FLOODS , CAUSES
& SOLUTION AND RIVER LINKING
More than 15% Rainfall deficiency
throughout India and Floods in Assam & Bihar
A flood is an overflow of water on land. Sometimes a river
might receive extra water, either from heavy rains or other natural disasters.
When this happens, the water overflows from its normal path in the river bed
and onto the dry land. This is called a flood.
Flash floods happen quickly. Extreme flooding can also be caused by a
tsunami or a large storm that will cause the sea to surge inland.
The most deadly flood was in 1931 in China and it had killed about
There are several causes of floods and they differ
from region to region. The causes may vary from a rural area to an urban area.
Some of the major causes of floods in India are given below.
Heavy rainfall: It is the
primary cause for floods in India. Especially, rainfall in a short span of time
is of much concern as they are leading to flash floods. For instance, in July ,
Mount Abu received the heaviest rainfall in over 300 years in a span of 24
hours. The hill station received an unprecedented 700 mm of rain in 24
As per a study instituted by the United Nations,
climate change phenomenon is believed to be behind flash floods across the
Siltation of the Rivers: Heavy
siltation of the river bed reduces the water carrying capacity of the rivers
and streams leading to flooding. For instance, as a result of siltation, the
Brahmaputra has been expanding – ranging from 2 km to 14 km – leading to
frequent flooding in the North East region.
Blockage in the Drains: Blocked
drains are the primary cause for the floods in urban areas, especially in
metros. For instance, failure of the drainage system is believed to be one of
the primary causes behind the Chennai floods in December 2015 that led to the
death of more than 400 people.
Landslides: They are
the major reason behind floods in hilly areas of the north and northeast. For
instance, in June 2013, landslides caused a blockage of flow of streams and
rivers in Uttarakhand and caused major floods, causing 5748 deaths.
Apart from the above reasons, natural hazards like
cyclones and earthquakes and encroachments of river banks and water bodies
Control Measures and Related Problems:
government has taken various steps to check or minimise the damage caused by
have been built as part of multi-purpose projects over several flood-prone
rivers. Some of these reservoirs are Konar, Panchet, Maithan and Tilaiya on
Damodar River, Hirakud on Mahanadi, Bhakra on Satluj, Pong on Beas, Ukai on
Tapti, Nagarjuna Sagar on Krishna.
drainage channels have been constructed to protect towns and land in
measures include collection of hydrological data and installation of flood
warning systems. These measures, however, have their share of drawbacks and do
not, in themselves, provide a comprehensive solution to the menace of flood.
construction of storage reservoirs is not enough.
conservation measures, upstream of the reservoir and around it, are required to
prevent silting of reservoirs through soil erosion. Silting reduces water
holding capacity of reservoirs, thus reducing their efficiency in absorbing the
overflow of flood water. According to a study, the rate of sedimentation of
reservoirs in India is three times the estimated rate (i.e., estimated when
they were built).
This has reduced
the life of reservoirs in India to one-third. Also, in case the floods are caused
by heavy rains in the downstream areas, the reservoirs are not effective. For
instance, in Punjab in recent years, the Bhakra and Pong reservoirs have hardly
been filled to capacity, while torrential rains caused, floods down streams,
affecting nearly half the state’s population.
are not a scientific solution:
Embankments are an
.unnatural way to check the flow of water. Often, the river level is above the
surrounding surface in case of an embanked stream, because silt gets
accumulated in the riverbed, instead of spiffing over onto the flood plain. The
flood plain, as a result, is deprived of fertile silt, year after year.
Also, in case a
breach occurs in a part of the embankment, the water will gush out at a very
high speed and cause more damage than a slowly rising unbanked river in flood.
The siltation results in floods even if there is moderate rainfall in the
catchment areas. The protection provided by embankments is unstable.
Zoning is a reliable and scientific method:
reservoirs and embankments, this is a ‘non-structural’ measure. This method is
based on the principle that, “where the river has the right of way, stays out
of its way”. Flood plain is the boundary or extent of the river movement about
its mean course. Topographically, it is lower than the surrounding areas and is
more prone to flooding.
means demarcating such zones and preventing indiscriminate development and
human settlement in such areas. In 1957, the Central Flood Control Board had
mooted the idea of demarcating flood zones and the measures to prevent
indiscriminate development and settlement in such areas. In 1975, the central
government circulated a model bill containing such provisions.
It also provided
for setting up of flood zoning authorities in all the states to take up surveys
and demarcation of flood zones or plains. It recommended legislative support to
prohibit the use of flood plains and removal of unauthorised constructions.
most states are yet to take the desired steps under pressure from influential
builders, developers and other vested interests. States, on the other hand, ask
for huge funds for relief measures and not much is done for long- term
protection of the flood-prone areas.
What is river linking/ Interlinking of
is a project of linking two or more rivers by establishing manually created
canals, and providing land areas that otherwise does not have river water
access and reducing the flow of water to sea using this means.
is based on the assumption that excess water in certain rivers can be diverted
to deficit rivers by establishing a channel network to interconnect the rivers
Drought prone Areas of India
In India Interlinking of River (ILR) programme is
of national importance and has been taken up on high Priority. The mission of
this programme is to ensure greater equity in the distribution of water by
enhancing the availability of water in drought prone and rain-fed area.
Inter-link project has been split into three parts: a northern Himalayan rivers
inter-link component, a southern Peninsular component and starting 2005, an
intrastate rivers linking component.
Under the National Perspective Plan (now called the National River
Linking Project )prepared by the Ministry of Water Resources, National Water
Development Agency (NWDA) has already identified 14 links
under Himalayan Rivers Component and 16 links under Peninsular Rivers
Component for inter basin transfer of water based on field surveys and
investigation and detailed studies.
of these, Feasibility Reports of 14 links under Peninsular Component and 2
links (Indian portion) under Himalayan Component have been prepared. Draft
Feasibility Reports of 7 link projects (Indian portion) of Himalayan
Component have also been completed
Flood prone areas of India
Various plans on River Linking in India
Organisations for River linking
The river linking project is being
managed by India’s National Water Development Agency (NWDA),
under its Ministry of Water Resources.
Advantages of River Linking
Hydropower generation: The river interlinking
project claims to generate total power of 34,000 MW (34 GW). Out of this,
4,000 MW will come from the peninsular component while 30,000 MW from the
Curb drinking water woes: The addition of hydropower is
expected to curb the drinking water woes of millions and supply water to
industries in drought-prone and water-scarce cities in south and west India
Irrigation: The river linking project claims to
provide additional irrigation to 35 million hectares (m ha) in the water-scarce western and peninsular regions.
Employment and Agriculture: In addition to irrigation the
project will further create employment, boost crop outputs and farm
incomes and multiply benefits through backward (farm equipment and
input supplies) and forward linkages (agro-processing industries). It may even
help for fishing.
Disadvantages of River Linking
Costs: The money planned to be spent on
the river linking project is not economically feasible to a country like India
Environmental: The environmentalists challenge
that the project lacks holistic assessment of socio-economic impacts such as
water-logging, salinisation and desertification. For example the Ken-betwa
river link project resulted in felling of more than 1.8 million trees and also
affected the Panna Tiger Reserve.
States acceptance: Many of the states are not
fully agreed with the river linking project as it may lead to the shortage of
water to upper basin state
Displacement of people: For the completion of
Interlinking River project, many big dams, canals and reservoirs will have to
be constructed due to which people around the land will be displaced.
Recent linking of rivers
Ken Betwa link project
aims to link the rivers of Ken and Betwa and transfer the surplus water
from Ken river to the betwa river through a canal to irrigate the
Bundelkhand region and it would benefit both Uttar Pradesh and madhya Pradesh
in terms of meeting irrigation drinking water and electricity needs of people
across 6 districts in the two states
link project has been declared as a National Project by the
Government of India
has received clearance from the Supreme Court of India, The National Board for
Wildlife (NBWL) and the Environmental clearance
Other projects under pipeline
Damanganga-Pinjal Link Project and
Par-Tapi-Narmada Link Project
of them are twin links concerning Maharashtra and Gujarat.
Damanganga-Pinjal Link Project benefits Maharashtra while Par-Tapi-Narmada Link
Project benefits Gujarat. The Detailed Project Reports of both links are ready.
Central Water Commission has completed techno-economic appraisal of
Damanganga-Pinjal Link Project while the techno-economic appraisal of
Par-Tapi-Narmada Link Project is in advance stage.
the governments of Maharashtra and Gujarat have finalized the MoU regarding the
Godavari-Cauvery(Grand Anicut) link
consensus on Mahanadi-Godavari and Godavari(Inchampalli)-Krishna link projects
due to large submergence involved, alternative studies have been carried out to
divert unutilized water share of Chhattisgarh State in Indravati sub-basin
in Godavari basin (as per GWDT award) to Cauvery through Godavari-Cauvery
link project. Technical Feasibility Note for this proposal was prepared and
sent to party states in 2017
Global examples of interlinking of
1. Rhine-Main-Danube canal
2. Illinois Waterway system
3. Tennessee–Tombigbee Waterway(USA)
4. Gulf Intracoastal Waterway(USA)
5. Dian Zhong Water Diversion
6. Murray–Darling basin(Australia)