Intermittently Closed & Open Lakes & Lagoons (ICOLL)

Council received grant funding from the Australian Government, through the (then) National Recovery and Resilience Agency’s Preparing Australian Communities Program – Local Stream, to undertake a scoping study for the implementation of a Total Flood Warning System (TFWS) covering three catchments within the Shoalhaven LGA. The three catchment areas are Burrill Lake, Lake Conjola and Tabourie Lake. These catchments are characterised by being exposed to flash flooding and comprising ICOLLs with existing low-lying historic development adjacent to these coastal lakes.

Measures to improve flood warning and response through the implementation of a TFWS were recommended in the individual catchments' Floodplain Risk Management Study and Plans (FRMS&P) to reduce flood impacts and the risk to life within these catchments. This project will be undertaken in accordance with the NSW Flood Prone Land Policy, the NSW Flood Risk Management Manual (2023) and in close collaboration with the NSW State Emergency Service (SES), the NSW Department of Planning and Environment (DPE), and other agencies and stakeholders.

Council has engaged a contractor, Manly Hydraulics Laboratory (MHL), to assist with the preparation of the ICOLL Catchments Flash Flood Warning System Scoping Study.

Project Objectives

The primary objectives of this study are to scope the requirements and determine feasible options for the implementation of a fit-for-purpose location-based flash flood warning system for the three catchments to predict lake levels in a flood event, provide early warning, and assist with flood response and pre-flood entrance management procedures. The scoping study will also provide advice on the system design for an optimal TFWS based on the scoping work, which includes operational protocols and preliminary costing for both the capital and ongoing maintenance costs of the systems for Council consideration.

Consultation

Community consultation is an important role for the successful implementation of a TFWS. Comprehensive community consultation will be undertaken throughout the project.

This includes:

• An initial online community survey to provide initial contact with the community stakeholders and to enable feedback to inform subsequent stages of the project.
• Two public exhibition periods and drop-in sessions during the course of the project; one to exhibit flood warning system options and one to exhibit the preferred flood warning system.