Introduction+hydrology

Water Resource Engineering
Prepared by:-
Brijlata sharma
Assistant professor
JECRC Jaipur

VISION
To become a role model in the field of Civil
Engineering for the sustainable development of
the society.
MISSION
1) To provide outcome base education.
2) To create a learning environment conducive for
achieving academicexcellence.
3) To prepare civil engineers for the society with
high ethical values.

CIVIL ENGINEERING DEPARTMENT
Program Educational Objectives
1 To strengthen students with fundamental knowledge, effective
computing, problem solving and communication skills enable
them to have successful career in civil engineering.
2. To enable students in acquiring civil engineering’s latest
tools, technologies and management principles to give them
an ability to solve multidisciplinary engineering problems.
3. To impart students with ethical values and commitment
towards sustainable development in collaborative mode.
4. To reinforce students with research aptitude and innovative
approaches which help them to identify, analyze, formulate
and solve real life problems and motivates them for lifelong
learning.
5. To empower students with leadership quality and team
building skills that prepare them for employment,
entrepreneurship and to become competent professionals to
serve societies and global needs

Course Outcomes of WRE
CO 1 Various components of hydrologic cycle that affect
the movement of water in the earth.
CO 2 The concepts of movement of ground water beneath
the earth, Basic components of river Training works.
CO 3 The basic requirements of irrigation and various
irrigation techniques, requirements of the crops.
CO 4 Distribution systems for canal irrigation and the
basics of design of unlined and lined irrigation canals
design.
CO 5 Various Stream flow measurements technique,
Apply math, science, and technology in the field of water
resource Engineering.

Introduction
Definitions,
Water resources engineering is the quantitative
study of the hydrologic cycle -- the distribution
and circulation of water linking the earth's
atmosphere, land and water bodies. ...
Applications include the management of the
urban water supply, the design of urban
storm-sewer systems, and flood forecasting.

Functions And Advantages Of Irrigation
Definitions-Irrigation may be define as science of
artificial application of water to the land with the
crop requirement throughout the crop period.
Advantages Of Irrigation-
To increase food production.
It improves the yields of crops .
It improves the groundwater storage as water lost due to
seepage adds to groundwater storage.
We use it to help the growth of crops during the period
of inadequate rainfall.

DISADVANTAGES OF IRRIGATION
• Excessive seepage and leakage of water create
marshes and ponds all along the channels. The
marshes and the ponds in some time become
breeding areas for mosquitoes.
• It lowers the temperature and makes the locality
damp due to the presence of irrigation water.
• Excessive seepage into the ground raises the
water, hence causing waterlogging of the area.

classification for irrigation
1. Surface irrigation - flow, lift
2. Subsurface irrigation -

1 Surface irrigation
In surface irrigation, water moves over and
across the land by simple gravity flow to
wetland and infiltrate the soil.

2. Sprinkler irrigation
It is a popular method. Pipes carry some amount
of water to the fields and then sprays it directly
over the crops with high-pressure sprinklers.

3. Drip irrigation
With this type, the drip lines take water
near the root zone of plants and release
it drop by drop.

4. Center pivot irrigation
It involves a self-propelled system in
which a single pipeline moves on
wheeled towers in a circular pattern.

Indian crop seasons
The Kharif crops are rice, bajra, jowar,
maize, cotton, tobacco, groundnut, e.tc.
Rabi crops are wheat, barley, gram,
linseed, mustard, potatoes, etc
Summer crops
Winter crops
Zaid Crops pumpkin, cucumber, bitter groud.

Categories of Crops in India
 Food Crops (Wheat, Maize, Rice, Millets and
Pulses etc.)
Cash Crops-a crop which has to be encashed
in the market for processing, etc. as it cannot
be consumed directly by the cultivators.
(Sugarcane, Tobacco, Cotton, Jute and Oilseeds
etc.)
Plantation Crops (Coffee, Coconut, Tea, and
Rubber etc.)

HYDROLOGY
INRODUCTION-
. Hydrology means science of water.
. It is the science that deals with the
ccurance, circulation and distribution of
water on the earth.
. Hydrology is a broad subject of an inter-
disciplinary nature drawing support from
allied sciences.

HYDROLOGY DEALS WITH
• Estimation of water resources
• The study of processes such as precipitation,
runoff, evapotranspiration and their
interaction
• The study of problems such as floods,
droughts and strategies to combat them

ENGINEERING HYDROLOGY(APPLIED HYDROLOGY):
A study concerned with engineering applications
ENGINEERING HYDROLOGY APPLICATOINS:
• In design
• Operations of projects dealing with water supply
• Irrigation and drainage
• Water power
• Flood control
• Navigation
• Costal works
• Salinity control
• Recreational uses of water etc.

WATER FROM
OCEANS
ATMOSPHERE
GROUND
SUN
THE HYDROLOGIC CYCLE

THE HYDROLOGIC CYCLE:
 The hydrologic cycle is the general continuous circulation
of water from the oceans to the atmosphere, to the
ground and back to the oceas again.
 Sun is the main source of energy for hydrologic cycle.
 Let us consider the cycle begins with oceans

The various stages of hydrologic cycle are
 Evaporation
 Precipitation
 Infiltration
 Traspitation
It is a continuous process
Each path of hydrologic cycle may have one or more
of the following
 Trasportation of water
 Temporary storage
 Change of state

TYPES OF PRECIPITATION
PRECIPITATION
CONVECTIVE OROGRAPHIC CYCLONIC
NON-FRONTALFRONTAL
WARM FRONT COLD FRONT

FORMS OF PRECIPITATION:
 Rain
 Snow
 Drizzle
 Glaze
 Sleet
 Hail

RAINFALL MEASURMENT:
 Rainfall is expressed interms of the depth to which
rain water would stand on an area if allthe rain
were collected in it.
 Rainfall is measured by rainguage
 Rainguage is a cylindrical vessel assembly kept in
open to collect rain

 TYPES OF RAINGUAGE
TYPES OF RAINGUAGE
NON-RECORDING RAINGUAGE SELF RECORDING(AUTOMATIC)
SYMON’S GUAGE
STANDARD NON RECORDING
TYPE RAINGUAGE
•TIPPING BUCKET
•WEIGHING TYPE
•FLOAT TYPE
•TELEMETERING
•RADAR MEASURMENT

NON RECORDING TYPE RAINGUAGES:
 It does not record the rainfall directly but only
collect the rain water, which when measured gives
the total amount of rainfall at the given point of
time.

Precipitation gauge
1 - pole
2 - collector
3- support-
galvanized
metal sheet
4 – funnel
5 - steel ring
1. Non recording gauge

The graphic rain gauge
1-receiver
2-floater
3 siphon
4 recording needle
5drum with diagram
6-clock mechanism
The rainguages that automatically record the intensity of
rainfall over a period of time in the form of pen trace or a
clock driven chart.

COMPUTATION OF AVERAGE RAINFALL OVERA
BASIN:
 Inorder to compute the average Rainfall over a
basin or catchment area, the rainfall is measured at
a number of stations located in that area.
 If the basement area contains more than one
rainguage station then following methods are used
for computation of average rainfall.
 Arithmetic mean method
 Thiessen polygon method
 Isohytel method

Arithmetic mean method:
 Average rainfall is calculated by arithmetic average
of recorded rainfall at various stations of selected
area
 This is the simplest method of computing the
average rainfall over a basin. As the name
suggests, the result is obtained by the division of
the sum of rain depths recorded at different rain
gauge stations of the basin by the number of the
stations.
 iP
NN i1
P 
P1
N
1

 P2  ..... Pi .....Pn

Thiessen Polygon Method:
This is the weighted mean method. The rainfall is
never uniform over the entire area of the basin or
catchment, but varies in intensity and duration
from place to place. Thus the rainfall recorded by
each rain gauge station should be weighted
according to the area, it represents. This method is
more suitable under the following conditions:
- For areas of moderate size.
- When rainfall stations are few compared to the size
of the basin.
- In moderate rugged areas.

P 
P1A1  P2 A2  .....PmAm
A1  A2  ..... Am 

M
M
i
A
A
PP   i
i1
 Pi Ai
i1
Atotal
The ratio Ai/A is called the weightage factor of
station i

Thiessen Polygon Method Disadvantage:
The disadvantages of the
Thiessen method are its
inflexibility that is addition of
new station implies
construction of new polygon,
and it does not directly
account for
orographic influences of
rainfall.

isohyetal Method:
An isohyetal is a line joining places where the rainfall
amounts are equal on a rainfall map of a basin. An
isohyetal map showing contours of equal rainfall is
more accurate picture of the rainfall over the
basin. This method is more suited under the following
conditions:
- For hilly and rugged areas.
- For large areas over 5000 km2.
- For areas where the network of rainfall stations within
the storm area is sufficiently dense, isohyetal method
gives more accurate distribution of rainfall.

Isohyetal Method
• P1, P2, P3, …. , Pn – the values of theisohytes
• a1, a2, a3, …., a4 – are the inter isohytes area
respectively
• A – the total catchment area
• P - the mean precipitation over the catchment
A
a 




a
 
  
2
...a
22
Pn1Pn
n12
P1P2 P2P3
1
P 




 
m 
x
NM N N
N
P   ...
Pm
2
P

P2
1
x 1
 Before using rainfall data, it is necessary to check the
data for continuing and consistency
◦ Missing data
◦ Record errors
Estimation of Missing Data
• Given annual precipitation values – P1, P2, P3,… Pm
at neighboring M stations of station X 1, 2, 3 & m
respectively
• The normal annual precipitation given by N1, N2,
N3,…, Nm, Ni… (including station X)
• To find the missing precipitation, Px , of station X

Test for consistency record
• Let a group of 5 to 10 base stations in the
neighbourhood of the problem station X is selected
• Arrange the data of X stn rainfall and the average of the
neighbouring stations in reverse chronological order
(from recent to old record)
the average values of the group base stations
starting from the latest record.
as shown on the next
figure
• A decided break in the slope of the resulting plot is
observed that indicates a change in precipitation
regime of station X, i.e inconsistency.
• Therefore, is should be corrected by the factor shon on
the next slide
• Accumulate the precipitation of station X Px 
• Plot the Px  against Pavg 
and Pavg 

(Double mass curve techniques)
Double Mass Curve Analysis
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0 2.50.5 1 1.5 2
Accumulated annual rainfall of neigbouring stns in 10^3 cm
accumulatedannualrainfallofXstnin10^3cm

c
xcx
M
M
P  P
• a
•Mc

c Ma
a
• Pcx – corrected precipitation at any time period t1 at stationX
• Px – Original recorded precp. at time period t1 at
• station X
• Mc – corrected slope of the double mass curve Ma –

A few commonly used methods are
 Mass curve of rainfall
 Hytograph

0 – 8 8 – 16 16 – 24 24 – 32 32 – 40 40 – 48
Time, hours
Intensity,cm/hr
Hyetograph
- is a plot of the accumulated precipitation against time, plotted in
chronological order
Hyetograph of a storm
0.5
0.4
0.3
0.2
0.1
0

0 20 40 80 100 12060
Time, hour
accumulatedprecipitation,mm
Mass Curve of Rainfall:
The total accumulated percipitation is plotted against time
Mass curve of rainfall
60
50
40
30
20
10
0

RUNOFF:
It is a part of precipitation which is
transmitted through natural surface channels,
streams etc.
 Runoff is overlandflow and interflow which enters
stream immediately after precipitation
 Runoff includes



surface flow
interflow
groundwater flow

Runoff:
Runoff is defined as the portion of precipitation that
makes its way towards rivers or oceans as surface or
subsurface flow.

Classification of runoff according to source:
1. Surface runoff: Includes all overland flow as well as precipitation falling
directly onto
stream channels.
Overland flow: Portion of runoff that travels over the surface of the
ground to reach a stream channel and through the channel to the basin
outlet. This process occurs relatively quickly.
2.Subsurface runoff: Portion of runoff that travels under the ground to
reach a stream channel and to the basin outlet. It includes: a) interflow,
and b) groundwater runoff. Interflow: Portion of subsurface runoff that
travels laterally through the unsaturated zone or through a shallow
perched saturated zone towards a stream channel. This process is
slower than surface runoff.
Groundwater runoff: Portion of subsurface runoff that comes
from infiltration and subsequently percolation down to the water
table and eventually reaches a stream channel. This process
occurs relatively slowly

• Factors affecting Runoff:
1.Climate factors
a) Type of precipitation
b) Intensity of rainfall
c) Duration of rainfall
d) Area distribution of rainfall
e) Antecedent or Previous
precipitation
f) Other climatic factors that effect
• evaporation and
transpiration
2.Physiographic factors
a) Land use
b) Type of Soil
c) Area of the basin or catchment
d) Shape of the basin
e) Elevation
f) Slope
g) Orientation or Aspect
h) Type of drainage network
i) Indirect drainage
j) Artificial drainage

Estimation of Runoff:
1.Empirical Formulae (to find peak runoff)
a)Dicken’s formula
b)Ryve’s formula
c)Igles’s formula
d)Khosla’s formula
2.Rational Method
3.Unit Hydrograph Method

Runoff Calculations
Rational Formula:
This method was originally developed for urban catchments. Thus, the basic
assumptions for development of this method were made for urban
catchments. However, this method is fairly applicable to small agricultural
watersheds of 40 to 80 hectares size. The rational method takes into
account the following hydrological characteristics or processes: (1) rainfall
intensity, (2) rainfall duration, (3) rainfall frequency, (4) watershed area, (5)
hydrologic abstraction, and (6) runoff concentration.
Assumptions:
The Rational method is based on the assumption that constant intensity of
rainfall is uniformly spread over an area, and the effective rain falling on
the most remote part of the basin takes a certain period of time,
known as the time of concentration (Tc) to arrive at the basin outlet. If
the input rate of excess rainfall on the basin continues for the period of time
of concentration, then the part of the excess rain that fell in the most
remote part of the basin will just begin its outflow at the basin outlet and
with it, the runoff will reach its ultimate and the

RATIONAL METHOD
The Rational Method properly understood and applied can
produce satisfactory results for urban storm sewer and small on-
site detention design.
Rational Formula:
The Rational Method is based on the Rational Formula:
Q =CIA
Q = the maximum rate of runoff (cfs)
C = a runoff coefficient that is the ratio between the runoff
volume from an area and the average rate of rainfall depth
over a given duration for that area
I = average intensity of rainfall in inches per hour for a
duration equal to the time of concentration, tc
A = area (acres)

Factors affecting Evaporation:
Temperature - Warmer the evaporating surface, higher
the rate of evaporation.
Relative Humidity - drier air evaporates more water
than moist air
Wind Speed - When the winds are light, evaporation is
very low
Area of the Evaporating Surface – Larger areas of
evaporating surface increase the rate of evaporation
Air Pressure - Lower pressure on open surface of
the liquid results in the higher rate of
evaporation.
Composition of Water - Rate of evaporation is always
greater over fresh water than over salt water

Methods of measurement of evaporation:
A)Direct methods
Water Budget Technique
Lysimeter
oWeighing Type
oNon-weighing Type
B)Indirect methods
Aerodynamic method or Mass Transfer Method
Energy Budget Method
Penman Equation
Blaney & Criddle Method
Jensen Haise method
Hargreaves method or Pan Evaporation Method

Transpiration:
Transpiration is the process by which the water vapour
escapes from the living plant leaves and enters the
atmosphere.
Evapotranspiration
Evapotranspiration is the combined processes by
which water is transferred to the atmosphere from
open water surfaces and vegetation

Factors affecting Evapotranspiration
Climatological factors like percentage sunshine
hours, wind speed, mean monthly temperature and
humidity.
Crop factors like the type of crop and the percentage
growing season.
The moisture level in the soil.
Estimation of Evapotranspiration
Lysimeter
Class ‘A’ Pan Method
Penman Method
Hargreaves Method
Blaney & Criddle Method

Infiltration is the process of water entry into a soil from rainfall,
or irrigation.
Percolation is the process of water flow from one point to
another point within the soil.
Infiltration rate is the rate at which the water actually infiltrates
through the soil during a storm and it must be equal the
infiltration capacities or the rainfall rate, whichever is lesser.
Infiltration capacity is the maximum rate at which a soil in any
given condition is capable of absorbing water.
Infiltration

Factors affecting
infiltration
Condition of the land
surface (cracked,
crusted, compacted etc.)
Land vegetation cover
Surface soil characteristics
(grain size & gradation),
Storm characteristics
(intensity, duration &
magnitude)
Surface soil and water
temperature, chemical
properties of the water
and soil. Surface factors

Measurement of Infiltration
The rate of infiltration is initially high. It goes on reducing
with time and after some time it becomes steady. The
rate of infiltration for a soil is measured in the field as well
as in the laboratory. These are known as Infiltrometers
Types of Infiltrometers:
Flooding-type Infiltrometers
o Single-tube flooding Infiltrometers
o Double-tube flooding Infiltrometers
o Needle drip systems
oStand pipes
oSprinkler nozzles
oRotating boom
Sprinkling-type Infiltrometers or Rain Simulators

Infiltration indices:
The average
value of
infiltration is
called
Infiltration
Index.
Types:
ø - Index
W – Index
Where,
P = total storm precipitation (cm), R = total surface runoff (cm) ,
Ia = Initial losses(cm)
te = elapsed time period (in hours)

References
1. Madeeasy notes
2. https://www.nptel.ac.in › courses › 105 › 104
› 105104103
3. G. L. Asawa, Irrigation and Water Resources
Engineering.
4. B.C.Punmia, Irrigation and Water Power
Engineering

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