Hydrometric network design in hyper-arid areas: example of Atacama Desert (North Chile)

Efficient water management needs hydrological information provided by hydrometric networks. In arid and mountainous regions, hydrologic models for water resources management and forecasting require a large amount of data due to the temporal and spatial heterogeneity of hydrometeorological variables. The interaction of complex oceanic and atmospheric circulations makes North Chile one of the world9s most arid areas. Since the onset of large mining projects in the nineties, constant population and economic growth generates high pressure on water resources. The existing regional scale hydrometric network in Tarapaca allows for the description of general characteristics and trends at national, but not at water basin, level and therefore does not meet actual demands. Methods for hydrometric network design were designed for temperate areas in general. Based on a review of existing methodologies, the paper identifies multi-criteria analysis (MCA) as best adaptable to the context. It develops a methodology for hyper-arid areas, complementing MCA with stakeholder- and Geographic Information System (GIS) analysis as well as optimization. The paper optimizes the existing hydrometric network in the Tarapaca region, characterized by strong constraints regarding access and topography. Three MCA techniques are compared. The result is an optimized network consisting of 36 rainfall and 21 streamflow stations.