Principles of Groundwater Flow

1. Al-Azhar University-Gaza
Master Program of Water and Environmental
Science
Principles of Groundwater Flow
Ayat Atef Mahdy
Heba harara

2. Forms of energy that ground water
possesses

3. Mechanical Energy of a fluid

4. Bernoulli Equation

5. Hydraulic head

7. Head in water with variable
density

8. Force potential and hydraulic head

13. Darcy law

17. Reynolds number

19. Specific discharge and Average
Linear Velocity

21. Equations of Ground-Water
Flow

25. Gradient of Hydraulic Head

31. Flow net:
flow net must show boundaries:

32. Boundary condition is important when the
effect of transient stresses reach the boundary
1.Physical boundaries (impermeable rock
formation)
2.Hydraulic boundary ( groundwater divide ,
partly aquifer penetrating water bodies and
streamlines )
3.No flow boundary (fault zones and salt water
interface)

33. Formula:
q = K *p* h /f
,
• where: q= = total
discharge per unit
width of aquifer (L3/T)
• K = hydraulic
conductivity
• p = number of flow
tubes
• h = total head drop
• f = number of squares,
covering length of flow

34. Equations of groundwater flow
A) Steady flow in a confined aquifer
- Flow implies that the aquifer has a gradient (Remember: water
flows downhill)

36. B) Steady flow in an unconfined aquifer:
Aquifer isn't always fully saturated.
Gradient is not constant now.
Gradient increases in the direction of flow .

37. 2 problems:
- Equation for this sloping surface is much more complicated
- Also: recharge from the surface affects the gradient
- The solution: make some assumptions about boundary
conditions, calculate discharge through a section of the aquifer:

38. The equation for discharge (Dupuit equation):

40. Sieve analysis: