This document discusses how a physically-based numerical model can be used to quantify changes in groundwater flow and solute transport times in warming permafrost regions. The model couples equations to account for water partitioning and transport in partially frozen ground. Simulation results show that as permafrost degrades over 100 years of 0.05°C annual warming, travel times increase due to longer flow pathways, slower vertical infiltration, and seasonal freezing effects like cryosuction rerouting flow. Transport pathways also lengthen and change, highlighting the need to consider impacts on reactive solute transport and Arctic carbon cycle feedbacks to climate.

1. Modelling groundwater transport and
travel times in warming permafrost
Andrew Frampton1,2, Romain Pannetier1,2, Georgia Destouni1,2
1 Department of Physical Geography and Quaternary Geology
Stockholm University, Sweden
2 Bolin Centre for Climate Research
Stockholm University, Sweden
2015-10-14 Grundvattendagarna, Göteborg

2. Motivation
• Permafrost is perennially frozen ground (T<0 for two consecutive years)
• Covers ~24% of northern hemisphere
• ~1700 Gt carbon stored in, more than twice atmospheric content
• Permafrost carbon feedbacks – links between changing permafrost,
hydrology, solute transport and carbon release
• How quantify changes in groundwater flow, discharge and transport

3. Motivation
• Permafrost landscapes can be extremely dynamic and vulnerable
Imgs: National Snow and Ice Data Center, University of Colorado, Boulder.

4. Motivation
Imgs: Policy Implications of Warming Permafrost, UNEP 2012.
• Permafrost landscapes can be extremely dynamic and vulnerable

5. • Highly transient – systems seasonally dependent, variably
isolated/connected leading to complex exchange patterns
• Need for improved mechanistic understanding of interactions
between changing permafrost and groundwater flow and transport
• Field measurements costly, sites generally very remote
Woo (2012)
After van Everdingen (1990)
Cryohydrogeology – Groundwater in cold regions

6. • Physically-based numerical model
• Couples mass and energy conservation equations for water transport
in partially frozen ground
• Accounts for
− Partitioning of water between the liquid, vapour, and ice phases
− Cryosuction
− Advective transport (liquid, vapour) and diffusive transport (vapour)
− Conductive and convective transport of heat and latent heat transfer
Cryohydrogeology – Groundwater in cold regions
Painter (2011) Comput Geosciences; Frampton et al (2011), J Hydrol; Frampton et al (2013), Hydrogeol J
    



SDnnsn
t glp
pppp
glp
ppp
iglp
ppp 





  ,,,,
V
        Ee
glp
ppp
iglp
mmppp SThuus
t






  



,,,
1 V
• Mass conservation equations
• Energy conservation equations

7. How do water flows and associated inert solute
transport change in degrading permafrost?
Painter (2011) Comput Geosciences; Frampton et al (2011), J Hydrol; Frampton et al (2013), Hydrogeol J

8. Zoomed detail
Note cryosuction
Permafrost degradation and flow pathways during
100 yrs simulated warming (0.05 °C/yr)
Legend
Liquid saturation
Icesaturation
Pre warming
MAST -1 °C

9. Legend
Liquid saturation
Icesaturation
Pre warming
MAST -1 °C
Year 1
MAST -1 °C
Post warming
MAST 4 °C
Year 100
MAST 4 °C
Permafrost degradation and flow pathways during
100 yrs simulated warming (0.05 °C/yr)
Horizontal distance (m)Horizontal distance (m)

10. Changes in travel times
Pre warming Post warming
• Several processes contribute to increase in travel times
• Pathway lengths increase with degrading permafrost
• Warming induces slow vertical flow percolation rather than fast
horizontal saturated groundwater flow
• Seasonal freezing re-routes the carrier flow by cryosuction which
increases travel times
• Seasonal freezing-induced immobilization increases total travel
times Frampton and Destouni (2015), WRR

11. • Several processes contribute to increase in travel times
• Pathway lengths increase with degrading permafrost
• Warming induces slow vertical flow percolation rather than fast
horizontal saturated groundwater flow
• Seasonal freezing re-routes the carrier flow by cryosuction which
increases travel times
• Seasonal freezing-induced immobilization increases total travel
times
Changes in travel times
Frampton and Destouni (2015), WRR

12. Summary
• Cryohydrogeology – Groundwater in cold regions
• Arctic systems are delicate and prone to climate change
• Northern permafrost environments contain significant amounts of frozen
carbon, primarily in near-surface layers, with seasonal groundwater flow
• Physically-based modelling of main processes can be used to quantify
both hydrological and permafrost change subject to climate change
• Subsurface water discharge and solute transport travel times increase
with warming temperature trends
• Transport pathways also increase and change – may significantly impact
reactive transport
• Further considerations include addressing carbon transport, linking to
arctic permafrost-hydrological climate feedback mechanisms

13. Thank you for your attention!
Questions?