1. Some Quiz Questions
Unit: Subsurface Flow

2. Question for understanding
In general, ground water does not move between two points 1 and 2 when … (check all correct answers, one or more)
  points 1 and 2 have the same pressure
  points 1 and 2 are at the same elevation
  points 1 and 2 have the same energy
  points 1 and 2 are in a soil with very low permeability

3. Question for understanding
For water flow between points 1 and of 2 in the curved tube in the sketch below, when calculating hydraulic gradient i = Δh1,2/L, (a) L = L1, (b) L = L2 or (c) L = L3?

4. Problem related to the next quiz question
For the flow field in the figure below, calculate discharge (for a cross section perpendicular to the –horizontal– flow direction equal to 1 m2) when the hydraulic conductivity is 8640 m/day και 432 m/day in layers 1 and 2, respectively. In addition, calculate hydraulic head at cross sections at points Η and Μ and sketch a map with the equipotential lines (lines of equal hydraulic head).
Boundaries ΑΒ and CD are no flow boundaries and boundaries ΑC and ΒD are constant head boundaries, with known –as shown in the figure– hydraulic head, h

5. Question for understanding
Given the answers hH=4.67m, hM=1.33 m, for the problem of the previous slide, which one do you prefer among the three maps (a, b, or c) shown equipotential lines?
(a)
(b)
(c)

6. Question for understanding
The Laplace equation (2h=0) is valid when we have... (check all correct answers, one or more)
  constant fluid density
  homogeneous and isotropic soil
  no pumping, no injection
  something else

7. Kerogene* (LNAPL) release in coarse sand: estimate saturation, So
Residual saturation,So=?
LNAPL lens: possibility of pumping – further movement, So=?
water table
* dyed red