Sea Level Rise
Technical Guide Consultation
Urban and Coastal Water Reform Branch
Department of Environment, Climate Change and Water

Email: coast.flood@environment.nsw.gov.au

DRAFT FLOOD RISK MANAGEMENT GUIDE: Incorporating sea level rise benchmarks in coastal risk assessments

Sea level rise impacts

The Coastwatchers Association welcomes the Department's Draft Risk Management Guide incorporating sea level rise benchmarks in flood risk assessments.

The Eurobodalla is well known as a place of many waters and renowned for its fishing and oysters. The Coastwatchers' Association has been pro-active on monitoring development in the Eurobodalla in locations where it would likely have a detrimental impact on waterways.

Sea level rise due to global warming has also been a long-standing concern of Coastwatchers and we are aware that projected sea level rise could significantly impact upon the tidal range and flood levels of lower coastal waterways.

The resulting social, environmental and economic impacts could be devastating for our local communities.

Development Impacts on Waterways

ICOLLs and coastal wetlands are of immense concern, as are flood plains, creeks and rivers and estuaries, where much of the Eurobodalla's settlement has taken place. Also at risk from the predicted impacts of increasing sea level rise are infrastructure and drainage systems and their ability to cope in extreme storm events due to climate change.

Coastwatchers is concerned that many areas of new development in the Eurobodalla have been totally cleared of native vegetation. As a result the creation of new roadways, driveways and paved areas have increased the amount of impervious surfaces with a resulting increase in the amount of stormwater run-off into wetlands, creeks and estuaries. Their ability to cope with the increased storm water run-off has not yet been fully tested in an extreme storm event and we believe that many low-lying properties could be inundated during extreme events and further exacerbated by sea level rise.

There are also numerous dwellings on small acreage blocks along our rivers and around the estuaries and wetlands. Whilst the dwellings themselves are not on low-lying land their access routes often travel across land likely to be inundated by extreme weather events. Dairy farms in our river valleys face a similar but more serious problem of getting the milk off their properties each day if part of their access road is inundated. Incorporation of sea level rise benchmarks at the planning stage or as part of hazard mitigation strategies will reduce the frequency of such problems to these properties.

Application of sea level rise benchmarks

The Coastwatchers Association agrees that the degree of impact will certainly vary considerably on the tidal range and flood levels. It is essential and timely that The NSW Floodplain Development Manual 2005 and The Floodplain Risk Management: Guideline: Practical Consideration of Climate Change (DECC 2007) are updated to incorporate additional advice to adequately deal with the impacts of climate change on existing development areas and the potential changes to flood producing rainfall events caused by climate change.

The Coastwatchers Association supports the need to incorporate sea level benchmarks in The Flood Risk Management Guide to best manage and plan for floodplain risk and flood risk in planning decisions, hazard mitigation strategies and infrastructure design.

We would also like to see more than consideration of sea level rise in determining development applications. This is not strong enough. It needs to be more prescriptive and possibly be a SEPP in its own right.

Sheila Monahan

Sheila Monahan
President