INTAKE STRUCTURE

Introduction

The structure or device constructed in or near the source of water for the purpose of collecting or taking water from the source of water is called INTAKE STRUCTURE. Hence, main use of intake is to draw clear (free from pollution, sand and other floating material) water from surface source of water like river, canal, dam etc. Generally intake structures are constructed from the masonry or concrete. Water entering in the intakes is discharged to the withdrawal conduits from which water is transmitted(conveyed) to the treatment plant. This discharge is safely done either by natural(gravity) flow or by pump to the withdrawal conduits.

SITE SELECTION OR LOCATION CRITERIA FOR INTAKE STRUCTURE

Quality of water, cost of conveyance or economy, quantity of water, availability of good foundation and land near the water source are some criteria for the section of intake structure site location.

Intake must be well located on the upstream side of any city or industrial area and situated at purer zone of the souce so that best quality water can drawn.
It can never located near the waste water disposal point or downstream side of any city or industrial area. So, no contamination occur.
There must not be any navigation channel near the intake site because this channel pollute water from the waste discharge from ship.
For meandering river choose location of intake at outside of the curve where deposition of silt, sand, boulders are less due to faster flow of water.
Intake should be as near to the treatment plant so conveyance cost must be less.
Site should be selected where clear water free from mud, sand and other floating material is available. Hence, load on treatment plant is less and hence cost of purification also less.
The selected site should be accessible during the flood and even can draw water during the worst condition of water level in reservoir i.e. can draw water in driest period.
Intake should be located on good foundation stone. So, it's load transmitted safely to the soil.
The site should be selected so that further expansion can be done easily.

DIFFERENT TYPES OF INTAKE

Various types of intake structure can be given according to source of water, position of intake structure and availability of water in the intake tower.

According to source of water

According to position of intake

According to availability of water in the intake tower

RIVER INTAKE STRUCTURE

RIVER INTAKE As we know intake should be located at the upstream side of the city so pollution is minimum and this river intake should be sufficiently inside the river water so need of water can be supplied at every seasons of the year. Some river intakes are constructed near the bank of river when sufficient depth is available, some are created away from the bank of river when river bed is soft or unstable near bank, sometimes water level raised by constructing weir on the river and sometimes channel created and water led to the intake tower. This all situations divides river intake into two major types: (1) Single well type intake and (2) Twin well type intake. Parts of river intake are Intake well, Intake pipe and Jack well. River intake well has two parts, lower part is Jack well and upper part is surves pump house. SINGLE WELL TYPE RIVER INTAKE In single well type intakes water is directly enter into jack well through the penstockes (openings) created at different level. As ...

CANAL INTAKE STRUCTURE

CANAL INTAKE Canal intake structure An irrigation canal used as the source of water when other source are far from the city. Intake structure constructed near the bank of canal. An intake chamber created inside the canal using concrete or masonry having one bell mouth entry pipe inside it. Intake chamber has opening guarded with coarse screen and bell mouth entry protected with fine screen or mesh. Bell mouth entry located at expected low water level of the canal. Water enters from this bell mouth entry and conveyed through withdrawal conduits to sump well or city.

RESERVOIR INTAKE STRUCTURE

RESERVOIR INTAKE All rivers has not sufficient depth of flow throughout the year and hence dam constructed across the river to form a reservoir having sufficient depth for intake. This intake structure built upstream side near the dam and it is similar to the river intake. A typical reservoir intake well consists number of water entry ports located at various elevations so that relatively clear top water is only drawn at all seasons. All control on this entry ports is at topnof the well. Dry intakes and wet intakes formed according to the position of entry valves outer and inner of the well respectively.

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