Restoration prioritization framework for roadway high cut slopes to reverse land degradation and fragmentation

Land degradation is one of the most critical global environmental threats. The EU Biodiversity Strategy to 2020 has appointed land degradation and ecosystems fragmentation caused by transport infrastructures as crucial threats to biodiversity. Implementing environmental criteria in roadway project conception phase for restoring large cut slopes will prevent this threat. There is a lack of decision support systems to implement environmental criteria in the decision making procedure to restore high cut slopes. The major difficulties have been building consensus and ensuring traceability and transparency from the panel of experts. This paper presents a hybrid framework capable of dealing with environmental criteria and also with conventional territorial and economic criteria. The decision support procedure combines the Analytical Hierarchy Process with the Delphi technique and the VIKOR procedure. The experts' consensual decision-making process is properly documented, unambiguous and verifiable. The results of this study yielded that the functional and environmental criteria are the key factors in the decision-making process of large cut slope restoration projects. And it has been found the suitability of the cut-and-cover tunnels despite their higher cost and complexity of its construction.