System impacts of nature-based solutions on the Water, Energy, Land nexus on the Pinios River Basin, Greece
The Pinios River Basin (PRB) is the most agriculturally productive area in Greece. The continuous pressure on water, energy and land sectors in the basin have resulted in several key water-energy-land (WEL) nexus challenges, namely water availability, water quality, climate and natural hazards, biodiversity and habitat losses, soil quality, governance and infrastructure, and energy security. These WEL nexus challenges impact the PRB inhabitant’s livelihood and the long-term sustainability of agriculture. Nature-based solutions (NbS) have emerged as a group of options to address several WEL nexus challenges simultaneously. Despite the potential, there are significant gaps which hinder the design and implementation of NbS in the PRB. This research set out to fill some of these gaps.
The first step was to understand the role of NbS in addressing WEL nexus challenges. Seven different classes of NbS were identified which address the nexus challenges through the provision of ecosystem services (ES). The baseline and suitability analysis showed that the different classes of NbS would improve on the baseline ES and are physically suitable to the climatic, hydrological and topographical conditions in the PRB. The analysis of the enabling environment highlighted the key enablers and barriers to the adoption of NbS in the PRB, but the analysis was inconclusive as to whether the correct design and implementation of NbS were achievable.
The system dynamics of WEL nexus challenges, NbS, grey infrastructure (GYI) and socio-economic variables was represented through a casual loop diagram (CLD). The analysis showed that the classes of NbS were able to address all the nexus challenges through direct and indirect mechanisms. The comparison between NbS and GYI options showed different benefits and trade-offs with WEL nexus sectors. The CLD highlights several synergies between NbS and GYI. This emphasises the role grey/green hybrid approaches could play in minimising trade-offs across the WEL nexus. The largest barrier to the implementation of NbS is access to finance but the insurance industry was identified as key in overcoming this issue. The overall picture presented by the CLD depicts the complexity of the system but presents a strong basis for decision-makers to evaluate NbS, GYI and hybrid options in the face of uncertainty and new stressors on the PRB.