+ All Categories
Home > Documents > idrogeologia dhofar

idrogeologia dhofar

Date post: 02-Jun-2018
Category:
Upload: dave-thompson
View: 229 times
Download: 1 times
Share this document with a friend

of 30

Transcript
  • 8/10/2019 idrogeologia dhofar

    1/30

    Groundwater modeling study central Dhofar, Oman

    Thomas Mller1, Gerhard Strauch1

    1Helmholtz Centre for Environmental ResearchUFZ, Department of Hydrogeology, Leipzig

  • 8/10/2019 idrogeologia dhofar

    2/30

    Page 2

    HEADLINE ARIAL FETT 30pt

    Subline Arial Roman 30ptStudy Area

    study

    area

    Dhofar

  • 8/10/2019 idrogeologia dhofar

    3/30

    Page 3

    Study Area

    boreholeDAWKAH Town/ Village

    main Wadi channels

    no DEM

    surface water divide

    Digital Elevation Model (DEM) of the SRTM Data (Shuttle Radar Topography Mission; USGS 2006)

    100-200m

    1800 m

    Elevation

    0 50 100 km

    main roads

    Study Area

    boreholeDAWKAH Town/ Village

    main Wadi channels

    no DEM

    surface water divide

    Digital Elevation Model (DEM) of the SRTM Data (Shuttle Radar Topography Mission; USGS 2006)

    100-200m

    1800 m

    Elevation

    0 50 100 km

    main roads

  • 8/10/2019 idrogeologia dhofar

    4/30

    Page 4

    Study goals

    Goal I: Understanding the hydrogeological systemarid area and scarce data

    Goal II: Quantification of the water budget components

    precise determination of groundwater resources, recharge and

    safe yield

  • 8/10/2019 idrogeologia dhofar

    5/30

  • 8/10/2019 idrogeologia dhofar

    6/30

    Page 6

    Climate and Rainfall- considerable variations of climatic conditions between Salalah plain,

    - main weather systems: Frontal System, Cyclones, MonsoonDhofar Mountains and Najd

    Salalah plain Dhofar MountainsNajd

    Salalah plain

    Dhofar MountainsNajd

    100 mm/yr

    300 mm/yr

    70 mm/yr

    40 mm/yr

    0 100 km

    S N

    - average temperature: 6.1C to 44.6C, grand mean 26,2C

    - high ET rates

    - rainfall amount low and irregular, average 49mm/yr

    Monsoon

    Lower Umm Er Radhuma

    Upper Umm Er Radhuma

    RUS

    Dammam

    Salalah plain Dhofar MountainsNajd

    Salalah plain

    Dhofar MountainsNajd

    100 mm/yr

    300 mm/yr

    70 mm/yr

    40 mm/yr

    0 100 km

    S N

    - average temperature: 6.1C to 44.6C, grand mean 26,2C

    - high ET rates

    - rainfall amount low and irregular, average 49mm/yr

    Monsoon

    Lower Umm Er Radhuma

    Upper Umm Er Radhuma

    RUS

    Dammam

  • 8/10/2019 idrogeologia dhofar

    7/30Page 7

    Climate and Rainfall > Groundwater Recharge

    Arabian

    Sea

    0

    250

    500

    750

    [masl]

    0 8000 16000 24000 32000 40000 48000 56000 64000 [m]

    recharge

    amount ?

    increasing

    spring discharge

    2 to 5 weeks

    after the monsoon

    Monsoon

    two recharge mechanism

    1) Dhofar Mountains - Monsoon 2) interior Najd Cyclones, Frontal Systems

    - direct recharge - causing large short term floods

    Cyclonic Storms

    recharge?

    1) present day recharge in

    the Dhofar Mountains:

    3 to 9 Mm/year

    2) perched aquifers or

    infiltration to the deeper ground?

  • 8/10/2019 idrogeologia dhofar

    8/30Page 8

    southern Dhofar

    0.00

    50.00

    100.00

    150.00

    200.00

    250.00

    14 Nov 1984 11 Aug 1987 07 Mai 1990 31 Jan 1993 28 Okt 1995 24 Jul 1998 19 Apr 2001 14 Jan 2004 10 Okt 2006

    Spring Garsis [elevation 110 m a.ms.l.]

    date of observation

    discahrgeinl/s

    0.00

    50.00

    100.00

    150.00

    200.00

    250.00

    14 Nov 1984 11 Aug 1987 07 Mai 1990 31 Jan 1993 28 Okt 1995 24 Jul 1998 19 Apr 2001 14 Jan 2004 10 Okt 2006

    Spring Garsis [elevation 110 m a.ms.l.]

    date of observation

    discahrgeinl/s

  • 8/10/2019 idrogeologia dhofar

    9/30Page 9

    southern Dhofar

    106

    108

    110

    112

    114

    116

    118

    25-Mai-79 14-Nov-84 07-Mai-90 28-Okt-95 19-Apr-01 10-Okt-06 01-Apr-12

    date of observation

    GW-levelm

    a.m.s.l.

    GW-monitoring point [elevation 132 m a.m.s.l.] 200 m upstream to Ayn Garsis

    highest GW-levels in August/ September

    106

    108

    110

    112

    114

    116

    118

    25-Mai-79 14-Nov-84 07-Mai-90 28-Okt-95 19-Apr-01 10-Okt-06 01-Apr-12

    date of observation

    GW-levelm

    a.m.s.l.

    GW-monitoring point [elevation 132 m a.m.s.l.] 200 m upstream to Ayn Garsis

    highest GW-levels in August/ September

  • 8/10/2019 idrogeologia dhofar

    10/30Page 10

    Najd

    0

    500000

    1000000

    1500000

    2000000

    2500000

    3000000

    3500000

    4000000

    4500000

    11.08.1987 07.05.1990 31.01.1993 28.10.1995 24.07.1998 19.04.2001 14.01.2004 10.10.2006 06.07.2009

    560

    561

    562

    563

    564

    565

    566

    date of observation

    wadidischarge[m/d]

    GW

    le

    velma.m.s.l.

    Wadi station Ghadun

    monitoring well Aqu A

    Wadi Flow and Groundwater level approximately 60 km north of swd

    0

    500000

    1000000

    1500000

    2000000

    2500000

    3000000

    3500000

    4000000

    4500000

    11.08.1987 07.05.1990 31.01.1993 28.10.1995 24.07.1998 19.04.2001 14.01.2004 10.10.2006 06.07.2009

    560

    561

    562

    563

    564

    565

    566

    date of observation

    wadidischarge[m/d]

    GW

    le

    velma.m.s.l.

    Wadi station Ghadun

    monitoring well Aqu A

    Wadi Flow and Groundwater level approximately 60 km north of swd

  • 8/10/2019 idrogeologia dhofar

    11/30Page 11

    Najd

    0

    10

    20

    30

    40

    50

    60

    70

    80

    31. Jan 93 28. Okt 95 24. Jul 98 19. Apr 01 14. Jan 04 10. Okt 06 06. Jul 09

    0.00E+00

    5.00E+05

    1.00E+06

    1.50E+06

    2.00E+06

    2.50E+06

    3.00E+06

    3.50E+06

    4.00E+06

    4.50E+06

    date of observation

    rainfall[m

    m/day]

    Wadifl

    ow[m

    /da

    y]

    wadi flow

    rainfall

    0

    10

    20

    30

    40

    50

    60

    70

    80

    31. Jan 93 28. Okt 95 24. Jul 98 19. Apr 01 14. Jan 04 10. Okt 06 06. Jul 09

    0.00E+00

    5.00E+05

    1.00E+06

    1.50E+06

    2.00E+06

    2.50E+06

    3.00E+06

    3.50E+06

    4.00E+06

    4.50E+06

    date of observation

    rainfall[m

    m/day]

    Wadifl

    ow[m

    /da

    y]

    wadi flow

    rainfall

  • 8/10/2019 idrogeologia dhofar

    12/30Page 12

  • 8/10/2019 idrogeologia dhofar

    13/30

    Page 13

    Monitoring

  • 8/10/2019 idrogeologia dhofar

    14/30

    Page 14

    noble gases

    Isotopes and hydrochemistry

    stable isotopes

    and radionuclides

    Use of:

    see presentations Mr. Khalid Al-Mashaikhi and Mr. Christian Herb

    for origin and age dating of groundwater

  • 8/10/2019 idrogeologia dhofar

    15/30

    Page 15

    Water Demand

    - first water boreholes drilled in the Najd in the beginning of the 1970,

    - Agriculture major water consumer (~ 90%)

    since then more then 1000 boreholes were drilled

    - increasing population >> increasing domestic, industrial, commercialand municipal demand

  • 8/10/2019 idrogeologia dhofar

    16/30

    Page 16

    Impact on groundwater resources

    275

    285

    295

    305

    315

    325

    335

    1993 1994 1995 1997 1998 1999 2001 2002 2004 2005 2006

    1988

    Time

    GroundwaterLev

    el[m.a.s.l.]

    25 kmAqu C

    Aqu B

    Aqu A265

    Groundlevel329

    O

    2003

    275

    285

    295

    305

    315

    325

    335

    1993 1994 1995 1997 1998 1999 2001 2002 2004 2005 2006

    1988

    Time

    GroundwaterLev

    el[m.a.s.l.]

    25 kmAqu C

    Aqu B

    Aqu A265

    Groundlevel329

    O

    2003

    > use of fossil water

    > groundwater depletion

    limit of artesian flow 1988 and 2003observation values Aqu A, B, C in central Dhofar

  • 8/10/2019 idrogeologia dhofar

    17/30

    Page 17

    Study goals

    Goal I: Understanding the hydrogeological systemarid area and scarce data

    Goal II: Quantification of the water budget componentsprecise determination of groundwater resources, recharge and safe yield

  • 8/10/2019 idrogeologia dhofar

    18/30

    Page 18

    innovative tool for Assessment, Prognoses, Planning and

    Management of water resources

    Approach > Groundwater modeling

    local groundwater modelgroundwater levels maintained by present-day

    recharge

    fine model mesh

    vertical discretisation

    steady state calibrationpredevelopment state

    transient calibrationmodeling period 1970 to 2010

    short term simulation long term simulation

    regional groundwater modelchanging gradients due to changing climate

    conditions

    rough model mesh

    one model layer

    Isotopes and Chemistry2H, 18O, C14, C13, noble gases

    transient calibrationalong flow paths

    calibrated and validated localgroundwater model

  • 8/10/2019 idrogeologia dhofar

    19/30

    Page 19

    Geology

    0 100 km

    Upper

    Umm Er Radhuma

    UUER

    Lower

    Umm Er Radhuma

    LUER

    Tertiary

    Sediments

    (Hadramout

    Group)

    cretaceous

    sediments

    Arabian

    Sea

    Tertiary

    Sediments

    (Fars

    Group)

    0

    250

    500

    750

    [masl]

    0 8000 16000 24000 32000 40000 48000 56000 64000 [m]

    DAM

    RUS

    S N

  • 8/10/2019 idrogeologia dhofar

    20/30

    Page 20

    HydrogeologyFormation Lithology mean aquifer

    thickness

    (m)

    mean storage

    coefficient

    mean

    Transmissivity

    (m/day)

    Dammam

    (DAM)

    RUS

    Formation

    Limestone,

    with Marl

    Breccia, Marl,

    laminated

    gypsum

    21 3.2e-06 485

    Upper UER

    grey to brown

    dolomitic

    limestone

    16 1.0e-06 680

    upper part of

    Lower UER

    lower part of

    Lower UER

    olive, sparry

    limestone with

    shale

    23

    73

    1.5e-04

    1.4e-05

    556

    13

    - Aqu A (Central Najd) and Aqu B (Eastern Najd) have more local significance

    - Aqu C and Aqu D are the most important sources of Groundwater

    for domestic and agricultural use in the Najd

    (GRC 2008)

    Upper

    Umm Er Radhuma

    UUER

    Lower

    Umm Er Radhuma

    LUER

    0

    250

    500

    750

    [masl]

    16000 24000 32000 40000 48000 56000 64000 [m]

    RUS

    Aqu A

    Aqu B

    Aqu C

    Aqu D

    DAM

    direction of

    groundwater flow

  • 8/10/2019 idrogeologia dhofar

    21/30

    Page 21

    Conceptual model Najd Aquifer System

  • 8/10/2019 idrogeologia dhofar

    22/30

    Page 22

    Conceptual model Najd Aquifer System

  • 8/10/2019 idrogeologia dhofar

    23/30

    Page 23

    Conceptual model Najd Aquifer System

  • 8/10/2019 idrogeologia dhofar

    24/30

    Page 24

    Groundwater Model

    boreholes

    3-D body

    initial values + boundary conditions

    calibration

  • 8/10/2019 idrogeologia dhofar

    25/30

    Page 25

    Pre-development state

    GW-level

    Aquifer C and D in m amsl

  • 8/10/2019 idrogeologia dhofar

    26/30

    Page 26

    Present situation

    GW-level

    Aquifer C and D in m amsl

  • 8/10/2019 idrogeologia dhofar

    27/30

    Page 27

    Groundwater discharge

    - no monitoring of groundwater abstraction

    - use of satellite imagery for agricultural areas

    - assumptions for municipal and industrial demand

    Thumrait

    Hanfeet

    Heelat

    As SafaFarm

  • 8/10/2019 idrogeologia dhofar

    28/30

    Page 28

    Outlook

    - transient model for the period 1970 to 2010

    - including water chemistry and Isotopes

    - defining discharge areas and discharge amount

    - calibration of the transient model for the period 1996 to 2008

    - comparison of monitored and simulated values with increasing drawdown

    short-term modeling

    long-term modeling

    - developing model

  • 8/10/2019 idrogeologia dhofar

    29/30

    Page 29

    Acknowledgments

    Thanks

    for support and cooperation to the Ministry of Regional

    Municipality and Water Resources, Sultanate of Oman

    to the BMBF for funding the IPSWaT Scholarship

    and to my colleagues from the Department of

    Hydrogeology and Environmental Informatics

  • 8/10/2019 idrogeologia dhofar

    30/30

    Using a large scale groundwater model to quantify

    water resources availability in an arid area

    Thomas Mller1, Gerhard Strauch1

    1Helmholtz Centre for Environmental ResearchUFZ, Department of Hydrogeology, Leipzig

    Thank you very much for your attention!


Recommended