Water scarcity index in the Ambi river basin, Ecuador

The availability and use of water resources is currently a problem that affects the development of life and economic activities. Although Ecuador is one of the countries with the highest water availability per inhabitant, the increase in demand puts pressure on water supply sources. This study aimed to determine water scarcity during 1990-2017 in the Ambi river sub-basin, located in the province of Imbabura in Ecuador. For this purpose, the water scarcity index (IEH) was defined by calculating water supply and demand using Geographic Information Systems. The water supply was estimated using the SWAT hydrological model to simulate flows. The flows were validated with information from the Institute of Meteorology and Hydrology of Ecuador (INAMHI). The average value of water supply during the period 1990-2017 was 4.94 m(3)/s, and its total water demand was 17 m(3)/s. This shows that as supply decreases, demand increases. In addition, the values obtained for the IEH tripled from the period 1990-1996 to the period 2007-2018, going from 57.26 to 183.57%. Consequently, these results evidence the high pressure from the demand for the availability of water resources.