Darwin region water supply infrastructure upgrades

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Darwin region water supply infrastructure upgrades

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EARLY STAGE PROPOSAL
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POTENTIAL INVESTMENT OPTIONS
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INVESTMENT READY PROPOSAL
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PROJECT DELIVERY
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POST COMPLETION REVIEW

Darwin region water supply infrastructure upgrades

A graphic of the Australian continent with NT state shaded and small dot representing Darwin.
LOCATION
Darwin, NT
GEOGRAPHY
Smaller cities and regional centres
SECTOR
Water
OUTCOME CATEGORY
Access to Water
PROPONENT
NT Government
INDICATIVE DELIVERY TIMEFRAME
Near term (0-5 years)
ESTIMATED COST
$1,451.94 million (P90, outturn)
DATE ADDED
18 February 2022
Problem

Population growth and industrial development is driving increases in demand for water in the Darwin region.

The 2015 Northern Australia Audit found that an additional water source for Darwin is essential to support further growth of the city. At the same time, climate change is forecast to impact on supply by increasing evaporation and transpiration, which will lead to reduced inflows to reservoirs and decreasing yields.

Failure to expand Darwin’s water supply could constrain population and economic growth. It is also likely to impact on business and investor confidence.

Investment ready proposal

The Darwin Region Water Supply proposal involves upgrades to existing infrastructure and additional water infrastructure.  

There are two key components of the proposal :

  1. Returning Manton Dam to service –  increasing water supply for the short term (from 2025-2027).
  2. The Adelaide River Off-stream Water Storage (AROWS) scheme – increasing  medium to long term water supply

Strategic Fit

The proposal aligns with key initiatives identified within the Darwin Region Water Supply Strategy, which details the Northern Territory Government’s   plan to balance demand for water with supply capacity over time.

The proposal also aligns with a range of other  state and commonwealth government strategies, policies and priorities.

Societal Impact

The proposal is expected to deliver benefits to a range of users by providing improved access to a secure water supply, including industrial, agricultural and urban consumers.

The proponent’s stated benefit–cost ratio is 1.04, with a net present value of $44.05 million (7% real discount rate).

Deliverability

The proponent’s delivery approach recognises that the preferred option is comprised of two stages with different delivery timeframes and different complexities.

NT Power and Water Corporation (the NT’s provider of water and sewerage services) will lead the development of the Manton Dam RTS project (Stage 1), through a construct only delivery approach.

The preferred approach for delivery of the AROWS project (Stage 2), is through three work packages, using a delivery partner model.

Next steps

While there is a clear strategic case for this proposal, further analysis should be completed prior to progressing the AROWS component  of the proposal to:

  • mitigate risk that forecast agricultural and industrial demand, and revenue estimates are not realised
  • ensure that environmental impacts and related costs and benefits are fully accounted for in the economic modelling
  • ensure that demand management and water efficiency programs are implemented.

Refer to Infrastructure Glossary for terms and definitions.