Post Peak Water in the Cordillera Blanca, Peru: Toward a Redistribution of Water Resources.

Michel Baraer, École de Technologie Supérieure, Montreal, QC, Canada, Bryan G Mark, Byrd Polar and Climate Research Center, The Ohio State University, Columbus, OH, United States, Jeffrey M McKenzie, McGill University, Earth and Planetary Sciences, Montreal, QC, Canada, Kyung In Huh, The Ohio State University, Houghton, MI, United States, Oliver Wigmore, University of Colorado at Boulder, Boulder, CO, United States and Alfonso Fernandez, The Ohio State University, Columbus, OH, United States

Contact First Author: Michel Baraer; michel.baraer@etsmtl.ca

Abstract ID#: 35915

 

English Abstract:
Recent researches have shown that the upper Rio Santa and some of its tributaries that drain the western slopes of the glacierized Cordillera Blanca in Peru have already passed peak water, the moment of maximum water availability, and now exhibit decreasing dry season discharge as a consequence of glacial retreat. In addition, it was suggested that the glacier retreat impact of stream discharge is not uniform across the watershed. For instance, two different points along the Rio Santa were shown facing two different levels of glacier retreat impact on dry season discharge.

In the present study, we extend the exploration of the peak water situation spatial repartition by dividing the Rio Santa watershed into 26 sub catchments and analyzing the impact of the glaciers retreat on these sub catchments dry season hydrology. We measured stream discharge at 11 locations along the entire course of the Rio Santa and sampled water at 33 locations to analyze for major dissolved ions and the stable isotopes of water. We interpreted the sample characteristics using a distributed hydrochemical watershed mapping tool called the Hydro-chemical Basin Characterization Method (Baraer et al., 2014). Glacier retreat simulations were then used to project future hydrological changes as a function of glacier mass loss and evaluate the downstream repercussions.

The results confirm that the entire Rio Santa watershed has passed the peak water. An overall decline of the dry season discharge of 30% of the actual level is anticipated just upstream of the major coastal diversions installations, a level that situates below the present demand for coastal uses. The geospatial heterogeneity in glaciers hydrological influence on stream discharge is explained by differences in glacier cover as well as in glaciers retreat rates. The most pronounced discharge reduction should be observed in the central part of the Cordillera Blanca where towns like Huaraz, the province capital, should be deeply affected.

Back to: Changing Cold Regions: Climate, Cryosphere, Hydrology, Ecology IV