IRRIGATION SYSTEMS????

• SURFACE IRRIGATION SYSTEMS

• Diversion systems

• River systems

• Reservoir or tank system

• Canal system

• GROUNDWATER IRRIGATION SYSTEMS

• Openwells or dug wells

• Tubewells or borewells

WHAT AN IRRIGATION SYSTEM CONSISTS OF??

• The irrigation system consists of a main intake structure or

main pumping station,a conveyance system ,a distribution

system, a field application system, and a drainage system

• The main intake structure or main pumping station directs water

from the source of supply such as a reservoir or a river into the

irrigation system.

• The distribution system assures the transport of water through

field ditches to the irrigated fields.

• The field application system assures the transport of water

within the fields.

• The drainage system removes the excess water from the fields

4

Total Geographical Area : 13.01 M Ha. (4.0% of India)

Water Resources : 4.49 M.Ha.m (3.0% of India)

Population as on 2001 : 62.11 M (6.4% of India)

Districts : 29

Taluks : 206

Blocks (Revenue) : 385

Villages : 17,273

River Basins : 17

TAMIL NADU STATE

SURFACE WATER 853.0 TMC

GROUND WATER 733.4 TMC

TOTAL 1586.4 TMC

SURFACE WATER UTILIZED 95%

EXPLOITATION OF GROUND 78%

WATER

WATER POTENTIAL

Source-wise Net Area Irrigated in Tamil Nadu

7

Year Net Area Irrigated (Lakhs Ha.)

Tanks Canals Wells Others Total

1960s 9.36 8.82 5.98 0.46 24.62

1970s 8.98 8.84 7.75 0.35 25.92

1980s 5.90 8.89 10.67 0.24 25.70

1990s 5.31 7.69 10.58 0.14 23.72

1997-98 6.76 8.38 14.12 0.19 29.45

1998-99 6.90 8.34 14.77 0.18 30.19

1999-2000 6.33 8.67 14.54 0.18 29.72

2000-2001 5.89 8.33 14.49 0.16 28.87

Sources No.

1. SURFACE IRRIGATION SYSTEMS

2. CANALS a) Govt.2393

b) Private 2

2. RESERVOIRS 71

3. TANKS

a) Ayacut above 40 ha. 7933

b) Ayacut below 40 ha. 32386

Total 40319

4. GROUNDWATER SYSTEMS

WELLS

A) Tube Wells & Others

a) Govt. 1181

b) Private 286123

Total 287304

B) OPEN WELLS

a) Govt. 670

b) Private 1620721

Total 1621391

TOTAL NO. OF WELLS (A+B) 1908695

SURFACE IRRIGATION SYSTEMS

• In surface irrigation systems ,water is either

diverted from the rivers and streams when

they are flowing (diversion works) for

irrigating the standing crops or stored

upstream side by constructing barrier

across the flow (reservoirs /tanks)for future

use.

1.DIVERSION SYSTEMS

• The purpose of diversion work is mainly to raise the water level and divert the river or stream flow into canals to irrigate the standing crops of the anacut.

• Small dams are used to raise the river water level to feed an off -taking canal and or some other conveyance system.

• A diversion dam is called a weir or barrage.

• In earlier days emphasis was on diverting river and stream flows during rainy season .Such schemes were largely developed in indo-gangetic plains due to snow melt from the himalayas

• Later emphasis was given on construction of storage tanks as in south india.

RESERVOIR OR TANK SYSTEM

• Tank irrigation is a storage irrigation scheme,which utilises the water stored

on upsream side of earthern dam called the bund.These earthern bund

reservoirs are known as tanks,especially in south india.

• A large sized tank is termed as a reservoir.

• Reservois are generally dams made of any material (mansonry dam

,concrete dam,earth dam etc) whereas tanks are formed by earthern dams

only.These earthern bunds are called as tank bunds.

• Most of the existing tanks have a depth of 4.5m while a few are as deep as 7

to 9 m.and a few exceptional cases exceed 11m in depth.When the depth of

tank exceeds 12m the tank is generally referred as a reservoir.

• Tank bunds are usually provided with sluices or outlets for discharging water

from the tank for irrigation.In dam reservoir projects tanks are provided with

the surplus escape arrangements for spilling away the excess surplus water

that may enter the tank to avoid over topping of the bund

AMARAVATHI DAM BHAVANISAGAR

PERIYAR VAIGAI

KRISHNAGIRI MANIMUTHAR

METTUR SATHANUR

PAPANASAM

ALIYAR

CANAL SYSTEMS• Surface water stored in major and medium irrigation projects or diverted

directly is distributed directly for irrigation through the canal irrigation network

to reach the fields to be irrigated.

• The canal networks consists of canals,distributaries,watercourses and field

channels,which are termed according to their capacity and orientation with

respect to the head works.

• MAIN CANAL:It takes its supply directly from the reservoir or the river and

its capacity varies fron 280 to 425 cubic meter per sec in india.

• BRANCH CANALS:These canals take off from main canal and convey water

to different major parts of irrigated areas.Branch canals generally carry a

discharge from 4 to 8.5 cubic meter per sec.

• MAJOR DISTRIBUTORIES:They take off from branch canals and sometimes

from main canals and supply water to distributories or outlets.They generally

carry discharge between 0.75 and 5.5 cubic meter per sec.

• MINOR DISTRIBUTARIES:These are smaller channels taking their supply from major distributories and supplying water to outlets.The carrying capacity is less than 750 l per second.

• CANAL OUTLETS:They are provided in irrigation canal system at appropriate points.The size depends on irrigated area.Discharge of outlet varies with level of water in the channel.

• WATERCOURSE:It is any channel which is supplied with water from canal but which is not maintained at the cost of government.They pass through common land and are maintained by farmers.

• FIELDCHANNELS:They carry water to individual fields from the watercourse.

Canal irrigation is popular in deltaic and coastal areas accounting for 29

per cent of the net cropped area.

1. Kaveri Delta Canals-The Kaveri delta has the oldest and the longest

(6,400 km) irrigation canal system in the state. These canals taken off

from the Grand Anicut (built in 1889) irrigates about 5.15 lakh hectares of

land in Thanjavur and Tiruchchirappalli districts.

2. Mettur Canal System-these canals taken out from the Kaveri River

(Mettur dam) provide irrigation to 1.8 lakh hectares of land in Salem and

Coimbatore districts.

3. Lower Bhawani Project Canals-Bhawani Sagar reservoir has been

constructed over the Bhawani River to irrigate 78.917 hectares of land in

Coimbatore district.

.

4. Periyar Project Canals-a barrage has been built across the Periyar River

and its water is transported to the Suruliyar River (tributary of the Vaigai

River) through a 1737 m tunnel. This water is distributed through 432 km

long canals to irrigate about 40,000 hectares of land in Madurai, and

Ramanathapuram districts.

5. Katalai Canal-the Katalai High Level Canal irrigates 8,300 hectares of

land in Thanjavur and Tiruchchirappalli districts.

6. Manimuthar Project Canals-The Manimuthar is a tributary of the

Tamraparni river over which an earthen dam has been constructed. Canals

taken out from this dam irrigate 41,694 hectares of land in Tirunelveli

district.

7. Parambikulam-Aliyar Project Canals-this is a joint venture of Tamil Nadu

and Kerala states under which 244 km long canals have been constructed

to utilise the water from eight rivers to irrigate 97.13 thousand hectares of

agricultural land

KALINGARAYAN CANAL BUCKINGHAM CANAL

KAVERI-VAIGAI CANAL LOWER BHAWANI CANAL

GROUNDWATER IRRIGATION SYSTEMS

• Ground water is the underground water that occurs in the

standard zone of variable thickness and depth below the earths

surface.About 46 % of the total irrigated area in india gets its

irrigation water from this source.

• Groundwater is utilised through wells using various lifting

devices such as those using animal,manual,wind.diesel or

electric power.

• Use of open wells is the traditional method of tapping

groundwater .

• Use of tube wells is however a subsequent development.

OPEN WELLS OR DUG WELLS

• Dugout wells up to water bearing strata are called openwells or dugout wells..

• They have comparitively bigger diameter with low discharges of the order of 1 to 5 l per sec.

• The diameter of open wells generally varies from 2 to 9 m and they are generally less than 20 m in depth.

TUBE OR BORE WELLS

• Tube wells are sunk by inserting pipes below ground surface

through water bearing and non-water bearing strata.

• DEEP BORE WELLS:Are as deep as 70 to 300 m and tap more

than one aquifer.Such wells may yield as high as 200 to 220 l

per sec.Average yield however is of the order of 40 to 45 l per

sec.The diameter of the hole is 0.6 m upto 60 m depth and then

0.56 m below 60m.

• SHALLOW TUBE WELLS:Having 20 to 70 m depth may yield

as high as 15 to 20 l per sec if located at proper place.Such

wells can irrigate around 6 hectares.

• Depending on the entry of water through a cavity or screen

tube wells are classified into two categories.

• CAVITY TYPE TUBE WELL:draws water from the well and not

from the sides .It essentially consists of a pipe bored through

the soil and resting on the bottom of a strong clay layer.A cavity

is formed at the bottom and water from the aquifer enters the

well pipe through the cavity.

• SCREEN TYPE TUBE WELLS: can easily tap a number of

aquifers unlike a cavity well.These are of two types:

1. Strainer tube wells

2. Slottedpipe gravel packed tube wells