---
title: "Demand of village 2070 BS, base period 5 years"
subject: "Water Supply Engineering"
chapter: 3
key: "semester_5/water_supply_engineering:demand-c70"
source: https://www.bctengineer.com/q/semester_5/water_supply_engineering/demand-c70
site: BCT Engineering
---

# Demand of village 2070 BS, base period 5 years

Water Supply Engineering · Chapter 3: Quantity of Water

- Asked in: 2070 Chaitra, 8 marks
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/water_supply_engineering/demand-c70
- Whole chapter: https://www.bctengineer.com/md/semester_5/water_supply_engineering/chapter-3

## Question

Data obtained from a baseline survey of a village in year 2070 B.S. are as follows. Population of village = 2700, No. of day scholar students = 220, No. of big animals = 240, No. of small animals = 460. There are two offices, one health post. Calculate the water demand of that village in design year with base period of 5 years and design period of 20 years. Assume the population growth rate of that village as 1.89% per annum.

## Short answer

Design year 2095 BS, n=25, population 4312. Net demand 210128 l/d; adding 15% losses gives 241648 l/d = 241.65 m3/d = 2.80 l/s; maximum day demand 4.20 l/s.

## Answer

Survey year 2070 BS; base period 5 years and design period 20 years: design year 2095 BS, $n = 25$ years.

#### Design population
$$
P_{2095} = 2700\times(1.0189)^{25} = 4{,}312
$$

#### Water demand
**Design values assumed** (Nepal rural water supply practice): domestic 45 lpcd (public taps); day scholar 5 l/d; boarder 45 l/d; office staff 45 l/d with 10 staff per office; big animal (cow, buffalo) 45 l/d; small animal (goat, pig) 5 l/d; poultry 0.2 l/d; health post 1000 l/d; tea shop 500 l/d; losses and wastage 15% of net demand; maximum day factor 1.5 and peak hour factor 3. Fire demand is neglected.

| Demand | Quantity | Rate | Demand (l/day) |
|---|---|---|---|
| Domestic (45 lpcd) | 4,312 | 45 l/c/d | 194,028 |
| Day scholars | 220 | 5 l/c/d | 1,100 |
| Big animals | 240 | 45 l/d | 10,800 |
| Small animals | 460 | 5 l/d | 2,300 |
| Offices (10 staff each) | 20 | 45 l/staff | 900 |
| Health post | 1 | 1000 l/d | 1,000 |
| **Net demand** | | | **210,128** |

Losses and wastage $= 15\%$ of net demand $= 31{,}519$ l/day

$$
Q_{avg} = 210{,}128 + 31{,}519 = 241{,}648\ \text{l/day} = 241.65\ \mathrm{m^3/day} = 2.80\ \text{l/s}
$$

**Answer: Design population = 4,312; average water demand = 242 m$^3$/day (2.80 l/s); maximum day demand = 4.20 l/s.**

## Check yourself

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

1. Survey 2070 BS, base period 5 and design period 20 years. What is n?
   A. 20 years
   B. 25 years (design year 2095)
   C. 5 years
   D. 45 years
   Answer: B. Design year = 2070+5+20 = 2095, 25 years after the survey. (Key point: Design year)

2. Which is correct for 2 offices and 1 health post?
   A. Offices 2 x 1000 l/d; health post 45 l/d
   B. Offices 900 l/d; health post 340 l/bed/d
   C. Offices 2x10x45 = 900 l/d; health post 1000 l/d
   D. Offices 2 x 500 l/d; health post 500 l/d
   Answer: C. Offices use 10 staff at 45 l/staff/d; a health post is taken as 1000 l/d. (Key point: Institutional demands)

3. Given Q_avg = 2.80 l/s, the maximum day demand is
   A. 1.5 x 2.80 = 4.20 l/s
   B. 3 x 2.80 = 8.40 l/s
   C. 2.80/1.5 = 1.87 l/s
   D. 2.80 + 15% = 3.22 l/s
   Answer: A. Max day factor is 1.5. (Key point: Maximum day demand)

## Related in Water Supply Engineering

- [Rural village demand, survey 2070 BS, base year 2073](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Ademand-as70) — Water Supply Engineering, chapter 3
- [Population in survey year from design demand 800 m3](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Apop-s73) — Water Supply Engineering, chapter 3, asked 2×
- [Average demand, village survey 2013, design 25 years](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Ademand-c73) — Water Supply Engineering, chapter 3, asked 2×
- [Total demand, village survey 2013, design 15 years](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Ademand-c69) — Water Supply Engineering, chapter 3, asked 2×
- [Demand of rural municipality, base period 3 years](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Ademand-bk79) — Water Supply Engineering, chapter 3
- [Demand of new municipality 2016, 45,000 pop](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Ademand-a76) — Water Supply Engineering, chapter 3, asked 2×