AguasSubterráneas el la Cordillera Blanca, PeruJeffrey McKenzie (McGill University)

Daniel Chavez (McGill University)

Ryan Gordon (Syracuse University)

Laura Maharaj (McGill University)

Michel Baraer (École de technologie supérieure)

Bryan Mark (The Ohio State University)

Laura Lautz (Syracuse University)

Importance of Groundwater in the Proglacial Zone

Baseflow to Rivers and Streams, Sustaining Dry Season Flows

Temporal Storage and Release of Water

Potential Impacts on Water Quality

Water for Ecological Systems, such as wetlands

Groundwater Questions

1) After peak-water, is groundwater contribution to water resources significant?

2) What is the source and flow paths of groundwater?

3) Can we assess the groundwater ‘residence time’?

4) Is groundwater vulnerable?

Pampas – An Important Landform for groundwater in the Cordillera Blanca?

(Knox, 2009)

Quilcayhuanca

Yanamarey

Downstream ConfluenceHydrochemical mixing models

GlacierizedNon- glacierized

Glacier

No Glacier

YAN

Q3

Q2

Q1

YAN

Q1

Q3

Q2

mix

ing lin

e

1999 Mix (Q3) = 70% Non-Glacier Water

Q3

Q1

Q2

YAN

Mix

2004 Mix (Q3) = 50% Non-Glacier Water

Mark et al., 2004

Hydrochemical Basin Characterization Method (HBCM; Baraer et al., 2007)

Yanamarey Watershed

HBCMDry Season Groundwater in Other Valleys

(1) Llanganuco(2) Quilcay

(3) Querococha

Baraer et al., 2009

(4) Pachacoto

Rain Fed Groundwater Systems

Chavez et al., 2012

Talus

Bedrock

Glaciolacustrine

GPR Results

Mixed-Source Groundwater Systems

Llanganuco Upper Pampa, Viewed from Laguna 69

Debris

Fan

Talus

Meadow

Moraines

Laguna

69

Lag.

Broggi

Llanganuco Upper Pampa

Big spring

82.1 L/s

Flow

from fan

22.8 L/s total

Flow from

Moraine

5.2 L/s

Outflow from

Lag. 69

21.8 L/s

Outflow from

Lag. Broggi

35.8 L/s

Outlet

115 L/s

Discharge

and net

changes

METHOD - Double-slug

dilution gauging method

which provides:

discharge (Q)

net change in discharge

(∆Q)

gross gains and losses

(Qgain and Qloss )

Laura Lautz & Ryan Gordon

Syracuse University

Groundwater Travel Time

Geochemical Results

Travel time is ~ 1.5 to 3 years

Darcy Velocity Calculations

Groundwater velocity through talus is ~ 3 mm/d

Minimum travel time is greater than 1 year

Threats to Groundwater• Receding glaciers may impact

groundwater recharge in mixed-sourced aquifers

• Changes in precipitation regime due to climate change will affect recharge

• Human contamination of groundwater Very Difficult to Fix

• Increased ET due to warmer temperatures

Conclusions

RECHARGE Groundwater is recharged from precipitation

and glacier melt

STORAGE Groundwater is

stored over years in coarse

grained aquifers

RESOURCE

Groundwater is an important contributor to

dry season flows

THREATS

Groundwater is Vulnerable to

Climate Change and

Contamination

jeffrey.mckenzie@mcgill.ca