Selection of sustainable projects for floodplain restoration and urban wastewater management at the lower Chubut River valley (Argentina)

Urban growth causes environmental degradation of extended areas at the coastal floodplain of the Chubut River (Argentina). We developed procedures to identify environmentally sustainable engineering projects for floodplain restoration and urban wastewater management. We addressed specific questions about considering basic hydrological knowledge, stakeholders’ interests and social acceptance, and evaluated scoring methods that would be consistent, non-redundant and robust to various weighting criteria. Our procedures followed the following steps: (1) identification of sustainability paradigms adapted to local contexts; (2) development of hydrological modeling and collection of expert and stakeholders’ judgment in order to formulate a wide palette of feasible project alternatives; (3) development of a set of indicators of environmental sustainability to evaluate the project alternatives and test of their self-consistency; (4) evaluation of the proposed projects by means of a hierarchical multivariate analysis, estimation of the indicator weights through multivariate analyses of the un-weighted judgment scores, and reduction of the redundancy incurred during project evaluation. Finally, we identified a small set of highly ranked project alternatives to achieve floodplain restoration and sustainable urban wastewater management in the area and tested the obtained ranks for sensitivity and robustness to eventual bias in the estimation of environmental scores. We discuss the methodological developments presented in this study and their eventual application to similar landscape and urban planning scenarios.