AN ASSESSMENT OF THE NATURAL AND ANTHROPOGENIC FACTORS CONTROLLING THE DISTRIBUTION OF WELLS AND SPRINGS IN THE ARID, MID-MONTANE AREA OF THE COQUIMBO REGION, NORTH-CENTRAL CHILE

Arid and semi-arid zones, defined as areas recieving less than 50 cm of precipitation annually, and montane environments, located at an altitude between 200 and 1000 masl and having slopes exceeding 20h, together comprise more than 39% of the earth’s surface, exclusive of Antarctica and Greenland. In addition to their environmental and social importance, these areas have global economic significance; thus, a good understanding of the hydrological processes acting in these areas is critical. Development of sustainable, integrated water management strategies to cope with scarcity in these regions demands an understanding of the factors that control water availability, and particularly with respect to groundwater. Unfortunately, this knowledge is difficult to obtain, especially in large and/or remote areas. The cost and complexity of research carried over basin or greater areas means that few hydrogeological studies are pursued at the regional scale. This is particularly true in rural areas with low population densities; for example, the rain-fed mid-montane zones of north-central Chile. These arid and semi-arid regions are characterized by moderate to steep slopes, and depend exclusively on precipitation (either directly or as local recharge to groundwater) as a water source.

In a recent paper (Oyarzún et al., 2017, J. Arid Environments 142:31–35), it was shown that the distribution of wells in the rain-fed, middle mountain zones of the Coqumbo region exhibited two preferred orientations, NW and NE, that align with the structural fabric of the area. However, further analysis intended to unravel the factors that may determine or explain such distributions have not as yet been accomplished. The current work has as a general objective the assessment of factors both natural (e.g., hydrological, lithological, structural, and geomorphological) and anthropogenic (e.g., social, road connectivity, economic) that could explain the observed pattern of wells and springs in the area.