Water resources in tourist islands have been severely threatened, especially in the Galápagos Islands, where the increased local population has generated attractive income from the tourist services. In addition, the data regarding water supply and demand are scarce. This study investigates water supply and demand in Santa Cruz, the most populated island of Galápagos. The research encompasses a thorough assessment of the water supply crisis, as well as the quantification of water demand from different categories (domestic, tourist, restaurants and laundries) through surveys, in the absence of water metering. Also, specific water demand was assessed by installing 18 water meters. The results yield a wide range of water consumption, questioning the current assumption of water scarcity. Furthermore, a prognosis of water supply and demand was carried out, and also several intervention strategies were proposed such as rainwater harvesting, greywater recycling, leakage reduction, water meter installation, water demand reduction, as well as seawater desalination to cope with the future population growth. Due to the fragility of the ecosystem, these strategies were assessed through a Multi-Criteria Decision Analysis, considering environmental, technical, economic and social aspects, as well as relevant stakeholders' perspectives. finally, the water supply network of Puerto Ayora was evaluated in order to understand the need of the current intermittent supply regime. A methodology was developed to estimate the overflow of the domestic roof tanks (a common incidence amongst local population). The results question the practicality of individual household storage. The final results show that the current situation in terms of the lack of water quantity may not be real, as it has been thought for the last decades. The water issues refer more importantly to the water quality, as well as to the lack of proper water management practices.

Maria Fernanda Reyes Pérez was born in Quito-Ecuador in March 1983. She graduated from Universidad San Francisco de Quito (USFQ), in Quito, Ecuador, in June 2007, with a Bachelor Degree in Environmental Engineering. After her studies, she worked in USFQ in the Masters of Ecology Department, as well as participating in several projects an consultancies in environmental remediation. In 2011 she obtained her master's degree in Environmental and Energy Management from the University of Twente -The Netherlands, after which she taught a class in energy and Environment at USFQ, worked on several consultancy projects and worked at the Ministry of Public Health of Ecuador as environmental engineer.

While working at USFQ, she also contributed in several projects and researches in the Galápagos Islands. The main purpose of this research was to contribute with the environment, as well as with the local community. In 2012, Maria started her PhD at UNESCO-IHE in Delft, The Netherlands, and is currently a PhD candidate at the department of Environmental Engineering and Water Technology. Her research interest includes water demand management, water supply, water balance, multi-criteria decision analyses, water prognosis, environmental management and sustainability. She continues to work closely with the Galapagos Science Center, a research institute belonging to Universidad San Francisco de Quito and University of North Carolina at Chapel Hill, USA.