Sources of water (RAIN)

Surface Sources Ground Sources

Streams Springs

Lakes Infiltration Galleries

Ponds Infiltration Wells

Rivers Wells and Tube wells

Impounded Reservoirs

Oceans

Springs

•Natural outflow of GW @ earth’s surface.

•Gravity springs : GW table rises high & water overflows

though the sides of a natural valley or depression.

•Surface springs : an impervious obstruction supporting

underground storages becomes inclined causing water table

to go up & get exposed to ground surface.

•Artesian Springs : when water flowing through some

confined aquifer is under pressure.

Artesian spring

Aquifers & Aquicludes

Non artesian or Unconfined aquifers & well

Wells

•A water well is a hole usually vertical, excavated in the

earth to bring GW to the surface.

•Open Wells / Tube Wells.

Open Wells (Dug Wells)

•Open masonry wells, 2 – 9 m dia, less than 20 m depth.

Discharge 5 L/s

•Walls built of brick or stone masonry or precast concrete ring

•To improve yield of well, 10 cm dia hole @ centre of well is

made (Shallow well/Deep Wells)

•Shallow well rests in a pervious strata.

•Deep well rests on an impervious ‘mota’ layer & draws its

supply from the pervious formation lying below ‘mota’ layer.

•A shallow well might be having more depth than a deep well

Deep wells

Infiltration Galleries (Horizontal Wells)

•Horizontal tunnels (with holes on sides) constructed of

masonry walls with roof slabs to tap GW flowing towards

rivers/lake.

•Constructed @ shallow depths (3-5m) along the banks of

river either axially along or across GW flow.•Width (1m), depth (2m) , length (10 – 100m)

•If large GW quantity exists, porous drain pipes are provided

and they are surrounded by gravel and broken stone. •Yield, 15,000 L/day / Meter length•A collecting well @ shore end of gallery serves as sump

from where water is pumped.

Section of infiltration gallery

Infiltration galleries

•They are shallow wells constructed under beds of rivers.

•Deposits of sand exist at least 3m deep in river beds. As the

water percolates down, impurities are removed. Quality of

water is better than river water.

•They are sunk in series in the bank of the river.

•They are closed @ top & open & bottom. Manholes are

provided @ top for inspection.

•They are constructed of brick basonry with open joints.•Various infiltration wells are connected by porous pipes to

sump called jack well.

Infiltration Wells

•Structures used to withdraw water from various sources.

•Lake / Reservoir / River /Canal/ Intake.

Intakes

•Submersible intake.

•A pipe laid in the bed of the lake.

•One end is in the middle of the lake & is fitted with bell –

mouth opening covered with a mesh & protected by concrete

crib.

•Water enters in the pipe through bell-mouth opening & flows

under gravity to the bank where it is collected in a sump –

well & then pumped to TP.

Lake Intakes

•A circular masonry tower (4-7m dia) constructed along bank

of the river.

•Water enters in the lower portion of the intake (i/e sump –

well) from penstocks.

•Penstocks are fitted with screens to prevent entry of floating

solids.

• No. of penstock openings are provided in intake to admit

water @ different levels.

•Opening & closing of penstock valves is done with wheels

provided @ pump – house floor.

River Intakes

• Constructed inside river @ suitable place.

•A concrete circular shell filled with water upto water level

inside the river.

•Water enters through openings provided on outer circular

shell, as well as on inside shell.

•Water is taken to the bank of the river through the

withdrawal conduit in the sump well from where it is pumped

to WTP.

a) Wet Intakes

b)Dry Intake tower

•In wet intake tower, water enters first in the outer shell then

it enters in the inner shell.

•In dry intake, water enters directly withdrawal conduit.

•An intake tower constructed on the slope of the dam.

•Intake pipes are fixed @ different level to withdraw water at

all variations of water level.

•All inlet pipes are connected to one vertical pipe inside the

intake well.

•Screens are provided @ mouth of all intake pipes to prevent

entry of floating matter.

•Water entering the vertical pipes is taken to other side of the

dam by means of an outlet pipe.

Reservoir Intake

•At the top of intake tower, sluice valves are provided to

control flow of water.

•Valve tower is connected to the top of the dam by means of

foot-bridge gang- way.

•For earthen dams, intake towers are separately constructed.

•For RCC masonry dams, intake tower is constructed inside

the dam it self.

Reservoir Intake tower

Canal Intake

•No need to provide multiple ports, as water level in canal

remains constant.

•A pipe placed in a brick masonry chamber constructed

partly in the canal bank.•On one side of chamber, opening is provided with coarse

screen for entrance of water.

•A bell mouth fitted with a hemispherical fine screen is

provided @ the mouth of the pipe.•Outlet pipe carries water to the other side of the canal bank

from where it is taken to TP.•One sluice valve operated by a wheel from top of masonry

chamber is provided to control flow of water in the pipe.

Canal intake well

Dry intake tower standing in the river or reservoir