NATIONAL INSTITUTE OF TECHNOLOGY, ROURKELA -769008

END-SEMESTER EXAMINATION
SESSION: 2022-2023 (autumn)
B. Tech. 5th Semester

Subject Code: CE3401 Subject: Water Resources Engineering Dept. Code: CE

No. of Pages: 02 (Two) Full Marks: 50 Duration: 3 Hours

Q. Ma
Particulars (Answer all the questions)
No. rks
1. The rating curve of a current meter is given by 𝒗=𝟎.𝟓1𝑵𝒔+𝟎.𝟎3 m/s, where Ns is the revolution 5
per second. Find discharge if the current meter reading is shown in the Table below.
Distance from left (m) 0 1.0 3.0 5.0 7.0 9.0 11.0 12.0
Depth (m) 0 1.1 2.0 2.5 2.0 1.7 1.0 0
No. of Revolution 0 39 58 112 90 45 30 0
Time (s) 0 100 100 150 150 100 100 0

2. The following are the ordinates of the hydrograph of flow from a catchment area of 800 km2 5
due to a 6-h rainfall. Derive the ordinates of the 6-h unit hydrograph. Make suitable
assumptions regarding the base flow.

Time (h) 0 6 12 18 24 30 36 42 48 54 60 66 72
Discharge
40 65 215 360 400 350 270 205 145 100 70 50 42
(m3/s)

3. Characteristics of two catchments, M and N, measured from a map, are given below: 5

Item Catchment M Catchment N

Lca 76 km 52 km
L 148 km 106 km
2
A 2718 km 1400 km2

For the 6-h unit hydrograph in catchment M, the peak discharge is at 200 m3/s and occurs at 37
h from the start of the rainfall excess. Assuming the catchment M and N are meteorologically
similar, determine the elements of the 6-h synthetic unit hydrograph for catchment N using
Snyder’s method.

4. The following Table shows the Gumbel method’s estimated flood peaks and corresponding 5
return periods.
Peak flood (m3/s) Return period (Years)
35,500 60
51,250 120
Find out the amount of peak flood corresponding to a 500-year return period.
 5. In a 300 ha watershed, the CN value was estimated as 70 under the AMC-III condition. 5
(i) Estimate the value of direct runoff volume for the following 5 days of rainfall. The AMC on
18th May 2000 was of category III. Use standard SCS-CN equations.
(ii) Estimate the runoff volume if the CNIII value was 90.

Date 18 May 19 May 20 May 21 May 22 May

Rainfall (mm) 38 21 22 10 30

6. Monthly flow values in river during 2021 are given. 5

Au Oc N De
Month Jan Feb Mar Apr May June Jul Sep
g t ov c

Mean
monthly
60 35 30 22 19 30 60 90 110 85 75 60
flow
(𝑚3 /𝑠)

Calculate the minimum storage required to maintain a demand rate of 55 m𝟑/s numerically.

7. Observed values of inflow and outflow hydrographs at the end of a reach of a river are given 7
below. Determine the best values of K and x for use in the Muskingum flood routing method.
Time (h) 0 6 12 18 24 30 36 42 48 54 60 66
Inflow
20 80 210 240 215 170 130 90 60 40 28 16
(m3/s)
Outflow
20 20 50 150 200 210 185 155 120 85 55 23
(m3/s)

8. A reservoir has the following elevation, discharge, and storage relationships: 7

Elevation (m) 101.0 101.5 102 102.5 103 103.5 104 104.5
Storage (106 m3) 4.56 4.57 5.90 5.25 5.90 6.32 6.53 6.83
Outflow (m3/s) 0 20 34 50 79 115 120 133

The following flood hydrograph entered the reservoir when the reservoir level was at 101.50m.
Time (h) 0 6 12 18 24 30 36 42 48 54 60
Inflow
15 40 125 235 160 105 75 60 45 30 18
(m3/s)
Rout the flood and obtain the outflow hydrograph.

9. a Distinguish between (i) Field capacity and permanent wilting point (ii) recording and non- 3
recording rain gauge.

9. b Explain in brief the different structural measures to control the flood. 3

***Best of Luck***