Bodemdaling

Gilles Erkens &

de taskforce bodemdaling

Land subsidence: why bother?

17 juni 2014

17 juni 2014

What causes the land to subside?

Natural causes (geological processes):

Loading of the earth’s crust by ice sheets, sediment (delta’s), the ocean/sea

Compaction of older sediments after sedimentation

Anthropogenic causes (human-induced processes):

Oil/gas extraction (usually relatively deep)

Groundwater extraction (usually moderately deep)

Drainage of soils oxidation of peat, soil compaction

Loading of buildings, structures

Why discriminating between human-induced and natural processes?

Magnitude

Cooping strategy (mitigation versus adaptation)

9 m

land

subsidence

between

1925-1977

(52 years)

~ 17.3 cm/y

Impacts of land subsidence

17 juni 2014

1) Flooding 2) Damage to structures

Media Aandacht!

Problematiek: GW onttrekking

Groundwater extraction leads to subsidence Subsidence map of Jakarta 1974-2010:

-4,1 meter

-2,1 meter -1,4 meter

-0,7 meter

-0.25 meter

Extensometer at Jalan Tongkol

4,5 cm

1997

2007

3 cm

2009

2010

41 cm Jan84 Jan86 Jan88 Jan90 Jan92 Jan94 Jan96-35

-30

-25

-20

-15

Date

Pz.

Head (

m)

d:\Jakarta\Maathuis_data\CKG-PDK2.xls

Jan84 Jan86 Jan88 Jan90 Jan92 Jan94 Jan96-40

-38

-36

-34

-32

-30

Date

Pz.

Head (

m)

d:\Jakarta\Maathuis_data\CKG-PDK3.xls

Jan84 Jan86 Jan88 Jan90 Jan92 Jan94-20

-15

-10

-5

0

Date

Pz.

Head (

m)

d:\Jakarta\Maathuis_data\CKG-PDK4.xls

Subsiding cities: • Jakarta • HCMC • Bangkok • Manila • Dhaka • New Orleans • Singapore • Hanoi • Richmond • Shanghai • Venice • Lorca • Mexico City • and many more

Land subsidence vs absolute sea-level rise

17 juni 2014

The sinking cities assessment

17 juni 2014

1. How much subsidence is there?

2. What is causing subsidence?

A quick subsidence assessment for mega-cities:

Jakarta, Ho-Chi-Minh City, Dhaka, New Orleans, Bangkok

3. How much subsidence is predicted?

4. What impact has subsidence?

5. Who is responsible?

6. What are solutions?

The assessment aimed to: • Get insight in the

processes • To obtain a research

agenda for this topic • To list best practice

cases for others to learn

NEW ORLEANS

JAKARTA

TOKYO

DHAKA

HCMC

BANGKOK

De bijdrage van Deltares

17 juni 2014

We willen:

- De oorzaak begrijpen

- Een voorspelling kunnen maken

- Oplossingen kunnen aandragen

-4,1 meter

-1,4 meter -2,1 meter

-0,7 meter

-0.25 meter

-4,1 meter

-2,1 meter -1,4 meter

-0,7 meter

-0.25 meter New Orleans, USA

Jakarta, Indonesia

Methodologie: Integratie van monitoring en modellering

Geological model

of the subsurface

Geomechanical

modelling

Forecasted

ground-motion

Ground-motion

monitoring data

Va

l ida

tion

&Im

pro

ve

me

nt

Comparison &

inverse modelling

Risk analysis &

Decision making

Specific requirements to satellite data

Geological model

of the subsurface

Geomechanical

modelling

Forecasted

ground-motion

Ground-motion

monitoring data

Va

l ida

tion

&Im

pro

ve

me

nt

Comparison &

inverse modelling

Risk analysis &

Decision making

Specific requirements to satellite data

Geo(hydro)logical

modelling

iMOD SUB-CR

Meerwaarde van iMOD

• Directe koppeling met het grondwatermodel • Dezelfde schematisatie van de ondergrond, • Snel doorrekenen van effect grondwaterstandsverlagingen, • Inbrengen van grondwaterpompen

• Goed medium om ondergronddata te visualiseren

• Mogelijkheden tot 3D bekijken data • Mogelijkheden tot het tekenen van profielen

Geologisch + geohydrologisch model Droombeeld

17 juni 2014

Voorbeeld Ho Chi Minh City, Ngo Duc Chan 2008

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3/2

01

1

An

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x

Input View

Layers

8. Aquifer 1

7. Aquitard 1

6. Aquifer 2

5. Aquitard 2

4. Aquifer 3

3. Aquitard 3

2. Aquifer 4

1. Aquitard 4

0.000 10.000

1

2

3

4

5

6

7

8

1 2

1

-4

-59

-69

-119

-129

-169

-179

-249

1

-4

-59

-69

-119

-129

-169

-179

-249

Level (m)

Realiteit

Is gekoppelde modellering mogelijk?

2000: USGS Modflow SUB package

2005: USGS Modflow SUB-WT

2012: Deltares SUB-CR

2013: Deltares iMOD SUB-CR

•Interbeds: lenzen van lutumhoudende fijnzandige grondlagen in aquifers

•Aquitards: uitgestrekte lutumhoudende fijnzandige geologische afzettingen.

Kenmerken van het SUB-CR model

– Is een gekoppeld bodemdaling-grondwatermodel (geen fysisch ondergrondmodel)

–Maakt betere bodemdalingvoorspellingen door meenemen van kruip (secondary settlement) Gekoppeld aan iMOD

–3D-berekeningen

–Werkt op grote schaal (>1 km2): megasteden, hele delta’s

Resultaten uit Jakarta

Evaluatie bodemdaling voor scenario’s onttrekkingen

2) Extrapolatie huidige situatie 3) Herstel naar situatie 1995

Z2100 = - 3.88 m Z2100 = - 3.11 m

1) Toenemende verlaging 1m/jr 4) Snel herstel situatie 1995

Z2100 = - 5.69 m Z2100 = - 2.77 m

17 juni 2014

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17

/03

/20

11

Annex

Time-History (Fit)

Vertical 1 (X = 0.000 m; Z = 0.000 m)

Method = NEN - Bjerrum with Terzaghi (Linear strain)

Fit factors used

Coefficient of determination = 0.902

Depth = 1.000 [m]

Settlement after 49275 days = 3.879 [m]

0 10000 20000 30000 40000

4.000000

3.000000

2.000000

1.000000

0.000000

Se

ttle

me

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[m]

Measurement

0 10000 20000 30000 40000

Time [days]

-0.000010

-0.000005

0.000000

0.000005

0.000010

Lo

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[kP

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1960 1980 2000 2020 2040 2060 2080 2100

Year

Time (days)

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17

/03

/20

11

Annex

Time-History (Fit)

Vertical 1 (X = 0.000 m; Z = 0.000 m)

Method = NEN - Bjerrum with Terzaghi (Linear strain)

Fit factors used

Coefficient of determination = 0.902

Depth = 1.000 [m]

Settlement after 49275 days = 3.879 [m]

0 10000 20000 30000 40000

4.000000

3.000000

2.000000

1.000000

0.000000

Se

ttle

me

nt

[m]

Measurement

0 10000 20000 30000 40000

Time [days]

-0.000010

-0.000005

0.000000

0.000005

0.000010

Lo

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[kP

a]

1960 1980 2000 2020 2040 2060 2080 2100

Year

Time (days)

1960 1980 2000 2020 2040 2060 2080 2100

MS

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20

/03

/20

11

Annex

Time-History

Vertical 1 (X = 0.000 m; Z = 0.000 m)

Method = NEN - Bjerrum with Terzaghi (Linear strain)

Depth = 1.000 [m]

Settlement after 49275 days = 5.693 [m]

0 10000 20000 30000 40000

4.000000

2.000000

0.000000

Se

ttle

me

nt

[m]

0 10000 20000 30000 40000

Time [days]

-0.000010

-0.000005

0.000000

0.000005

0.000010

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Year

Time (days)

1960 1980 2000 2020 2040 2060 2080 2100

MS

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20

/03

/20

11

Annex

Time-History

Vertical 1 (X = 0.000 m; Z = 0.000 m)

Method = NEN - Bjerrum with Terzaghi (Linear strain)

Depth = 1.000 [m]

Settlement after 49275 days = 5.693 [m]

0 10000 20000 30000 40000

4.000000

2.000000

0.000000

Se

ttle

me

nt

[m]

0 10000 20000 30000 40000

Time [days]

-0.000010

-0.000005

0.000000

0.000005

0.000010

Lo

ad

ing

[kP

a]

Year

Time (days)

MS

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18/0

3/2

011

Annex

Time-History

Vertical 1 (X = 0.000 m; Z = 0.000 m)

Method = NEN - Bjerrum w ith Terzaghi (Linear strain)

Depth = 1.000 [m]

Settlement after 49275 days = 3.111 [m]

0 10000 20000 30000 40000

4.000000

3.000000

2.000000

1.000000

0.000000

Se

ttle

me

nt [m

]

0 10000 20000 30000 40000

Time [days]

-0.000010

-0.000005

0.000000

0.000005

0.000010

Lo

ad

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[kP

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18/0

3/2

011

Annex

Time-History

Vertical 1 (X = 0.000 m; Z = 0.000 m)

Method = NEN - Bjerrum w ith Terzaghi (Linear strain)

Depth = 1.000 [m]

Settlement after 49275 days = 2.765 [m]

0 10000 20000 30000 40000

4.000000

3.000000

2.000000

1.000000

0.000000

Se

ttle

me

nt [m

]

0 10000 20000 30000 40000

Time [days]

-0.000010

-0.000005

0.000000

0.000005

0.000010

Lo

ad

ing

[kP

a]

Toekomstige ontwikkelingen

iMOD SUB-CR

Inzetten in nieuwe case studie gebieden: New Orleans, Jakarta

Gebruik voor opbouw van ondergrondmodellen en

informatiesystemen van delta steden

Gebruikmaken van bestaande Modflow-modellen voor floodrisk

studies

Koppeling met beleidsbeslissingsmodellen en kostenmodules

uit het schade-onderzoek

17 juni 2014

4D: Jurong Island

17 juni 2014

Thank you