Master of Science (MS)
In the wake of recent hurricanes, coastal managers in Louisiana have begun integrating infrastructure protection and habitat restoration. Concurrent with this change, emphasis has been placed on marsh creation (MC) techniques that rely on mechanical dredges and sediment conveyance pipelines to rapidly build new land. The costs and benefits of this approach are increasingly compared to more natural and slower methods using fresh water diversions (FWD), yet such comparisons are not typically inclusive of time and risk considerations. Data for more than 300 coastal wetland restoration projects were evaluated for the statistical development of generic acreage trajectories and restoration cost models. These models were incorporated into a benefit-cost construct and sensitivity analyses were conducted to examine the relative importance of specific project attributes related to time, distance, project scale, discount rate, and site-specific land loss rates. Benefit uncertainty was addressed through incorporation of climatological and political risk within an expected valuation framework. Case studies were examined for MC and FWD projects under hypothetical acreage targets and locations. As expected, project period and scale were found to be inversely correlated with unit cost ($/acre). Likewise, discount rate, distance from source material to project site, and specific sub-costs associated with dredge mobilization were positively related to unit cost. The degree of these effects, however, differed greatly between the two generic models. The most pronounced finding is that the relatively slow rate of restoration from FWD projects negatively affects project feasibility. Furthermore, the incorporation of project-specific types of risk (hurricane impacts and social constraints) was found to compound the problems associated with slower performing projects. Perhaps most importantly, simulations for both FWD and MC projects indicated that required break-even annual benefits were considerably larger than actual benefits reported as accounting from similar projects in the non-market ecosystem valuation literature. This finding suggests the need for a reevaluation of current spending to ensure the most cost-effective combination of attributes in project selection. The decision framework provided here allows restoration managers to increase efficiency in the allocation of limited funding for coastal restoration.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Wang, Hua, "Economic assessment of rapid land-building technologies for coastal restoration" (2012). LSU Master's Theses. 3669.