As peak flows move downstream toward the Lower Lakes, Transport Department officials are monitoring several spots on the highway adjacent to Lake Albert between Ashville and Waltowa.

Rising water levels combined with tides and winds threaten to inundate the Princes Highway and a 60km per hour speed limit is in place, with the department warning conditions may change quickly.

Closure of the section of road would force road users to detour via the Dukes Highway and McIntosh Way to Meningie.

Upstream at Renmark, where the peak flow passed between December 25 and December 27, Renmark Paringa Mayor Peter Hunter said water levels are dropping rapidly.

Muddy lawns and debris are emerging as floodwater that lapped DefenCell barriers in the main street recedes.

“At the levees you can see where the water was and can see it’s dropped 250 millimetres, in some spots 300 millimetres – it’s down almost a foot along there,” Hunter said.

“At Bert Dix park (near Paringa Bridge) the ground is at a lower angle and the water has dropped back to the river about 20 metres to 30 metres. There’s dirty grass where it was inundated not that long ago.”

Falling River Murray water leaves a thick sludge at Bert Dix Memorial Park at Renmark. Photo: Grant Schwartzkopff

The town’s 38-kilometre levee network is checked daily with Hunter saying the system had held up well to peak flows now working their way downstream to towns near Murray Bridge.

The council has plans to hard-pack the tops of most levee banks built to protect Renmark and Paringa so they were not “starting at zero” if a flood happens again in “one, three or in five years’ time”.

While roads covered with thick sludge are beginning to emerge from the water, Hunter said it will be a huge process to check for damage and ensure water beneath the bitumen has dried out before re-opening the routes to vehicles.

“On one road it looks fine but when you walk on the bitumen it’s like a sponge and moves up and down,” Hunter said, adding that engineers would need to assess each road before it could be used.

The council also has dropped rocks into sections of gouged-out riverbank to prevent further erosion.

Hunter hopes the region, recently hived off into Zone A along the River Murray region by the State Government in planning its recovery phase, is allowed to reopen waters to boats and recreation soon.

Premier Peter Malinauskas revealed the new management plan on January 1 to create eight river zones across the state to make it easier to assess, remove or add restrictions on fishing, boating, canoeing or access to the river.

Surveying River Murray flooding in Renmark during December. From left: Renmark Mayor Peter Hunter, Premier Peter Malinauskas, Berri Barmera Mayor Ella Winnall, Loxton Waikerie Mayor Trevor Norton. Photo: Belinda Willis

Hunter warned that despite water levels dropping in his region, there are still perils from fast-flowing water and submerged debris.

He said owners of about 150 houseboats in the region needed to be vigilant about loosening off tie ropes daily as the water continues to recede.

“They may find if they don’t loosen off the ropes that their bows of the boats will be on the bank,” Hunter said.

Water levels are also falling at Loxton and Waikerie, where the ferry has resumed services limited to light vehicles, school buses, emergency vehicles and heavy vehicles up to 19 metres in length.