Workshop on Engineered Barrier PerformanceWorkshop on Engineered Barrier Performance

Related to Low-Level Radioactive Waste,Decommissioning and Uranium Mill Tailings Facilities

Related to Low-Level Radioactive Waste,Decommissioning and Uranium Mill Tailings Facilities

P d i i A id S ilP d i i A id S ilPedogenesis in Arid Soils:Biotic and abiotic processes operating at all scales

Pedogenesis in Arid Soils:Biotic and abiotic processes operating at all scales

NRC HeadquartersAugust 5, 2010

Todd G. Caldwell1Todd G. Caldwell1

Eric V. McDonald and Michael H. Young2Eric V. McDonald and Michael H. Young2

1Di i i i f E th d E t S i R NV1Divisision of Earth and Ecosystem Sciences, Reno NV2Division of Hydrologic Sciences, Las Vegas NV

BackgroundBackground

S il d l t l ti d d iS il d l t l ti d d iS il d l t l ti d d iS il d l t l ti d d iFunction of climate, parent material, topography,

biology and time.Function of climate, parent material, topography,

biology and time.

Soil development, evolution and pedogenesis Soil development, evolution and pedogenesis Soil development, evolution and pedogenesis Soil development, evolution and pedogenesis

biology and time. Morphological change from depositional sediment to

soil (Pedogenesis) P d i f t ff t h d li t

biology and time. Morphological change from depositional sediment to

soil (Pedogenesis) P d i f t ff t h d li t Pedogenic features affect hydraulic processes at various scales, both temporally and spatially

Pedogenic features affect hydraulic processes at various scales, both temporally and spatially

ESB are a geomorphic landform that will evolve ESB are a geomorphic landform that will evolve

Soil development and ESBsSoil development and ESBsSoil development and ESBsSoil development and ESBs

Surface soils will co-evolve with vegetation Compacted or engineered soils evolution Surface soils will co-evolve with vegetation Compacted or engineered soils evolution

Soil Development by Soil OrderSoil Development by Soil Order

Aridisol DevelopmentAridisol Developmentp PPT < 500 mm Dust Accumulatory

p PPT < 500 mm Dust Accumulatory Calcic vs. Sodic Calcic vs. Sodic

From Birkeland, P.W. (1999) Soils and Geomorphology.

From Dan and Yaalon (1982)

BackgroundBackground

Hydraulic properties in arid systems are a function of both biotic and abiotic processesHydraulic properties in arid systems are a function of both biotic and abiotic processes

Abiotic processes: Dust accumulation

Abiotic processes: Dust accumulation

function of both biotic and abiotic processesfunction of both biotic and abiotic processes

Dust accumulationDecrease in infiltration rates and increased water

holding capacity

Dust accumulationDecrease in infiltration rates and increased water

holding capacity Formation of soil structure, horizon development

and accumulationRegional scale variability (1-10 km2)

Formation of soil structure, horizon development and accumulation

Regional scale variability (1-10 km2)Regional scale variability (1 10 km )Quaternary time scales (1-1,000 ka)Regional scale variability (1 10 km )Quaternary time scales (1-1,000 ka)

SourcesSources andand SinksSinks

SilverSilverLake

Infiltration

SodaLake

Wind Lake

Pedologic Development of an Interspace Desert Soil

Pedologic Development of an Interspace Desert Soil

DustDustDust

Dust

Av HorizonFan Deposit

DustDust

Av HorizonFan Deposit

Av1Av2 Av Horizon

HorizonB tAv Horizon

HorizonB tBtky1

Btky2

TimeTimeBkyBky

Pedology of Desert SoilsPedology of Desert Soils

6

Av Thickness

(cm)2

3

4

5

Plutonic MixedQ t M it

Modern 0.1k 1k 10k 100k0

1

Quartz MonzaniteVolcanic MixedLimestone-Marble

Surface Age, Structure, and DyeSurface Age, Structure, and DyeQf6 Qf5

D th 2Qf2 Qf3 Depth = 2 cmQf6 < Qf5 < Qf3 < Qf2

~0.5 ---------> 80 kaMatrix ------> Macro

Meadows, D.G., M.H. Young, and E.V. McDonald. 2008. Influence of relative surface age on hydraulic properties and infiltration on soils associated with desert pavements. Catena 72:169-178.

Hydraulic Conductivity and Surface AgeHydraulic Conductivity and Surface Age

10-2

1 2 5

3.0

3.5

Ksa

t (cm

sec

-1) 10-3

Surface (Av)Subsurface (B)

an K

sw -

log

cm d

-

1.5

2.0

2.5

K

10-5

10-4

mea

0.0

0.5

1.0

y = -0.5546 x + 3.5089 r2 = 0.9254

Geomorphic Surface

Qf3 Qf5 Qf6 Qf7 Qf810

Soil Surface Age - log years

1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

Old Young

Predictable decrease in Ks of the Av horizon: Subsurface horizons remain highly conductivePredictable decrease in Ks of the Av horizon: Subsurface horizons remain highly conductive

Young, M.H., E.V. McDonald, T.G. Caldwell, S.G. Benner, and D.G. Meadows. 2004. Hydraulic properties of a desert soil chronosequence in the Mojave Desert, USA. Vadose Zone J. 3:956-963.

Weak Soil Development

Young depositsSand rich textureDevelopment Sand-rich textureLimited HorizonationLoose matrixLoose matrixHigh Infiltration

Strong Soil Old DepositsStrong Soil Development

Old DepositsClay-rich textureComplex HorizonationCemented matrixLow InfiltrationStevenson, B.A., E.V. McDonald, and T.G. Caldwell. 2009. Root patterns for Larrea tridentata in relation to soil morphology in Mojave Desert soils of different ages, p. 312-338, In R. H. Webb, et al., eds. The Mojave Desert: Ecosystem processes and sustainability.

A soil chronosequence YPG

A soil chronosequence YPG

Substitution of space for time (0.4 to 400 ka)

Time quantified through Time quantified through cosmogenic dating, 10Be or 36Cl

Pedogenic processes quantified through soil development index

Intermediate

Pedology of Desert SoilsCibola Range - YPG

Pedology of Desert SoilsCibola Range - YPG

~25 ka: CRF 2C

0

~100 ka: CRF 3B

0

~1 ka: CRF 1B

0

CLAY

50 50

)

50

SAND

SAND

SAND SILT CLAY

SILT

100 100

dept

h (c

m)

100

150

200

150

200

150

200

Percent

0 25 50 75 100200

Percent

0 25 50 75 100200

Percent

0 25 50 75 100200

Fines increase horizons develop as clays translocate deeperFines increase horizons develop as clays translocate deeperFines increase, horizons develop as clays translocate deeper into the profile; proxy for extreme climatic events

Fines increase, horizons develop as clays translocate deeper into the profile; proxy for extreme climatic events

Pedology of Desert SoilsCibola Range - YPG

Pedology of Desert SoilsCibola Range - YPG

0 0 0

~25 ka: CRF 2C ~100 ka: CRF 3B~1 ka: CRF 1B

0

50

0

50

0

50

dept

h (c

m)

100 100 100

150 150 150NOx Cl-

SO42-

mg g-1

0 5 10 15 20 25200

mg g-1

0 5 10 15 20 25200

mg g-1

0 5 10 15 20 25200

4

Total Salts

Salts (and carbonates) concentrate in deeper horizonsSalts (and carbonates) concentrate in deeper horizonsSalts (and carbonates) concentrate in deeper horizons Depths are dependent on solubility and adsorptionSalts (and carbonates) concentrate in deeper horizons Depths are dependent on solubility and adsorption

Background, cont.Background, cont.Background, cont.Background, cont.

Hydraulic properties are a function of both bioticbiotic and abiotic processesHydraulic properties are a function of both bioticbiotic and abiotic processes

Biotic processes: Biotic processes:

bioticbiotic and abiotic processesbioticbiotic and abiotic processes

Faunal burrowingRoot growth and decay Faunal burrowingRoot growth and decayNutrient cycling and turnoverResource translocationNutrient cycling and turnoverResource translocation

Resulting in local scale variability (1-3 m2)Temporally short time periods (10-100 years)Resulting in local scale variability (1-3 m2)Temporally short time periods (10-100 years)

Soil and Vegetation - YPGSoil and Vegetation - YPG

Old Pavement

Soil and Vegetation YPGSoil and Vegetation YPG

Old Pavement

Young Flood PlainIntermediate

Larrea tridentata

Larrea tridentatatridentatatridentata

Holocene Surfaces ( )(young)

Greater canopy volume

Taller plant height

“Happier” vegetation

Stevenson, B.A., E.V. McDonald, and T.G. Caldwell. 2009. Root tt f L t id t t i l ti t il h l ipatterns for Larrea tridentata in relation to soil morphology in

Mojave Desert soils of different ages, p. 312-338, In R. H. Webb, et al., eds. The Mojave Desert: Ecosystem processes and sustainability.

Density and volume as a function of surface ageDensity and volume as a function of surface age

Yo ng All ialYoung Alluvial

Old Alluvial

Hamerlynck, E.P., J.R. McAuliffe, E.V. McDonald, and S.D. Smith. 2002. Ecological responses of two Mojave Desert shrubs to soil horizon development and soil water dynamics. Ecology 83:768-779.

Young Surface

Old Surface

Rooting DensityRoot cm-2

Numerical SimulationsNumerical SimulationsS il W t Fl CNumerical SimulationsNumerical SimulationsS il W t Fl CSoil Water Flux - CanopySoil Water Flux - Canopy

Root - HoloceneRoot - PleistoceneRoot PleistoceneFlux - HoloceneFlux - Pleistocene

Hydraulic Conductivity and Surface Age

Hydraulic Conductivity and Surface AgeSurface AgeSurface Age

Shafer, D.S., M.H. Young, S.F. Zitzer, T.G. Caldwell, and E.V. McDonald. 2007. Impacts of interrelated biotic and abiotic processes during the past 125 000 years of landscape evolution in the northern Mojave Desert, Nevada, USA. J. Arid Environ. 69:633-657.

Biotic Process and Pedogenic DevelopmentBiotic Process and Pedogenic DevelopmentBiotic Process and Pedogenic DevelopmentBiotic Process and Pedogenic Development

100

InterspaceCanopy

[cm

hr-1

]

10

K s

K for:

Qf3 Qf5 Qf61

Canopy - Interspace Ks for:interspace is age dependentcanopy is uniform

From canopy to interspace: Gradients exist in soils and hydraulic properties to 1 2 x R

Canopy Interspace

properties to 1.2 x Rnorm

Caldwell, T.G., M.H. Young, J. Zhu, and E.V. McDonald. 2008. Spatial structure of hydraulic properties from canopy to interspace in the Mojave desert. Geophys. Res. Lett. 35, L19406:doi:10.1029/2008GL035095.

Rise and demise of a plant mound

Rise and demise of a plant mounda plant mounda plant mound

McAuliffe, J.R., and E.V. McDonald. 2006. Holocene environmental change and vegetation contraction in the Sonoran Desert. Quaternary Res. 65:204-215.

Pedogenesis, Hydrology, and Plant Dynamics: Implications to Engineered Surface Barriers

Pedogenesis, Hydrology, and Plant Dynamics: Implications to Engineered Surface BarriersImplications to Engineered Surface BarriersImplications to Engineered Surface Barriers

ESB ≈ geomorphic landformESB ≈ geomorphic landform

Feedback between the soil and VegetationVegetation•Canopy height/volume

Feedback between the soil and VegetationVegetation•Canopy height/volume•Canopy height/volume•Shrub abundance•Rooting depth and lateral spread

•Canopy height/volume•Shrub abundance•Rooting depth and lateral spreadg p p•Plant type•Water use efficiency (E vs. T partitioning)

g p p•Plant type•Water use efficiency (E vs. T partitioning)

•Immediate impacts [10-100s years]•Immediate impacts [10-100s years]

Pedogenesis, Hydrology, and Plant Dynamics: Implications to Engineered Surface Barriers

Pedogenesis, Hydrology, and Plant Dynamics: Implications to Engineered Surface BarriersImplications to Engineered Surface BarriersImplications to Engineered Surface Barriers

ESB ≈ ‘ultimately old’ geomorphic landformESB ≈ ‘ultimately old’ geomorphic landform

Feedback between the soil and CLIMATECLIMATE•Water dust and salt influx

Feedback between the soil and CLIMATECLIMATE•Water dust and salt influx•Water, dust and salt influx•Av horizon development•Hydraulic properties Ks [↓] and WRC [↑]

•Water, dust and salt influx•Av horizon development•Hydraulic properties Ks [↓] and WRC [↑]y p p s [↓] [↑]•Matrix to macropore flow transition•B(t and k) horizon development

f f

y p p s [↓] [↑]•Matrix to macropore flow transition•B(t and k) horizon development

f f•ET mechanisms shift for T to E•Runoff and potential for erosion [↑]•ET mechanisms shift for T to E•Runoff and potential for erosion [↑]

Long-term impacts [0.10-10 ka]Long-term impacts [0.10-10 ka]

Soils as a paleoclimatic proxy for long-term numerical simulations

Soils as a paleoclimatic proxy for long-term numerical simulations

Qf2a

Storm dynamics in Yuma, AZ (1918 – present)

100-yr resolutionMCM and CCM3100-yr resolutionMCM and CCM3MCM and CCM3 Developed against

local climate patterns

MCM and CCM3 Developed against

local climate patternspatternsImplemented

stochastically

patternsImplemented

stochastically

Mean annual precipitation to 40 kaMonthly temperatures and potential ET

Rapid Soil Formation:Landmine and IED detection

Rapid Soil Formation:Landmine and IED detection

Soil structure and horizonation • dielectric properties• Signal attenuationD f d d i

Soil structure and horizonation • dielectric properties• Signal attenuationD f d d i• Defeat and detection

Soil disturbance• Is there a signal?H l d it l t?

• Defeat and detection

Soil disturbance• Is there a signal?H l d it l t?• How long does it last?• How long does it last?

Incipient soil formationThe initial stages of soil formation

• Dielectric properties• Signal attenuation

The initial stages of soil formation • Dielectric properties• Signal attenuation

155 Shellg

• Defeat and detection

Soil disturbance• Is there a signal?

g• Defeat and detection

Soil disturbance• Is there a signal?

1GHz GPR Grid

• How long does it last?• How long does it last?

Consideration and Future DirectionsConsideration and Future Directions

Analog soils for ESB consideration Alluvial soils

Analog soils for ESB consideration Alluvial soils Alluvial soils

Extrapolation well beyond historical time Record of extreme events

Archaeological soils

Alluvial soils Extrapolation well beyond historical time Record of extreme events

Archaeological soils Archaeological soils Incipient soil development

Archaeological soils Incipient soil development

Additional inputs: long-term numerical simulations Pedogenic processes affecting hydraulic properties

Additional inputs: long-term numerical simulations Pedogenic processes affecting hydraulic properties Implementation of vegetation dynamics Benchmark these simulations to chronosequence observations Implementation of vegetation dynamics Benchmark these simulations to chronosequence observations