Beach bits: Beyond the horizon we ought to see

In our last edition, Naomi Edwards wrote about sand movement along Gold Coast’s beaches. There is no doubt that the management of our river of sand presents many challenges for individual beaches. In this story, Naomi helps us understand the regional context and how it impacts good coastal management decisions.

Decisions on how and why Gold Coast beaches are managed are directed by detailed assessments of natural coastal processes. This includes assessment of short and long-term trends of sand movement along the coast between beaches, and onshore and offshore – from sand dunes to sand bars. This constantly moving “sand river” directly affects the health of the beach. Sometimes the beaches reflect these coastal processes on a larger or regional scale, for instance sediment budget trends from northern NSW to beyond the Gold Coast Seaway.

Understanding these large-scale, regional “sediment budgets” must be the foundation for decisions made today that incorporate long-term trends of beach movement, historically and projected into the future.

Dr Darrell Strauss from the Griffith Centre for Coastal Management highlighted how such conclusions can be reached through numerical models of coastal processes.

“Simulating long term changes due to natural variations in sand supply can assist managers to estimate volumes of sand which may be required to increase beach width in a particular area. This information can be integrated into a more simple output approach, for instance, a Beach Volume Index, a measure of the amount of sand in an area at a particular time. Coastal managers can then start to answer the challenging questions of why a beach may experience an increase net loss of sand or why another beach has more sand.”

Responding to coastal issues from a regional perspective has been detailed in a report commissioned by the National Climate Change Adaptation Research Facility to understand the approaches to coastal risk assessments across Australia.

The report titled, Approaches to risk assessment on Australian coasts: A model framework for assessing risk and adaptation to climate change on Australian coasts, discusses various conclusions for regional coastal management, which can be approached by sediment cell planning.

As sand doesn’t stop at jurisdiction boundaries recent post but dynamically moves freely in the active coastal zone by a diversity of un-controllable variables,decisions will still have unknown components with various associated risks.1 This is why it is important to continue to study the science of the coast to build on previous knowledge to ensure right decisions are made from regional to local scales.1

“Just as what happens in your neighbours’ yard can impact you, what happens across the border can influence Gold Coast’s beaches”, said Dr Darrell Strauss.

More information at griffith.edu.au/coastal-management.

1 Woodroffe, CD, Cowell, PJ, Callaghan, DP, Ranasinghe, R, Jongejan R, Wainwright, DJ, Barry, SJ, Rogers, K & Dougherty, AJ 2012, Approaches to risk assessment on Australian coasts: A model framework for assessing risk and adaptation to climate change on Australian coasts, National Climate Change Adaption Research Facility, Gold Coast, 205 pp.

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