MidCoast Council is preparing to open Farquhar Inlet following the consistent heavy rainfall over the last few days and a flood warning for MidCoast catchments.
With more than 100mm of rainfall received over the past 24 hours, and a severe weather warning for damaging winds and heavy rain issued by the Bureau of Meteorology, Council intends to open the inlet in accordance with flood management plans for the Manning.
A Smiths Lake opening is also on the radar to assist in keeping flood levels at bay in the south if conditions worsen.
Council's contractors and staff have been on standby since the flood watch was received mid-morning on Thursday from the SES and Bureau of Meteorology who, along with Council's emergency management team, were monitoring rainfall and river heights.
"We have been monitoring weather and catchments conditions for weeks now and this system will trigger the need to open the inlet as water level and subsequent river flow will drive a sufficient opening," explained Evan Vale, Council's Team Leader of Coastal, Flooding and Drainage.
The inlet was last opened in February 2020.
Evan explained the location of the opening is determined on a number of factors including using the lowest section of the beach which is the previous closure point, and linking to a deep back channel resulting in a good release point for the river. This location also avoids erosion of Farquhar Park reserve and reduces sand infill within the Scotts Channel and South Arm as the channel closes.
"The opening is a flood management measure, to allow a quick opening to ease river levels. When the water level behind the beach berm reaches or is predicted to reach the required trigger of 1.6m at the Farquhar gauge we excavate a narrow channel to allow flood waters to exit and scour the entrance."
Opening the inlet this afternoon is purely to alleviate flooding in the area upstream to about Croki. Above Croki the entrance opening has no impact on flood levels.
"We do need to stress that the natural dynamics of the system will eventually close the inlet again, once this rain eases and river flows slow. This could happen quickly if follow up rain does not eventuate.
"It is also essential to have sufficient water level difference between the estuary and ocean and sufficient river flow to drive an opening. We often see community comments suggesting to open the inlet when there is little height difference and river flow. This creates a poor opening which quickly closes resulting in a poor use of resources. It is all in the timing," added Evan.
Members of the public are reminded that the opening will cause changes in the area and to take care and stay clear of the running waters.
