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Clarence Valley Council has embarked upon a major planning process for floodplain management in the Clarence Valley which will eventually result in several Floodplain Management Plans covering the whole of the floodplain.
Significant progress has been made in developing a Floodplain Risk Management Plan for Grafton and the Lower Clarence.
A valley wide flood study review was completed in 2013. The review used more accurate survey data than previous models, and was also able to incorporate extensive information from the January 2013 flood. The study indicates that the Grafton and Maclean levees would experience some overtopping in a 1 in 100 year flood. Council adopted the study review in March 2014, and the review flood model has been adopted as the basis for establishing flood planning levels (residential floor levels) in accordance with Council’s existing floor heights policy, with the exception of North Grafton. While the flood study considered climate change scenarios, the NSW State Government is currently developing new guidance for Councils regarding appropriate sea levels to adopt. However, it is likely that the recommended sea levels to account for climate change will actually be lower than those adopted for the model. Council therefore decided to wait until the revised guidance on predicted climate change sea levels is available and modelled before including climate change impacts in its flood planning levels. Flood planning levels in North Grafton will be determined separately through the Floodplain Risk Management process.
A review of flood mitigation measures and management for Brushgrove was considered by Council in 2013. A revised Grafton and Lower Clarence Floodplain Risk Management Plan has been prepared to identify the revised flood management actions for Brushgrove, including the report prepared by Consultants, GHD.
Enquiries regarding implications of the 2013 Flood study update to the Grafton and Lower Clarence Floodplain Risk Management Plan should be Council’s Strategic Planning section.
The 2004 flood study indicated that the flood levee at Ulmarra is lower than the 1 in 100 year flood level and Council has decided to prepare a Floodplain Risk Management Plan for the town accordingly.
Ulmarra is also vulnerable to flooding from the Coldstream River behind the town and consideration is being given to such management strategies as house raising, levee improvements, flood proofing of dwellings and improved evacuation plans.
Flooding in the Alipou Creek basin has been identified as an extremely important issue for affected residents. Alipou Creek has a large catchment area which floods quite quickly during heavy rain, and Council has recently completed a Floodplain Risk Management Plan to outline possible measures to alleviate the hazard.
Consultation with property owners and the public generally has been able to identify available options. Such options as culvert upgrading, road access improvements, house raising and floodgate modifications are all included in the plan.
The township of Iluka is isolated in most floods by inundation of Iluka Road near the Esk River.
Larger floods would present a risk to life and property as evacuation via Iluka Road would not be possible. The Floodplain Management Committee has identified appropriate strategies for dealing with floods at Iluka, and public meetings were held in 2006 to seek input to the process. The levee at Iluka is lower than the 1 in 100 year flood, and parts of the town are also vulnerable to localised flooding from heavy rainfall.
The Floodplain Risk Management Plan for Iluka has now been publicly exhibited and subsequently adopted by Council. Funding will now be sought to implement the management measures.
Council adopted the Yamba Floodplain Risk Management Plan, and Study, at its Meeting held on 24 February, 2009. Yamba lies at the mouth of the Clarence River floodplain, on its southern bank. It represents a major urban centre in the lower Clarence River valley and has a permanent population in the order of 6,000 residents, whci doubles during peak holiday season.
There is a long history of flooding on the lower Clarence floodplain, particularly at Graftopn. At Yamba, there is only limited flood history as flooding has not caused the devasting damage that has ccurred elsewhere. The last significant flood on the Clarence River was in March 2001 but this did not cause damage to the township. The May 1996 flood recorded lower levels upstream in the Clarence River but resulted in more flooding problems at Yamba than in March 2001 due to higher ocean levels at the time of the flood.
The Yamba Floodplain Risk Management Plan and Study have been prepared to identify the nature and extent of the flood risk to Yamba and to identify a range of measures to manage those impacts. They therefore provide a basis for future planning, infrastructure and emergency management decisions by Council, State Government Agencies and the wider community.
Most of the rural villages on the Clarence Valley floodplain have no flood protection. Hence work has commenced on identifying strategies to improve safety in rural villages and surrounding areas.
Such strategies as house raising and flood proofing of dwellings are likely to be employed along with better flood preparedness and awareness amongst landowners.
As the first stage of developing a Floodplain Risk Management Plan for the village of Glenreagh, in September 2013 Council adopted the Glenreagh Flood Study. Council has resolved to proceed to preparing a Floodplain Risk Management Study, but the timing of the study will be subject to financial assistance from the State Government.
Glenreagh Flood Study (9.5Mb)