GWMWater managing director Jeff Rigby said the ongoing supply was possible as a result of December 18 and 19 rainfall which sustained inflows to Lake Wartook.

"Lake Wartook has been able to maintain its near full supply level in recent weeks while releases have been made for Green Lake," Mr Rigby said.

"That weekend's rainfall has provided further inflows into the reservoir, with the mild weather conditions throughout December also helping the situation."

Mr Rigby said Green Lake was holding 2680 megalitres, with a water depth of about two metres and water reaching the bottom of the boat ramp.

"Of this water, 1260 megalitres has been supplied via releases from Wartook Reservoir, with the remainder attributed to local catchment runoff," he said.

"The continued supply arrangement at 80 megalitres a day will see a further 1120 megalitres supplied to Green Lake, with the lake expected to be holding about 4000 megalitres on January 4, equating to an overall depth of about 2.9 metres.

"Losses through summer due to evaporation are estimated to be up to 0.8 metres, so the lake should still be at least two metres deep in April 2011.

"Even with these losses, the volume provided should enable most of the typical forms of water-based recreation to occur at Green Lake over the summer period."

Mr Rigby said the supply situation would be reviewed again on January 4.

Lake group reconvenes - page 13.