Publication Abstract

Expert-driven approaches to assessments of long-term coastal geo-hazard

Expert-driven approaches to assessments of long-term coastal geo-hazard

P. Larcombe and D.Morris*

Coastal developments with multi-decadal to centurial life-spans present a problem to regulators, developers, consultants, local interest groups and, indeed, applied scientists - How to assess the coastal hazards that might be associated with such developments? Over such timescales, the regional and local hydrodynamic and sedimentary processes will be fundamental controls for most other “environmental” issues, and extrapolation of hydrodynamic models to predict geomorphology is inappropriate.

We draw on work evaluating coastal geo-hazards faced through the lifetime of potential new major coastal power stations, covering design, construction, operation and decommissioning. Our purpose was to produce a forecast of the ‘likely’ route(s) of coastal change, and thus develop a 100-year strategic view of coastal geo-hazards.

Using a small group of technical experts, a series of intensive workshops were held, driving a 3-stage approach:

1. Development of a series of bounding snapshots (‘plausible future geo-scenarios’); a range of bigpicture possibilities for coastal evolution. This involved defining the main geomorphological possibilities, each not limited by known processes, the range of ‘predicted’ ones or by likelihoods.
2. Development of semi-quantitative 'likely future coastal forecasts' with clarification of key issues, especially weaknesses in arguments. These ‘forecasts’ describe explicit pathways of coastal development with tentative timings, alternative routes, sketches and caveats. All forecasts are ‘likely’, but their coastal geo-hazards vary.
3. Production of ‘formal predictions of future coastal change’ (not executed at the time of writing), building on, rather than passively excluding, the vital thinking performed in developing the coastal forecasts, to focus clearly on key environmental and engineering issues.

This expert-driven approach explicitly and transparently acknowledges and includes strengths and weaknesses in data, information and understanding, capturing the range of inherent uncertainties. Technical and non-technical understanding increases through the hazard-focussed process, increasing confidence in and accessibility and use of the results.

Reference

P. Larcombe and D.Morris* (2012) Expert-driven approaches to assessments of long-term coastal geo-hazard. Coasts and Ports 2011: Diverse and Developing: Proceedings of the 20th Australasian Coastal and Ocean Engineering Conference and the 13th Australasian Port and Harbour Conference, 2011, p.398-403 (ISBN: 9780858258860)

http://search.informit.com.au/documentSummary;dn=708923952884622;res=IELENG

P. Larcombe and D.Morris*

Coasts and Ports 2011: Diverse and Developing: Proceedings of the 20th Australasian Coastal and Ocean Engineering Conference and the 13th Australasian Port and Harbour Conference, 2011, p.398-403 (ISBN: 9780858258860)