---
title: "Outlet discharge from kor table (rice, wheat)"
subject: "Irrigation and Drainage Engineering"
chapter: 2
key: "semester_6/irrigation_and_drainage_engineering:outlet-discharge-rice-wheat-kor"
source: https://www.bctengineer.com/q/semester_6/irrigation_and_drainage_engineering/outlet-discharge-rice-wheat-kor
site: BCT Engineering
---

# Outlet discharge from kor table (rice, wheat)

Irrigation and Drainage Engineering · Chapter 2: Irrigation Water Requirements

- Asked in: 2062 Baisakh (old course), 8 marks
- Video: [Water requirement of crop Numerical || Sum of Discharge Required and Required capacity of Reservoir](https://www.youtube.com/watch?v=E-VERQbA-dw) — Professor Nidhi Trivedi
- 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-rice-wheat-kor
- Whole chapter: https://www.bctengineer.com/md/semester_6/irrigation_and_drainage_engineering/chapter-2

## Question

Calculate the discharge required at the outlet for wheat and rice crop using following data.

| Crop | command area (Ha) | kor period | kor depth |
|---|---|---|---|
| Rice | 5000 | 18 | 19 |
| Wheat | 3500 | 26 | 15 |

## Short answer

Rice: Q = (5×10⁷ ×0.19)/(18×86400) = 6.11 cumec. Wheat: Q = (3.5×10⁷ ×0.15)/(26×86400) = 2.34 cumec. Crops are in different seasons, so design discharge = 6.11 cumec (the larger).

## Answer

**Assumption:** kor period is in days and kor depth in cm.

**Formula:** $Q = \dfrac{A\,d}{T\times 86400}$

**Rice:** $A = 5000$ ha $= 5\times10^7$ m$^2$, $T = 18$ days, $d = 19$ cm $= 0.19$ m

$$
Q_r = \frac{5\times10^7\times0.19}{18\times86400} = 6.109\ \text{m}^3/\text{s}
$$

**Wheat:** $A = 3500$ ha $= 3.5\times10^7$ m$^2$, $T = 26$ days, $d = 15$ cm $= 0.15$ m

$$
Q_w = \frac{3.5\times10^7\times0.15}{26\times86400} = 2.337\ \text{m}^3/\text{s}
$$

Rice (kharif) and wheat (rabi) are grown in different seasons, so the outlet is designed for the larger value.

**Answer: rice needs 6.11 cumec and wheat needs 2.34 cumec; design discharge = 6.11 cumec.** (If both were irrigated together, the sum would be 8.45 cumec.)

## Check yourself

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

1. What units are assumed for the kor period and kor depth?
   A. Kor period in days and kor depth in cm
   B. Weeks and mm
   C. Hours and m
   D. Weeks and cm
   Answer: A. The answer assumes days and cm, so d = 19 cm = 0.19 m. (Key point: Assumptions)

2. What is the discharge for rice (5000 ha, 18 days, 19 cm)?
   A. 2.34 cumec
   B. 6.11 cumec
   C. 8.45 cumec
   D. 1.10 cumec
   Answer: B. Q = 5e7 x 0.19/(18 x 86400) = 6.109 cumec. (Key point: Rice discharge)

3. What is the discharge for wheat (3500 ha, 26 days, 15 cm)?
   A. 6.11 cumec
   B. 4.2 cumec
   C. 2.34 cumec
   D. 0.9 cumec
   Answer: C. Q = 3.5e7 x 0.15/(26 x 86400) = 2.337 cumec. (Key point: Wheat discharge)

4. Which value is the design outlet discharge and why?
   A. 8.45 cumec, the sum
   B. 2.34 cumec, the smaller
   C. 4.22 cumec, the average
   D. 6.11 cumec, because rice and wheat are in different seasons so the larger governs
   Answer: D. Kharif rice and rabi wheat do not overlap, so only the larger is needed. (Key point: Design discharge)

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