. Objectives

• Provide safe drinking water
• Ensure adequate quantity
• Maintain proper pressure
• Achieve continuous and economical supply

2. Main Components of a Water Supply System

🌊 A. Source of Water

Common sources:

• Surface water (rivers, lakes)
• Groundwater (wells, tube wells)
• Springs (in hilly regions like Nepal)

Selection depends on:

• Quality
• Quantity
• Distance from demand area

🚰 B. Water Demand Estimation

You calculate how much water is needed.

Includes:

• Domestic use
• Commercial/institutional use
• Fire demand
• Losses (leakage)

Typical standards:

• 100–135 liters per capita per day (lpcd)

🧪 C. Water Quality & Treatment

Raw water must be treated.

Common processes:

1. Screening
2. Sedimentation
3. Filtration
4. Disinfection (chlorination)

Based on guidelines like those from World Health Organization.

🏗️ D. Intake Structure

Structure to collect water from source:

• River intake
• Reservoir intake

🧴 E. Treatment Plant Design

Design depends on:

• Turbidity
• Bacteria content
• Chemical impurities

🏢 F. Storage System

• Overhead tanks (OHT)
• Ground reservoirs

Purpose:

• Balance supply and demand
• Maintain pressure

🚿 G. Distribution System

Network of pipes delivering water.

Types:

• Dead-end system
• Grid system
• Ring system

⚙️ H. Pumping SystemUsed when gravity flow is not possible.

Includes:

• Pumps
• Rising mains

3. Important Design Considerations

• Population forecasting (20–30 years)
• Peak demand factors
• Pipe sizing (based on flow & velocity)
• Pressure management
• Leakage control

4. Basic Planning Steps

1. Study area & population
2. Identify water source
3. Estimate demand
4. Test water quality
5. Design treatment process
6. Plan storage & distribution
7. Prepare cost estimate

5. Software Commonly Used

• EPANET – pipe network analysis
• AutoCAD – drawings
• Excel – calculations

6. Key Formulas (Simple)

Demand = Population × lpcd

• Peak Demand = Average Demand × Peak Factor
• Velocity in pipe = 0.6 – 2.0 m/s (typical)

7. If You’re Preparing a DPR / Assignment

Include:

• Area map
• Population forecast
• Demand calculation
• Source selection
• Treatment design
• Pipe network layout
• Cost estimate