Billions of litres of water have arrived at the top of the Menindee lake system.

A year after an estimated million fish turned up dead in the Darling River and Menindee Lakes, fresh flows have renewed hope for businesses and growers.

For the Barkindji people of the region, the water is profoundly important.

“It's good to see water in here. Now we can go back to our fishing, camping, all sorts of stuff now the river's flowing,” local Barkindji man Clint Ferguson has told the ABC.

“It's our lifeblood. It means everything for us, our river. Take that away, and we got nothing.”

Grape-grower Steve Howse says the new water arrived at the perfect moment.

“Post-harvest from here moving forward until next year's crop is really important to us,” he told reporters.

“The vine stores starch and carbohydrates. I suppose it's the energy like a bear, it's hibernating for next year's crop.

“Storing it with bad water is not good for us, so a bit of fresh water coming in is going to be great.”

WaterNSW forecasts that up to 285 gigalitres could reach Menindee, which have a capacity of more than 1,700 gigalitres.

The agency says it will begin releasing some of the water to the lower Darling River in coming weeks, attempting to connect it end to end for the first time in years.