Irrigation & Hydrology (General Engineering) (SSC JE)

Total Questions: 55

31. Weight of the concrete gravity dam is computed by taking unit weight of concrete as [BPSC AE (Civil) 25.03.2022 ]

Correct Answer: (b) 2.4 t/m³
Solution:

Unit weight of gravity dam concrete is equal to 2400 kg/m³.
1 tonne = 100 kg
2400 kg = 2.4 tonne
Unit weight in t/m3 = 2.4 t/m³

32. Floodplain mapping is which type of flood control measure? [BPSC AE (Civil) 25.03.2022 ]

Correct Answer: (c) Non-structural
Solution:

Flood control measures–
1. Structural measure
2. Non-structural measure
Non-structural mitigation measure–
1. Food plain mapping
2. Response planning
3. Flood forecasting.

33. The dam's lakes [BPSC AE (GEN. ENGG.) 11.11.2022 ]

Correct Answer: (c) change markedly the local ecological conditions, vary the pressure applied to the land and groundwater level
Solution:

The dam's lakes change markedly the local ecological conditions, vary the pressure applied to the land and groundwater level.

34. Consumptive use of water by a crop means water consumed by [BPSC AE (Civil) 14.10.2022 ]

Correct Answer: (d) evaporation and transpiration
Solution:

Consumptive use or Evapotranspiration (Cu)–
• The amount of irrigation water required to meet the evapotranspiration needs of the crop during its full growth is called consumptive irrigation requirement.
• The consumptive use of water for a crop is the depth of water consumed by the plant in the process of evapotranspiration.
• It may be supplied partly by precipitation and partly by irrigation.

35. The GCA of an irrigation canal is 50000 hectares out of which 80% is CCA. If the intensity of irrigation for Rabi season is 60% and for Kharif season is 20%, then the crop ratio will be [BPSC AE (Civil) 14.10.2022 ]

Correct Answer: (d) 0.33
Solution:

36. Out of 120 cm of water pumped into a canal, 80 cu m of water could be supplied to a field. 60 cu m of water was stored in the root zone while water required in root zone prior to irrigation was 80 cu m. The storage efficiency of irrigation is [BPSC AE (Civil) 14.10.2022 ]

Correct Answer: (a) 75%

37. The depth of root zone for a particular crop is 100 cm. If the dry unit weight of soil is 2.0 gm/cc of the field and its field capacity and permanent wilting point being 20% and 10% respectively, then the maximum storage capacity of irrigation water in cm will be [BPSC AE (Civil) 14.10.2022 ]

Correct Answer: (b) 20
Solution:

38. The duty is largest [BPSC AE (Civil) 14.10.2022 ]

Correct Answer: (a) on the field
Solution:

The term duty means the area of land that can be irrigated with unit volume of irrigation water. Duty represents the irrigating capacity of a unit, it is relation the between the area of a crop irrigated and the quantity of irrigation water required during the entire period of the growth of that crop.

39. According to Lacey's theory, the silt supporting eddies are generated from [BPSC AE (Civil) 14.10.2022 ]

Correct Answer: (c) sides as well as bottom of channel
Solution:

Lacey's silt theory–According to Lacey, for a given discharge on silt factor (silt charge) all the dimensions such as width depth and longitudinal slope are all fixed by nature.
• If channel section is too small and slope too steep scour will occur till regime is attained. On the contrary, if section is too large and slope too flat, silting will take place till final regime is established.
• Still supporting eddies are generated from perimeter of the channel and not only from bed with. Hence, Lacey considered the hydraulic mean depth as the variable for silt supporting.

40. Garret's diagram is based on [BPSC AE (Civil) 14.10.2022 ]

Correct Answer: (a) Kennedy's theory
Solution:

Garret's diagram give the graphical method of designing the channel dimensions based on Kennedy's theory. The original diagrams were prepared in FPS units. The diagram has the discharge plotted onte abscissa. The ordinates on left indicate the slope and that on right the water depth in the channel and critical velocity (VO). The discharge lines are curved and bed width lines are shown dotted.