shareholders say it’s been completed just in time.
Tasman mayor Tim King says the benefits of the dam have been highlighted over the past six weeks, with the region dealing with a significant drought.
“We've been through a very dry summer here in the top of the South Island and it had got to the point we had significant water restrictions on households, irrigators and commercial users – we managed to start releasing water just in time to both lift those restrictions and prevent any more significant ones.”
He has been involved with the dam since the last drought during the summer of 2000/01. Back then, he said other regions were considering similar projects – with Tasman the only one to have completed a significant water storage project in the two decades since then.
“The general feeling is one of relief that we've got to this point, satisfaction that we've actuallly managed to achieve the outcome and that it has demonstrated the benefits that were always predicted – and an underlying sense of frustration about the length of time it has finally taken and the cost.”
Construction began on the dam in early 2019 and was due to be complete in late 2021. Its projected cost at the time was $104 million, which had since grown to $198.2m.
The Tasman District Council owns 51% of the dam, with 49% owned by Waimea
Irrigators, who represent about 200 shareholders – a mix of horticultural growers, lifestyle block owners and three dairy farmers, across a catchment of 5000 hectares.
Waimea Irrigators chairperson Murray King said the recent drought was “as bad as it gets”, potentially worse than previous droughts, which had been the catalyst for the project in the first place.
“If you compare it back to the 2000/01 drought the lower reaches of the Waimea River actually went dry so had we not had this environmental flow release back a few weeks ago, we would have been in the
same situation, with a cease take and that has quite serious consequences.”
Shareholders pay an one-off subscription cost (currently about $7000), then an annual charge (just over $1000) per hectare, per year for 30 millimetres of water, per hectare, per week.
King said the dam's construction had been a “long and protracted process” that had been “quite tortuous and frustrating” at times.
“This dam is designed to last for 100 years, it will probably last for 200 – unfortunately one generation ends up paying for it all but we are here because of the benefits of our forebears who have invested in infrastructure elsewhere.”
Waimea Water chief executive Mike Scott said the dam valves were opened in early March, “just in the nick of time“as the region felt the effects of the drought.
The reservoir holds 13 million cubic metres of water and Scott said about 20% was released during March to supplement the river flow and support the aquifer, which helped to stave off the impact of the drought.
He said the dam had been a very challenging project, with several cost overruns and time delays.
“The geology we encountered was different to what we presumed and in hindsight, we probably should have done better with the design before we started. Secondly, Covid and the associated delays in the supply chain and border restrictions certainly impacted the project.
With 30 years since the last publicly funded large dam was constructed in Clyde, it had highlighted the need for the country to consider how to deliver infrastructure more efficiently.
Scott said it was a large project for a small region, and it came at a significant cost for a small ratepayer base and shareholders to fund, but it would service the community for at least 100 years.
Its final cost is forecast at $198.2m, but that could be pushed out due to a dispute with the joint-venture contractor who built the dam.
Fulton Hogan and Taylors Contracting initiated adjudication with Waimea Water in 2022 in a dispute over the independent engineer's decision.