Lowering lake levels and the continued dry weather has forced Meridian Energy to reduce the rate at which water flows from Lake Te Anau to 80 cumecs, a flow below its usual minimum flow.

Meridian Energy spokesperson Andrew Feierabend said the hydro electric company identified last week that Lake Te Anau was at increased risk of breaching its equinoxial limit should the normal 115 cubic metres per second (cumec) limit continue.

Equinoxial limits apply in March and April and are designed to minimise the effect of equinoxial wind patterns on exposed lake shorelines.

Te Anau's Lake Control gates. Photo: Southland App

Meridian Energy subsequently reducing lake flows through the Te Anau Lake Control (TLC) after consultation with the Fish & Game Council and Ngāi Tahu, and approval from the Guardians of Lakes Manapouri, Monowai and Te Anau (Guardians).

Feierabend also said Meridian Energy was managing its generation at the Manapōuri Power Station to reduce risk associated with the equinoxial requirements in Lake Manapōuri.

Guardians chairperson Madeleine Peacock said they had received and approved a request from Meridian Energy on 24 March to step down the flow at the TLC to below the minimum 115 cumecs.

Peacock said the most recent lake level information she had (24 March) showed Lake Te Anau was still in the top half of the lake's low operating range and sitting at 201.3m.

Lake guidelines show Lake Te Anau should avoid going below 201.1m during equinoetial periods, and Lake Manapouri 176.2m.

Peacock said it was quite natural for lakes to go low at times and that shorelines needed exposure to sunlight and oxygen from time to time in order for seedbeds of native plants like macrophytes to germinate.

However low lake level limits and exposure durations were in place to protect both freshwater mussel communities and shorelines from wind damage, she said.

Peacock said the Guardians didn't currently have any concerns, but were keeping a watching brief on the situation and were in regular contact with Meridian.

The upper Waiau River at Rainbow Reach. Photo: Southland App

Fiordland Jet owner Chris Adam said on Saturday (26 March) the Upper Waiau River was dropping quite quickly causing changes in the number of channels.

He said while it was totally safe boating, locals did need to be aware of the dry parts now and not take it for granted.