WA Coastal Inundation Assessment was undertaken to help the Western Australian Government develop a strategic approach to challenges presented by coastal inundation hazards.
Initial review of the readiness of Coastal Managers to respond to coastal inundation hazard, and the need for adaptative practices due to sea level rise was undertaken through a guided questionnaire. Consultation undertaken provided important information about the status of inundation management at a local government level across Western Australia. It elucidated additional information on the existing knowledge base and practices; investigated existing exposure, management capacity, decision-making context, and available information.
Results of the questionnaire highlighted that practices for coastal inundation management were strongly related to existing perception of hazard. However, most Coastal Managers considered that future change would challenge existing resources, including financial and staff capacities.
Key considerations from this consultation with local Coastal Managers towards the Statewide inundation assessment included:
Existing information from CHRMAP provides a significant knowledge base for inundation management, but adaptation pathways tied directly to inundation are rarely identified.
Asset information presently available is inconsistent and generally lacks detail regarding financial or economic valuation, typically provided in value ‘classes’.
Mitigation options have mainly been considered based on exposure thresholds, with expense perceived as a critical influence on choice of viable options.
There is limited consideration of inundation parameters (e.g. depth, speed of onset) and damage, except to disregard short duration inundation of non-habitable, robust assets.
There is a general lack of integration between land-use planning, building requirements and disaster risk management tools.
Supporting agencies vary around Western Australia.
Coastal Hazard Risk Management and Adaptation Plans (CHRMAP) are a significant source of knowledge for management of coastal inundation hazard. However, CHRMAP focus on long-term land-use planning, and consequently may restrict incorporation of other phases of Flood Risk Management, specifically through building design guidelines and emergency management. Although these elements are within the jurisdiction of Coastal Managers, they are rarely incorporated into present-day coastal inundation management.
The anticipated need for a wider perspective, and management scope, for coastal inundation management is demonstrated by changing international practices for Flood Risk Management. It is noted that transition from tolerance through to strategic risk management is generally related to increasing investment in flood hazard zones. Consequently, expansion of coastal inundation hazard with sea level rise is expected to provide an equivalent pressure.
Recognising existing focus on planning elements, they consequently provide an important gateway towards refining coastal inundation management. Review of existing planning instruments was conducted through a 'planning framework health check' for each Local Government, specific to whole-of-system coastal inundation management. It is important to note there are few right or wrong outcomes, but these checks indicate potential constraints to using various coastal inundation management tools. Applicability or benefit of these tools to each LG was not assessed.
Overall, there is wide variability in how well existing planning frameworks support holistic coastal inundation management. There is some influence of historic inundation, socioeconomics or local morphology (i.e., driven by present day needs). However, the main factor affecting the status of the planning framework is the maturity of coastal adaptation planning for each Coastal Manager. This is a direct reflection of CHRMAP development being a primary source of inundation management knowledge.
A constraint developed by the longer-term perspective and planning focus of CHRMAP is that a relatively limited range of mitigation options have been considered. Consequently, existing planning frameworks do not support use of the full range of coastal inundation management tools. This doesn’t align with Coastal Managers' expressed interest for a choice of approaches, able to be effective and fit-for-purpose across a range of scales
コメント