Water resource engineering civil engineer

1. Water Resources Engineering
 Introduction
 Elementary Hydrology and Hydrological cycle
 Watershed Development, Objectives and Components
 Water requirements and its conservation
 Sources of Water
 Hydraulic structure of storage
 Specific terms of Hydrology
Introduction:
Water is an essential requirement for human life, plants and animals. Life cannot exist
without water. It is the natural free gift to the human. It is available in various forms such as
rivers, lakes, streams etc. the demand of water is increase everyday and available sources of

2. water in form of rain is more or less constant. Therefore now days, it becomes necessary to
maintain, conserve and uses these resources very carefully.
Elementary Hydrology and Hydrological cycle:
Hydrology is referring as a science which deals with rainfall, rainfall losses, surface runoff
and other water surveys.
Hydrology is also referring as deals with behavior and distribution of water in atmosphere
and on the earth.
Hydrological cycle
 As shown in fig., Evaporation can be take place from the surface of oceans and clouds
are formed.
 Due to condensation of clouds, rain or snow will be fallen over the land.
 The few portion of rain or portion of melted snow penetrates into the soil and
remaining portion move across the land as surface runoff.

3.  The surface runoff flows down the slopes and converted into the various streams and
discharge into the river.
 The few portion of rain or melted snow which are penetrates into the soil is join with
the underground water and increase the level of underground water.
 The river water flows towards the oceans and again evaporation can be take place
from the surface of the oceans as well as the soil moisture which is transpired by
plants and trees enters the atmosphere in form of vapour and this cycle is again
repeated.
 The science of hydrology is concerned with the quantity of available water and play
important role in the considerations of water resources.
 Hydrological cycle links up all the components of the hydrosphere into the single unit.
Hydrosphere indicates the aqueous envelop of the earth and it includes oceans, rivers,
lakes, well, soil moisture and water vapour in the atmosphere.
Watershed Development, Objectives and Components:
 A watershed can be defined as the catchment area of a particular stream or river. It
also refers as the area from where the water to a particular drainage system like a
river, pond and streams comes from.
Catchment area is the area through which the rain water drains from starting point to any
point on the river or stream.
 Watershed development refers to the conservation, regeneration and the judicious use
of natural resources like land, water, plants and animals.
 People and environment are interdependent to each other. Any change in surrounding
environment directly affects the people living therein.
 Watershed development is an art and technique which try to make best possible
balance between natural resources and human being in the environment.
 A proper watershed development is very essential in India to meet future requirement
of water for entire year. (As India is an agricultural country and we get rain during
monsoon season only. Hence lots of storage required to meet the requirement for
irrigation as well as domestic purpose.)
 Watershed development is comprehensive, integrated approach of land and water
resources management.
 The watershed area can be easily found from counter maps.
Objectives of Watershed developments:
 Improve the ability of the land to hold the water
 To encourage restoration of ecological balance
 To conserving soil and water

4.  To control desertification
 To promote economic development of village community
 To increase crop yield and mitigate the adverse effects of drought on crops and
livestock’s
Components of watershed development:
The main components of watershed development are:
1. Human Resource Development
2. Soil and land management
3. Crop and water management
4. Afforestation
5. Rural energy management
6. Livestock management
 Human Resource Development:
Awareness training about watershed development through NGO, VWC (Village water
committee) is provided to farmer.
 Soil and land management:
The soil conservation method should be adopted in the catchment area. The soil
erosion can be decreased by intercepting the erosive power of wind, rain etc., by
decreasing the slope of the land, by increasing the roughness of the land surface, by
vegetative covers etc.
Agricultural land should be properly leveled to obtain uniform growth of plants with
optimum quantity of water. Along the slope of the hilly area, contour bunds or terrace
bunds should be constructed at different levels. The deep ploughing by tractor is much
efficient.
 Crop and water management:
The crop rotation should be practiced for maintaining fertility of the land for
obtaining maximum yields with minimum supply of water
Water management should be for proper utilization of water by cultivators.
 Afforestation:
To reduce soil erosion and greening aspects growth of plantations or tree in water area
or restricted area is preferable
 Rural energy management:
By replacing traditional fuel sources, local degradation of environment should be
prevented.
 Livestock management:
The livestock (like cows, bullock, sheep, goats etc.) population can be grow by
constructing small structure which provides water availability and by taking steps for
their food and health.

5. Water requirements and its conservation:
Water requirements for different uses
Domestic purpose Irrigation purpose Hydropower Navigation
Water required for
bathing, cooking,
washing etc. for
daily uses
Water required for
proper growth and
maturity of the crops
Hydropower required
to generate the
electricity by using
energy of flowing
water
It is the cheapest
means of transport
without any
consumption of
water
Water required per
day per capita
Domestic use:
135 lit/day/person
Industrial use:
50 lit/day/person
Commercial use:
20 lit/day/person
Public utility:
10 lit/day/person
Water losses:
55 lit/day/person
Total:
270 lit/per/person
Certain quantity of
water required for
every crop
Continuous flow of
water required to
ensure continuous
production of
hydropower
To sustain
downstream flow
for navigation,
water should be
released from
storage reservoir
The water requirement
may vary from soil to
soil, crop to crop and
from period to period
Total water required
for public supplies
=Design population
*Per capita
demand*365
Needs for water conservation:
Life on the earth cannot be sustained without water. The demand for fresh water is increased
everyday and an available source of good water is in form of precipitation of rain water only
which is more or less constant. The fresh water available on the land surface is in forms of
rivers, lakes, reservoirs etc. and it is also more or less constant. Therefore, conservation of
fresh water is prime need and hence efforts are required in this area.
Following are general efforts for water conservation
1. New techniques should be found out for reducing water requirements of industries
against high water demand.

6. 2. Local bodies should install water meters to prevent misuse of water. (Like leakage of
water, turn off tape when not in use.)
3. The dumping of sewage in to the natural water resources should be prevented.
4. By reducing evaporation losses, conveyance losses, seepage losses, infiltration losses
etc.
5. To construct a series of small dams on tributary streams.
6. Use drip irrigation method
7. Use lined canals which reduce seepage.
8. Install waste water treatment plant so waste water should be recycled and used for
other purpose.
9. Use such cooling system which uses less water.
Sources of water:
 The basic sources of water in India are rainfall or snowfall. About 71% of the earth
surface is covered with water. Total volume of the water in hydrosphere is estimated
to be 1.4 billion km3; out of these 97% are ocean water and 3% fresh water.
 The available fresh water is continuously collected, purified and distributed through
hydrological cycle.
 The available fresh water comes from:
1. Surface water sources
2. Ground water sources
 Surface water sources: 1. Lakes, 2. Ponds, 3. Rivers, 4. Storage Reservoirs.
 Lakes:
A natural lake represents a large body of water within the land. The catchment
area of lake is very small and hence quantity of water available is very low. So
lake consider as source of water supply for small towns. The water available
from lake is generally free from undesirable impurities and can be safely used
for drinking purpose.
 Pond:
A pond is smaller than a lake and it is manmade body. A pond is formed due
to excessive digging of ground. The quantity of the water stored is very small
compare to lake and contain many impurities, hence not used for drinking
purpose. It only used for washing of clothes, animals etc.
 River:
River is important sources of water. The water which does not evaporate it
runs -off the surface through river. Large River is main source of water supply
for many cities. The river water contains silts and suspended impurities so it
required treatment before drinking purpose. The rivers are generally fed by
rains. The dam is constructed over Perennial River when water is used for
multiple uses. The weir is generally constructed on a non perennial river to
store water for water supply in winter and summer season.
 Storage reservoirs:

7. An artificial lakes formed by the construction of dams across a valley or river
is termed as storage reservoir. The water stored in the reservoir can be used for
multiply purpose. The quantity of water stored in the reservoir is same as lake.
It is suitable for drinking and water supply for small cities.
Hydraulic structure of storage (Only dam):
A dam is a hydraulic structure constructed over a river or natural streams to store water on its
upstream side. It is an impervious barrier put across a river.
 Gravity dam:
 It is a concrete structure with its cross sectional approximately in triangular
shape
 The self of the dam resist the forces which are exerted on it
 These types of dam is permanent ones, less maintenance and most commonly
used.
 It is suitable for any height
 The various forces like water pressure, self weight, wave pressure, silt
pressure, uplift pressure, earthquake force etc. are acting on foundation.
 Gravity dams are particularly used across narrow openings between hills with
very steep side slopes.
 Earthen dam:
 It is made of locally available materials such as soils, gravels etc. and
therefore are most economical
 These types of dam usually provided for sites where suitable foundation at
reasonable depth may not be available.
 Now days, it is more common even for higher height with advance knowledge
of soil mechanics.
 Ukai dam or Tapi River is an example of earthen dams.
 Rockfill dams:
 A rockfill dam is an embankment which uses variable sizes of boulders or
rocks to provide stability and an impervious membrane to provide water
tightness.
 Recently composite earth and rockfill type of embankment dams are widely
adopted.
 Tehri dam across river Bhagirathi is example of composite dam with height
261m.
 Arches dam:
 A dam which is constructed in form of an arch supported on abutments is
called arch dam.

8.  It is curved in plan and carries a major part of its water pressure horizontally
to the abutments by arch action. The abutment of an arch should be very
strong.
 It is masonry or concrete dam.
 It is suitable for V- shaped valley.
 Buttress dams:
 A buttress dam consists of a number of buttresses or piers dividing the space
into a number of spans.
 To store the water between these buttress, panels are constructed of horizontal
arches or flat slabs.
Special Terms:
 Precipitation: Condensed water vapour that falls to the earth surface in the form of
rain, snow, sleet etc. is known as precipitation
 Run-off: The ways by which water moves across the land is called as runoff
 Surface run off: The net quantity of rain water which remains on the surface of the
earth after all rainfall losses ( rainfall losses in form of evaporation, Infiltration,
Evapotranspiration) termed as surface runoff
 Infiltration: the rain water which is percolates below ground is known as infiltration.
 Evapotranspiration: Evapotranspiration means evaporation+ Transpiration
Evaporation means a process through which water on ground surface or lake can
return to the atmosphere as vapour
Transpiration means water used by plants may return to atmosphere as vapour through
transpiration which occurs when water passes through leaves.