Waitaki Lakes campers have been warned to watch lake levels after heavy rain in the Southern Alps over the past week.
Meridian Energy Ltd and Environment Canterbury (ECan) have urged holidaymakers to be aware of possible spilling from Lakes Tekapo and Pukaki over Christmas week, due to heavy rains.
Those falls have seen a sharp and continuing rise this week in the levels of the two storage lakes, which feed the Waitaki hydro system.
Up until Friday, Mt Cook had 632mm of rain, 445mm falling on Tuesday and Wednesday alone.
There is also a MetService severe weather outlook in place for a high risk of heavy rain in the Southern Alps tomorrow.
Meridian spokeswoman Claire Shaw said that, as a result of some recent significant weather events, there might be some flow releases in the week from today.
''Having the lakes full is, of course, a good thing as Meridian plans for the winter, but we are watching our lakes, as the recent rain events have boosted our inflows,'' she said.
ECan spokesman Graham Sullivan said both ECan and Meridian were reminding campers and anglers to be mindful of the possibility of rising water levels in the Tekapo River and to factor this into camping and fishing activities in the Waitaki catchment.
''Water levels can rise quickly, and with little warning, and people in the Tekapo and Pukaki area need to keep a close watch on river conditions. Stay safe this holiday,'' he said.
Thousands of campers are around the Waitaki lakes at present and those who have chosen low-lying spots close to the water, particularly around lakes Benmore, Aviemore and Waitaki, need to watch lake levels after any further major rain in the upper catchment.
Central South Island Fish and Game Council officer Graeme Hughes said that, eventually, any spill had to find its way down the Waitaki River.
The coloured water entering the lakes would affect the fishing, as it would in the rivers.
''Sadly, it appears there will be a lot of new fishing gear looking for some clean water to fish.
Lakes Aviemore and Waitaki may be high but the water should remain fishable for several days before the flood flows affect water clarity,'' he said.
The time it took to clear would depend on the inflows.
Small high-country tarns and lakes that had no inflows would remain clear and fishable, but many were restricted to fly fishing only.
The Waitaki River would be clear at Kurow but at flows exceeding 500cumecs it could become unfishable down-river.
''Not great news. However, it will give the didymo a fright and we will get some great clean-water fishing as soon as normal water levels resume,'' Mr Hughes said.
