1. INTRODUCTION HYDROLOGY and HYDROGEOLOGY HYDROLOGY:
Scope of Hydrogeology
Historical Developments in Hydrogeology
Hydrologic Cycle
groundwater component in hydrologic cycle,
Hydrologic Equation
HYDROLOGY:
the study of water. Hydrology addresses the occurrence, distribution, movement, and chemistry of ALL waters of the earth.
HYDROGEOLOGY: includes the study of the interrelationship of geologic materials and processes with water,
origin
Movement
development and management

2. More comprehensive definition:
Geologic materials
Rocks
Minerals
Processes
Mechanical processes
Chemical processes
Thermal processes
More comprehensive definition:
it is "the study of the laws governing the movement of subterranean water, the mechanical, chemical, and thermal interaction of this water with the porous solid, and the transport of energy and chemical constituents by the flow".

3. Hydrogeology Descriptive science Analytic and Quantitative science
Why hydrogeology?
Exploration
Development
Inventory
Management

4. A. Physical Hydrogeology
Scope Of Hydrogeology
A. Physical Hydrogeology
Exploration:
Development:
Inventory:
Management:
B. Chemical hydrogeology
chemistry and transport of contaminants
chemical characteristics of groundwater
chemical evolution along flow paths
C. Groundwater in eng. applications and other earth sciences:
subsidence, sinkholes, earthquakes, mineral deposits etc.
D. Mathematical Hydrogeology:
an approximation of our understanding of the physical system

5. THE BUSINESS OF HYDROGEOLOGY
Groundwater Supply and Control
Design test wells
Construct productive wells
Develop regional sources of groundwater
Review cost estimates
Determine water quality
Involve in aquifer protection and water conservation
Designing dewatering wells for construction and mining projects

6. Solution of Groundwater Contamination Problems
Remediate contaminated aquifers
Design Groundwater monitoring and quality plans
Analyze collected groundwater samples
Propose waste disposal sites for:
Petrochemical plants
Mining industries
Municipal wastes
Gasoline storage tanks

7. Develop new methods and techniques
Research and Academy
Develop new methods and techniques
Solve hydrologic and contamination problems
Help developing new equipment
Geophysical devices
Sampling apparatus
Develop computer programs to solve hydrogeologic problems
Pumping test software
Numerical simulators
Hydrogeologic mapping programs

8. HISTORICAL DEVELOPMENT OF HYDROGEOLOGY
Old nations
Chines
Egyptians
Romans
Persians
Arabs
Central
trough
Portgarl and wheel
Shaft to prime mover

9. Mother well
Qanat
End of qanat
Water table
Impermeable rock
Mountain
Water producing section
Alluvium

10. Islamic Civilization Canals and water ways Storage ponds
Mathematics and geometry
Physical sciences

11. Nineteenth Century 1856 Darcy’s law
1885 Water flow under artesian conditions
1899 Flow of groundwater & field observations

12. Twentieth Century 1923 Groundwater in USA
1928 Mechanics of porous media
1935 Solution of transient behavior of water
1940 Development of governing flow equations
1942 Well hydraulics fundamentals
1956 Chemical character of natural water

13. 1960 Regional geochemical processes
1970 Geothermal energy resources
1975 Environmental issues
1980 Contaminant transport
1985 Stochastic techniques
1990’s modeling and management issues

14. Hydrologic Cycle
Saline water in oceans accounts for 97.2% of total water on earth.
Land areas hold 2.8% of which ice caps and glaciers hold 76.4% (2.14% of total water)
Groundwater to a depth 4000 m: 0.61%
Soil moisture .005%
Fresh-water lakes .009%
Rivers %.
>98% of available fresh water is groundwater.
Hydrologic CYCLE has no beginning and no end
Water evaporates from surface of the ocean, land, plants..
Amount of evaporated water varies, greatest near the equator.
Evaporated water is pure (salts are left behind).

15. When atmospheric conditions are suitable, water vapor condenses and forms droplets.
These droplets may fall to the sea, or unto land (precipitation) or may evaporate while still aloft
Precipitation falling on land surface enters into a number of different pathways of the hydrologic cycle:
some temporarily stored on land surface as ice and snow or water puddles (depression storage)
some will drain across land to a stream channel (overland flow).
If surface soil is porous, some water will seep into the ground by a process called infiltration (ultimate source of recharge to groundwater).

16. Below land surface soil pores contain both air and water: region is called vadose zone or zone of aeration
Water stored in vadose zone is called soil moisture
Soil moisture is drawn into rootlets of growing plants
Water is transpired from plants as vapor to the atmosphere
Under certain conditions, water can flow laterally in the vadose zone (interflow)
Water vapor in vadose zone can also migrate to land surface, then evaporates
Excess soil moisture is pulled downward by gravity (gravity drainage)
At some depth, pores of rock are saturated with water marking the top of the saturated zone.

17. Top of saturated zone is called the water table.
Water stored in the saturated zone is known as ground water (groundwater)
Groundwater moves through rock and soil layers until it discharges as springs, or seeps into ponds, lakes, stream, rivers, ocean
Groundwater contribution to a stream is called baseflow
Total flow in a stream is runoff
Water stored on the surface of the earth in ponds, lakes, rivers is called surface water
Precipitation intercepted by plant leaves can evaporate to atmosphere

18. Groundwater component in the hydrologic cycle
Vadose zone = unsaturated zone
Phreatic zone = saturated zone
Intermediate zone separates phreatic zone from soil water
Water table marks bottom of capillary water and beginning of saturated zone

19. Distribution of Water in the Subsurface

22. Units are relative to annual P on land surface
100 = 119,000 km3/yr)

24. Input - Output = Change in Storage (1)
Hydrologic Equation
Hydrologic cycle is a network of inflows and outflows, expressed as
Input - Output = Change in Storage (1)
Eq. (1) is a conservation statement: ALL water is accounted for, i.e., we can neither gain nor lose water.
On a global scale
atmosphere gains moisture from oceans and land areas E
releases it back in the form of precipitation P.
P is disposed of by evaporation to the atmosphere E,
overland flow to the channel network of streams Qo,
Infiltration through the soil F.
Water in the soil is subject to transpiration T, outflow to the channel network Qo, and recharge to the groundwater RN.

25. The groundwater reservoir may receive water Qi and release water Qo to the channel network of streams and atmosphere.
Streams receiving water from groundwater aquifers by base flow are termed effluent or gaining streams.
Streams losing water to groundwater are called influent or losing streams

26. A basin scale hydrologic subsystem is connected to the global scale through P, Ro , equation (1) may be reformulated as
P - E - T -Ro = DS (2)
DS is the lumped change in all subsurface water. All terms have the unit of discharge, or volume per unit time.
Equation (2) may be expanded or abbreviated depending on what part of the cycle we are interested in. for example, for groundwater component, equation (2) may be written as
RN + Qi - T -Qo = DS (3)

27. => groundwater is hydrologically in a steady state.
Over long periods of time, provided basin is in its natural state and no groundwater pumping taking place, RN and Qi are balanced by T and Qo, so change in storage is zero. This gives:
RN + Qi = T + Q0 (4)
=> groundwater is hydrologically in a steady state.
If pumping included, equation (4) becomes
RN + Qi - T -Qo - Qp = DS (5)
Qp= added withdrawal.

28. As pumping is a new output from the system,
water level will decline
Stream will be converted to a totally effluent,
transpiration will decline and approach zero.
Potential recharge (which was formerly rejected due to a wt at or near gl) will increase.
Therefore, at some time after pumping starts, equation (5) becomes:
RN + Qi - Qo - Qp = DS (6)

29. A new steady state can be achieved if pumping does not exceed RN and Qi.
If pumping exceeds these values, water is continually removed from storage and wl will continue to fall over time. Here, the steady state has been replaced by a transient or unsteady state.
In addition to groundwater being depleted from storage, surface flow has been lost from the stream.

30. Example groundwater changes in response to pumping
Inflows
ft3/s
Outflows
1. Precipitation
2475
2. E of P
1175
3. gw discharge to sea
725
4. Streamflow to sea
525
5. ET of gw 25
6. Spring flow

31. P –ETp – ETgw –Qswo – Qgwo –Qso = ∆S
Example, contd.
Write an equation to describe water balance.
SOLUTION:
Water balance equation:
Water input from precipitation – evapotranspiration of precipitation – evapotranspiration of groundwater – stream flow discharging to the sea – groundwater discharging to the sea – spring flow = change in storage
P –ETp – ETgw –Qswo – Qgwo –Qso = ∆S

32. Example, contd 2475 – 1175 -25 -525 -25 = ∆S 0=
Is the system in steady state?
Substitute appropriate values in above equation:
2475 – = ∆S 0=