Worksheets16/01/2026 AE_ EE: SOURCES OF WATER
Total questions: 10
Worksheet time: 5mins
A geological formation is found to have a high porosity of 45% but a laboratory test reveals its permeability to be extremely low. This formation can effectively store significant amounts of water but cannot yield it to a well. How would this formation be best classified?
Aquifer
Aquitard
Aquifuge
Aquiclude
In the design of a tube well, the primary factor that accounts for the lower yield of a cavity-type well compared to a strainer-type well is:
The absence of a strainer, which increases head loss
Its typical construction in a single water-bearing stratum
The spherical flow geometry, which limits the water withdrawal to the bottom of the well
Its economical construction, which implies the use of less efficient materials
A confined aquifer is 20 meters thick. The coefficient of permeability of the aquifer material is 4×10−4 m/s. Calculate the transmissivity of the aquifer in m2/day.
0.008
691.2
0.48
8.0
Which of the following statements most accurately distinguishes between the zone of aeration and the zone of saturation?
The zone of aeration contains no water, while the zone of saturation is completely filled with water.
Water in the zone of aeration exists under hydrostatic pressure, while water in the zone of saturation does not.
The zone of aeration is the primary source for groundwater wells, while the zone of saturation only contains capillary water.
The zone of saturation is where water is under hydrostatic pressure, separated from the overlying zone of aeration by the water table.
In a groundwater system, a high surface infiltration rate does not guarantee a high rate of groundwater recharge. This discrepancy is most likely caused by:
The presence of a highly permeable aquifer at great depth
High atmospheric temperature leading to excessive evaporation from the soil surface
The presence of a low-permeability layer, such as a clay lens, in the percolation path
A high value of specific retention in the surface soil layers
For a given aquifer material, the specific yield is 0.25 and the porosity is 0.35. What is the specific retention?
0.10
0.60
0.71
0.0875
A well is classified as a deep well if its depth is greater than:
9 m
17 m
25 m
The depth of the first impervious stratum
A tube well constructed in fine sandy strata is most likely to be which of the following types?
Strainer type well
Abyssinian type tube well
Slotted type (Gravel packed) well
Cavity type well
What is the fundamental difference in the flow mechanism between permeability (k) and transmissivity (T)?
Permeability is a property of the aquifer's thickness, while transmissivity is a property of the fluid.
Permeability describes flow through a unit cross-sectional area, while transmissivity describes flow through the entire saturated thickness of the aquifer over a unit width.
Permeability is measured in m²/day, while transmissivity is dimensionless.
Permeability applies only to confined aquifers, while transmissivity applies only to unconfined aquifers.
A well has a measured specific capacity of 0.0025 m2/s. If the desired yield from this well is 45 liters per second, what would be the expected drawdown in the well?
180 m
1.8 m
18 m
0.1125 m
