This presentation highlights the occurrence of floods in India as a part of Environmental Studies. A brief idea about traditional methods of water management and the phenomenon of bio-precipitation is also included. Various sources from the internet were referred during this compilation.

1. -Krutika Deshpande

2. Introduction
 A flood is an overflow of water that submerges land
that is usually dry.
 The word "flood" comes from the Old English word
“flod”.
 Floods are an area of study of the discipline hydrology
and are of significant concern in agriculture, civil
engineering and public health.
 Hydrology is the scientific study of earth’s water and
its movement in relation to land.

3. Principle types of floods
 Areal: Floods in flat or low-lying areas like floodplains
or local depressions.
 Riverine (Channel): Floods occurring in all types of
rivers, streams and channels.
 Estuarine and coastal: Flooding in estuaries
with combination of sea tidal surges.
 Urban flooding: Particularly in more densely
populated areas.
 Catastrophic: Associated with major infrastructure
failures.

4. Effects of Floods
1) Primary effect:
 It includes loss of life and damage to buildings,
structures, including bridges, sewerage canals,
roadways, canals.
 They damage power transmission and power
generation.
 Loss of drinking water treatment and water supply
results in loss of drinking water or severe water
contamination.
 They raise the risk of waterborne diseases which
include typhoid, giardia, cryptosporidium,cholera,etc.

5. Effects of Floods
2)Secondary effects:
 Economic hardship due to a temporary decline in
tourism, rebuilding costs, or food shortages leading to
price increases is a common after-effect of severe
flooding.
 The impact on those affected may cause psychological
damage to those affected, in particular where deaths,
serious injuries and loss of property occur.

6. 2019 Indian Floods
 Eleven states of India were affected by floods due to heavy
rains in July-September 2019. At least 50 people died and
about a million people were displaced due to it.
 More than 5,300 personnel of the National Disaster
Response Force (NDRF) were deployed for relief and rescue
missions along with personnel of State Disaster Response
Force (SDRF) and local police in each state. Several
columns of Indian Armed Forces were also deployed. The
NDRF rescued over 42,000 people in six states (Kerala,
Karnataka, Maharashtra, Andhra Pradesh, Madhya Pradesh
and Gujarat).

9. Causes for Man made floods

10. Infrastructural failures
 Floods can be caused by a breaking or failure of
infrastructure that can cause large quantities of water
to flood a local area.
 Another example is when dams break due to faulty
construction or maintenance, or when they are
overwhelmed due to heavy precipitation.

11. Development and infrastructure in
flood-prone areas
 The development and building of infrastructure in
flood-prone areas, such as along rivers, near ocean
shorelines, or near river deltas, has led to an increase
in vulnerability to flooding because the natural
resiliency of these ecosystems has been compromised.

12. Deforestation
 When deforestation occurs in a particular area, there
are no more trees help soak up the precipitation and
prevent flow of water over the landscape. Without
these natural protections, there is an increased risk of
flooding and erosion whenever it rains.

14. Impermeable surfaces
 In developed areas, such as in urban areas, there is
commonly a large amount of impermeable surfaces
like roads and other concrete structures that do not
allow water to permeate back into the soil.
 When large amounts of rain falls on these
impermeable surfaces, the water can accumulate and
lead to flooding in low-lying areas if it is not directed
properly.

15. Bridge constriction
 Sometimes, bridges that have been built over rivers
can slow the discharge of water and reduce the river’s
capacity to hold more water.

16. Flood embankments
 Flood embankments that are intended to increase the
water-holding capacity of rivers can potentially
prevent flood water from draining back into the rivers
during large precipitation events.

17. Climate change
 Due to an increased level of human-
produced greenhouse gases in the atmosphere, the
world’s climate is changing and getting warmer.
Among many other climate change impacts, some
regions are now experiencing increased precipitation
and flooding.
 As melting of the world’s glaciers occurs due to warmer
global temperatures, sea level rise is occurring around
the world, also leading to an increased risk of flooding
in low-lying coastal regions and in heavily urbanized
floodplains such as the Ganges-Brahmaputra.

18. Measures to prevent floods

19. Measures to prevent floods
 In places with frequent flooding, construction and
development should be restricted.
 If not possible, infrastructure must be suitably built to
tackle it. Flood resilience involves waterproofing homes
and businesses.
 Laws against faulty dam construction should be made
severe to prevent loss of life due to negligence.
 Infrastructure related with water bodies must be well
maintained according to the weather forecast.
 Advance warning and pre-planning can
significantly reduce the impact from flooding.

20. Measures to prevent floods
 By restoring natural ecosystems, such as wetlands and
coastal ecosystems such as Mangrove forests, we will
restore some of nature’s capacity to deal with flood events.
 By planting trees and reforesting areas that have been
deforested, we can restore the landscape’s ability to take up
and store precipitation.
 Remeandering straightened rivers by introducing their
bends once more increases their length and can delay the
flood flow and reduce the impact of the flooding
downstream.

21. Measures to prevent floods
• When we engage in development, our development must
incorporate permeable surfaces that allow water to
recharge groundwater supplies, instead of simply allowing
precipitation to runoff and flood vulnerable areas.
• Percolation trenches can be used to manage runoff on sites
with limited space.

22. Measures to prevent floods
 By moving forward with a sustainable future where only
clean energy is used, and by working with Nature’s
limits in our own daily lives, we can ultimately help to
reduce the risk of flooding as greenhouse gases are
reduced and we strive to turn the tide of a warming
planet.
 We can plant trees in urban areas and intentionally
develop parks and reserves for natural ecosystems that
retain the ability to take up rainwater and other
precipitation.

23. Socio-Hydrology
 It is an interdisciplinary field studying the dynamic
interactions and feedbacks between water and people.
 It includes the historical study of the interplay
between hydrological and social processes,
comparative analysis of the co-evolution and self-
organization of human and water systems in different
cultures, and process-based modeling of coupled
human-water systems.

24. Water resource management
 Water resource management is the activity of
planning, developing, distributing and managing the
optimum use of water resources.
 It adapts to the current and future issues facing the
allocation of water influenced by the growing
uncertainties of global climate change.
 Eg: Urban Decision Support System–is a wireless
device with a mobile app that uses sensors attached to
water appliances in urban residences to collect data
about water usage and is an example of data-driven
urban water management.

25. Integrated water resource management
 Political will and commitment: Political will at all levels can
help unite all stakeholders and move the process forward.
 Basin management plan and clear vision: Water
resources development coordinated among various sectors and
users is facilitated by the preparation of a master plan that
reflects the individual sector plans and offers the most effective
and efficient utilization of the resource.
 Participation and coordination mechanisms, fostering
information-sharing and exchange: The identification of key
stakeholders can be facilitated through interviews and meetings.
Initial sharing of general basin-wide data and information, and
further sharing of more specific information, will assist the self-
sustaining system.

26. Integrated water resource management
 Capacity development: Capacity development and training
priorities should be expressed at all levels, including that of
decentralized local government
 Well-defined flexible and enforceable legal frameworks
and regulation: It is necessary to assemble and review the full
range of existing laws and regulations that apply to water-related
activities and determine how existing legislation adapts or can
be better adapted to accommodate sustainability and integration
with regard to water resources management.
 Water allocation plans: As water is a shared resource, water
rights should be flexible in terms of allocation in order to
accommodate changes. Preparing a master plan that reflects
individual sector plans facilitates the coordination among
various sectors and advocates the most appropriate utilization of
a basin’s resource.

27. Integrated water resource management
 Adequate investment, financial stability and sustainable cost
recovery: Various combinations and roles of international financing
and donors such as government grants, public resources, user charges
and taxes, donor funds, basin environmental trust funds can be
considered as funding options.
 Good knowledge of the natural resources present in the
basin: Adequate knowledge and information on the water
resources inventory and human resources of the basin is desirable.
Including scientists as water resource managers can help maintain and
accrue sound knowledge of the natural resources.
 Comprehensive monitoring and evaluation: Monitoring and
evaluation are essential for ensuring that the current management
of water resources is properly implemented, and to identify the needs
for adjusting management strategies. Upgrading new technologies is
vital for effective performance both of local and central water
management.

28. Traditional water conservation systems

29. Jhalara
 Jhalaras are typically rectangular-shaped stepwells that
have tiered steps on three or four sides. These
stepwells collect the subterranean seepage of an upstream
reservoir or a lake.

30. Bawari
 Bawaris are unique stepwells that were once a part of
the ancient networks of water storage in the cities of
Rajasthan.

31. Johads
 Constructed in an area with naturally high elevation
on three sides, a storage pit is made by excavating the
area, and excavated soil is used to create a wall on
the fourth side.

32. Kund
 A kund is a saucer-shaped catchment area that gently
slope towards the central circular underground well.

33. Baoli

34. Baoli
 These beautiful stepwells typically have beautiful
arches, carved motifs and sometimes, rooms on their
sides.
 Baolis within villages were mainly used for utilitarian
purposes and social gatherings.
 Built by the nobility for civic, strategic or philanthropic
reasons, baolis were secular structures from which
everyone could draw water.

35. Pat System
 Diversion bunds are made across a stream near the
village by piling up stones and then lining them with
teak leaves and mud to make them leak-proof.

36. Bioprecipitation
 The term bioprecipitation refers to the role bacteria play as
causative agents of precipitation via ice nucleation.
 P. syringae has been implicated as an atmospheric
"biological ice nucleator“.
 The accepted precipitation model is that soot, dust and
other inert things form the nuclei for raindrops and
snowflakes.
 P. syringae also produces ice nucleation active (INA)
proteins which cause water (in plants) to freeze at fairly
high temperatures (-4 to -2 °C).
 InaZ is thought to promote ice formation by being a
template for ice crystals.

37. Bioprecipitation
 Recent research suggests that bacteria may be present in
clouds as part of an evolved process of dispersal. It has
been suggested that the bacteria are part of a
constant feedback between terrestrial ecosystems and
clouds. Recent evidence has suggested the species plays a
larger role than previously thought in
producing rain and snow.
 Clouds play a vital role in driving the climate system and
bacteria could therefore be considered as climate altering
factors.
 Many ski resorts use a commercially available freeze-
dried preparation of ice-nucleating proteins derived from
the bacterium species Pseudomonas syringae to make snow
in a snow gun.