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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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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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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What is physics?

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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

Energy

Universe

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Matter Water, ar, solute, soil particles.

Energy

Universe

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Energy Energy (calorie, radiation,

temperature)

Universe

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temperature)

Universe Pedosystem (the entire soil)

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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!!


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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.


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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)

Different views on the soil

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http://abouthydrology.blogspot.com.br/2014/05/water-in-soil-and-aquifer-mostly-first.html

Field methods

• Reference

• Geophysical

Mathematical methods

• Statistical

• Empirical

• Process-based

• Seismic

• Electric

• Electromagnetic

3. State-of-art: Methods for estimating the soil depth

MEMPS

• Trench opening

• Augering

• Penetrometers

Field methods – Reference

Field Methods > Geophysical methods

Electromagnetic methods – Ground Penetrating Radar (GPR)

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;


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


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

Natural disaster occurences in the study area

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Results

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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)


• 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 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.

Soil development along time (Kobiyama et al., 2012)

Soil

thic

knes

s (m

)

Time (year)

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[email protected]

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!

curitiba, 4 round table 2: modeling spatial and temporal ... · soil is the loose material composed...

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