Open AccessFog harvesting potential for domestic rural use and irrigation in San Cristobal Island, Galapagos, Ecuador
Author(s) -
Paulina Echeverría,
Christian Domínguez,
Marcos Villacís,
Sophie Violette
Publication year - 2020
Publication title -
cuadernos de investigación geográfica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 20
eISSN - 1697-9540
pISSN - 0211-6820
DOI - 10.18172/cig.4382
Subject(s) - environmental science , water balance , evapotranspiration , interception , hydrology (agriculture) , orographic lift , irrigation , rainwater harvesting , archipelago , physical geography , geography , atmospheric sciences , precipitation , meteorology , geology , ecology , geotechnical engineering , archaeology , biology
The Galapagos Archipelago is a semiarid zone scarce of superficial water resources. Due to its geographic location and the presence of oceanic currents, these islands are covered by fog during seven months along the year which could represent a potential source of water supply. In this study, the feasibility of fog collection for domestic rural use and irrigation was investigated using two Standard Fog Collectors (SFC) of 50% and 35% shade coefficient of 1 m2 and a cylindrical fog net (CFN) of 0.15 m2 at 600 m of elevation in the windward side of San Cristobal Island (Galapagos). The methodology applied consists in the quantification of the monthly and annual water balance at different altitudes in an average and dry years, using the orographic gradients of rainfall, evapotranspiration and cloud water interception. The latter was used to estimate the fog water availability to satisfy any water deficit. Fog water interception was estimated using a geometric model and the use of different climatic variables. On the other hand, water demand in the rural zone for domestic consumption and livestock was estimated with the quota method, and the water demand for agriculture was estimated through the water balance. Results show that the amount of fog captured reaches 7.9, 5.9 and 3.4 mm/d with 50-SFC, 35-SFC and CFN, respectively. Comparing these results with other locations in the world, fog water collection in Galapagos is above the average. A fog gauge system of 50-SFC was designed at different elevations to cover the 25% and 15% of the water deficit in the average and dry year, respectively.