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© 2019, IJSRMS All Rights Reserved 1
International Journal of Scientific Research in _______________________________ Research Paper .
Multidisciplinary Studies E-ISSN: 2454-9312
Vol.5, Issue.8, pp.01-11, August (2019) P-ISSN: 2454-6143
Development of S Curve for Mini-Watershed of Raichur City Karnataka
Mohammed Badiuddin Parvez1
*, M Inayathulla2
1,2
Department of Civil Engineering, UVCE, Bangalore University, Bangalore, Karnataka, India
Corresponding Author: parvezuvce@gmail.com Tel.: +919060506390
Available online at: www.isroset.org
Received: 10/Jul/2019, Accepted: 24/Aug/2019, Online: 31/Aug/2019
Abstract- Unit Hydrograph (UH) is the most famous and generally utilized technique for analysing and deriving flood
hydrograph resulting from a known storm in a basin area. For ungauged catchments, unit hydrograph are derived using either
regional unit hydrograph approach. Central Water Commission (CWC) derived the regional unit hydrograph relationships for
different sub-zones of India relating to the various unit hydrograph parameters with some prominent physiographic
characteristics. The Study Area is located between Latitude 15º57′58′′ N to 16º11′25.6′′ N and 77º18′1′′ E to77º32′5.3′′ E
Longitude and covers area of 360.97 km2
, having maximum length of 26.17 km. The maximum and minimum elevation of the
basin is 533 m and 323 m above MSL, respectively. The Peak discharge of unit hydrograph obtained is 311.469 m3
/s. The final
cumulative discharge is 1458.55 m3
/s.
Keywords: Unit hydrograph, Flood hydrograph, Slope, Synthetic Parameter CWC.
I. INTRODUCTION
Flood estimation in ungauged catchment is one of the most
frequent applications of surface hydrology in general and
rainfall-runoff modelling in particular. The
geomorphological parameters are mostly time-invariant in
nature and therefore, geomorphology based approach could
be the most suitable technique for modelling the rainfall-
runoff process for ungauged catchments. Unit Hydrographs
have been proposed by several engineers as a tool to
simulate runoff hydrographs from rainfall for ungauged
catchments. Traditional techniques for design flood
estimation uses historical rainfall-runoff data for unit
hydrograph derivation. Such techniques have been widely
applied for the estimation of design flood hydrograph at
the sites of gauged Catchment. The estimation of design
flood hydrograph is easy if information about runoff at the
site is available. In cases where the available runoff data are
inadequate for the complete hydrologic analysis, for such
cases the available information of the nearby catchment or
the information of the region can be used to carry out the
further analysis. This approach attempts to establish
relationships between model parameters and physically
measurable Catchment characteristics for gauged
catchments. These relationships are then assumed to hold for
ungauged Catchments having similar hydrologic
characteristics (CWC, 1986).
Floods are caused by weather phenomena and events that
deliver more precipitation to a drainage basin than can be
readily absorbed or stored within the basin. Any relatively
high stream flow overtopping the natural or artificial banks
in any reach of a stream is termed as flood. An overflow or
inundation that comes from a river or other body of water
and causes damage. The Unit Hydrograph (abbreviated as
UH) of a drainage basin is defined as a hydrograph of direct
runoff resulting from one unit of effective rainfall which is
uniformly distributed over the basin at a uniform rate during
the specified period of time known as unit time or unit
duration. The unit quantity of effective rainfall is generally
taken as 1mm or 1cm and the outflow hydrograph is
expressed by the discharge ordinates.
Section I contains the introduction of CWC, Section II
contain the Study Area and methodology adopted, Section
III contain the result and discussions, Section IV concludes
research work with future directions.
II. MATERIALS AND METHODS
A. Study Area
The Study Area is located between Latitude 15º57′58′′ N to
16º11′25.6′′ N and 77º18′1′′ E to77º32′5.3′′ E Longitude and
covers area of 360.97 km2
, having maximum length of 26.17
km. The maximum and minimum elevation of the basin is
533 m and 323 m above MSL respectively[8]. It is divided
into seven subwatersheds as (S2A, S2B, S12C, S2D, S2E,
S2F and S2G). Location of the study area is shown in figure
1. The average mean daily temperature varies from 22 to
410C respectively.

Int. J. Sci. Res. in Multidisciplinary Studies Vol. 5(8), Aug 2019
Figure 1 Location Map of Study Area
Figure 2 Subwatershed
Figure 3 Points selected
Figure 4 Location
B. Methodology
Snyder (1938) gave some empirical relationships for
development of synthetic unit hydrograph for a ungauged
catchment based on his studies carried out in USA for
several catchments in the Appalachian Highland relating

shape of the UH to physiographic characteristics of the
catchment and information of the nearby gauged
catchments. The characteristics of the watersheds and their
Unit hydrographs, prepared for several watersheds in a
sub-zone, is correlated by regression analysis and the
equations for synthetic unit hydrograph are derived for
estimating design flood for ungauged watersheds. (CWC,
1986) The unit hydrograph characteristics such as peak
(Qp), time to peak (tp), width of hydrograph at 50% of
peak volume (W50), width of hydrograph at 75% of peak
volume (W75), width of the rising side of unit hydrograph
in hours at ordinate equal to 75% of UH peak (WR75),
time base (tB) etc. has been computed on the basis of
physiographic features.
Figure 5: Methodology adopted to derive a CWC Unit Hydrograph Ordinates and S-curve
III. RESULTS AND DISCUSSIONS
No information of flood runoff is readily available for the
study area, hence, to derive flood runoff or flood
hydrographs, unit hydrographs were derived by CWC
method by using following parameters below
Study area is extracted using ArcGIS software
Determination of synthetic t-hr unit hydrograph parameters
Draw approximate UH using Qp, tm, WR50, WR75, W50, W75, TB
UHO at suitable intervals
Direct
Runoff Depth
=1cm
Adjust UHO in falling
limb after F50 point
Final Unit Hydrograph Ordinates
Determination of S curve
Final S curve

A. Determination of physiographic parameters
The point of interested area is extracted from SRTM DEM 30m using ARCHYDRO software. S is to be determined using the
elevation of the main stream at a number of significant points along it. Usually, the length of the stream from a point where an
important tributary joins it up to another where the next tributary joins it called as a stream segment. S calculated as the
average slope of all the stream segments and calculated using the expression
S= (∑Li (Di-1+Di))/L2
… (3.10)
Where Li is the length of ith
segment in km, Di, Di-1 are the height above the datum (RL of the outlet of the basin) with respect
of RL of contour at the ith
and (i-1) th
locations in meters, L is the length of the longest stream in km
tp = 0.553(LLc/√s)0.405 …(3.11)
qp = 2.043/(tp)0.872 …(3.12)
W50 = 2.197/(qp)1.067 …(3.13)
W75 = 1.325/(qp)1.088 …(3.14)
WR50 = 0.799/(qp)1.138 …(3.15)
WR75 = 0.536/(qp)1.109 …(3.16)
TB = 5.038(tp) 0.733 …(3.17)
Tm = tp+(tr/2) …(3.18)
Qp = qp x A … (3.19)
Figure 6: Typical CWC Unit Hydrograph
Table 1
S2A
Point No Segment length Li in Km Elevation from outlet Di in m (Di + Di-1) Li(Di+Di-1)
0
1 1.1 47 104 114.4
2 1.17 42 89 104.13
3 2.39 25 67 160.13
4 1.63 17 42 68.46
5 2.01 9 26 52.26
6 1.87 4 13 24.31
Σ Li(Di+Di-1) 523.69
S = Σ Li (Di+Di-1)/L^2 4.985

S2C
Point No
Segment length Li in
Km
Elevation from outlet Di
in m
(Di + Di-1) Li(Di+Di-1)
0
1 1.84 53 104 191.36
2 1.07 48 101 108.07
3 3.05 36 84 256.2
4 2.67 21 57 152.19
5 2.86 12 33 94.38
6 2 5 17 34
Σ Li(Di+Di-1) 836.2
S = Σ Li (Di+Di-1)/L^2 3.094
S2D
0
1 3.07 48 104 319.28
2 5.43 22 70 380.1
3 3.19 12 34 108.46
4 2.84 7 19 53.96
5 1.38 1 8 11.04
Σ Li(Di+Di-1) 872.84
S = Σ Li (Di+Di-1)/L^2 3.160
S2E
0
1 0.65 29 104 67.6
2 3.09 18 47 145.23
3 3.17 12 30 95.1
4 3.1 5 17 52.7
5 3.11 1 6 18.66
Σ Li(Di+Di-1) 379.29
S = Σ Li (Di+Di-1)/L^2 2.315

S2F
0
1 3.61 37 104 375.44
2 2.96 29 66 195.36
3 3.2 19 48 153.6
4 1.84 13 32 58.88
5 3.43 8 21 72.03
6 3.02 5 13 39.26
Σ Li(Di+Di-1) 894.57
S = Σ Li (Di+Di-1)/L^2 3.318
S2B
0
1 1.54 42 104 160.16
2 1.71 33 75 128.25
3 3 19 52 156
4 1.53 14 33 50.49
5 1.84 8 22 40.48
6 1.59 2 10 15.9
Σ Li(Di+Di-1) 551.28
S = Σ Li (Di+Di-1)/L^2 3.528
S2G
0
1 2.89 25 104 300.56
2 1.91 16 41 78.31
3 2.73 8 24 65.52
4 2.15 3 11 23.65
5 1.65 1 4 6.6
Σ Li(Di+Di-1) 474.64
S = Σ Li (Di+Di-1)/L^2 5.429

Figure 7 Unit Hydrograph of S2A
B. Determination of synthetic tr-hr Unit graph parameters
Table 2 Parameters of tr- hr. Unit Hydrograph
Subwatershed Area
Sq_km
tp
(hr)
qp
m3
/s/km2
W50
(hr)
W75
(hr)
WR50
(hr)
WR75
(hr)
TB
(hr)
Tm
(hr)
Qp
m3
/s
S2A 34.820 2.069 1.084 2.016 1.214 0.729 0.490 8.583 2.569 37.741
S2B 72.600 2.240 1.011 2.171 1.309 0.789 0.529 9.097 2.740 73.429
S2C 38.180 3.167 0.748 2.997 1.818 1.113 0.740 11.729 3.667 28.542
S2D 52.960 3.181 0.745 3.008 1.826 1.117 0.743 11.765 3.681 39.447
S2E 55.530 2.839 0.822 2.707 1.639 0.998 0.666 10.825 3.339 45.668
S2F 71.510 3.521 0.682 3.307 2.011 1.236 0.820 12.676 4.021 48.743
S2G 35.220 2.086 1.076 2.032 1.223 0.735 0.494 8.636 2.586 37.899
Total Qp 311.469
C Preparation of tr-hr Synthetic unit graph

Figure 8 Unit Hydrograph and S Curve

Table 3: CWC Unit Hydrograph ordinates
Sl
No
S2A S2B
Time in
hours
UHO
in
m3/s
(Qi+Qi+1)/2
volume in
m3
Depth (m)
Cumulative
discharge in
m3/s
Time in
hours
UHO
in
m3/s
(Qi+Qi+1)/2
volume in
m3
Depth (m)
Cumulative
discharge in
m3/s
1 0.00 0.00 0.00 0.00 0.00 0.00
2 1.00 9.00 4.50 16200.00 0.00047 4.50 1.00 17.00 8.50 30600.00 0.00042 4.50
3 1.84 18.87 13.94 42139.44 0.00121 18.44 1.95 36.71 26.86 91844.10 0.00127 31.36
4 2.08 28.31 23.59 20381.76 0.00059 42.03 2.21 55.07 45.89 42953.04 0.00059 77.25
5 2.57 37.74 33.03 58256.10 0.00167 75.05 2.74 73.43 64.25 122589.00 0.00169 141.50
6 3.29 28.31 33.03 85600.80 0.00246 108.08 3.52 55.00 64.22 180315.72 0.00248 205.71
7 3.86 18.87 23.59 48406.68 0.00139 131.67 4.12 36.70 45.85 99036.00 0.00136 251.56
8 5.00 10.00 14.44 59241.24 0.00170 146.10 5.00 25.00 30.85 97732.80 0.00135 282.41
9 6.00 6.00 8.00 28800.00 0.00083 154.10 6.00 18.00 21.50 77400.00 0.00107 303.91
10 7.00 3.00 4.50 16200.00 0.00047 158.60 7.00 12.00 15.00 54000.00 0.00074 318.91
11 8.00 1.00 2.00 7200.00 0.00021 160.60 8.00 6.00 9.00 32400.00 0.00045 327.91
12 8.58 0.00 0.50 1044.00 0.00003 161.10 9.10 0.00 3.00 11880.00 0.00016 330.91
Sl
No
S2C S2D
Time in
hours
UHO in
m3/s
(Qi+Qi+1)/2
volume in
m3
Depth
(m)
Cumulative
discharge in m3/s
Time in
hours
UHO in
m3/s
(Qi+Qi+1)/2
volume in
m3
Depth
(m)
Cumulative
discharge in m3/s
1 0.00 0.00 0.00 0.00 0.00 0.00
2 1.00 5.00 2.50 9000.00 0.00024 4.50 1.00 8.00 4.00 14400.00 0.00027 4.50
3 2.00 10.50 7.75 27900.00 0.00073 12.25 2.00 14.00 11.00 39600.00 0.00075 15.50
4 2.55 14.27 12.39 24522.30 0.00064 24.64 2.56 19.72 16.86 33989.76 0.00064 32.36
5 2.93 21.41 17.84 24405.12 0.00064 42.48 2.94 29.59 24.66 33728.04 0.00064 57.02
6 3.67 28.54 24.98 66533.40 0.00174 67.45 3.68 39.45 34.52 91961.28 0.00174 91.54
7 4.75 21.41 24.98 97102.80 0.00254 92.43 4.76 29.59 34.52 134213.76 0.00253 126.06
8 5.55 14.27 17.84 51379.20 0.00135 110.27 5.57 19.72 24.66 71893.98 0.00136 150.71
9 6.00 12.00 13.14 21278.70 0.00056 123.40 7.00 12.50 16.11 82934.28 0.00157 166.82
10 7.00 8.00 10.00 36000.00 0.00094 133.40 8.00 8.50 10.50 37800.00 0.00071 177.32
11 8.00 6.00 7.00 25200.00 0.00066 140.40 9.00 6.00 7.25 26100.00 0.00049 184.57
12 9.00 4.00 5.00 18000.00 0.00047 145.40 10.00 3.00 4.50 16200.00 0.00031 189.07
13 10.00 2.00 3.00 10800.00 0.00028 148.40 11.00 1.00 2.00 7200.00 0.00014 191.07
14 11.00 1.00 1.50 5400.00 0.00014 149.90 11.77 0.00 0.50 1386.00 0.00003 191.57
15 11.73 0.00 0.50 1314.00 0.00003 150.40

Sl
No
S2E S2F
Time in
hours
UHO
in m3/s
(Qi+Qi+1)/2
volume in
m3
Depth (m)
Cumulative
discharge in
m3/s
Time in hours
UHO
in m3/s
(Qi+Qi+1)/2
volume in
m3
Depth (m)
Cumulative
discharge in
m3/s
1 0.00 0.00 0.00 0.00 0.00 0.00
2 1.00 9.00 4.50 16200.00 0.00029 4.50 1.00 8.00 4.00 14400.00 0.00020 4.50
3 2.00 18.00 13.50 48600.00 0.00088 18.00 2.00 16.00 12.00 43200.00 0.00060 16.50
4 2.34 22.83 20.42 24987.96 0.00045 38.42 2.79 24.37 20.19 57406.14 0.00080 36.69
5 2.67 34.25 28.54 33905.52 0.00061 66.96 3.20 36.56 30.47 44966.34 0.00063 67.15
6 3.34 45.67 39.96 96383.52 0.00174 106.92 4.02 48.74 42.65 125902.80 0.00176 109.80
7 4.31 34.25 39.96 139540.32 0.00251 146.88 5.21 36.56 42.65 182712.60 0.00256 152.45
8 5.05 22.83 28.54 76030.56 0.00137 175.42 6.09 24.37 30.47 96513.12 0.00135 182.92
9 6.00 15.00 18.92 64689.30 0.00116 194.33 8.00 14.00 19.19 131916.06 0.00184 202.10
10 7.00 11.00 13.00 46800.00 0.00084 207.33 9.00 10.00 12.00 43200.00 0.00060 214.10
11 8.00 8.00 9.50 34200.00 0.00062 216.83 10.00 7.00 8.50 30600.00 0.00043 222.60
12 9.00 6.00 7.00 25200.00 0.00045 223.83 11.00 3.50 5.25 18900.00 0.00026 227.85
13 10.00 3.00 4.50 16200.00 0.00029 228.33 12.00 1.50 2.50 9000.00 0.00013 230.35
14 10.83 0.00 1.50 4482.00 0.00008 229.83 12.68 0.00 0.75 1836.00 0.00003 231.10
Sl No
S2G
Time in hours UHO in m3/s (Qi+Qi+1)/2 volume in m3 Depth (m)
Cumulative discharge in m3/s
1 0.00 0.00 0.00
2 1.00 9.00 4.50 16200.00 0.00046 4.50
3 1.85 18.95 13.98 42763.50 0.00121 18.48
4 2.09 28.42 23.69 20463.84 0.00058 42.16
5 2.59 37.90 33.16 59688.00 0.00169 75.32
6 3.32 28.42 33.16 87144.48 0.00247 108.48
7 3.88 18.95 23.69 47748.96 0.00136 132.17
8 5.00 12.00 15.48 62395.20 0.00177 147.64
9 6.00 6.00 9.00 32400.00 0.00092 156.64
10 7.00 3.00 4.50 16200.00 0.00046 161.14
11 8.00 1.00 2.00 7200.00 0.00020 163.14
12 8.64 0.00 0.50 1152.00 0.00003 163.64

Figure 9 S Curve of S2G
IV. CONCLUSIONS
Using very limited data makes this model very useful for an
ungauged catchment aiming at event prediction. Equivalent
discharge is the maximum discharge that takes place in a
Catchment which can be used to design hydraulic structures.
To derive flood runoff or flood hydrographs, unit
hydrographs were derived by central water commission
method. This information is useful to derive flood
hydrograph along the stream. This drainage network analysis
and application of the UH can provide a significant
contribution towards flood management program. Thus, the
present model could be applied to simulate flood
hydrographs for the catchments that have not been studied
yet. The Peak discharge of unit hydrograph obtained is
311.469m3
/s. The final cumulative discharge is 1458.55
m3
/s.
REFERENCES
[1]. Jayaram Reddy P (2004). “A text book of Hydrology”, 2nd
Edition, Laxmi publication pvt limited, New Delhi, 530 Bernard,
M. M., (1932), “Formulas for rainfall intensities of long
durations”. Trans. ASCE 6:592 - 624.
[2]. CWC (1986). Flood estimation report for Kaveri basin subzone
3(i). Directorate of Hydrology (small Catchments), Central Water
Commission, New Delhi
[3]. Iowa Storm water Management manual version 2, 2C-7 Runoff
Hydrograph Determination, December 5, 2008.
[4]. Clark, C.O. (1945). “Storage and the Unit hydrograph”.
Transactions of the American Society of Civil Engineers
110:1491-46.
[5]. Mohammed Badiuddin Parvez, M Inayathulla “Generation Of
Intensity Duration Frequency Curves For Different Return Period
Using Short Duration Rainfall For Manvi Taluk Raichur District
Karnataka”, International Research Journal of Engineering and
Management Studies (IRJEMS), Volume: 03 Issue: 04 | April -
2019.
[6]. Mohammed Badiuddin Parvez, and M Inayathulla. "Generation of
Short Duration Isohyetal Maps For Raichur District Karnataka"
International Journal Of Advance Research And Innovative Ideas
In Education Volume 5 Issue 2 2019 Page 3234-3242
[7]. Mohammed Badiuddin Parvez, and M Inayathulla. " Derivation
Of Intensity Duration Frequency Curves Using Short Duration
Rainfall For Yermarus Raingauge Station Raichur District
Karnataka" International Journal of Innovative Research in
Technology Volume 6 Issue 2 July 2019 Page 1-7
[8]. Mohammed Badiuddin Parvez, Chalapathi K and M Inayathulla. "
Geomorphological Analysis of Two Mini-Watersheds in Raichur
City Karnataka" International Research Journal of Engineering
and Technology (IRJET) Volume 6 Issue 6 June 2019 Page 2896-
2901
[9]. National Programme on Technology Enhanced Learning, Indian
Institute of Technology, Kharagpur (2010), “The Science of
Surface and Ground Water”, module 2 Version 2 CE IIT- Lesson
3 Rainfall Runoff relationship.
AUTHORS PROFILE
Mohammed Badiuddin Parvez Is a life
member of Indian Water Resources
Society, ASCE Born in Gangavathi,
Obtained his BE in Civil Engineering in
the year 2009-2013 from UVCE,
Banagalore and M.E with specialization
on Water Resources Engineering during
2013-2015 from UVCE, Bangalore University and Pursuing
Ph.D from Bangalore University. And has 3 years of
teaching experience. Till date, has presented and published
several technical papers in many National and International
seminars, Journals and conferences.
M Inayathulla Is a life member of
Environmental and Water
Resources Engineering (EWRI), ASCE,
WWI, ASTEE, ASFPM. Born in
Karnataka, Obtained his BE in Civil
Engineering in the year 1987-1991 from
UBDT, Davanagere and M.E with
specialization on Water Resources Engineering during 1992-
1994 from UVCE, Bangalore University and got Doctorate
from Bangalore University in the year 1990-1995. Presently
working as Professor at UVCE, Bangalore University, India.
And has more than 25 years of teaching experience. Till
date, has presented and published several technical papers in
many National and International seminars and conferences

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