EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Modelling the glacier-hydrology of two large catchments in the Peruvian Andes

Catriona L. Fyffe1, Emily Potter2,3, Andrew Orr4, Thomas E. Shaw5, Edwin Loarte6, Katy Medina6, Evan Miles5, Florian von Ah5, Michel Baraer7, Alejo Cochachin8, Joshua Castro9, Nilton Montoya9, Matthew Westoby1, Duncan J. Quincey2, and Francesca Pellicciotti1,5
Catriona L. Fyffe et al.
  • 1Northumbria University, Engineering and Environment, Geography and Environmental Sciences, Newcastle-Upon-Tyne, United Kingdom of Great Britain – England, Scotland, Wales (
  • 2School of Geography, University of Leeds, Leeds, UK
  • 3Department of Atmospheric and Cryospheric Sciences, University of Innsbruck, Austria
  • 4British Antarctic Survey, Cambridge, UK
  • 5Swiss Federal Institute for Forest, Snow and Landscape Research, Zürich, Switzerland
  • 6Instituto Nacional de Investigación en Glaciares y Ecosistemas de Montaña, Huaraz, Perú
  • 7École de Technologie Supérieure, Université du Québec, Montréal, Canada
  • 8Autoridad Nacional del Agua, Perú
  • 9Universidad Nacional San Antonio Abad del Cusco, Cusco, Perú

Glacier meltwater is a vital component of river discharge in the Peruvian Andes, providing an important source of dry season runoff for communities, agriculture and fragile mountain ecosystems. Previous hydrochemical and modelling studies have identified the importance of glacier meltwater to downstream runoff and analysis of runoff records suggest ‘peak water’ has passed already. These studies, however, have been confined to the Rio Santa basin and the models applied have simplifications in their treatment of glacier melt and evolution. Our objectives are to i) determine the past glacier contribution to streamflow, determining when peak water passed and quantifying the recession of the glacier contribution to runoff; ii) predict future glacier evolution and its consequent impacts on water resources; and iii) to compare the hydrological response of catchments in central and southern Peru and establish their future response to glacier recession.

To meet these objectives we have applied the hourly physically-oriented, glacio-hydrological model TOPKAPI-ETH to two catchments in the Peruvian Andes: the Rio Santa in the Cordillera Blanca (4953 km2) and the Rio Urubamba draining the Cordilleras Vilcanota, Urubamba and Vilcabamba (11048 km2), the two most glacierised catchments in Peru. Past glacier recession has been substantial and future temperature rise is likely to lead to further glacier retreat, threatening water security in both regions. The model is forced with hourly atmospheric inputs from high-resolution (4 km), bias-corrected Weather Research and Forecasting (WRF) model outputs, which are downscaled to the TOPKAPI-ETH model resolution (100 m), using temperature and precipitation lapse rates defined from the WRF data for all sub-catchments of each domain. To reduce equifinality in model parameters we calibrate the model in a stepwise manner, using a combination of in-situ and remotely sensed data. Melt model parameters are calibrated based on full energy balance simulations at five sites across the two domains, with albedo parameters also derived from calibration with measured data. We calibrate the temperature decrease over glacier ice in an iterative manner using the WRF air temperatures, observed weather station data and the energy balance model outputs. Precipitation undercatch is a key unknown but it is constrained by careful comparison of modelled glacier surface mass balances with those inverted from remotely sensed data, while hydrological routing parameters are identified through calibration against hourly runoff records collected within the catchments. 

We use the model outputs to unravel the water balance characteristics of both catchments, their main drivers, including the relative importance of glacier and snow melt components within catchment runoff, and how they vary seasonally, inter-annually and through time due to glacier recession. By applying the model to two catchments with contrasting climatologies and glacier characteristics we are also able to disentangle the reasons for their distinct future trajectories. 

How to cite: Fyffe, C. L., Potter, E., Orr, A., Shaw, T. E., Loarte, E., Medina, K., Miles, E., von Ah, F., Baraer, M., Cochachin, A., Castro, J., Montoya, N., Westoby, M., Quincey, D. J., and Pellicciotti, F.: Modelling the glacier-hydrology of two large catchments in the Peruvian Andes, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10540,, 2022.


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