Permafrost-Influenced Geomorphic Processes

Torre Jorgenson

environmental research & servicesenvironmental research & services

Overview of Geomorphic Processes• Coasts

– Storm surges, sedimentation, salinization, permafrost degradation• Floodplains

– Changing flooding, sedimentation, – Channel migration

• Coastal Plain-Lowlands– Thermokarst lakes, waterbody creation– Lake expansion and shrinkage – Paludification, organic matter accumulation– Ice-wedge Degradation

• Uplands– Loss of permafrost aquatard, drainage– Thaw slumps– Thermokarst Lakes in Extremely ice-rich loess (yedoma)

• Mountains– Slope Failure

North Slope Ecological ProfileC

oast

al W

ater

Coa

stlin

e

Jago Coastal Plain

Flo o

dpla

in

Up

lan

ds

Glaciated Uplands

I cy Coast

Coastal Plain

OkpilakMountains

Sadlerochit Uplands

Lakes

Lowland sDwarf Shrub

edge-

Lacustrine Wet S eadowedge M

Upland Tussock Tundra

Coastal WetSedge Tundra

Coastal Grass and Dwarf Shrub Tundra

Mesic shurbbytussock tundra

Upland Low birch-Willow shrub

Upland Tall Alder Shrub

River

Riverine Barrens

Riverine low willow shrub

Riverine Dryas

Riverine Wet Sedge Meadow

Alpine acid barrens

Alpine Dryas Dwarf Shrub

Intrusive,felsic

Quaternary,glacial

Sedimentary,NoncarbonateQuaternary,

alluvial-marineQuaternary,marine

Hula

hula

Mounta

ins

Beaufort Coastal Plain

Brooks Foothills

Beaufort Coast

0

500

1000

1500

2000

2500

3000

Elev

atio

n (m

)

Brooks Range

IntrusiveFelsic

Quaternary,Alluvial

Coastal Ecosystems

• Sedimentation (up to 10 cm in big year)

• Storm Surges (1970 to 2 m)

• Salinization (up to 15 km inland)

• Sea Level Rise (3 mm/yr)

Barrier Island and Lagoon Ecosystems

Tundra Cliff and Sandy Shore Ecosystems

Delta Ecosystems

Summer

DON

DOC

NO3

ThermokarstSalinity

Temperature

Wind

Organic Mat

Ground ice

PO4

Active Dunes

Inactive Dunes Tidal

Flats

Precipitation

Sea Level

Wave Energy

Sea

Sediment

Discharge

Winter

Produced for ARCN-NPS by M. T. Jorgenson and D. M. Sanzone

OCEANOGRAPHIC ­­¯­­

Sea Level Storm surges Sea Ice Fetch Length Wave Energy

GEOMORPHIC Shoreline Erosion Barrier Island Migration Marine Sedi. Transport Land Sediment Deposit. Dune Formation/Scouring Thermokarst

­DDDD­

CHANGE

Coastal Geomorphic Processes

October 2002 Storm at Barrow

2000 Beaufort Lagoon

-1.0

-0.5

0.0

0.5

1.0

1.5

7/13/2000 7/23/2000 8/2/2000 8/12/2000 8/22/2000 9/1/2000 9/11/2000 9/21/2000

DATE

WA

TE

R L

EV

EL

(m)

Mininum

MaximumMean tidal range = 0.31 m

1.0 m on 11-12 August

Storm Surges

Coastal Erosion

Deltaic Environments

Salinization: Salt-killed tundra

FLUVIAL PROCESSES

Changing flooding, sedimentation, Channel migration

Changes over Time:

Increasing height,

Decreasing flooding frequency,

Decreasing sedimentation,

Increasing organics,

Decreasing thaw depths,

Decreasing water depths

Decreasing pH

Increasing ground ice,

Increasing susceptibility to thermokarst,

GEOMORPHIC PROCESSES ON RIVER FLOODPLAINS

Upland Sandy Low

Scrub

Upland Barrens

Riverine Barrens

Riverine Low and

Tall Scrub

Riverine Wet

Meadow

Lowland Wet

Meadow

Lowland Deep Lake

Riverine Wet

Meadows

Riverine Lake -

Connected

Riverine Marsh

1000-2000 years for development

Low Water

1-2 yr3-4 yr

5-25 yr

25-200 yr

Massive or Crossbedded Sand

Rippled sands/fines, with detrital organicsLayered fines

Masssive organics

Layered fines w/ clay

Layered Organics

Eco

typ

es

Decreasing Flooding and Sedimentation

Riv

er

Riverbed/ Riverbars

Active-floodplain

Cover Deposit

Inactive-floodplain

Cover Deposit

Abandoned- floodplain

Nuiqsut

Eas

t Cha

nnel

Col

ville

Riv

er

Nech

elik

Channel

Eroded Riverbed/Sandbar

Riverbed/Sandbar Deposition

Unchanged Riverbed/Sandbar

Thaw Basin Drainage/Deposition

Other Eroded Terrain

Unchanged Terrain

Lake-level Change

Unchanged Water

In-field Facilities

Pipelines

N 0

SCALE IN MILES

Proposed Project

Areas of Erosion and Deposition

1 2

Area (%)1.3

2.6

7.6

1.8

1.0

58.8

0.9

26.1

Landscape Change from 1955 to 1992,Central Colville River Delta

8.2% of area changed over 37 yr2.3% of land erodedAt current rate it would take about 1700 years to rework entire delta

Erosion and Deposition

Lowland and Lacustrine Ecosystems

Lowland Hydrology:8-11 ka surfacePoorly integrated surfaceSnow-melt rechargeSummer Draw-down

Coastal Plain Geomorphic Model

Eolian SandLoess

Thaw Lake

Coastal Plain with Moist/ Dry Tundra

Ice-rich Thaw Basin with Wet Tundra Ice-poor Thaw Basin

with Wet Tundra

1992Jun AugJul

1991Jun AugJul

-500

-400

-300

-200

-100

0

100

200

1990

Jun AugJul

Class A Pan Evaporation

Net Water Balance

Precipitation

NE

T W

AT

ER

BA

LA

NC

E (

mm

)

Shoreline Erosion and Lake Basin Development

0.7% of land was eroded over 45-56 year period, 0.01%/yrAt this rate it would take 8400 years to rework the surface.

In-filling of Lake Margins

1945

Wetting location

Drying location

Time Series: Beaufort Coastal Plain

1982

Pond shifts

Pond develops

2001

Pond drains

Pond develops

Ponds drains

1982

2001

Micro-topographic Effects of Ice-wedge Degradation

Alluvial-marine Deposit(gently rolling)

Ice-poor Thaw Basin

Ice-rich Thaw Basin Margin

Before Disturbance

Thermokarst After Disturbance

Shallow Water

Deep and Shallow Water

Wet Tundra, Deep and Shallow Water

Before DisturbanceActive Layer (m)Segregated Ice (% vol)Wedge ice(% vol)

After DisturbanceActive Layer (%)Mound Settlement (m)Trough Settement (m)Drainage

0.3 0.4 0.3 0.4 0.471 64 64 64 6020 15 20 15 0

0.8 0.8 0.8 0.8 0.80.6±0.3 0.4±0.3 0.3±0.1 0.4±0.3 0.4±0.3

1-2 1-2 1-3 1-2 0partial none none/partial none none

Water

Active Layer

Ice Wedges

Ice-rich Thaw Basin Center

Ice-rich Thaw Basin Margin

Deep and Shallow Water

Deep Water

Alluvial-marine Deposit(gently rolling)

Ice-poor Thaw Basin

Ice-rich Thaw Basin Margin

Before Disturbance

Thermokarst After Disturbance

Shallow Water

Deep and Shallow Water

Wet Tundra, Deep and Shallow Water

Before DisturbanceActive Layer (m)Segregated Ice (% vol)Wedge ice(% vol)

After DisturbanceActive Layer (%)Mound Settlement (m)Trough Settement (m)Drainage

0.3 0.4 0.3 0.4 0.471 64 64 64 6020 15 20 15 0

0.8 0.8 0.8 0.8 0.80.6±0.3 0.4±0.3 0.3±0.1 0.4±0.3 0.4±0.3

1-2 1-2 1-3 1-2 0partial none none/partial none none

Water

Active Layer

Ice Wedges

Water

Active Layer

Ice Wedges

Ice-rich Thaw Basin Center

Ice-rich Thaw Basin Margin

Deep and Shallow Water

Deep Water

Stable Permafrost

Degrading Permafrost

Alluvial-marine Deposit(gently rolling)

Ice-poor Thaw Basin

Ice-rich Thaw Basin Margin

Before Disturbance

Thermokarst After Disturbance

Shallow Water

Deep and Shallow Water

Wet Tundra, Deep and Shallow Water

Before DisturbanceActive Layer (m)Segregated Ice (% vol)Wedge ice(% vol)

After DisturbanceActive Layer (%)Mound Settlement (m)Trough Settement (m)Drainage

0.3 0.4 0.3 0.4 0.471 64 64 64 6020 15 20 15 0

0.8 0.8 0.8 0.8 0.80.6±0.3 0.4±0.3 0.3±0.1 0.4±0.3 0.4±0.3

1-2 1-2 1-3 1-2 0partial none none/partial none none

Water

Active Layer

Ice Wedges

Ice-rich Thaw Basin Center

Ice-rich Thaw Basin Margin

Deep and Shallow Water

Deep Water

Alluvial-marine Deposit(gently rolling)

Ice-poor Thaw Basin

Ice-rich Thaw Basin Margin

Before Disturbance

Thermokarst After Disturbance

Shallow Water

Deep and Shallow Water

Wet Tundra, Deep and Shallow Water

Before DisturbanceActive Layer (m)Segregated Ice (% vol)Wedge ice(% vol)

After DisturbanceActive Layer (%)Mound Settlement (m)Trough Settement (m)Drainage

0.3 0.4 0.3 0.4 0.471 64 64 64 6020 15 20 15 0

0.8 0.8 0.8 0.8 0.80.6±0.3 0.4±0.3 0.3±0.1 0.4±0.3 0.4±0.3

1-2 1-2 1-3 1-2 0partial none none/partial none none

Water

Active Layer

Ice Wedges

Water

Active Layer

Ice Wedges

Ice-rich Thaw Basin Center

Ice-rich Thaw Basin Margin

Deep and Shallow Water

Deep Water

Stable Permafrost

Degrading Permafrost

Water-tracks

Hillslope Geomorphic Processes

Increased drainage, south-facing slopesThaw slumpsThermokarst Lakes in extremely ice-rich loess (yedoma)

Foothills Model

Precipitation- Leaching Gradient

Snow PhenologySpring

Fall

Thermokarst Gullies and Water Tracks, Healy

Thaw Slumps

Photo by Andrew Balser

Deep Thermokarst Lakes

Seward Peninsula

CONCLUSIONS

• Regional Factors– Cold climate leading to permafrost development

• Coastal Processes (16% of Coastal Plain including Lagoons, 5% land)– Sediment deposition, salinization, thermokarst– Spread of halophytic vegetation, salt-killed tundra

• Fluvial Processes (9% of area)– Flooding leading to sediment deposition– Channel migration, erosion, and thaw lakes– Feedback from ice aggradation of flooding regime– Willow thickets, legumes, productive wet sedge

Lacustrine Processes (14% areas in lakes, 39% in basins) Differential sediment deposition Shoreline Erosion (0.1%/yr) Lake Drainage (3% of landscape over 100’s yrs) Carbonate inputs, strong pH gradientsThermokarst

Ice Wedge Degradation (>3%, up to 20%)Tussock loss, wet sedge increase, redistribution of water

Hillside ProcessesDeeper Drainage,Gully formation, Thaw slumpsDeep Thermokarst Lakes

CONCLUSIONS