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ICAR AIEEA-PG Water Resources Management, Floods & Canal Systems: practice questions

ICAR AIEEA-PG — Agricultural Engineering & Technology (Major Subject Group 10) · India · National Testing Agency for ICAR

Original practice questions written to the published syllabus · not past papers
10worked here, free
66written to this exam in this subject
9syllabus units

What this subject covers

Managing water at the scale of reservoirs, canals and river basins, including floods and farmer participation.

In the exams: ICAR AICE subject 40 Units 7–8; ICAR AIEEA-PG Unit VII; electives in the ICAR 6th Deans' Committee B.Tech

What ICAR AIEEA-PG asks from it

ICAR AIEEA-PG — Agricultural Engineering & Technology, Unit VII

Definitions and short calculations: storage zones, Bligh and Khosla, outlet flexibility, rational method, Gumbel, risk, Muskingum coefficients, project classification and canal operation terms.

Where the 66 questions fall

How our questions for ICAR AIEEA-PG spread across the units of Water Resources Management, Floods & Canal Systems. Difficulty: 29 easy, 23 medium, 14 hard.

Diversion works12
Flood estimation9
Reservoirs8
Canal operation8
Water resources of a country7
Water quality management7
Minor irrigation6
Flood control measures5
Water users' associations and participatory irrigation management4

10 practice questions, worked

Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.

1 · Water resources of a country · medium

A project costs 500 million currency units, has a 50-year life, annual operation and maintenance of 10 million and annual benefits of 60 million. At 8% interest, using the capital recovery factor, what is the benefit-cost ratio?

  1. 3.00
  2. 0.12
  3. 1.18
  4. 1.47
Answer and working

C. 1.18

CRF = 0.08 × 1.08⁵⁰ ÷ (1.08⁵⁰ − 1) = 0.0817. Annual capital cost = 500 × 0.0817 = 40.9; total annual cost = 40.9 + 10 = 50.9; BCR = 60 ÷ 50.9 = 1.18. 3.00 ignores interest (500/50 + 10 = 20); 1.47 leaves out O&M (60 ÷ 40.9); 0.12 divides benefits by the full capital cost.

Further reading: Loucks and van Beek, Water Resource Systems Planning and Management

2 · Reservoirs · hard

A catchment of 800 km² yields 1,200 t/km² of sediment a year to a reservoir with 95% trap efficiency. The deposit's dry bulk density is 1.2 t/m³. What volume of sediment is deposited each year?

  1. 0.91 Mm³
  2. 0.76 Mm³
  3. 1.09 Mm³
  4. 0.80 Mm³
Answer and working

B. 0.76 Mm³

Mass trapped = 800 × 1,200 × 0.95 = 912,000 t; volume = 912,000 ÷ 1.2 = 760,000 m³. 0.80 omits trap efficiency; 0.91 forgets to divide by bulk density; 1.09 multiplies by 1.2 instead of dividing.

Further reading: Morris and Fan, Reservoir Sedimentation Handbook

3 · Reservoirs · hard

A reservoir of 50 Mm³ receives 0.4 Mm³ of sediment a year (as deposited volume), with a constant trap efficiency of 90%. How long until half of its capacity is lost?

  1. About 139 years
  2. About 56 years
  3. About 69 years
  4. About 63 years
Answer and working

C. About 69 years

Deposited per year = 0.4 × 0.9 = 0.36 Mm³; half capacity = 25 Mm³; time = 25 ÷ 0.36 = 69.4 years. 63 ignores trap efficiency; 139 is for the full capacity; 56 multiplies by 0.9 instead of dividing. In practice trap efficiency falls as capacity is lost, so life is computed in steps.

Further reading: Morris and Fan, Reservoir Sedimentation Handbook

4 · Canal operation · hard

Why do designers prefer proportional or slightly sub-proportional outlets near the tail of a distributary?

  1. So that the water level in each watercourse downstream controls the discharge entering every field channel
  2. So that farmers can adjust their own outlets freely without causing any change in the distributary flow
  3. So that when the distributary runs low, head outlets do not take more than their share and starve the tail
  4. So that tail outlets receive their full discharge even while the distributary is closed for maintenance work
Answer and working

C. So that when the distributary runs low, head outlets do not take more than their share and starve the tail

Fair sharing of fluctuations protects the tail. A hyper-proportional outlet upstream takes extra when levels rise and the effect cascades. No outlet delivers when the channel is closed; downstream control would make the outlet non-modular.

Further reading: Garg, Irrigation Engineering and Hydraulic Structures

5 · Flood estimation · medium

Using Ryves' formula Q = C·A^(2/3) with C = 6.8 (Q in m³/s, A in km²), what is the peak flood from a 500 km² catchment?

  1. About 152 m³/s
  2. About 719 m³/s
  3. About 3,400 m³/s
  4. About 428 m³/s
Answer and working

D. About 428 m³/s

Q = 6.8 × 500^(2/3) = 6.8 × 63.0 = 428 m³/s. 719 uses Dickens' exponent 3/4; 3,400 uses A to the power 1; 152 uses A^0.5.

Further reading: Subramanya, Engineering Hydrology

6 · Flood control measures · medium

Which problem is commonly caused by long flood embankments along an aggrading alluvial river?

  1. Floods downstream become smaller because the embankments store most of the flood volume
  2. Groundwater levels in the protected area rise permanently above the ground surface
  3. The river bed degrades rapidly, undermining bridge piers and weirs far upstream of the reach
  4. The river bed rises between the embankments, increasing the consequence of a breach
Answer and working

D. The river bed rises between the embankments, increasing the consequence of a breach

Confined sediment deposits between embankments, raising the bed and flood levels, so breaches become more damaging; embankments also cause drainage congestion behind them. They store little volume, so they do not reduce downstream floods.

Further reading: WMO/GWP Integrated Flood Management

7 · Minor irrigation · hard

A tubewell yields 30 L/s and runs 10 h a day. Peak crop demand is 6 mm/day and application efficiency is 75%. What area can it serve at peak?

  1. 5.4 ha
  2. 13.5 ha
  3. 1.35 ha
  4. 18.0 ha
Answer and working

B. 13.5 ha

Daily volume = 0.030 × 36,000 = 1,080 m³; effective = 810 m³; area = 810 ÷ 0.006 = 135,000 m² = 13.5 ha. 18.0 ignores efficiency; 5.4 uses 4 h; 1.35 slips a decimal.

Further reading: Garg, Irrigation Engineering and Hydraulic Structures

8 · Water users' associations and participatory irrigation management · easy

What distinguishes irrigation management transfer from participatory irrigation management?

  1. Transfer applies only to groundwater schemes and tubewells; participation applies only to canal systems
  2. Transfer hands management of part or all of a system to users; participation involves them alongside the agency
  3. Transfer gives users ownership of the dam and headworks; participation gives them only the main canal
  4. Transfer means users pay the agency a higher fee each season; participation means they pay no fee at all
Answer and working

B. Transfer hands management of part or all of a system to users; participation involves them alongside the agency

PIM involves users in planning, operation, maintenance and finance; IMT shifts responsibility (sometimes ownership) to user organisations, usually below a stated level. Neither is defined by fee level or water source.

Further reading: FAO / IWMI reviews of irrigation management transfer

9 · Water users' associations and participatory irrigation management · medium

Which Indian state passed the Farmers' Management of Irrigation Systems Act in 1997, an early state law creating water users' associations?

  1. Himachal Pradesh
  2. Andhra Pradesh
  3. Punjab
  4. Rajasthan
Answer and working

B. Andhra Pradesh

Andhra Pradesh's 1997 Act created WUAs across its irrigation commands and was followed by other states' laws. The other states passed their own laws at different times.

Further reading: Government of Andhra Pradesh, 1997

10 · Water quality management · medium

What is the WHO drinking water guideline value for nitrate?

  1. 50 mg/L as nitrate (NO3)
  2. 1.5 mg/L as nitrate (NO3)
  3. 50 mg/L as nitrate-nitrogen (NO3-N)
  4. 10 mg/L as nitrate (NO3)
Answer and working

A. 50 mg/L as nitrate (NO3)

WHO gives 50 mg/L as NO3, roughly 11 mg/L as NO3-N. 10 mg/L is the US limit expressed as nitrate-nitrogen, not as nitrate; 50 mg/L as N would be about 220 mg/L as nitrate; 1.5 mg/L is the fluoride value.

Further reading: WHO Guidelines for Drinking-water Quality

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Read the subject

Water Resources Management, Floods & Canal SystemsThe full study manual, free ICAR AIEEA-PGFormat, sections and how it has changed

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Water Resources Management, Floods & Canal Systems for other exams

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