Understanding Dartmouth Dam operations

Dartmouth Dam pondage. Photo courtesy Murray-Darlng Basin Authority

Understanding Dartmouth Dam Operations

Dartmouth Dam is located on the Mitta Mitta River, downstream of the confluence of the Mitta Mitta and Dart Rivers.

The dam captures runoff from the alpine catchment and regulates flows in the Mitta Mitta River downstream. It is the largest storage in the River Murray system, with a capacity of 3,856 GL. When full, Dartmouth holds more than 40% of the Murray system's total storage capacity.

What is Dartmouth Dam's role?

Dartmouth Dam is the River Murray system's primary reserve storage, often referred to as a drought reserve.

Water stored in the system supports irrigation, domestic and stock supplies, urban water consumption and hydroelectricity generation.

Water is transferred via the Mitta Mitta River to Lake Hume when required, helping maintain water security across the Murray-Darling Basin, particularly during dry periods.

How are releases managed?

Planned releases from Dartmouth Dam are designed to balance the delivery of water entitlements and water orders to the southern Basin states while minimising impacts on downstream communities.

Operational requirements are set out in the Objectives and Outcomes for River Operations in the River Murray System 2026, approved by the Basin Officials Committee (BOC). Changes in river level are managed to reduce the risk of riverbank instability between the Dartmouth Pondage and Lake Hume, and to provide adequate warning of significant river level fluctuations in the Mitta Mitta River.

The timing and volume of releases depend on water availability in downstream storages, particularly Lake Hume, as well as water demand across the River Murray system.

In wetter years, little or no transfer from Dartmouth may be required.
In drier years, larger transfers may occur to replenish downstream storages and support Basin water demands.

Flood Management

Although Dartmouth Dam was not designed specifically for flood mitigation, it has significantly reduced downstream flood peaks since construction. As a result, the lower Mitta Mitta River experiences:

Fewer moderate floods
Reduced flood frequency
Reduced connection with river benches and floodplain habitats.

Read here for more information: Managing floods at Dartmouth Dam | Murray–Darling Basin Authority

What does this mean for the Mitta Mitta River?

River operations have changed the way the lower Mitta Mitta River functions compared to its natural flow regime. Reduced flooding can affect floodplain connectivity, vegetation condition and sediment movement, while changes in water level fluctuations may contribute to riverbank erosion in some locations.

Summary: Who does what?

Murray-Darling Basin Authority: Directs the operation of Dartmouth Dam on behalf of the Basin governments, determining how much water should be released, when water is transferred, sets downstream flow targets and coordinates operations across the broader River Murray system.
Goulburn-Murray Water (GMW): Operates Dartmouth Dam and associated infrastructure on behalf of MDBA.
AGL operates the hydroelectric generation infrastructure associated with Dartmouth Dam, including the Dartmouth Power Station, Dartmouth Pondage and Banimboola Power Station. Power generation is undertaken within the operational constraints and release requirements set for the system.
North East CMA (NECMA): Has no operational role in managing releases from Dartmouth Dam. NECMA works with landholders and communities on river health, including responding to concerns about riverbank erosion and supporting river restoration activities.

Stay informed

Residents can subscribe to Mitta Mitta Flow Advice: Subscribe | Murray–Darling Basin Authority or view current notices here: Newsroom | Murray–Darling Basin Authority_Mitta Mitta

Storage volumes, release rates and river heights can be viewed here: The River Murray

Understanding Dartmouth Dam operations