---
title: "Channel-end discharge, rabi and kharif"
subject: "Irrigation and Drainage Engineering"
chapter: 2
key: "semester_6/irrigation_and_drainage_engineering:outlet-discharge-rabi-kharif-400ha"
source: https://www.bctengineer.com/q/semester_6/irrigation_and_drainage_engineering/outlet-discharge-rabi-kharif-400ha
site: BCT Engineering
---

# Channel-end discharge, rabi and kharif

Irrigation and Drainage Engineering · Chapter 2: Irrigation Water Requirements

- Asked in: 2063 Baisakh (old course), 8 marks
- Video: [Discharge Required for Rabi and Kharif Seasons: Irrigation and Flood Management](https://www.youtube.com/watch?v=XGEaUQkSCJY) — E.T.E. Suman
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/irrigation_and_drainage_engineering/outlet-discharge-rabi-kharif-400ha
- Whole chapter: https://www.bctengineer.com/md/semester_6/irrigation_and_drainage_engineering/chapter-2

## Question

Determine the discharge at the end of the irrigation channel. CCA at outlet = 400 ha; Intensity of irrigation for rabi = 65%; Intensity of irrigation for kharif = 30%; outlet discharge factors for rabi = 1500 ha/cumec and for kharif = 800 ha/cumec. Assume losses in conveyance = 6% of the outlet discharge.

## Short answer

Rabi area 260 ha, Q = 260/1500 = 0.1733 cumec. Kharif area 120 ha, Q = 120/800 = 0.150 cumec. Design outlet discharge = 0.1733 cumec. With 6% conveyance loss, channel head discharge = 0.1733 + 0.0104 = 0.184 cumec.

## Answer

**Given:** CCA = 400 ha; intensity rabi $= 65\%$, kharif $= 30\%$; outlet discharge factor (duty) rabi $= 1500$ ha/cumec, kharif $= 800$ ha/cumec; conveyance loss $= 6\%$ of the outlet discharge.

**Areas:** rabi $= 0.65\times400 = 260$ ha; kharif $= 0.30\times400 = 120$ ha.

**Outlet discharge for each season**

$$
Q_{rabi} = \frac{260}{1500} = 0.1733\ \text{cumec},\qquad Q_{kharif} = \frac{120}{800} = 0.1500\ \text{cumec}
$$

The design outlet discharge is the larger one: $Q_{outlet} = 0.1733$ cumec (rabi).

**Conveyance loss**

$$
\text{Loss} = 0.06\times 0.1733 = 0.0104\ \text{cumec}
$$

$$
Q_{channel\ head} = 0.1733 + 0.0104 = 0.1837\ \text{cumec}
$$

**Answer: discharge required at the outlet (end of the channel) = 0.173 cumec; the channel must carry 0.184 cumec at its head to allow for the 6% loss.**

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What areas are irrigated in rabi and kharif?
   A. 260 ha rabi and 120 ha kharif
   B. 65 ha and 30 ha
   C. 400 ha both
   D. 120 ha rabi and 260 ha kharif
   Answer: A. Intensity x CCA: 0.65 x 400 and 0.30 x 400. (Key point: Seasonal areas)

2. How is the outlet discharge for each season obtained?
   A. Q = area x duty
   B. Q = area / outlet discharge factor (duty)
   C. Q = duty / area
   D. Q = area x intensity
   Answer: B. Rabi 260/1500 = 0.1733 cumec; kharif 120/800 = 0.15 cumec. (Key point: Outlet discharge)

3. Which discharge is adopted for the outlet?
   A. Kharif, 0.150 cumec
   B. The sum, 0.323 cumec
   C. Rabi, 0.173 cumec, the larger
   D. The average, 0.162 cumec
   Answer: C. The seasons differ, so the larger controls. (Key point: Design season)

4. How is the 6% conveyance loss applied and what is the head discharge?
   A. Subtracted: 0.163 cumec
   B. Added to 400 ha
   C. Ignored: 0.173 cumec
   D. Loss = 6% of outlet discharge is added: 0.1733 + 0.0104 = 0.184 cumec
   Answer: D. The loss is stated as 6% of the outlet discharge, so add 0.0104 cumec. (Key point: Channel head discharge)

## Related in Irrigation and Drainage Engineering

- [Outlet discharge: wheat and rice, 10000 ha](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Akor-outlet-discharge-wheat-rice-10000ha) — Irrigation and Drainage Engineering, chapter 2
- [Duty and minor discharge, wheat 400 ha](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Aminor-wheat-400ha-duty-discharge) — Irrigation and Drainage Engineering, chapter 2
- [Duty and head discharge, 4000 ha channel](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Aduty-head-discharge-4000ha-70pct) — Irrigation and Drainage Engineering, chapter 2
- [Interval and outlet discharge, 11 hour canal](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Acanal-operation-hours-interval-outlet) — Irrigation and Drainage Engineering, chapter 2
- [GCA, CCA, NCA, intensity and pattern](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Agca-cca-nca-intensity-pattern) — Irrigation and Drainage Engineering, chapter 1, asked 4×
- [Outlet discharge from kor table (rice, wheat)](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Aoutlet-discharge-rice-wheat-kor) — Irrigation and Drainage Engineering, chapter 2

## Related in other subjects

- [Define conveyance of an open channel](https://www.bctengineer.com/question.md?key=semester_4%2Fhydraulics%3Adefine-conveyance-open-channel) — Hydraulics, chapter 5, asked 2×
- [Corner stresses of 400 x 800 column (250 kN)](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Acolumn-stress-400x800-250kn) — Concrete Technology and Masonry Structure, chapter 8, asked 7×
- [Corner stresses of 400 x 800 column (200 kN)](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Acolumn-stress-400x800-200kn) — Concrete Technology and Masonry Structure, chapter 8, asked 7×
- [Receiving-end voltage infinite at 1500 km](https://www.bctengineer.com/question.md?key=semester_8%2Fhigh_voltage_engineering%3Alossless-line-1500km-infinite-voltage) — High Voltage Engineering, chapter 3