Hydrochemical evaluation of changing glacier meltwater contribution to stream discharge: Callejon de Huaylas, Peru / Evaluation hydrochimique de la contribution évolutive de la fonte glaciaire à l'écoulement fluvial: Callejon de Huaylas, Pérou

Abstract

Discharge measurements, precipitation observations and hydrochemical samples from catchments of the Callejon de Huaylas watershed draining the Cordillera Blanca to the Rio Santa, Peru, facilitate estimating the glacier meltwater contribution to streamflow over different spatial scales using water balance and end-member mixing computations. A monthly water balance of the Yanamarey Glacier catchment shows elevated annual discharge over December 2001-July 2004 compared to 1998, with net glacier mass loss in all months. Glacial melt now accounts for an estimated 58% of annual mean discharge, 23% greater than 1998-1999. At Lake Querococha, below Yanamarey (3.4% glacierized), a hydrochemical end-member mixing model estimates that 50% of the streamflow is derived from the glacier catchment. Average concentrations from the Rio Santa leaving the Callejon de Huaylas (8% glacierized) are modelled as a mixture with 66% deriving from glacierized tributaries of the Cordillera Blanca as opposed to the non-glacierized Cordillera Negra end member.

Clarifying regional hydrologic controls of the Marañón River, Peru through rapid assessment to inform system-wide basin planning approaches

“…Glacier meltwater is responsible for the majority of streamflow in some Cordillera Blanca headwater catchments (Mark et al, 2005) and can be especially critical for dry-season discharge (Baraer et al, 2012). The percent glacierized area of headwater catchments is significantly related to the specific discharge of that basin (Mark and Mckenzie, 2007), with ice melt's role diminishing for larger basins where rainfall and snowmelt dominate.…”

Spatio‐temporal tracer variability in the glacier melt end‐member — How does it affect hydrograph separation results?

“…Tracers applied within this method should be conservative, that is, no change in signature (e.g. due to isotopic fractionation or chemical reaction of solutes with geology) except due to mixing of different waters (Baraer, McKenzie, Mark, Bury, & Knox, 2009;Mark, McKenzie, & Gómez, 2005). Environmental tracers, such as electrical conductivity (EC), and stable isotopes of water, such as oxygen-18 (δ 18 O), have been used in tracer-based hydrologic studies of glacierized catchments (e.g., Engel et al, 2016;Rodriguez, Ohlanders, Pellicciotti, Williams, & McPhee, 2016;Williams, Wilson, Tshering, Thapa, & Kayastha, 2016).…”

Evaluating Glacier Volume Changes since the Little Ice Age Maximum and Consequences for Stream Flow by Integrating Models of Glacier Flow and Hydrology in the Cordillera Blanca, Peruvian Andes

“…This valuable natural water storage affects runoff characteristics in glacierized catchments and downstream river flow regimes. However, the decrease in glacier volume due to climate change causes a net loss of water from storage, leading to a significant ephemeral increase in meltwater runoff from high alpine drainages, followed by a decrease in runoff to regional stream flows [1][2][3][4][5]. The reduction in glacier size diminishes the amount of glacier melting and is associated with a decrease in direct runoff [6,7].…”