Mitigation Options for Future Water Scarcity: A Case Study in Santa Cruz Island (Galapagos Archipelago)

Abstract

Santa Cruz Island (Galápagos Archipelago), like many other tourist islands, is currently experiencing an exponential increase in tourism and local population growth, jeopardizing current and future water supply. An accurate assessment of the future water supply/demand balance is crucial to capital investment for water infrastructure. This paper aims to present five intervention strategies, which are suggested to solve the future water crisis. The strategies combined include environmentally sustainable options such as rainwater harvesting, greywater recycling and water demand management, as well as desalination. These strategies were evaluated under four population growth scenarios (very fast, fast, moderate and slow growths) by using several Key Performance Indicators (KPI's) including water demand, leakage levels, total costs, energy consumption, rainwater delivered and greywater recycled. Moreover, it also aims to develop a methodology for similar islands, using the WaterMet 2 modelling approach, a tool for integrated of sustainable-based performance of urban water systems. The results obtained show that by 2044 only a small portion of the future water demand can be covered assuming business as usual. Therefore, desalination seems to be the most viable option in order to mitigate the lack of water at the end of the planning period considering the growth trends. However, strategies comprising more environmentally friendly alternatives may be sufficient, but only under slow population growth scenarios.

Assessment of Groundwater Quality in Parts of Ijoko Area, Sango-Otta Axis of Southwestern Nigeria

“…The primary objective was to find the most suitable and sustainable solution to overcome lack of water supply. The five intervention strategies shown in Table 1 and Figure 1 were obtained from the study carried out by Reyes, et al [23]. Therefore, the basis for the input data for the MCDA were the results obtained in the previous-mentioned study, for the end of the forecast period (2045).…”

“…Then, different software were evaluated, and the DEFINITE software was selected as the tool for this analysis. DEFINITE was developed to help improve the quality of decision, by methodical procedures which lead experts through a number of interactive assessment sessions [23]. It uses an optimization approach, which integrates all the information provided by the involved stakeholders into a full set of value functions leading to a scientific based 'best' alternative [24].…”

“…The data used for scoring and populating the 'effects table' were obtained from Reyes, et al [25], including the following Key Performance Indicators (KPIs): water demand, water losses, energy use and costs. In the study by Reyes, et al [23], results were obtained for four growth scenarios. However, in the analyses for this paper, only the results from the moderate-growth scenario were used (4% annual growth for tourism and 3% for local population).…”

“…Then, the total weight was calculated based on the product of weight-level 1 and weight-level 2. The result obtained from this calculation became the actual weight for the MCDA evaluation [23].…”

Analysis for water mitigation options using MCDA: A case study in the Galapagos islands

“…3 RESEARCH METHODOLOGY First, the problem was defined as the water supply deficit in the town of Puerto Ayora in the year 2044. In order to solve this issue, the study made by [17], developed with the help of the WaterMet 2 model [18] forecasted the water demand coverage over a 30-year planning horizon, proposing five intervention strategies. The results for the end of the forecast period (2045) were the basis for the input data for the MCDA.…”