Irrigation and Hydropower of Telangana - Telangana PCS Exam Notes

Irrigation and Hydropower of Telangana

Hydropower in Telangana

Hydroelectric Power — what is it?

It is a form of energy … a renewable resource.
Hydropower provides about 96 percent of the renewable energy in the United States. Other renewable resources include geothermal, wave power, tidal power, wind power, and solar power.
Hydroelectric powerplants do not use up resources to create electricity nor do they pollute the air, land, or water, as other powerplants may.
Hydroelectric power has played an important part in the development of this Nation’s electric power industry.
Both small and large hydroelectric power developments were instrumental in the early expansion of the electric power industry.
Hydroelectric power comes from flowing water … winter and spring runoff from mountain streams and clear lakes.
Water, when it is falling by the force of gravity, can be used to turn turbines and generators that produce electricity.

HOW HYDROPOWER WORKS

Hydroelectric power comes from water at work, water in motion.
It can be seen as a form of solar energy, as the sun powers the hydrologic cycle which gives the earth its water.
In the hydrologic cycle, atmospheric water reaches the earths surface as precipitation. Some of this water evaporates, but much of it either percolates into the soil or becomes surface runoff.
Water from rain and melting snow eventually reaches ponds, lakes, reservoirs, or oceans where evaporation is constantly occurring
Moisture percolating into the soil may become ground water (subsurface water), some of which also enters water bodies through springs or underground streams.
Ground water may move upward through soil during dry periods and may return to the atmosphere by evaporation.
Water vapor passes into the atmosphere by evaporation then circulates, condenses into clouds, and some returns to earth as precipitation.
Thus, the water cycle is complete. Nature ensures that water is a renewable resource.

Dams

Height of dam and mass of water behind the dam determine useful energy.
Efficiency is very good to excellent, generally 80 to 90% efficient in converting potential energy to electrical energy.

Irrigation

Classification of irrigation projects

Irrigation projects are classified in different ways, however, in Indian context it is usually classified as follows:

Major project: This type of project consists of huge surface water, storage reservoirs and flow diversion structures. The area envisaged to be covered under irrigation is of the order over 10000 hectare.
Medium project: These are also surface water projects but with medium size storage and diversion structures with the area under irrigation between 10000 hectare and 2000 hectare.
Minor project: The area proposed under irrigation for these schemes is below 2000Ha and the source of water is either ground water or from wells or tube wells or surface water lifted by pumps or by gravity flow from tanks. It could also be irrigated from through water from tanks.

The major and medium irrigation projects are further classified as

Direct irrigation method
Storage irrigation method.

Each of the two classifications is explained in subsequent sections. But before that, it may be worthwhile to discuss here a few terms related to irrigation projects which may also be called irrigation schemes.

Direct and Indirect (Or Storage) Irrigation Methods

Direct Irrigation method

In this project water is directly diverted from the river into the canal by constructing a diversion structure like weir or barrage across the river with some pondage to take care of diurnal variations.
It also effects in raising the river water level which is then able to flow into the offtaking channel by gravity.
The flow in the channel is usually controlled by a gated structure and this in combination with the diversion structure is also sometimes called the headworks.

Storage Irrigation Method

For this type of irrigation schemes part of the excess water of a river during monsoon which other wise would have passed down the river as a flood is stored in a reservoir or tank found at the upstream of a dam constructed across a river or stream.
This stored water is then used for irrigation is adopted when the flow of river or stream is in excess of the requirements of irrigated crops during a certain part of the year but falls below requirements or is not available at all in river during remaining part of the year.
Since the construction site of a storage reservoir is possible in regions of undulating topography, it is usually practiced in non deltaic areas.

Irrigation Project Structures

As might have been noticed from the irrigation scheme plans in the previous section, a number of structures are required for the successful implementation of a project. Some of these are:

Storage structure and appurtenant works

Dams
Spillways and energy dissipators
Sluices and outlets

Diversion structure and appurtenant works

Barrage (weirs are not commonly used these days for sizeable projects)
Canal head regulator
River training works
Canal water conveyance structures
Canal sections and layout
Cross regulators
Drops
Turnouts

Surface Irrigation Methods

In this system of field water application the water is applied directly to the soil from a channel located at the upper reach of the field.
It is essential in these methods to construct designed water distribution systems to provide adequate control of water to the fields and proper land preparation to permit uniform distribution of water over the field.
One of the surface irrigation method is flooding method where the water is allowed to cover the surface of land in a continuous sheet of water with the depth of applied water just sufficient to allow the field to absorb the right amount of water needed to raise the soil moisture up to field capacity.
A properly designed size of irrigation stream aims at proper balance against the intake rate of soil, the total depth of water to be stored in the root zone and the area to be covered giving a reasonably uniform saturation of soil over the entire field.
Flooding method has been used in India for generations without any control what so ever and is called uncontrolled flooding.
The water is made to enter the fields bordering rivers during folds.
When the flood water inundates the flood plane areas, the water distribution is quite uneven, hence not very efficient, as a lot of water is likely to be wasted as well as soils of excessive slopes are prone to erosion.
However the adaptation of this method doesn’t cost much.

The flooding method applied in a controlled way is used in two types of irrigation methods as under:

Border irrigation method
Basin irrigation method

As the names suggest the water applied to the fields by this inundates or floods the land, even if temporarily. On the other hand there are many crops which would try better if water is applied only near their root zone instead of inundating.

Border irrigation

Borders are usually long uniformly graded strips of land separated by earth bunds (low ridges).
The essential feature of the border irrigation is to provide an even surface over which the water can flow down the slope with a nearly uniform depth.
Each strip is irrigated independently by turning in a stream of water at the upper end.
The water spreads and flow down the strip in a sheet confined by border ridges. When the advancing water reaches the lower end of the border, the stream is turned off.
For uniform advancement of water front the borders must be properly leveled. The border shown in the figures above are called straight borders, in which the border strips are laid along the direction of general slope of the field.
The borders are sometimes laid along the elevation contours of the topography when the land slope is excessive. Thos method of border is called contour border method of irrigation

Basin Irrigation

Basins are flat areas of land surrounded by low bunds. The bunds prevent the water from flowing to the adjacent fields.
The basins are filled to desired depth and the water is retained until it infiltrates into the soil. Water may be maintained for considerable periods of time.
Basin method of irrigation can be formally divided into two, viz; the check basin method and the ring basin method.
The check basin method is the most common method of irrigation used in India.
In this method, the land to be irrigated is divided into small plots or basins surrounded by checks, levees (low bunds)

Furrow Irrigation

Furrows are small channels, which carry water down the land slope between the crop rows.
Water infiltrates into the soil as it moves along the slope. The crop is usually grown on ridges between the furrows.
This method is suitable for all row crops and for crops that cannot stand water for long periods, like 12 to 24 hours, as is generally encountered in the border or basin methods of irrigation

Subsurface irrigation methods

As suggested by the name, the application of water to fields in this type of irrigation system is below the ground surface so that it is supplied directly to the root zone of the plants.
The main advantages of these types of irrigation is reduction of evaporation losses and less hindrance to cultivation works which takes place on the surface.
There may be two ways by which irrigation water may be applied below ground and these are termed as:

Natural sub-surface irrigation method
Artificial sub-surface irrigation method

Sprinkler Irrigation System

Sprinkler irrigation is a method of applying water which is similar to natural rainfall but spread uniformly over the land surface just when needed and at a rate less than the infiltration rate of the soil so as to avoid surface runoff from irrigation.
This is achieved by distributing water through a system of pipes usually by pumping which is then sprayed into the air through sprinklers so that it breaks up into small water drops which fall to the ground.
The system of irrigation is suitable for undulating lands, with poor water availability, sandy or shallow soils, or where uniform application of water is desired.
No land leveling is required as with the surface irrigation methods.
Sprinklers are, however, not suitable for soils which easily form a crust.
The water that is pumped through the pump pipe sprinkler system must be free of suspended sediments.
As otherwise there would be chances of blockage of the sprinkler nozzles.

Drip Irrigation System

Drip Irrigation system is sometimes called trickle irrigation and involves dripping water onto the soil at very low rates (2-20 litres per hour) from a system of small diameter plastic pipes filled with outlets called emitters or drippers.
Water is applied close to the plants so that only part of the soil in which the roots grow is wetted, unlike surface and sprinkler irrigation, which involves wetting the whole soil profile.
With drip irrigation water, applications are more frequent than with other methods and this provides a very favourable high moisture level in the soil in which plants can flourish.

Telangana Micro Irrigation Project

“Each drop of water is precious. Government is committed to giving high priority to water security. It will complete the long pending irrigation projects on priority and launch the ‘Pradhan Mantri Krishi Sinchayee Yojana’ with the motto of ‘Har Khet Ko Paani’.
There is a need for seriously considering all options including linking of rivers, where feasible; for ensuring optimal use of our water resources to prevent the recurrence of floods and drought.
By harnessing rain water through ‘Jal Sanchay’ and ‘Jal Sinchan’, we will nurture water conservation and ground water recharge. Micro irrigation will be popularised to ensure ‘Per drop-More crop’

TELANGANA STATE MICRO IRRIGATION PROJECT (TSMIP)

Micro Irrigation Project (MIP), a unique and comprehensive project, launched in November 2003 with an objective of enhancing the crop productivity by improving the water use efficiency, Fertilizer, Labour efficiency etc., through Micro Irrigation Systems.
So far in Telangana 5.01 lakh nos of farmers covered with an area of 4.79 lakh ha by utilizing Rs.2074.72 crores up to 2013-14.
Presently 10.06 lakh ha potential area is available for micro irrigation in Telangana State.
During the year 2014-15 Micro Irrigation programme is implementing with 55,630 ha (Drip-39,700 ha, Sprinkler – 15,930 ha) in state

Annual Action Plan 2015-16

The total net area irrigated in Telangana 17.73 lakhs Ha
Tanks – 1.50 Lakh Ha.; Canals – 0.90 Lakh Ha; Ground Water – 15.25 Lakh Ha.(86%)
Area Covered under Micro Irrigation upto 2013-14 4.79 lakhs Ha
Area to be covered during 2014-15 0.55 Lakh Ha.
Balance potential area for Micro Irrigation 9.91 Lakhs Ha
Minium 18 years is required to cover the balance area
85% of farmers of the State are SF and MF and are mostly dependent on Ground water irrigation.
Soils are mostly Chalka and gravel type with poor water retention capacity.
Keeping in view of the above facts, 1 Lakh Ha.
Area is proposed in Action plan 2015-16

Drip Irrigation 75,000 Ha +
Sprinklers Irrigation 25,000 Ha
Subsidy Rs.806.25 Crores

Hydropower Projects in Telangana

S. No.	Name	District	Basin	River
1	Nagarjunasagar Hydroelectric Project	Nalgonda	Krishna	Krishna
2	Nagarjunsagar Tail Pond Hydroelectric Project	Bellary	Krishna	Krishna
3	Nizamsagar Hydroelectric Project	Hyderabad	Godavari	Godavari
4	Pochampad Hydroelectric Project	Nizamabad	Godavari	Godavari
5	Priyadarshini Jurala Hydroelectric Project	Mahabubnagar	Krishna	Krishna
6	Singur Hydroelectric Project	Medak	Godavari	Majeera
7	Srisailam Hydroelectric Project	Mahabubnagar	Krishna	Krishna

Nagarjunasagar Hydroelectric Project

S. No.	Attribute	Value
1	Hydroelectric Project Name	Nagarjunasagar Hydroelectric Project
2	Hydroelectric Project Name Alias
3	State	Telangana, Andhra Pradesh
4	Districts	Nalgonda
5	River	Krishna
6	Basin	Krishna
7	Hydroelectric Region	Southern HE Region
8	Total Installed Capacity (MW)	968.6
9	Type of Project	Major (> 25 MW)
10	Hydroelectric Project Status	Completed
11	Purpose	Hydroelectric
12	Owner	State
13	Owner Name	APGENCO

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