CE 6001, Unit 3 Conveyance and Distribution of water

 

🔹 3.1 Conveyance of Water

Conveyance means the process of transporting water from the source (like a river, dam, or treatment plant) to the city or storage points.

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✅ 3.1.1 Types of Pipes Used for Conveyance of Water:

Different types of pipes are used based on the pressure, type of soil, water quality, and cost. Common pipe materials include:

1. Cast Iron (CI) Pipes

   • Strong and durable.

   • Common in municipal supply.

   • Heavy and prone to corrosion.

2. Ductile Iron Pipes

   • Improved version of cast iron.

   • More flexible and strong.

   • Less prone to leakage.

3. Steel Pipes

   • Used for long-distance and high-pressure flow.

   • Strong, but can corrode.

4. PVC (Polyvinyl Chloride) Pipes

   • Lightweight and corrosion-resistant.

   • Used for domestic and small-scale pipelines.

5. HDPE (High-Density Polyethylene) Pipes

   • Flexible and suitable for underground work.

   • Resistant to chemicals and corrosion.

6. Concrete or RCC Pipes

   • Used for large-diameter pipelines and drainage.

   • Heavy and not flexible.

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✅ 3.1.2 Choice of Pipe Material

While selecting the pipe material, consider:

• Cost: Initial and maintenance costs.

• Strength: Based on pressure requirement.

• Corrosion resistance: For chemical-rich or salty water.

• Ease of Installation: Some pipes are easier to handle.

• Life Span: Durability of the material.

• Terrain conditions: Hilly, flat, rocky areas.

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✅ 3.1.3 Types of Joints & Valves: Use, Location, and Function

Types of Pipe Joints:

1. Spigot and Socket Joint – Common in CI pipes.

2. Flanged Joint – Easy to dismantle; used in plants.

3. Welded Joint – Used in steel pipes for leak-proof sealing.

4. Rubber Ring Joint – Used in PVC/HDPE pipes; allows flexibility.

Types of Valves:

Valve Type	Use & Location	Function
Sluice Valve	At pipe junctions or branches	Start/stop water flow
Air Valve	At high points in pipeline	Removes trapped air
Reflux (Check) Valve	After pumps	Prevents backflow
Pressure Relief Valve	In high-pressure zones	Releases excess pressure
Scour Valve	At lowest point of pipe	Drains out water for cleaning

🔹 3.2 Distribution of Water

Distribution refers to supplying treated water from service reservoirs to houses, industries, and public places.

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✅ 3.2.1 Methods of Water Distribution

3.2.1.2 Gravity System

• Water flows naturally from high-level reservoirs.

• No pump needed.

• Cheapest and most reliable method.

• Needs elevated storage tanks or hilly terrain.

3.2.1.3 Pumping System

• Pumps lift water directly into pipelines.

• Used where ground level is flat or source is low.

• Expensive and depends on electricity supply.

3.2.1.4 Combined System (Pumping + Gravity)

• Water is first pumped to a reservoir or overhead tank.

• Then it flows by gravity.

• Reliable and efficient for modern cities.

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✅ 3.2.1.5 Service Reservoirs – Functions and Types

Functions:

• Store water during low demand and supply during high demand.

• Provide pressure in distribution.

• Act as emergency backup during pump failure.

Types:

1. Elevated Service Reservoir (ESR) – Overhead tanks.

2. Ground-level Reservoir (GLR) – Built at surface level.

3. Underground Reservoirs – For safety and space-saving.

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✅ 3.2.1.6 Layouts of Distribution Systems

3.2.1.6.1 Dead End System

• Branched layout with many ends (like tree branches).

• Simple and low cost.

• Problem: Water stagnates at ends; difficult to clean.

3.2.1.6.2 Grid Iron System

• Network layout with interconnections.

• Continuous circulation of water.

• Better pressure and easier to isolate faults.

3.2.1.6.3 Circular or Ring System

• Circular loop around the city with branches inside.

• Uniform pressure and high reliability.

• Slightly higher cost.

3.2.1.6.4 Radial System

• City is divided into zones, each with a central reservoir.

• Shorter pipe lengths and better pressure control.

• Complex design and costlier.

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✅ 3.2.1.6.5 Suitability, Advantages & Disadvantages

System	Suitability	Advantages	Disadvantages
Dead End	Small towns/villages	Cheap, simple	Water stagnation, hard to clean
Grid Iron	Cities with planned roads	Easy fault detection, good flow	High cost
Circular	Large towns	Equal pressure, good reliability	Expensive
Radial	Modern urban layouts	Efficient zoning and control	Difficult to redesign/modify