curitiba, 4 round table 2: modeling spatial and temporal ... · soil is the loose material composed...
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Natural Disasters Research Group - GPDEN
Hydraulic Research Institute - IPH
Federal University of Rio Grande do Sul – UFRGS, Brazil
Soil depth estimation and its spatial (and temporal)
distribution
Masato Kobiyama; Gean P. Michel
Curitiba, 4 – 8th May, 2015
3rd Brazilian Soil Physics Meeting (BSPM)
Round Table 2: Modeling spatial and temporal
variability of soil physical attributes
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Presentation0. Simple questions
1. Introduction: van Genuchten (1994) New issues and
challenges in….
2. Soil, physics and soil physics
3. State-of-art: Methods for estimating the soil depth
4. Development of MEMPS
5. Case Study: Application of MEMPS to a steep basin
6. Final considerations
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0. Simple questions
Why do we need to know spatial and temporal variability
of soil physical attributes?
To understand the nature of soil.
To perform the computational simulation better.
What are soil physical attributes?
Hydraulic conductivity, bulk density, total porosity, etc.
How about soil depth?
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Attributes
(Ks, ρ, etc.)
Soil depth
(attribute?)
I think that soil depth might be one
of the important soil physical
attributes.
Vertical soil column Distributed vertical soil column
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van Genuchten, M.Th. (1994) New issues and challenges in soil
physics research. In: Transactions of 15th World Congress of
Soil Science (Acapulco, Mexico. 10-16 July 1994), Int. Soc. of
Soil Sci. and the Mexican Soc of Soil Sci., p.5-27.
1. Introduction: van Genuchten (1994) New issues and
challenges in….
Soil physics may be defined as the application of the principles
of physics to the characterization of soil properties and the
understanding of soil processes,……. This definition implies
that soil physics is a subdiscipline of both physics and soil
science.
Soil science PhysicsSoil physics
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van Genuchten, M.Th. (1994) New issues and challenges in soil
physics research.
Early studies of soil physics (1900s to 1940s) generally involved soil
structure and soil aggregation, soil pore space, field soil water status,
capillarity and soil water retention, …., soil mechanics,….. soil
salinity, diffusion, heat content, etc.
……………………………………………
Soil physicists must remain concerned about the physical
environment of plants…... At the same time, soil scientists/physicists
have also a responsibility to address soil and groundwater pollution
problems…….at local, regional, and global scales.
…………………………………………….
The following examples illustrate the need for a more broadly
defined framework of soil physics research.
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van Genuchten, M.Th. (1994) New issues and challenges in soil
physics research.
1. Soil physics research can no longer be confined to the upper soil
horizons between the soil surface and a depth of 2 m traditionally
viewed …………. in the entire vadose zone between the soil surface
and the groundwater table, even if the vadose zone is hundreds of
meters deep …………….
2. Soil physicists are increasingly becoming participants in global-
scale hydrologic research…………..
3. Soil physicists must be interested in media other than the
weathered and fragmented outer layer of the earth’s terrestrial surface
usually referred to as soil. ……… in fractured rock and other…….
4. Soil physicists must be concerned with fluids other than water, …
5. Soil physicists must be equally concerned with agricultural
chemicals (fertilizers, etc.) as well as with nonagricultural chemicals,
including radionuclides, etc.
The focus of soil physics research has gradually
broadened from mostly agricultural production issues
to more comprehensive studies of subsurface water flow
and chemical transport geared toward environmental
issues.
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2. Soil, physics and soil physics
What is soil?Soil is the loose material composed of weathered rock and other
minerals, and also partly decayed organic matter, that covers
large parts of the land surface of the Earth (Wild, 1993).
Soil is the weathered and fragmented outer layer of the earth’s
terrestrial surface, formed initially through the disintegration and
decomposition of rocks by physical and chemical processes and
influenced subsequently by the activity and accumulated
residues of numerous species of microscopic and macroscopic
biota (Hillel, 2003)
Soil is a term understood by almost everyone, yet the meaning of
this term may vary between different people, and soil can be
defined in many ways (Tan, 2009)
Different interests in the soil
Soil science is the study of
the soil in all its ramified
manifestations and facets: as
a central link in the
biosphere, as a medium for
the production of agricultural
commodities, and as a raw
material for industry and
construction ………….
Because of its varied
interests and concerns, soil
science itself is commonly
divided into several
subdivisions,……………….
(Hillel, 2003)
Soil Physics, Soil Chemistry,
Soil Biology,…..
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Physics is the branch of science concerned with the properties of
matter and energy and the relationships between them. It is based
on mathematics and traditionally includes mechanics, optics,
electricity and magnetism, acoustics, and heat. It can also embrace
applied fields such as geophysics and meteorology.
(Collins English Dictionary)
Physics is the natural science that involves the study of matter
and its motion through space and time, along with related
concepts such as energy and force. More broadly, it is the general
analysis of nature, conducted in order to understand how the
universe behaves. (Wikipedia)
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Physics is “the study of matter, energy, and the interaction
between them”…… physics is asking fundamental questions and
trying to answer them by observing and experimenting.
Physicists ask really big questions like:
How did the universe begin?
How will the universe change in the future?
How does the Sun keep on shining?
What are the basic building blocks of matter?
(http://www.physics.org)
One of the principal subjects in physics is the UNIVERSE!
A general question is how large the universe was in the past, is now
and will be in the future.
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What is soil physics?
Soil physics is the study of soil physical properties and
processes. It is applied to management and prediction under
natural and managed ecosystems. Soil physics deals with the
dynamics of physical soil components and their phases as
solids, liquids, and gases (Wikipedia).
The soil physics is a subarea of Agronomy (Dourado Neto
et al., 2013).
Soil science PhysicsSoil physics
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Soil physics: The branch of soil science that deals with the state and
transport of matter and with the state and transformations of energy
within the soil, as well as between the soil and the adjacent domains
(namely, the atmosphere above and the substrata below).
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To understand Soil Physics, I used to read:
Baver, L.D. et al. (1972) Soil Physics, 4th ed. New York: Wiley.
Hillel, D. (1980) Fundamentals of Soil Physics / Application of
Soil Physics. New York: Academic Press.
Campbell, G.S. (1985) Soil Physics with BASIC.
….etc.
And, to understand Soil Physics more, I am reading:
There is my personal (or professional)
dissatisfaction to these books!!!!
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Physics Soil Physics
Matter Water, ar, solute, soil particles.
Energy Energy (calorie, radiation,
temperature)
Universe
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Physics Soil Physics
Matter Water, ar, solute, soil particles.
Energy Energy (calorie, radiation,
temperature)
Universe Pedosystem (the entire soil)
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Physics Soil Physics
Matter Water, ar, solute, soil particles.
Energy Energy (calorie, radiation,
temperature)
Universe Pedosystem (the entire soil)
QUESTIONS
How did the universe begin?
How large is the universe?
How will the universe change
in the future?
QUESTIONS
How did the soil begin?
How large is the soil?
How will the soil change in
the future?
Key-word: Soil Depth
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For whom is Soil Physics?
For farmer
For land manager
For agronomist
For hydrologist
For meteorologist
For geomorphologist
For pedologist
etc.
To what does Soil Physics contribute?
For agriculture
For land management
For agronomy
For hydrological research
For meteorological res.
For geomorphic res.
For pedological res.
etc.
What kind of information
is strongly required?
Soil Depth!!
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My personal (or professional) complain to these books
1. Soil Physics and Soil Physical Characteristics
2. Water Properties in Relation to Porous Media
3. Particle Sizes, Shapes, and Specific Surface
4. Clay, the Colloidal Component
5. Soil Structure and Aggregation
6. Water Content and Potential in the Soil
7. Water Flow in Saturated Soil
8. Water Flow in Unsaturated Soil
9. Solute Movement and Soil Salinity
10. Gas Content and Composition in the Soil
11. Gas Movement and Exchange with the Atmosphere
12. Temperature and Heat Flow in the Soil
13. Stress, Strain, and Strength of Soil Bodies
14. Water Entry into Soil
15. Surface Runoff and Water Erosion
16. Redistribution and Retention of Water in Soil
17. Groundwater Drainage and Pollution
18. Evaporation from Bare Soil and Wind Erosion
19. Plant Uptake of Soil Moisture
20. Water Balance and Energy Balance in the Field
21. Irrigation and Water Use Efficiency
No soil depth!!
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1.Water
2. Potentials
3. Water flow in soil
4. Soil – plant – atmosphere relations
5. Soil Heat Flow and Temperature
No soil depth!!
My personal (or professional) complain to these books
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1. Soil Solid Phase.
2. Water Retention in Soil.
3. Water Movement in Soil.
4. Water Flow Under Natural Conditions.
5. Soil Thermal Regime.
6. Soil Aeration.
7. Chemical Transport in Soil.
Appendix A: Methods of Analyzing
Spatial Variations of Soil Properties.
Books on soil physics do not deal with
the soil depth (or thickness) in detail.
My personal (or professional) complain to these books
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GERRARD, J. (1992) Soil Geomorphology: An integration of
pedology and geomorphology. London: Chapman & Hall, 269p.
The soil thickness and regolith at any point will depend on the
relative rates of soil removal and soil formation.
In thin soil, very little water is retained and weathering rates are
low. In very thick soils, water moves so slowly towards the
weathering front that the rate of weathering is again below the
potential maximum. Thus, weathering and soil formation are at a
maximum at intermediate soil thickness.
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Michel & Kobiyama
Soil Depth Estimation: Part 1 – Field Methods
Soil Depth Estimation: Part 2 – Mathematical Methods.
Revista Brasileira de Germorfologia (in Portuguese)
(submitted)
Field methods
• Reference
• Geophysical
Mathematical methods
• Statistical
• Empirical
• Process-based
• Seismic
• Electric
• Electromagnetic
3. State-of-art: Methods for estimating the soil depth
MEMPS
Field methods
• Reference
• Geophysical
Mathematical methods
• Statistical
• Empirical
• Process-based
• Seismic
• Electric
• Electromagnetic
MEMPS
Mathematical methods – Empirical
min
minmax
minmaxmax ee
ee
zzzz ii
min
minmax
minmaxmax tantan
tantan
ii
zzzz
1 leC CKz
teeeec zADfHffT 1,0,1,121
Saulnier et al. (1997) J Hydrol
Catani et al. (2010) WRR
Schulz et al. (2008) ESPL
z – soil depth
e – elevation
θ – slope
z – soil depth
KC – calibration parameter
Ce – curvature index
η – toposequence index
ψ – landslide index
Tc – Colluvium thickness
He – Slope heigth
De – Distance downslope from
escarpment
Ae – Adjustment factor
zt – Soil depth in hillslope toe
Principle for the Process-based models:
Geomorphic Transport Laws (Dietrich et al.,
2003)
ρs – Soil density
ρr – Rock density
eb – Bedrock
elevation
qs – Soil transport
vector
Geomorphic scale
Mass balance between soil transport and
production (Adapted of Heimsath et al., 1995)
Mathematical methods – Process based models
Critical soil depth proposed by Iida (1999)
tancoscos20
g
cz
s
c
tantantancos21
gg
cz
ws
c
a) For dry conditions:
b) For saturated conditions:
zc0 – Critical depth of dry soil;
zc1 – Critical dep.of saturated soil;
ρs – Soil density;
c – Soil cohesion;
g – Gravitational acceleration;
θ – Slope;
ϕ – Soil internal friction angle.
And how about the critical depth at field conditions?
Mathematical methods – Process based models
MEMPS (Modelo de Estimativa da Máxima
Profundidade do Solo)
4. Development of MEMPS
•Idea of Iida (1999)
•Combination of infinite slope stability model + steady
state hydrological model.
•Use of the saftey factor (FS).
•Maximum soil depth.
Infinite slope stability model
strengthshear Minimum
strengthshear ActualFS
plgW s
tan)( uc
l
W
sin
l
W
cos
sincos zg s
2cos zg s
τ – Shear stress;
σ – Normal stress;
c – Cohesion;
u – Pore pressure;
ϕ – Soil internal friction angle
W – Soil weight;
g – Gravitational acceleration;
ρs – Soil density;
θ – Slope;
l – Slope length;
z – Soil depth;
h – Water table height ;
p – Soil thickness
2cos hgu w
Using Law of Mohr-Coulomb,
tan)( uc
2cos hgu w
tan)cos²cos(cossin 2 hgzgczg wss
cossin
tan)cos²cos( 2
zg
hgzgcFS
s
ws
sincos zg s 2cos zg s
strengthshear Minimum
strengthshear ActualFS
Infinite slope stability model
τ – Shear stress;
σ – Normal stress;
c – Cohesion;
u – Pore pressure;
ϕ – Internal friction angle
ρs – Soil density;
ρw – Water density;
θ – Slope;
l – Slope length;
z – Soil depth;
h – Water table height ;
p – Soil thickness
aqQe
bhKbhiKQ sss cossincos
qt
h
a
Qs
aqQs
bhKaq s cossin
Qe – Inlet flow;
Qs – Outlet flow;
Ks – Saturated hydraulic
conductivity;
i – Hydraulic gradient;
b – Contour length;
a – Uplope area;
q – Steady state recharge
rate;
θ – Slope;
z – Soil depth;
h – Water table height
Steady state hydrological model
Equation of mass conservation of kinematic wave
sincossinmax
TbbzKQ ss
sinmax
Tb
aq
Q
Qw
s
s
z
h
zKb
bhKw
s
s
sincos
cossin
sincos
zKb
aq
z
hw
s
sincos
sKb
aqh
Wetness
(m/m)
defined by
O´Loughlin
(1986)
sin
tan1coscos
z
h
zg
c
FSs
w
s
sin
tansincos
.1.cos
cos
zKb
aq
zg
c
FSss
w
s
tantan
cossintan
cos2
ss
w
s
c
Kb
aq
g
c
z
tantan
cossin,mintan
cos12
s
c
s
w
s
c
Kb
aqz
g
c
z
cossin
tan)cos²cos( 2
zg
hgzgcFS
s
ws
sincos
zKb
aq
z
h
s
When the system is at the limit equilibrium, FS is equal to 1...
MEMPS (Modelo de
Estimativa da Máxima
Profundidade do Solo)
Comparison between MEMPS and Iida´s model
(Dry condition)
(Saturated con.)
(MEMPS)
c = 11.9 kPa
q = 0.005 m/day
a = 300 m3
b = 5 m
ϕ = 30.5o
Ks = 0.38 m/day
ρs = 1800 kg/m3
ρw = 1000 kg/m3
Jaguar Creek basin (25 km2), Rio Grande do Sul state, Brazil
5. Case Study: Application of MEMPS to a steep basin
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MEMPS TRIGRS KANAKO 2D
•Steady state recharge rate
(q)
•Soil cohesion (c)
•Soil internal friction angle
(ϕ)
•Saturated hydraulic
conductivity (Ks)
•Soil density (ρs)
•Upslope area (a)
•Contour length (b)
•Slope (θ)
•Precipitation series (P)
•Soil cohesion (c)
•Soil internal friction angle
(ϕ)
•Saturated hydraulic
conductivity (Ks)
•Soil density (ρs)
• Saturated hydraulic
diffusivity (D0)
•Residual water content (θr)
•Saturated water content
(θs)
•Soil depth (z)
•Initial water table depth (d)
•Initial infiltration rate (IZLT)
•Hydrograph (Q)
•Fluid density (ρf)
•Sediment concentration (C)
•Erosion rate (δe)
•Deposition rate (δd)
•Sediment concentration on
the movable bed (C*)
•Manning’s roughness
coefficient (nm)
•Particle diameter (dp)
•Soil density (ρs)
•Soil depth (z)
Input data Measured data
Estimated data
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6. Final considerations – What will our group do in
Rio Grande do Sul, Brazil?
Using Physics for soil formation
research, we need to do:
•Development of the MEMPS
•Creation of a model to calculate
the time variability of soil depth.
•Creation of Landscape Evolution
Model with field observation.
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Grupo de Pesquisa de Desastres Naturais (GPDEN), www.ufgs.br/gpden
Instituto de Pesaquisas Hidráulicas (IPH)
Universidade Federal do Rio Grande do Sul (UFRGS), Brazil
Thank you very much!