This study examines and defines the flood behaviour of the Richmond River and Fawcetts Creek around Kyogle township area including the associated floodplain. The study is aimed at producing information on flood behaviour for a wide range of flood events under existing floodplain conditions, using the most up-to-date modelling techniques currently available. It complies with the requirements of a Flood Study as per Stage 1 of the NSW Government’s Flood Policy.
Kyogle is situated at the confluence of the Richmond River and Fawcetts Creek within the Richmond River Valley of New South Wales. Fawcetts Creek is an easterly tributary comprising 129.1 km² of the 886.2 km² total catchment area upstream of the study area.
The major urban areas of Kyogle township are located on higher ground to the south-east of the confluence of the watercourses. The suburb of Geneva, located on the western side of the Richmond River, is also mostly on higher ground. However a considerable number of properties in the area known as “The Flat”, which is bounded to the north by Fawcetts Creek and to the west by the Richmond River, are located on floodprone land. Properties along the western side of Fawcett Street in the north of Kyogle are also subject to flooding.
During the major flood that occurred along the entire length of the Richmond River on 20 February 1954, 10 people lost their lives within Kyogle. Additionally, 10 houses were swept away and a further 159 homes were damaged by floodwaters. Since this time, flood events of a smaller magnitude have been experienced in 1974, 1976, 1978, 1980, 1987, 1996 and 2001. January 2008 saw the largest flood to hit Kyogle since the 1954 flood. The January 2008 event was approximately a 1 in 50 year Average Recurrence Interval (ARI) event. Experiencing a flood of this magnitude during the course of the flood study process gave Council an opportunity to verify its flood modeling against a large event with a range of data from pluviograph stations and stream gauges and surveyed flood levels provided by the public and the SES.
Council’s consultants on the Floodplain Risk Management Study project, BTM WBM, subsequently prepared the “2008 Flood Event Hydraulic Model Calibration Discussion Paper” which was completed in June 2008. This discussion paper identified some minor changes to the hydraulic flood model based on the calibration against the January 2008 flood event. This then led to a further discussion paper the “Revision of Design Event Modelling Discussion Paper” prepared by BMT WBM in August 2008. This discussion paper shows the changes to the original flood mapping provided with the 2004 Flood Study due to the re-calibration of the hydraulic model.
At its Extraordinary Meeting of January 28, 2009, Council resolved to place on public display the draft Kyogle Floodplain Risk Management Study and draft Kyogle Floodplain Risk Management Plan. An information session and public meeting were held on February 19, 2009 at the Kyogle Memorial Hall. The information session during the afternoon was attended by around 20 people, with the public meeting in the evening attracting a total of 60 people, including Councillors and Council staff. The draft documents were well received, and a preliminary plan of the proposed levee bank and flood breakout channel were also on display for the information of affected residents and owners.
The Kyogle Floodplain Risk Management Study and Kyogle Floodplain Risk Management Plan were formally adopted by Council at the Ordinary Meeting of April 20, 2009.