Fondecyt

From snowfall to streamflow: a modeling approach to assess the water budget of Norte Chico upper catchments

Chile's National Fund for Scientific and Technological Development (FONDECYT) granted my research project in October 2009.

Norte Chico is a semiarid area in Chile spanning Coquimbo and Atacama regions, between 26°S and 32°S latitude. In this region, as many others in the world, water resources originate from mountains. The annual snowfall in the high-altitude areas of the Andes Cordillera (above 2500 m) controls most of the streamflow and groundwater recharge. A better knowledge of snow cover and snowpack dynamics might help water managers to forecast water availability and sharing among water users (agriculture, urban consumption, mining industries).

Project N°11090445. Fondecyt Iniciacion

2009: 24'318'000 CLP

2010: 11'456'000 CLP

Total: 35'774'000 CLP (~US$ 75'000)

Main results

1. A snow and weather monitoring station was set up for the project
2. A precipitation grid for the Norte Chico was generated
   1. Bourgin, P-Y (2010) Spatial interpolation of the precipitation in the Norte Chico region, Chile, Master's thesis, Université Pierre et Marie Curie, Paris.
   2. Proceeding paper, What do we know about high-altitude precipitation in the semi-arid Andes of Chile? Société Hydrotechnique de France meeting, Lyon, March 2011
   3. Journal paper: Bourgin et al. (2012), La Houille Blanche
   4. Journal paper: Bertin et al. (2014), Effects of wind-driven spatial structure and environmental heterogeneity on high-altitude wetland macroinvertebrate assemblages with contrasting dispersal modes, Freshwater Biology, doi:10.1111/fwb.12488
3. We analyzed the effects of the wind transport and sublimation on the snow patterns
   1. Gascoin S., S. Lhermitte, C. Kinnard, K. Borstel, G. E. Liston (2013), Wind effects on snow cover in Pascua-Lama, Dry Andes of Chile. Advances in Water Resources, 55, 25-39, doi:10.1016/j.advwatres.2012.11.013

Water in Norte Chico: a schizophrenic system?

The Norte Chico region is located in northern Chile between 26°S and 32°S (Figure 1). This region is characterized by a dramatic east-west topographic gradient. Only 200 km separate the Pacific Ocean coastline from the Argentinean boarder in the Andes, where the altitude can exceed 5000 m. The consequence is a strong longitudinal climatic gradient. The annual precipitation is generally lower than 100 mm along the coast and exceeds 300 mm in the high mountains. Conversely, the mean annual temperature decreases eastward, in such a way that, at the regional scale, most precipitation falls in the form of snow. On the other hand, the Norte Chico’s population and agricultural resources are concentrated in low altitude semi-arid areas, where river flow is extensively used for irrigation. This means that water input areas are separated from the output areas.

Tacked on to this spatial asymmetry, the Norte Chico hydrological system is affected by a pronounced climate seasonality. Almost all of the significant precipitation events occur in winter (May-September), whereas the water demand in the cultivated valleys is the highest in summer. Thus, from a hydrological point of view, the Norte Chico system appears schizophrenic both in time and space. This specificity is well emphasized in the few hydrological studies dedicated to the region’s catchments (Favier et al., 2008, Souvignet et al. 2008, Vicuña et al., submitted). However, it is equally important to point out that such hydro-climatic setting is a typical feature of many regions of the world (e.g. High Atlas, Pamir Mountains, Eastern Turkey, etc.). More than half of humankind relies on water resources from mountain areas (Liniger et al. 1998). Viviroli et al. (2007) estimated that 37% of global mountain area provides important water resources, especially in arid and semi-arid regions, like the Norte Chico.