CE2301 IRRIGATION ENGINEERING Sixteen Marks Questions With Answers 2014

Anna University, Chennai

SIXTEEN MARK QUESTIONS

UNIT-1

1) What are the merits and demerits of irrigation? Merits of irrigation:

• Reduced water stress

• Better germination and stands

• Higher plant populations

• More efficient use of fertilizer

• Improved varieties

• Leaching of salts

• Frost protection

• Plant/soil cooling

• Chemical application

• Wind erosion control

Waste disposal

Demerits of irrigation Rising of water table Formation of marshy lands Dampness in weather

2) What are the factors affecting duty?

Soil characteristics Climatic condition Rainfall

Base period

Type of crop

Topography of agricultural land

Method of ploughing Method of irrigation Water tax

3) Briefly explain about irrigation efficiencies?

1.Water conveyance efficiency

2. Water application efficiency

3. Water use efficiency

4. consumptive use efficiency

4) What are the consumptive use of water?

consumptive use of water is defined as the total quantity of water used for the growth of the plantsby transpiration and the amount lost by evaporation. Methods of consumptive use of water:

1.Lysimeter method

2.Field experimental method

3.Soil moisture study

5) Briefly explain about planning and development of irrigation project?

Planning of irrigation project: Availability of irrigation water

Selection of probable site for barrage or dam

Discharge observation for the river Marking of alignment of main canal Marking of G.C.A

Final survey

Preparation of drawings

Office works

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UNIT-2

1.Briefly explain about canal irrigation?

Types of canal irrigation:

1.Inundation irrigation

2.Perenniel irrigation a)Direct irrigation system b)storage irrigation system

2.Briefly explain about lift irrigation? Types of lift irrigation:

Lifting of water by man or animal power

Lifting of water by Mechanical power

By man or animal power: Doon

Mote

Swinging basket

Wind lass

Persian wheel

By Mechanical power: Open well

Deep well

Shallow well

3.Briefly explain about surface irrigation? Types of surface irrigation:

Furrow Method

Contour farming method

Flooding method

4.Briefly explain about flooding methods? Flooding methods:

a)Controlled flooding

Free flooding Basin flooding Check flooding Border strips

Zig- zag method b)uncontrolled flooding

5.Briefly explain about sprinkler irrigation methods? Types of sprinkler irrigation:

Perforation on lateral pipes

Fixed nozzles on lateral pipes

Rotating sprinklers

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UNIT-3

1. What are types of dams?

Based on Materials: Rigid dam

Non rigid dam

Based on structural behavior: Solid gravity dam

Arch dam

Buttress dam

Embankment dam

2. Briefly explain about types of spillways?

types of spillways: Drop spillway Ogee spillway Syphon spillway

Volute siphon spillway

Trough spillway

Shaft spillway

3. What are the causes of failure of Earthen dam?

1.Hydraulic failure

2.Due to seepage failure

3.Erosion

4.Structural failure

5.sloughing

4. What are types Weirs?

The subsurface flow of water place on important

role for the stability of hydraulic structures like weir or barrage

Types of Weirs: Masonry Weir Rockfill weir Concrete weir

5.What are forces acting on a dam?

Forces acting on a dam:

§ Weight of the dam

§ Water pressure

§ Uplift pressure

§ Seismic force

§ Silt pressure

§ Wave pressure

§ Ice pressure

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UNIT-4

1. What is the necessity of river training works?

· Proper protection work should be adopted.

· In rainy season , the flood water may submerged the vast cultivated area by overflowing the tank.

· The erosion of river water may damage the structure .

2. Describe in brief different Stages of river training works?

stages of river training works: Rocky stage

Boulder stage Trough stage Delta stage

3. What are the types of spurs? Types of spurs:

Bamboo spur

Timber spur

Boulder spur

4.State the types of canal falls? Types of canal falls:

Ogee fall Rapid fall Stepped fall Trapezoidal fall

5.Briefly explain about classification of cross drainage works?

classification of cross drainage works: Aqueduct

Super passage

Level crossing

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UNIT-5

1.Briefly explain about on-farm-development works?

· Formation of field channels

· Formation of internal irrigation channels

· Field drains

· Drops in field drains

· Crossing on field drains whenever required.

2.What are the types of water losses? Types of water losses:

Absorption losses

Percolation losses Evaporation losses Transpiration losses

3.What is the need for PIM?

Sustained need and the need for accurate and timely information.

Reducing that people themselves are solution

agents for than need and problems.

Cutting down time consuming long methods of survey which give results after considerate time.

4.Briefly explain about factors depending losses? Permeability of water

Depth of water

Velocity of water

Amount of silt

Age of the channel