Victoria's overflowing dams have been blamed for adding to flood crisis

Many of them are spilling for the first time in decades.

It has focused attention on how the storages are managed to capture water for irrigation and urban supplies and not to prevent flooding.

For instance, one of Victoria's biggest water managers, Goulburn Murray Water, says its primary role is to harvest and store customers' water entitlements.

"GMW's water storages are not designed or operated specifically for flood mitigation, although they do provide downstream flood peak reduction benefits where possible."

GMW says it "aims to have the storages at 100 per cent at the conclusion of flood events to maximise water availability for future use by our customers".

Even the Thomson Dam, which provides most of Melbourne's water, is on the verge of spilling for the first time since 1996.

The spillway gates have already been opened at Lake Eildon which last reached capacity almost 30 years ago.

Lake Eppalock is spilling for the first time in six years.

No surprise then that smaller dams like Lake Wartook in the Wimmera or Rosslynne Reservoir at Gisborne are spilling.

For Rosslynne, it is spilling for the first time since 1996.

The Loddon River's big storages, Laanecoorie, Cairn Curran and Tullaroop reservoirs are all full.

Lake Glenmaggie in Gippsland is full, perhaps the only place in the state still with "room" in the storages is western areas of the state.

A flooded Wimmera River is expected to provide the first flows for many years in dry lakes to the north but Rocklands Reservoir, west of the Grampians is 39 per cent full.

The massive Murray River storages like Dartmouth Dam has been spilling for weeks after filling for the first time also since 1996.

Critics say the dam operators had ample warning to create room in the big storages for inflows once the third La Nina forecast was announced and helped prevent some of the flooding downstream.

They point to the decision by the Murray-Darling Basin Authority back in August to remove the lock weir at Mildura to prepare for a Murray River flood.

The last time the weir was removed was in 2016.

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Meanwhile, the Victorian government is delivering grants to help farmers and business owners clean up their properties

The $19.5 million program will provide a one-off $10,000 payment to primary producers directly affected by the floods.

The grants will cover activities like the removal and disposal of debris and injured or dead livestock, repairing essential equipment, fixing and replacing fencing, buying fodder, water and water storage, salvaging damaged crops, grain or feed, and hiring or purchasing materials to clean up a property or equipment.

Primary producers whose properties have been directly hit are also eligible for concessional loans of up to $250,000 to restore or replace damaged assets, and meet general expenses incurred while the clean-up is underway.

Flood-affected primary producers can also claim up to 50 per cent of transport costs - up to $15,000 - for the transport of emergency fodder or stock drinking water, and moving stock to agistment, sale or slaughter.