Why this Topic is Important for ECET
In Civil Engineering exams like ECET 2026, Irrigation is a high-weightage area under Environmental & Hydrology. Questions on canal irrigation and its types are commonly asked because canals form the backbone of Indian irrigation. Understanding canal design and types helps in solving both theory-based and numerical problems. This topic connects with duty, delta, water requirements, and canal efficiency — all crucial for scoring well.
📘 Concept Notes
1. Introduction to Canal Irrigation
- Definition: Irrigation through an artificial channel (canal) constructed from a river, reservoir, or dam.
- Provides water for agriculture, reduces dependence on rainfall.
- Canals may be perennial (water available year-round) or inundation (seasonal).
2. Classification of Canals
(A) Based on Lining
- Unlined Canals
- Earthen canals without lining.
- Advantages: Low cost.
- Disadvantages: High seepage, erosion, weed growth.
- Lined Canals
- Masonry, concrete, or stone lining provided.
- Advantages: Less seepage, high efficiency, durability.
- Disadvantages: Expensive.
(B) Based on Purpose
- Irrigation Canals → Supply water for agriculture.
- Power Canals → Supply water for hydropower.
- Navigation Canals → Used for water transport.
- Combined Canals → Serve more than one purpose.
(C) Based on Discharge & Command
- Main Canal → Takes off directly from headworks (largest).
- Branch Canal → Offshoot from main canal.
- Major/Minor Distributaries → Carry water to fields.
- Water Courses (Field Channels) → Final channels supplying fields.
(D) Based on Situation/Source
- Perennial Canals
- Take off from reservoirs/dams.
- Supply water throughout the year.
- Example: Indira Gandhi Canal (Rajasthan).
- Inundation Canals
- Take off directly from rivers without control structures.
- Supply water only during floods.
3. Merits of Canal Irrigation
- Reliable water supply.
- Higher crop yield.
- Supports multiple cropping.
4. Demerits of Canal Irrigation
- Waterlogging & salinity.
- High initial construction cost.
- Displacement of land for canal alignment.
⚙️ Formulas
Duty-Delta Relation:
where
= Delta (cm of water depth required for crop)
= Base period (days)
= Duty (hectare/cumec)
Discharge Requirement:
where
= discharge (cumec)
= area irrigated (hectares)- = duty
🔟 10 MCQs
Q1. Canal irrigation is most suitable in areas of:
a) Heavy rainfall
b) Moderate rainfall
c) Low rainfall
d) Snowfall
Q2. A canal without lining suffers mainly from:
a) High construction cost
b) Seepage losses
c) Easy maintenance
d) Navigation problem
Q3. The Indira Gandhi Canal is an example of:
a) Inundation canal
b) Perennial canal
c) Navigation canal
d) Power canal
Q4. If duty (D) = 2000 ha/cumec and base period (B) = 100 days, find delta.
a) 43.2 cm
b) 864 cm
c) 0.043 cm
d) 432 cm
Q5. The main canal takes off from:
a) Branch canal
b) Reservoir headworks
c) Field channel
d) Distributary
Q6. Which type of canal requires less maintenance?
a) Unlined canal
b) Lined canal
c) Field channel
d) Inundation canal
Q7. Navigation canals are primarily meant for:
a) Irrigation
b) Transport
c) Hydropower
d) Flood control
Q8. Inundation canals supply water mainly during:
a) Summer
b) Winter
c) Flood season
d) Perennial flow
Q9. Discharge required to irrigate 4000 ha with duty 2000 ha/cumec = ?
a) 1 cumec
b) 2 cumec
c) 4 cumec
d) 0.5 cumec
Q10. Major disadvantage of canal irrigation is:
a) Cheap water
b) Increased fertility
c) Waterlogging
d) Multiple cropping
✅ Answer Key
| Q | Answer |
|---|---|
| 1 | c |
| 2 | b |
| 3 | b |
| 4 | a |
| 5 | b |
| 6 | b |
| 7 | b |
| 8 | c |
| 9 | b |
| 10 | c |
🧠 Explanations
- Q1: Canal irrigation is useful in low rainfall areas → (c).
- Q2: Unlined canals → high seepage → (b).
- Q3: Indira Gandhi Canal → perennial canal → (b).
- Q4: Formula
→ (a). - Q5: Main canal originates from headworks → (b).
- Q6: Lined canals resist seepage, erosion → less maintenance → (b).
- Q7: Navigation canals → water transport → (b).
- Q8: Inundation canals work during flood season → (c).
- Q9:
→ (b). - Q10: Main issue = waterlogging → (c).
🎯 Motivation / Why Practice Matters
For ECET 2026 Civil, irrigation topics often have direct numerical formula-based questions and conceptual MCQs. Canal irrigation is frequently asked because of its practical importance in Indian agriculture.
👉 Practicing these questions builds speed (fast formula recall) and accuracy (avoiding silly unit mistakes) — giving you an edge in competitive exams.
📲 CTA
🔥 Join our WHATSAPP group for ECET 2026 updates and discussions →
👉 Join Here
