Water Resources Engineering - Online Test

Q1. A 2 km pipe of 0.2 m diameter connects two reservoirs. The difference between the water levels in the reservoir is 8 m. The Darcy Weisbach friction factor of the pipe is 0.04. Accounting for frictional entry and exit losses, the velocity in the pipe in (m/sec) is
Answer : Option A
Explaination / Solution:



Q2. A settling tank is designed for a surface overflow rate of  Assuming specific gravity of sediment particles = 2.65, Density of water, rw = 1000 kg / m3, dynamic viscosity of water mwater = 0.001 Ns / m2 and stokes law is valid. The approximate minimum size of particles which can be completely removed is
Answer : Option B
Explaination / Solution:

To calculate minimum size of particles equating settling velocity to overflow rate, we get


Q3. The transplantation of rice requires 10 days and total depth of water required during transplantation is 48 cm. During transplantation there is an effective rainfall (useful for irrigation) of 8 cm. The duty of irrigation water in hectare/ cumecs is
Answer : Option B
Explaination / Solution:

D = 864B / ∆ hectares / cumecs = (864×10)/((48-8)×10) = 216  hectares / cumecs

Q4. A multistorey building with a basement is to be constructed. The top 4 m contains loose silt below which dense sand layer is present upto a great depth. Ground water table is at the ground surface. The foundation consists of the basement slab of 6 m width which will rest on the top of dense sand as shown in figure. For dense sand saturated unit weight is 3 20kN / m3 and bearing capacity factor, Nq = 40, Nγ = 45, for loose silt saturated unit weight = 18kN / m3 , Nq = 15, Nγ = 20 . Effective cohesion is 0. Neglect depth factor average elastic modulus E, and Poisson ratio µ of dense sand is 60 ×102 kN / m2 and 0.3 respectively, using factor of safety = 3. (Take influence factor = 2)
The net safe bearing capacity (in kN / m3) of foundation is  

Answer : Option C
Explaination / Solution:



Q5. In a compaction test, G, w, S and e represent the specific gravity, water content, degree of saturation and void ratio of the soil sample, respectively. If  γrepresents the unit weight of water and γd represents the dry unit weight of the soil, the equation of zero air voids line is
Answer : Option B
Explaination / Solution:
No Explaination.


Q6. A mild-sloped channel is followed by a steep-sloped channel. The profiles of gradually varied flow in the channel are
Answer : Option D
Explaination / Solution:
No Explaination.


Q7. The flow in a rectangular channel is subcritical. If width of the channel is reduced at a certain section, the water surface under no-choke condition will
Answer : Option A
Explaination / Solution:
No Explaination.


Q8. The correct match of Group I Group II is
Group I                                                     Group II 
P. Evapotranspiration                               1. Penman method 
Q. Infiltration                                             2. Snyder’s method 
R. Synthetic unit hydrography                  3. Muskingum method 
S. Channel Routing                                  4. Horton’s method
Answer : Option B
Explaination / Solution:
No Explaination.


Q9. Group I gives a list of devices and Group II gives the list of uses.
Group I                             Group II
P. Pitot tube                      1. Measuring pressure in a pipe 
Q. Manometer                  2. Measuring velocity of low in a pipe 
R. Venturimeter                3. Measuring air and gas velocity 
S. Anemometer                4. Measuring discharge in a pipe
The correct match of Group I with Group II is
Answer : Option C
Explaination / Solution:
No Explaination.


Q10. Consider the following unit processes commonly used in water treatment; rapid mixing (RM), flocculation (F), primary sedimentation (PS), secondary sedimentation (SS), chlorination (C) and rapid sand filtration (RSF). The order of these unit processes (first to last) in a conventional water treatment plant is
Answer : Option D
Explaination / Solution:
No Explaination.