Sources of Water

◆Sources of Water◆

1) Surface Sources
• The major source of surface water is rainfall.
• It contains dissolved & suspended impurities.
• e.g. Rivers, canals, lakes, ponds, spring etc.
• River is the purest source among surface sources due to self-cleaning nature.
• River water contains highly suspended impurities only.

2) Sub- Surface Sources
• Major source is Underground water below water table.
• It contains dissolved impurities (dissolved gases & minerals.)
• e.g. wells, infiltration galleries & infiltration wells.

• Infiltration Galleries.

➔These are the large tunnels placed along bank of river.
→These are placed at depth of 3 m to 5m below ground surface.
→It consist of perforated pipes that collect the seepage water & transfer to galleries.

Infiltration Wells
➔ These are the open wells which are placed at suitable interval along the bank of river.
➔ These are subjected to atmospheric pressure.

Intakes Structures
The structures which are used to collect surface waters from their sources are known as Intake structures.

Types of Intake
1) On the basis of Use
i) River Intake
ii) Canal Intake
iii) Lake Intake
2) On the basis of function/Operation
i) Submerged
ii) Tower

Well
A water well is a vertical hole excavated below the ground surface to excavate ground water.

Open Well
• The well in which flowing velocity of water is less than critical velocity is known as open well.
• The critical velocity is the max permissible velocity above which the movement of soil particles take place along with water.
• Max. discharge of open well is 5 liters per second (5lps)

Shallow Well
• It is a type of open well that can be excavated up to certain depth of first
permeable layer.

Deep Well
• This well is excavated up to complete depth of first permeable layer below ground surface.
• The discharge of deep well is always more than discharge of shallow well.

Tube Wells
• It is a long-perforated pipe i.e. dug below the ground surface up to no. of permeable & impermeable layers.
• Max. value of discharge is 50 lps