Coastal Adaption and Engineering Hardening

One effect of climate change may be increased hurricane frequency or intensity due to changes in atmospheric and geoclimatic factors. It has been hypothesized that wetland restoration and infrastructure hardening measures may improve infrastructure resilience to increased hurricane frequency and intensity. This paper describes a parametric multi-criteria decision model used to assess the potential disaster risk mitigation synergies between wetland restoration and infrastructure hardening using electric power network protection as a case study. We employ a hybrid economic input-output life-cycle analysis (EIO-LCA) model to capture construction costs and life-cycle emissions for transitioning from the current electric power network configuration to hardened network configuration and construction costs and life-cycle emissions associated with wetland restoration. Uncertainty in the climate change – hurricane linkage is accounted for through a probabilistic hurricane simulation model, and parametric sensitivity analysis for important engineering and economic variables and scientific parameters explaining wetland impacts on hurricane storm surge. Three cases for a small project area are evaluated: (1) all existing equipment is overhead; (2) existing equipment is moved underground; and, (3) wetlands are restored in addition to moving existing equipment underground. In this preliminary study, we include wetland restoration sufficient to attenuate storm surge height by 2 ft using dredged material wetlands. Under a base case, Category 3 hurricane (10 ft storm surge, 130 mph maximum wind speeds) scenario, our preliminary results indicate that undergrounding of existing overhead electric power network equipment in the project area will decrease the expected costs associated with Category 3 hurricanes over a 50 year project horizon when environmental impacts are taken into account. This conclusion differs from the general conclusion reached in the literature that undergrounding is not cost effective, as we take a societal perspective and include failure costs and environmental costs to society. Moreover, this cost-effective protective effect of undergrounding is further enhanced with modest investment in wetland restoration, further emphasizing the need for effective policy interventions. In the final paper we expand these preliminary results in application to a model city to include coastal wetland restoration, and a parameterized decision analysis framework to evaluate decisions concerning wetland restoration on the basis of several dimensionless criteria.