Characterization of snow processes and their implications on runoff generation.Semi-arid Andes - Central Chile

Yohann Videla-Giering 1,4 John Pomeroy2 and James McPhee 3,4

Abstract Understanding the role of physical processes on the volume and residence time of extratropical Andean

snowpack is critical for successful water resources management in Central Chile. The lack of direct, long term

observations, motivates the use of hydrological modeling for hypothesis testing and process understanding,

with the aim to achieve robust hydrological predictions under global change scenarios. To this end, we force the

CRHM model with data from the Era-Interim re-analysis for the 2000-2017.

Study Area: Morales & Yeso Basins

0

10

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80

0

5

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20

25

30

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40

Apr Jun Aug Oct Dec Feb

Pp [mm]T [ºC]Yeso Embalse Estation - 2500 masl.

Precipitation Temperature

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100

200

300

400

Abr Jun Ago Oct Dic Feb

Runoff[m3/s]

Maipo en San Alfonso Maipo en las Melosas

Volcán en Queltehues Olivares antes de junta con Río Colorado

Maipo en el Manzano

• Basin-averaged elevation: 3300 masl

27.5

Km2

61.3

Km2

5000

Km2

Yeso Basin

Morales Basin

Maipo Basin

Approach: Hydrological model - CRHM

ሻ𝜕(𝜌𝑐𝑇

𝜕𝑡+ 𝜌𝑙𝑐𝑙𝑉𝑙

𝜕𝑇

𝜕𝑍+ ∆ℎ𝑖𝑙𝑀𝑖𝑙 =

𝜕

𝜕𝑍𝑘𝑒𝑓𝑓

𝜕𝑇

𝜕𝑍

𝑑𝑄

𝑑𝑡= 𝛥𝑄 = 𝑅𝑛 + 𝑄𝑒 + 𝑄ℎ + 𝑄𝑔 + 𝑄𝑚 + 𝑄𝑑

𝑘𝑊

𝑚−2

Downscale HRU’s Generation Hydrological modelling

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100

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SWE

[mm

]

Soil Temp Shortgrass and SrhubsNormal cond.

+2ºC Temp Soil

+3º Temp Soil

Performance: SWE, IWE & Hydro-Signatures

Energy Balance: Climate sensitivity

SWE: Snow cover & Snow Extend

• Relevant soil water storage component in narrow valley bottoms

Approach: Hydrologic Model Structures

376

512

413

461

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416

0.72

0.68

0.56

0.53

0.52

0.45

SW

E [

mm

] &

Sn

ow

Dep

th[

cm]

Aver

age

Wav

elen

gth

[µm

]

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20

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58

Fresh snow Old snow

Soil

Jully - NIR 720[µm]

Conclusions

• 80% of summer runoff (DJF) comes from glacial melting.

• Snow and ice melt contribute to runoff throughout the entire year, dispelling the

notion of distinct accumulation and melt seasons.

• Notorious change in snow line and season

length during 2010 - 2015.

• Stabilization of SCA over 2650 meters.

• Temperatures during and after snowfalls

explain Snow Extend

Runoff: Water Fluxes & Storage

Material and Methods Results

1 Department of Geology, Faculty of Physical and Mathematical Sciences, Universidad de Chile, 2 Centre for Hydrology, University of Saskatchewan, Saskatoon, SK, Canada. 3 Department of Civil Engineering, Faculty of Physical and Mathematical Sciences, Universidad de Chile. 4

Advanced Mining Technology Center, Faculty of Physical and Mathematical Sciences, Universidad de Chile, Santiago, Chile. yv.giering@Gmail.com - john.pomeroy@usask.ca - jmcphee@uchile.cl

4th INARCH workshop, 24th – 26th October 2018, Santiago and Portillo, Chile