Water Management Strategies Using Multi-Criteria Decision Analysis in Santa Cruz Island (Galapagos Archipelago)

Islands threatened by tourism around the world are under significant stress due to overutilization of (scarce) water resources. The continuous increase of water demand in Puerto Ayora, the main touristic centre of the Galápagos, has become a threat for the water supply system, portraying the current situation unsustainable on the long-term horizon. For this reason, a Multi-Criteria Decision Analysis (MCDA) is tested as a suitable methodology in the presence of scarce data, leading to a set of indicators and intervention strategies, aiming to mitigate the future water demand coverage. The current analysis revealed the most sustainable solution, including environmental, technical, economic and social criteria, by using the DEFINITE software. The results indicate that best option for most of the stakeholders' groups is the option combining all proposed-sustainable options like greywater recycling, specific demand reduction and rainwater harvesting.