It includes the Hydrological propertiesof water bearing starta and ground water in hydrological cycle

1. GROUND WATER
CONTAMINATION
PREPARED BY- HARDI SUKHADIYA

2. HYDROLOGICAL PROPERTIES OF
WATER BEARING STRATA &
GROUND WATER IN
HYDROLOGICAL CYCLE

3. Hydrological Properties Of
Water Bearing Strata
Porosity
Void ratio
Specific yield
Permeability
Hydraulic conductivity

5. Porosity
The ratio of volume of voids to the
volume of formation multiplied by 100.
Proportion of void space: pore space,
cracks, vesicles
• Gravel : 25-45% (1K - 10K), clay: 45-55%(<.01)
• Sandstone: 5-30% (0.3 - 3), granite: <1 to
5%(.003 to .00003)
 Higher porosity in well rounded,
equigranular, coarse grained rocks.

6. Void Ratio
Ratio of the volume of voids to the volume of soil.
𝑉𝑟 =
𝑉𝑣
𝑉𝑠
× 100

7. Specific Yield
The specific yield is the actual amount of water that will drain out of saturated
soil and rock by gravity flow.
It is also called EFFECTIVE POROSITY. 𝑆 𝑦 =
𝑉𝑦
𝑉 𝑓
× 100

8. Permeability
Measure of how readily fluid
passes through a material.
Depends on the size of the pores
and how well they are
interconnected.
Clay has high porosity but low
permeability.

9. Hydraulic Conductivity
In Darcy law,
or
K is the hydraulic conductivity or permeability constant.
It depends on
• soil matrix ( porosity, pore size distribution, tortuosity of soil pores )
• Water properties ( viscosity, density )
𝑄 𝛼 𝐼𝐴 𝑄 = 𝐾𝐼𝐴

11. Ground Water In
Hydrological Cycle
Ground water constitutes one portion of hydrological cycle.
Formations of ground water
Recharge of ground water
• Natural ( like precipitation, lake, stream flow)
• Artificial ( like irrigation, seepage from canal)
Discharge of ground water
• Natural ( like oceans, lakes, streams)
• Artificial ( like pumpage from wells)

13. THANK YOU