National University of Malaysia 1 Groundwater (Our Hidden Asset) Class: Special lecture II for Regular Course 5th grade students Oct. 9th (WED) 15:35-16:20 28-Jan-14 Wan Zuhairi Wan Yaacob (Assoc. Prof, PhD) Faculty of Science and Technology National University of Malaysia 43600 Bangi, Selangor, MALAYSIA.
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National University of Malaysia
1
Groundwater (Our Hidden Asset)
Class: Special lecture II for Regular Course 5th grade students
Oct. 9th (WED) 15:35-16:20
28-Jan-14
Wan Zuhairi Wan Yaacob (Assoc. Prof, PhD) Faculty of Science and Technology
National University of Malaysia 43600 Bangi, Selangor, MALAYSIA.
National University of Malaysia
• What is Groundwater
• Groundwater as a resource
• Groundwater and Geotechnical Problems
• Groundwater movement in soil
• Conclusion
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Content:
National University of Malaysia
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What is Groundwater?
National University of Malaysia
4
Two Types of Water
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Hydrogeology (Groundwater) Subsurface water
Hydrology (Surface water)
Unsaturated
Saturated
Water table
National University of Malaysia Groundwater
• Groundwater is a water that is found underground and is stored in the pore spaces (between grains) of porous geologic formation called an “aquifer”.
• The importance of groundwater is easily overlooked.
• Groundwater is a hidden asset, out-of-sight and out-of-mind.
Water Cycle
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National University of Malaysia
Groundwater
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Piezometric surface
• Aquifer (permeable) • Aquitard (Impermeable) • Artesian well • Water table • Piezometric surface
National University of Malaysia
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Groundwater as a Resource
National University of Malaysia
Groundwater and the world’s freshwater supply
"...Altogether, (groundwater) aquifers store 97% of the planet's (available) freshwater."
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National University of Malaysia
Water Usage in Large Cities in the World
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National University of Malaysia
Water Usage in Malaysia
35
5
60
Groundwater utilization by sector
Industrial
Agricultural
Domestic
3
97
Water use by source
Groundwater
Surface water
10
Surface water
Ground water
• Japan (13%) • South Korea (32%)
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National University of Malaysia
• Kelantan : 70% of its water source is from groundwater.
Groundwater
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“Air Kelantan”
Production well
Crystal clear groundwater
Privately owned tube well
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My hometown
National University of Malaysia
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Surface water vs Groundwater
Slide from Dr. Saim Suratman (NAHRIM, Malaysia)
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Source: Dr Saim Suratman, NAHRIM
Sg. Langat, Selangor
Sg. Jeli, Kelantan
SW GW
SW GW
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National University of Malaysia
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Bank Infiltration
Fresh Water
River Water
Type of filtration that works by passing water to be purified for use as drinking water through the banks of a river or lake.
National University of Malaysia
Source: Dr Azuhan Mohamed, Groundwater Expert.
Groundwater !!
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This is what people normally see This is what people should be able to see
National University of Malaysia
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National University of Malaysia
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Source: Dr Azuhan Mohamed, Groundwater Expert.
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National University of Malaysia
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Groundwater and Geotechnical Problems
National University of Malaysia
1. Groundwater & Mining
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Groundwater to mining engineer (eg. Penjom Gold Mine)
PENJOM GOLD MINE, MALAYSIA
How to manage the influx of groundwater into the open pit mine?
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Vaiont Dam, Italy
2. Groundwater & Stability of Dam
Before After
National University of Malaysia
Trigger factor: the fluctuation of groundwater level
Vaiont Dam, Italy
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Slip surface
Water level before
Water level after
National University of Malaysia
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Trigger factor: the fluctuation of groundwater level
Ancient Slip surface
Water level before Water level after
Before
After
Dam Reservoir Old landslide area
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Groundwater & Foundation
Expensive house
Crack developed under the house and surrounding area Problem: The foundation of the house failed,
Resulting cracks and unstable foundation.
National University of Malaysia
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Groundwater & Foundation
Reason for failure - Fill material = silt + gravel + boulder material - High K values - Channeling (old river) - Higher new water level/high water pressure
After development
Fill material
Retaining Wall
Before development
Original WT
Old river (diverted)
National University of Malaysia
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Groundwater & Foundation
National University of Malaysia
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Groundwater & Foundation Groundwater Modeling using Visual MODFLOW Pro
National University of Malaysia
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Groundwater Contamination
Groundwater Remediation at Taman Beringin Landfill site Malaysia
Drilling (boreholes)
National University of Malaysia
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Groundwater Contamination
Groundwater Remediation at Taman Beringin Landfill site Malaysia
National University of Malaysia
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Groundwater Remediation at Taman Beringin Landfill site Malaysia
Groundwater Modeling using Visual MODFLOW Pro
National University of Malaysia
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Groundwater Movement
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31
A measure of how easily a fluid (e.g., water) can pass through a porous medium (e.g., soils)
Loose soil
- easy to flow
- high permeability
Dense soil
- difficult to flow
- low permeability
water
Hydraulic conductivity
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National University of Malaysia
Darcy’s Law
• Darcy’s experiment
• Henry Darcy
• French engineer
• 1856
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National University of Malaysia
Darcy’s Law
Z = 0 (Datum) Z1, Z2 Elevation of manometer h1, h2 Elevation of fluid ∆𝒍 Distance of manometer