CamScanner

CamScanner
 Khulna University of Engineering & Technology
Department of Civil Engineering
B. Sc. Engineering 4th Year 2nd Term Regular Examination, 2020
CE 4261
(River Engineering)

Full Marks: 120 Time: 1.5 hrs

N.B. i) Answer any two questions from each section in separate script.
ii) Figures in the right margin indicate full marks.
iii) Assume reasonable value for any missing data.

Section – A

1. (a) Distinguish between (10)

i. Rapids and step-pool system and
ii. Fluvial system and Delta
(b) Briefly explain the classification of rivers according to Brice (1983) with neat (11)
sketches.
(c) The width of the particular channel at Sirajganj point of Jamuna river is 1100 m (09)
and at upstream section the width is 2000 m. If the flow depth at upstream
section is 5.0 m in dry and 7.0 m in wet season, determine the depth difference
between two sections and its seasonal variations due to width contraction.

2. (a) What are the variables govern the meandering process? How does a (09)
meandering river form from a straight one?
(b) Explain with neat sketches, how shoals are formed at convex side of the river (11)
bend?
(c) At a certain cross-section of a river, following data are known: width = 700 m, (10)
maximum flow depth = 10.0 m, velocity = 2.5 m/s and mean diameter of bed
material = 0.15 mm. If you want to construct abutment of a bridge at the bank,
estimate the maximum scour depth.

3. (a) Differentiate with neat sketches (20)

i. Undercutting and Gullying
ii. Entrancing and Armoring
iii. Shoaling and Braiding and
iv. Anastomosing and Anabranching
(b) At a certain cross-section of a river, following data were recorded (10)
Maximum discharge = 10,000 m3/s
Highest flood level = 110.5 m
River bed level = 104.5 m
Width of the river = 2.1 km
4 square bridge piers having sides of 2m each are aligned with 450 to the
direction of flow. Determine the maximum scour depth.

Page 1 of 2
 Section – B

4. (a) What is meant by river training? What are the design considerations that used (10)
for river training works?
(b) Write short note on sandbagging for river bank protection work. (05)
(c) The following hydraulic data are given to a bridge site of a river. (15)
Maximum discharge = 9000 cumecs
Highest flood level = 110 m
River bed level = 105 m
Average diameter of river bed material = 0.16 mm
Design and sketch guide banks including the launching apron to train the river.

5. (a) What are the difference between bars, ripples, dunes and anti-dunes (08)
(b) Analyze the bedforms with the sediment load for the following cases, (10)
i.   0 ; q  0
ii.  slightly less than 0; q  0
The symbols have their usual meaning.
(c) Calculate the shield parameters for a river from the following data: (06)
2
dimensionless
Dimensional bed shear stress = 0.01 N/m ,
density of the sediment = 1200 Kg/m3 and
the diameter of sediment = 1 mm
(d) Determine the fall velocity of a sediment particle from the data given as: (06)
sediment diameter = 0.25 mm
density of sediment = 650 Kg/m3 and
kinematic viscosity = 10-6 m2/s
by using stokes law and Inertia law.

6. (a) Explain the threshold condition for sediment movement. (10)

(b) Write the name of different types of dredgers. Describe the working principle of (14)
any one of them.
(c) Calculate the sediment discharge in tonnes/year for a river at certain section (06)
where the average annual discharge is 3600 m3/s and the average annual
suspended sediment concentration is 190 mg/L.

--------------------------------

Page 2 of 2
 Khulna University of Enginee ring & T echnology
Department of Civil Engineeri~g .
B . Sc. Engineering 4 th year 2 00 term Regular Examination, 2019
C E 4261
(River Engineering}

Full Marks: 21 O Time: 3 hrs

N .B. i) . Answer any three questions from each section In separate script.
ii) Figures in the right margin indicate full mar1<s.
S e c tion - A
Why the H imalayan rivers carry huge amount of sediments? Characterise the (08)
/ (a)
Brahmaputra and Ganges rivers with respect to large rivers in the world .
(b) Distinguish between - (16)
i. Rocky and Boulder r iver stage.
ii. Straight and Meandering river.
i ii. Deltaic and Tidal river.
iv. Non-paranial and V irgin river.
(c) Briefly explain different types of rivers flowing on alluvial flood plain . (11}

2. (a) Define local scour. Explai n with neat sket ches d ifferent types of local scour that (10)
_/ are caused according to the sediment supply from upstream and discharge In
downstream.
(b) What are the different types of bridge scour? Write down the various factors (12)
that affect the long term bed changes.
(c) At a certain cress-section of a river, following data were recorded : (13)
Maximum discharge = 20,000 m 3 /sec.
H ighest nood le vel = 1 C2.5 m .
R iver bed level = 95.5 m .
Maximum width = 1 .5 km .
Estimate the maximum scour depth for construction of the following structure:
i. Four rectangular bridge piers measuring 2 .0 m thick and 4 .0 m longare
aligned at 45° with the flow.
ii. Vertical abutment of 300 m long o ·,1er sand bed.
iii. Normal groyne of length 300 m prnvld e d at ccncave bank.

3. (a) Derive the general equation for mass-conservatlon of sedimem and ~xplain the (1 O)
/ aggradation and degradation process.
(b) Explain with sketch , any three types or degradation commonly occur in river (12)
bed.
(c) D e scr;be w ith neat sketch, how local si::our Is occurred around bridge p ier. (13)

4. (a) D istinguis h between - (12)

i. N lckpoint and Headcut.
ii. Anastomosing and Anabranchlng.
iii. Avulslon and Perched r ivers.
(b) Why transverse rotary currents get developed In a straight reach of a river? (13)
How and why shoals are formed at convex s ide of a bend?
(c) What is Armoring? What are the conditions to form' Armor layer? (10)

Page 1 o f 2
 Section - B
(OS)
5. (a) Sketch a typical section of a levee with rts dimensions.
/ (b) Describe the groynes with rts different alignmenL
(10)
(05)
{c) Write short notes on porcupines.
(15)
(d) Data given below for a guide bank:
Maxlmum discharge = 9000 m 3 /s.
Highest flood level = 110 m .
River bed level= 104 m .
Average diameter of river bed material = 0 .12 mm
Aflux = 0 .76 m
Free board = 1.3 m .
Design and sketch guide banks at a bridge site of a river.

6. (a) Define bedform. Describe the different types of bedforms. (15)

(b) Describe the following bedload tra nsport rate formula - (06)
1
q :! .1C ( l - ...l p)
2
where, the symbols have th e ir u s ual mean ings.
(c) Sketch double-valued s tag e-d isch arge relationship . (05)
{d) Analyze the bedforms w ith the sed ment load for th e follmv, g cases (09 )
i. q, = O; q. > 0
ii. q, = O; q, < 0
111. q, sl ightly greater than O: q . > 0
The symbols have their usual m eaning s.

Show that the equation for Shield s paramet~rs ('r

0

) are· { 15)
Tc
T• = -- - -
(}',, - y )D
The symbols have their usual m ea nings.
(b) State and explain the B a gnold's h ypothesis ( 1 957) for b ed load transport. ( 15)
(c) Calculate the fall velocity of a sediment partide f rom fo llovting data: ( 05)
=
D so 0.24 mm, R = =
1 .60, kinematic viscosity 1 . 1 " 1 ~ m 2 /s .
Use (I) Stokes law and (ii) Inertia law .

8 (a) Write down the various re~uirements for a navigable waterway. ( 10)
/ (b) Distinguish between temporary and permanent river improv eme nts. Why do (10)
you suggest temporary river improvement rathe r than a permanen t one ?
(c) What is the principle of dredging operation? Explain the working principle of (15)
main four types of dredgers ....

Page 2 of 2
(
Khulna University of Engineering & Technology
Department of Civil Engineering
B.Sc. Engineering 4 th Year 2 nd Term Regular Examination, 2018
CE 4261
(River Engineering)

Full Marks: 210 Time: 3 hr5

N.B. i) Answer any three questions from each section in separate s cript.
ii) Figures in the right margin indicate full marks .

Section -A

1. (a) Describe briefly the fluvial system of a river course from its source to outfall. (10)
(b) Describe different types of rivers based on topography of river basin. (15)
(c) Distinguish between (10)
(i) Straight and meandering rivers
(ii) S inuous point bar and sinuous braided rivers

2. (a) Distinguish among clear water scour, live bed scour and equilibrium scour. (10)
(b) Explain the following bridge scours (15)
(i) General scour (ii) Constriction scour and (iii) Pier scour
(c) Explain the alluvial changes of the Jamuna River in Bangladesh with neat (10)
sketches.

3. (a) Explain the aggradation and degradation process of river bed by applying the (10)
principle of continuity.
(b) What are the different types of aggradation and degradation commonly occur (16)
in river bed? Explain three types from each with neat sketches.
I
(c) Classify the Indian Rivers. Why do the Himalayan Rivers carry huge amount of (09)
sediments?

4. (a) Why do transverse rotary currents get developed in a straight reach of a river? (12)
How are shoals formed at the convex side of a bend?
(b) Describe the m·echanics of formation of meandering river from a straight one. (08)
(c) At a certain cross-section of a river, following data were recorded. (15)
Maximum discharge= 13,000 cumec
Highest flood level = 107.5 m
River bed level= 102.5 m
Width of the river= 2.30 km
Average bed particle size = 0 .80 mm
Estimate the maximum possible scour depth for the construction of the
following structures.
(i) 2m by 4m bridge pier aligned a.tan angle of 45° with the direction of flow.
{ii) 50m long spill through abutment (1V: 2H).
(iii) A groin extended 500m inside the river with an angle of so 0 with the bank.
(iv) Abutment in the river (use Lacey's regime method). 1

Page 1 of 2
 ornry nnd r nrmnnrmt rlvlir tralnln~
5. (a) t ont· ~prn!nry mnt11od rnthnr thnn n ()'1rm11n'1nt
Distinguish botwo
doos ono suggon n or,,
,;~0,
tth~~,.
'f

(b) What aro tho mothodn gonornlly ndortod lo !min n rlYllr l'ltnprirat1111 'i ,: I 11,1
the sandalling mothod,
a
(c) Data given below rofor to quldc t>n~k: ~ 1
Max/mum dlochargo ~ OµOO m If>
Highest flood lovol ;;: 108 m
River bod lo vol == 102 m
Average diameter of rlvor hod material ,... 0, 12 mm
Afflux == a.BB m, Free board ==1,5 m
, Velocity head = 0.16 m,
Design and sketch guide banks at a bridge olto of tho river,

6. (a) State and explain the Ashlda-Mlchlke (1972) bod load formuln, (15)
(b) Show that the equation of critical threshold shlold number J,; (15}
4 µ ,,
Tc= - - -- p- ,,
3 (C0 +11C1,)
Where the symbols have their usual meanlngo,
(c) Calculate the fall velocity of a sediment particle from the following data ueing (OS)
(i) Stokes law (ii) Inertia law.
Dso = 0.25mm, R = 1.65m, v = 1.1 x1 o·0 m2/s,

7. (a) What are bedforms? Describe different types of bedforma with neat oketche~, (15)
(b) Derive Rousean distribution for suspended sediment, (12)
(c) Explain the Exner equation for the conservation of bed sediment for turbidity (OB)
current.

8. (a) What are the navigation water ways? Mention the navigation requlrement6 for (10)
various purposes,
(b) Define dredging, Name the types of dredging that are conducted in (10)
Bangladesh with example, What are the impacts of dredging?
{c) Write down the name of the different types of dredger, Describe the working (1 5)
principle of any one for the same,

------·-----------------------
 Khulna University of E11gineerin:J & Technology
. Department of Civil Engineering
s. · ·
Sc. Engrneenng 4 th year 2 nd term R egu Iar Examination, 2017
CE 4261
(River Engineering)

Full Marks: 210

Time: 3.0 hrs
N .B. i) Answer any three questions from each section in separate script.
ii) Figures in the right margin indicate full marks.

Section -A

1. (a) Define fluvial system. Briefly explain different parts of a fluvial system. (10)
(b) Describe different rivers in the following classes: (14)
(i) Rivers in upper reaches :1
(ii) Rivers in lower reaches .r
(c) Classify the rivers according to channel pattern and .e.J:plain them. (11)
,'

2. (a) Distinguish between (16)

(i) Sinuous point bar and sinuous braided river
(ii) Scour and local scour
(iii) Constriction scour and confluence scour
(iv) Clear water scour and live bed scour
(b) At a certain cross-section of a river the recorded maximum discharge is 13,000 cumec, (14)
the R .L. of bed level . and highest flood level are 100.5m and 106.5m, respectively. If
the width of the river is 2 .0 km, estimate the maximum scour depth for
(i) Vertical and spill through abutment of 300m long over a sand bed . .
(ii) A square pier of 2.0m sides and
(iii) A 500.0m long groin inclined at 60° wrtri the direction of flow at convex
bend. ;
(c) Why do the Himalayan rivers carry huge ~mount of ~-iidiments? (05)
i·

3. (a) Explain why the sediments are found in :suspensiori -in straight river as well. How are (12)
shoals formed at convex side of a bend?
(b) Describe the mechanics of formation of meandering •iver from a straight one. (10)
(c)
1'
Describe he local scour and flow pattern around a bridge pier with neat sketch. (13)

4. (a) Explain the aggradation and degradation process of river bed by applying the principle (08)
of continuity.
(b) Differentiate with neat sketches (15)
(i) Shoaling and braiding
· (ii) Anastomosing and Anabranching
(iii) Avulsion and perched river ·

(c) What are the different types of degradat/on commC'. ,ly occur In river bed? Explain any (12)
three of them. . )1
 Se@Qn - B
- I

• , t t,,pes of 'gr\·,ynes' which are common\

. . t ketches the d1fferen , Y U~<Jo
5. (a) Explain with nea s . . Bangladeshi rivers.
for controlling and training f rotecting c:ities from floods.
the use of levees or p
Write short notes on 'd > site of a n·ver from the data given below:
Design and sketch guide banks at a bn ge3 .
Maximum discharge = 8000 m /s
Highest flood level = 106m
River bed level = 101 m .
Average diameter of river bed material = 0.10mm
Afflux = 0.80m
Velocity head = 0.15m

(15)
5-.--- (a) State and explain Bagnold's bed load formula

·--..,, (b) Show that the terminal velocity (V,) of a spherical rartlcle yields, V, = F, Where
(05)

) (c)
the symbols have their usual meanings.
Derive an expression of Shield's paramr.:ter from sodiment transport principle theory,
(15)

i.e. r• = r e/pRgD where the symbols hav e.• their usur, meanings.

7. (a) Define bed forms. Expiain different types l)f bed forn (~ with neat sketches. (15)

(b) What are the effects of bed forms on river stage? (05)

(c) Derive the bed form equation of z. = 2A.e1<c:1t cos[k _-S - Crt) - <p] , where the symbols (15)
have their usual meanings. _;,...-----==------
_

8. (a) Derive diffusion-dispersi<?n ~-g~_~tion for suspended sediment. (15)

r • . - ···
(b) E~1!1 t_b._e various_meas.lJrefillJ.gla~..adoP-ted for achieving navigability of the r ver. (13)
(c) Describe Lan Kalinske distribution with figure for suspended sedlme~. (07)

1) OL.,-~----------·-------------
 KJ1uJna University ofEngineedng & Technology
Departtnent of Civil Engineering
B.Sc. Engineering 4Lh Year 2 nd Term, Regular Examination 2016
CE 4261 '
(River Engineering)
Full Marks: 210
Time: 3.0 hrs
N.B.:
.i).) A
. _ns,~er _any th r_ee questi~ns_ fr~m each section in separate script.
11 F 1gu1es 111 the nght margm md1cate full marks.

Section-A -
- - --.::::..::;.::..:~~~~- -- - - ·- - - -
1. (a) Describe different types of cha,mel plan form based on sinuosity. (10)
(b) Distinguish between (16)
(i) Rocky and boulder river stage,
(ii) Deltaic and tidal river,
(iii)Sinuous point bar and sinuous canaliform, and
(iv)Himalayan and Non-Himalayan rivers.
(c) Characterize the Brahmapu~ra and Ganges river with respect to large rivers in the world (09)
in tenns of flow and sedimen·t transport.
2. (a) Descrihe with m:<lt sketches, the behaviour cfriver at (i) straight reaches and (ii) Bends. (13)

(b) Explain the alluvial changes of the Jamuna river in Bangladesh with neat sketches. (12)

(c) Two sections in a river are 2km apart. The upstream and downstream sediment (10)
2
discharges are 5 .0 and 5.2 m /s per 1:1nit width, respectively. What will be the changes
in bed elevation after 1-hour? Given, the porosity of bed material is 0 .2.

3. (a) Distinguish between scour and local scour. Explain different types of Local scour with (12)
practical examples.
(b) Describe the local scour and flow pattern around a bridge abutment with sketches. (10)

(c) A 200m long bridges is to be constructed over a sand-bed charmel with 300m long spill (13)
through abutment 1 V:2H. Six rectangular bridge piers measuring 1 .Sm thick and 12m
long are aligned with the flow. At a design 100-yr flow discharge of 850 m 3/s, the
upstream flow velocity is 3. 75 mis and the flow depth is 2.8m upstream of the piers.
Estimate (i) the abutment scour depth and (ii) the pier scour depth.

4. (a) Define aggradation and degradation process. Explain with neat sketches, different types (13)
of degradation commonly occur in river bed.

(b) Distinguish between (12)

(i) Shoaling and Braiding
(ii) Anastomosing and Ana branching, and
(iii)Perched river and avulsion
(c) Write down the various requirements for a navigable waterway. (10)

Page I of 2
 Section-B

5. ·)
(n \Vh~t is meant b)' the term river training works? What are the different objectives $ .

by it?

(b) What are the methods available to train a river permanently in Bangladesh? Explain any l..

three methods of the same.

(c) Design and sketch a guide bank including launching apron from the following hydraulic (15)
data:
- M:1,ximum discharge= 15,000 m3/s
- Highest flood level = 108 m
- River bed level ;-y02 m
- Dia of river bed material = 0.12 mm
6. (a) Distinguish between temporary and permanent river improvement. When do you suggest (06)
temporary river improvement rather than a permanent method?
(b) V✓ hat are t.he methods that are generally adopted to train a nver tcrnpornri!y 111 (15)
Bangladesh? Explain the bundling system with neat sketches.

(c) What are the methods available for bank protection? Explain any three method~. (14)

7. \(.,)
,, V.7hat is foll vdoc ity? For the motion of sediment partide show that ( 10)

(b) Explain the DuBoy's forn1'. .1la to pcedict the bed load from a river. ( 1O")

(c) Derive nn expression for two dimensional vertical diffusion equation for sediment. (15)

8. (a) Explain the idealized bed forms i.n ~lluvi.al channel according tr> Simon et ul. (] 0)

(b) \Vhat are the methods available to predict the bed form in river'? Explain Van Rijn (12)
approach.
(c) Explain the Colby formula to estimate the total load from a river. (13)
 t:i_uina Uni_versity of Engineering & Technol
Departrnent of Civil Engineering ogy
'• I
4 th nd
'leer no ye ar 2 term Regular Exam! t·
CE 4261 na ron, 2015
(River Engineering)
J
T lmo: 3 hrs
,/1.nsw or .-i ny t11roo questions from each se t' I
• •)
11
F • c ion n separate script
.'
1
~1gur0s in t 1e rig ht margin Indicate full ma k ·
r s.
.' Section -A
1. (a) · W hat is m eant by th e te rm river t . . .
·t
I .
raining work? Wnte down the d ifferent objectives served by (08)

(b) W hat a re the meth 0 d ·

s av a ilable to train a river permanently in Bangladesh? Explain any (12)
three m ethods. ·
(c)
D es ign a guide bank including launching apron from the following data: (15)
- Design discharge = 8 ,800 m 3/s
Maximurn depth of flow = 8 m
A verage d iameter of river bed material = 0.12 mm

2. (a) Distinguish between temporary and permanent river improvements. When a temporary river (06)
is suggested rather than a permanent one?
(b) What a re the methods available that are generally adopted to train a river temporarily? (15)
Explain any one method of the same.
(c) What are the methods ava ilable for bank protection? Explain any three methods of the (14)
:.. s am e .

3. (a) Explain the idealized bed forms in alluvial channel according to Simon et. al. (08)
(b) What is the principle of dredging operation? Explain the crooking principle of the main four (12)
types of dredgers.
(c) E xplain the Colby formula to estimate the total load from a river. (15)

4. (a) What is fall velocity? Explain the influence of particle shape and concentration on it. (08)
(b) Derive an expression for two-dimensional vertical diffusion equation for sediment. (12)
(c) Explain the Du-Boy's formula to predict the bed load from a river. (15)

Section - B
5. (a) Describe with neat sketches, the fluvial system of a river course from its source to outfall. (09)

(b) Distinguish between: (16)

i) Rocky and boulder river stage
ii) Aggrading and degrading river
iii) Deltaic and tidal river and
iv) Sinuous point bar and sinuous braided river.
(c) Describe different types o( _
c hannel planform based on sinuosity. (10)

6. (a) Describe with neat sketches, the behavior of rivers at - (14)

i) Straight reaches and
ii) Bends.

Page 1 of 2
 . h . of formation of a meandering river from a straight .
(b) Describe the mec anic 5 rivl!l
variables govern the meandering process. . ? r ,
Why the Himalayan rivers carry huge ar:ioun~ of sed1ml~nts . Characterize the th
(c)
and Ganges rivers with respect to large nvers in the_wor . a.'1\,

7. (a) Distinguish between -

i) Scour and local scour
ii) Clear water scour and live bed scour and
iii) Constriction scour and confluence scour.
(b) Describe with neat sketches, the local scour and flow pattern around a bridge abutment.

(c) At a certain cross-section of a river the recorded maximum discharge is 14,000 cumec, depth (13)
of river is 6 m and width of 2.3 km. Estimate the maximum scour depth for -
i) Vertical and spillthrough abutment of 400 m long over a sand bed.
ii) A circular pier of 3.0 m diameter and
iii) A normal groin of 500.0 m long provided at convex bend.

8. (a) vVhat are the importances of river navigation? Write down the different objectives serve by it. (10)
(b) Describes the various measures that are adopted for achieving navigability. (1 5)
(c) Explain the fluvial process of the Jamuna river with neat sketches. (10)
 t<hulnn University of Engineering & Technology
Departrnent
11
of Civil Engineering
s, Sc, Engineering 4 ' Yenr 2nd Torm (R0gulnr) Exornlnntlon 201 '1 1
CE 4261
(River Engineering)

Full ~,arks : 2 ·10

Tlmo: 3 tim
N.B. Answer Erny three questions from oncll socllon In sopornto ocrlpt.
ii) Figures in tho right margin lndlcnto full marks.

Section - A

1. (a) \Nhat is meant by the term river engineering? Write down the different (08)
objectives served by it
(b) What are the methods available to train a river pern,anently In Bangladesh? (12)
Explain any three methods of the same.
(c) Design and sketch a guide bank from the following data: (15)
- Maximum discharge= 10,000 m 3/s
- Highest flood level= 110 m
- River bed level = 102 m
- River bed material size = 0.1 0 mm

2. (a) Distinauish between temporary and permanent river improvements. When do (06)
a
you s~ggest ilie teniporary improvem'e nt rather than permanent one?
(b) What are the methods that are generally adopted to train a river temporarily? ( 14)
Explain any one method of the same.
(c) What are the methods that are generally adopted for bank protection? Explain (15)
any three methods of the same,

3. (a) What is fall velocity? Show that the finite fall velocity of a spherical particles (08)

yields I/I,= J 4
3 CD
g AD. Where the symbols have their usual meanings.

(b) Derive an expression for two-dimensional vertical diffusion equation for (15)
sediment.
(c) Explain Du-Boy's bed-load formula.
(12)

4. (a) Expl~in the idealized bed forms in alluvial channels according to Simon (1 O)
et. al.
(b) What are the n:iethods available to predict the bed form in river? (12)
Explain Simon's and Richardson's approach.
(c) ~tat~ and explain Van Rijn total load formula to predict the sediment transport (13)
in a nver.
 E!
-
section -

f ldoallzod rlvor-couroo from Ito oourcu ((y~l

Briefly describe the fluvlal syntom o an
5. (a)
to outfall. . (1 8)
(b} Differentiate the characteristics of rivers botwoon.
i) Rocky river stage and Bouldor river stago
ii) Aggrading, Degrading and Stable rivers
iii) Deltaic and tidal rivers the channel patterns and (10)
(c) Define sinuosity. Based on sln'uoslty, classify
describe briefly.

13
6. (a)
Explain how transverse rotary currents get developed In a straight reach of a •( )
river. How and why shoals are formed at conv0x side of a bed? . ,
(b) Explain different types of meanders with neat sketches. Describe the (14)
mechanics of formation of a meand,~ring river from a straight one.
(08)
(c) For a alluvial river of 50m width, find the typical meandering parameters.

7. (a) Describe different types of local scours based on the sediment supply from (09)
upstream and its discharge characteristics In the downstream.
(b) Describe the local scour and flow pattern around a bridge pi_er with neat (13)
sketch.
(c) A river having width of 20m is contracted at downstream to 1Om. If the (13)
3
upstream depth of water is 1Om and the discharge is 150 m /s, detennins the
constriction scour depth at downstrnnm section. Neglect tl,e head loss
between the two sections.

8. (a) What is meant by river navigation? Explain it~ importance in modern system (1 0)
of transport.
(b) Deduce the expression for mass-conservation of sediment (Exner equation) (10)
and explain the aggradatlon and degradation process of rive·r bed using the
expression.
(c) At a certain cross-section of a river the maximum recorded discharge Is (15)
14,000 cumec, depth of water Is 6m and the width Is 2.3 km. If a 400m long
abutment is constructed over sa·nd bed, determine the maximum scour depth
for (i) vertical type and II) spill through type (1V:2H) abutment.
 Khulna University of Engineering & Technology
.De~art~ent o:,dCivil Engineering
s. Sc. Engrneenng 4 Year 2 Term Regular Examination 2 013
CE 4261 '
(River Engineering)

Full Marks: 210 Time: 3 hrs

N.B. i) Answer any three questions from each section in separate script.

i i ~ e right margin Indicate ful:~::ion - A

(08)
• Define river training works and classify it based on purpose.
(12)
~ Write short notes on .(B"Guide bank ~roynes (iii}-Artificial cut-offs.
(15)
~ Design a Bell's bund by using the following data:
Maximum discharge= 25000 cumec; HFL = 110 m; River bed level= 100 m;
Average diameter of bed material '= 0.11 mm.
After designing, sketch the Bell's bund including launching apron.

(20)
2. ~Define o.ne-dimensional vertical diffusion equation for sediment particles.
(10)
~ Explain the sediment transport mechanism in a river.
¥ Describe the forces acting on sediment particles.
(05)

(15)
3. ~ State and explain the Van Rijn Tctol loaC: formula.
diameter (iii) Sphercity (iv) (1l.)}
~ Define (i) Standard raii diameter (ii) Sedimentation
7 s;-.ape factor (v) Critical shield vaiue .
(10)
~ Explain the working principle of Sandals with neat sketch.

Describe the classification of bed forms according to Simons and Richardson (15)
4. a)
(1961) with neat sketch.
.(10)
~ State the names of available sediment transport formula .
(10)
~ Determin.e the total sediment load for a river from the data given below by Colby
Total load formula: _ _
Average depth of flow = 15 ft; width of the river = 2 km; Mean velocity :s: 6 ft/sec;
median particle size = 0.4 mm: water temperature = 80°F; Concentration of fine
sediment= 70000 ppm.

Section - B
(12)

· • -headed and Hockey headed river

~ocky and Boulder rrver stage - -
# -:: a
Describ~-th~mation of meandering river from a straight orie.
___ .......... . are tile \lanables.that_govero the mea,ndering process?
~ - ~ith neat sketch, show the various parts of a hea _ l · -- -

';Y ··o~scribe witli neat sketch, the flow pattern and scouring phen~mena around a
bridge pier and abutment.
 .1 c.J In a otrolgl1t roach or a rlvor? Haw
l ot dovolopo
6 Why transverse rotary curron s fJ lcJo or a bond?
· • . t convex n
and why shoals are formed a cJltlon of a rlvor? (~)
r t110 bralcJod con
~ What are tho primary causes or Bangladesh with neat sketch. (06)
1/ f ti Jamuna rlvor n I
.c-)· Explain the·alluvlal changes o 1O h rt r scrlptlon on confluence (08)
✓/ I ur Write a s o '
3/' Differentiate between scour and loco sco .
scour and constriction scour. f discharge 2000 (06)
_/, fOr an alluvial river o
Find the typlcal meandering parnmoters ..
7 m3/sec.
(07)
/ • 'th . t to large rivers in the
7. 3/ Characte'rize the Brahmaputra and Ganges river w1 respec .
world in terms of flow and sediment transport.
(05)
~ Write down the conditions to be satisfied for improving the navigability by open
channel method?
# Based on Brice classification, explain different types of channel pattern observed in
(08)

~ nature.
~ At a certain x-section of a river , following data are recorded: (15)
Maximum discharge, Q = 12000 m3/s;
maximum width = 2.1 km;
highest flood level = 106.0 m;
river bed level = 102.0 m.
Estimate the maximum scour depth for the following structures.
i) Six circular piers aligned with the flow (use CSU equation)
ii) ?Sm long spillthrough abutment 1V: 2H, over a sand bed.
iii) Normal groyne of 500m length provided at concave bank.
iv) Blunt abutment in a river having bed particle size of 0.25 mm using the equation
proposed by Inglish as well as by .t.hm.ed.

8. / Explain clear water scour, live bed scour and equilibrium scour with neat ~ketch. {06)
~ Differentiate betvv1een following aggradation and degradation process with neat (16)
/ sketches.
i) Caving and Gullying
ii) Entrenching and Armoring
~hoaling and Braiding
~nastomosing and anabranching
~ Wharis river navigation? Explain its importance in the modem system of transport. (07)
~ Di~erentiate between: - (06)
i) Suspended load and wash load ·
ii) Bed load and bed material load

END
 Khulna University of Engineering & Tech
D epa rt men t o f C 1v1I• . no 1ogy
Engineeri
s. Sc. Engineering 4 th Year 2 nd Term Exam/ t' ng
CE na 10n, 2012
4261
(River Engineering)
Full Marks: 210
Time: 3 .0 hrs
N.B.: i) Answer any three questions from e h · ·
ii) Figures in the right margin Indicate ~ar~!.c t,on rn separate script.

Section-A

1. ✓What is meant by the term river training? What are the different objectives served by (08)
it?

),bJ What are the different methods available that are generally adopted in Bangladesh to (12)
train a river permanently? Explain any three methods of the same. "

~ Design and sketch guide bank~ at a bridge site of a river from the data given below: (15)

-Maximum discharge = 9,000 m 3/s

-Highest flood level ~ 108 m
-River bed level = 101 m
-Average diameter of river bed material= 0.12 mm

2. ~ Distinguish between temporary and permanent river improvements. When do you (06)
suggest temporary river improvement rather than permanent one?
ftS) What are different methods that are commonly used for temporary river improvement? (14)
Explain any one method.

~ What are the purposes of bank protection? What are the different method~ available (15}
for it? Explain any three methods of the same.

) (a) What is fall velocity? Show that the balance of forces acting on a sediment particle (10)

under ~uilibrium condition yields - U.

2

gt:JJ
~ ! tan(q,)
01

3a Cv(a + a3 )
2

Where the symbols have their usual meanings.

~ State and explain Du-Bay's bed load formula. (10)

~ Derive an expression for two-dimensional vertical diffusion equation for sediment. (15)

4. Ja). Explain the idealized bed forms in alluvial channels according to Simon e.t al. with neat (10)
/ sketch.
✓ What are the methods available to predict the bed forms in rivers? Explain any one (15)
method of the same.

(9Y Explain the Colby formula to predict the total load of a river. (10)
 Section-B

Sinuosity, explain different types of channe,

5. ~ Define Sin.uosity. Based on i:.,

observed in nature. ~

~ Differentiate between-
(i) Rocky and Boulder river stage
-._#

(ii) Tidal and Deltaic river -..;I/ . . ~

(iii) Sinuous and Non Sinuous braided river
,~ . d. · · f m a straight one. What (10)
3/ uescribe the mechanics of formation of a ~ean enng;'~
. are the variables that govern the meandenng proc~_
ss .

~ Explain the char3C~ristics of Himalayan Rivers. Why these riv~rs carry huge amount (06)

of sediment? ---</ . ,

Explain the aggradation and degradation process of river bed by the principle of (09)

continuity.
What are the different types of aggradation and degradation commonly occur in river (17)
bed? Explain three types from each with neat sketches.

$s;} Explain the alluvial changes of the Jamuna river in Bangladesh with neat sketches. (09)

7. ~ Diff~rentiate between scour and local scour. Describe different types local_;c9 ur for (10)
1 different combinations of upstream and downstream sediment discharge.- < . /

~ Describe with neat sketches, th~ flow pattern and scouring phenomena around a (10)
bridge pier and abutment. ~
~ t a certain cross-section of a river, following data were recorded: (15)

Maximum discharge = 11,000m3/sec

Highest flood level= 108.0 m
River bed level= 103.0 m
Maximum width = 2.2 km \, /

Estimate the maximum scour depth for construction of the following structures:
i) Six circular piers aligned with the flow (use CSU equation).
ii) 50m long spill through abutment 1V:2H, over a sand bed.
iii) Blunt abutment in a river having bed particle size of 0.25mm using the equation
· proposed by Inglish as well as by Ahmed.

8. (a) ~at is meant by river navigation? Explain its importance in modem system of (08)
transport

(b) Write down the various requirements for a navigable waterway. (10)

(c) What are the conditions need to be satisfied for the improvement of navigability by (17)
open channel method? Explain the different techniques available for it.
 Khulna University of Engineering & ;echnoloay
·. D.~ Pa~~ent ofd Civil .Eng ineering ....
8. Sc. Engineering 4 year 2n term Regular E xam I~a tion, 2011
(;E 426 1
(River Engineering)

Full Marks: 2 10
,• / . T ime: 3.0 hrs
N.S,
I) Answer any three GUestions fror., each ~~ction in separot~ s~~lpt.
Ii) Figures In lhe right margin Indicate full marks. · .

Section -A ·
"~~-:~.{~!!.:,
,. (a) ~at ls meant ~y the t~rm river training,? What a~e t~e di~~r~~t ~~jecti~es sirved b~ it? . (08) )
~ What are the different meth~ds th~~--~re generally adoote_9_to train a river temoor2n1v?· (12)
Explain any one method of the:s2me with n·eat sketches. ·
::,~(:) Design and sketch guide b~-~k-s at a cridg~-~-~ ;;f-~ i i~;cr fror.i the da.ta given .b-~low: / · ('15) · .,
3
(i) Maximum discharge = 8500 m /~ec. . .
(ii) Highest flood level = 107 ni
(iii) River bed level = 101 m and
(iv) . Av~rage diameter of river bed material =· 0.10 mm_.

'
2. (a) W:ier. do you suggest · temp~rar; river improvemen_t rather than perma;.ent (05}
:r.iprcvement?
~ What are the differenU:!Jethods_~x.ailable _th_a_t_a_r_g__gen~.~~lly adopted in 8af')glad_es~_to (? 5)
train a river permanen1l{'.? Expl~in any three methods· of.the same.- ·----·- - ··
r \Nhat are the purposes of bank p;ctt=~iion? What
for it? Explain ~ny three meth;ds of the same.
are the different r:r,ethqds available
· · .. .. · '
('i 5)

. .. .

3. Pf What is fall velocity? Show t~at the fin.ite tail :~elocity' of a spherical particle yields (08)

Ws Ji:n1W
where the symbols ha~e .t heir usual meanings.
)b1 State and explain..Du-Boy's bed-load formura·. . . . (12)
Jpt Derive
•
an expression for two-dimensional ver.ical diffusion eguati~n :for sea\ment.
., ..., = I
('l5)

4. _yr' Cxplaln the ideal;zed bed formS ir, alluvial channels accord_ing to Simon et L. wi:~·n~a: (j 0)
sketches. · . . 1. ·

jiJ( What are the _method~ availabie to piedi~i the bed fo_rms in riv~rs? ~xpl~in Van Rijn ti 2)
,. . . a ~roach of the same. . .. · . · . · . .=
. ..
State and expl~in the Colby formula fo estimate the total bed load. . (13)
 ·Section - B

I
.. (OB)
I .
P, ~ C lass! y the rivers based on : .
~ .?(!) Topography o( river basin 'v
• {j~ -flood hydrograp~\V .
~ 11 -Sinuosity and \/"'
~v ndian rivers / .
(09)
~xplal different types of rlvers in flood plains.~ · ..
(09)
~ e s.er be with suitable d!agram, the. fl~vla~ syste~ _of a river-course.
o-)~ -~ \,(? . :· .
~x"(~-- ~ af terlze· the Brnlimaputra an~ J,an~~s · ri~er: with · respe~t to large r_ivers in the (09)
f\ world Ir terms of flow and se9iment tran~port.. ~

6. (a) What ls meant by river navigation?" Explai~-:.its importance in modern SY.stem of (08)
transp6rt. · · · · · · · · - .
¥oescri~e t~e mechanics ·of formation. ·of a -~~_anderi_~~.: rive~ _from a s~raight one. What (09)
are theI variables govern the meandenn_
•
g pro~ess? v-,1
, •• •
.
~ h y t~~nsvers~ rotary curren~s ·get.de~eloped .i_ri',Wight reach· of a river? How and (09)
why s~oals are formed at conve_
x side of a _bend?_ ..:. .
I . .. . .
\1,~ Find the typic~I ~ea~dering param~ters for ~". -~~,-~vial ~iver of 500 m widtn_j (09) ·

y,::J;fl
1/
De~ne the terms :Scour' and .'Local sco_u r' ·with examples.

P:escribe different typ~s of_loc~I scours _for different co_

mbination or _upstream and
· ._. (04)

(091
dpwnstream sediment discharge. ·· · · · · , '··
0

~~sc~ibe_~ith rieat sketch;. the flow patt~~0 a·nd_ ~cb~ring _J>h~~omena_·a~Oll~d a bridge (09)
pier. . · · · ·.
,,,,,,,.,,, • , . •• • I • • ••• • •

••,\ ~ At a certain crcss-_sectio_n o_f ~ ~iver, followi~_g_da_ta·_were_~~corded: . · (13)

'- a) MaximiJm discharge= 20,000 m3/sec. .· . .

b) Highest fiood level = 108.0 m , ,
c) River, bed ·1evel.= .1Q2.5 m ·
d) Maxi/2ium width. = 2.0 m
. .
Estimate U]e ·ma~imum scour dept~.- for. construction of the following structures:
(i) Four circular bridge piers, each of 3.0 mdiameter (Use. CSU equation)
m
(ii) 200 lqng v·ertical abutment ~yer a :sa.nd ·bed channel and .
. (iii) Normal groyne of length .= 400.0 ·m at convex bank. ·
.,

8. •(a) E?Cplaih the aggradation and degradation process of river bed ~y t~P. principle of (09)
continuity. . .
{b). What are·the different types of aggradation··and degradr;ition commonly occur In a river (17)
r~ach. Explain two types from each with ·r,eat sketches.
(c) ~xplain with neat sketche.s; the lateral . migration and ..changes In cross-section (09)
geometry of the Jamuna river ~ith time. . . •. · .
------.--·--- --.
. .
..
 Khulna University of Engineering & Te h
. . c no 1ogy
. epartment of c,v,r Engineering
D
s. Sc. Engineering 4th Year 2nd Term Regular E . .
CE xaminatron, 2010
4261
(River Engineering )
Full Marks: 210
Time: 3 hrs
N.B. I) Answer ~ny thr~e questions from each section In separate script.
ii) Figures m the right margin indicate full marks.
iii) Necessary graphs will be supplied.

Section -A

~ y explain the fluvial system of a river with neat sketch. (11)

(9( Cl.9s1i'fy the rivers based on plan form. With other characteristics, describe (12)
.)flem based on sinuosity.
~ Differentiate the characteristics of rivers among (i) Sinuous and Non-sinuous (12)
braided (ii) Deltaic and Tidal rivers (iii) Himalayan and Non-Himalayan rivers.

2. (a) at is meant by river navigation? Write down the various requirements of (08)
navigable waterways.
Describe the mechanics ..Qfigr~].fillo of iii rneaReefffl9 rjverfrom--a-straight--one (10)
(c) Why transverse rotary currents get developed in a straight reach of a river? (11')
How and why shoals are formed at convex side of a bend?
(d) For an alluvial river of 60 m width, find the typical meandering parameters. (07)

3. (a) Define aggradation and degradation of a river bed. Applying the principle of (09)
continuity, explain the aggradation and degradation process of a river bed.
(b) Differentiate between following aggradation and degradation processes Wiih (16)
neat sketches (i) Caving and Gullying (ii) Entrenching and Armoring (iii)
Shoaling and Braiding (iv) Anastomosing and Anabranching.
(c) Explain the alluvial changes of the Jamuna River in Bangladesh with neat (10)
sketches.

4. (a) Explain clear water scour, Live bed scour and Equilibrium scour with neat (07)
sketch.
(b) Describe with neat sketches; how local scour is occurred around bridge pier. (13)
(c) The width, depth and mean flow velocity of a river is given as 30 m, 6 m and (15)
0.5 m/s, respectively. Estimate the possible scour depth for the construction of
the following structures.
(i) a rectangular pier of width 2 m aligned with the flow and have a shape factor
of 1.2 (use Colorado State University equation).
(ii) An inclined groyne which is extended up to 4 m inside the river from the
bank. (use a factor of 1.1 for the angle of attack).
(iii) An abutment in the river, where the average diameter of the bed material =
0.25 mm (use regime method of Lacey)
 Section - e_
. . What are the different objectives (08)
What is•meant by the term river training?
5. (a)
served by it? . adopted to train a river (12)
11
(b) What are the different methods that are genera y 'th neat sketches.
permanently? Explain any three methods of the same WI .
• b 'd site of a river. Maximum (15)
5
(c) The following hydraulic dat~ pertains to a Ir~ ~~ m River bed level= 100
discharge= 8000 cumecs,_Highest flood l~ve_ ' si n and sketch
m, Average diameter of nver bed material - ~.11 m~. 0 e 9
guide banks including the launching apron to train the rrver.

6. (a) When do you suggest temporary river improvement rather than a perma~ent (OB)
improvement? What are the different methods available for temporary river
improvement?
(b) Explain any one method of the temporary river improvement with neat (12)
sketches. ·
(c) What are the purposes of bank protection? What are the different methods (15)
available for it? Explain any three methods of the same.

7. (a) Explain the ·idealized bed forms in alluvial rivers according to Simon et. al. (10)
with neat sketches.
(b) What are the methods available for the prediction of bed form in rivers? (10)
Explain any one method.
(c) Derive an expression for two dimensional verticai diffusion equation for (15)
sediment.

8. (a) What are the forces acting on a sediment particle? Derive the expression, (10)
u.2/9£1D ~ 4/3 (1/a 2Co) {03'(02+Q3)} tan (q,), for tt:a motion or equilibrium of a
sediment particle on a river bed. Where the symbols have their usual
meanings.
(b) State and explain Van Rijn formula to estimate the total sediment load from a (15)
river.
(c) Determine the total sediment load for a river from the following data by Colby (10)
total land formula. Average depth of flow= 6 m, width of river= 2.5 km, mean
velocity = 2 m/sec, median particle size = 0.50 mm, water temperature =
70°F, concentration of fine sediment = 90000 ppm. [Necessary graphs will be
supplied].
 Khulna University of Engineering & To h
P,e partment of Civil En ; . . ~ nolor1y
B.' Sc. Engineering 3 rd Year 2nt1 T g neer,ng
9E 4261 erm Exa mination, 2008
. (Ri~_er Engineering)
Full Marks: 210
Time; 3,0 hr~
N.B.: (,,'\ Answer any three questions r . . .
rn)) Figures In the right margin ln~~~t;ach section in G'JParato 8f?r1pt.
Assume reasonable value for 'any mT~~~~ data
(
-, ,

Section~A

1.
(a) Briefly describe the fluviaf system of an idealized river course from its source to outfall. (07)
(b) Describe different types or rivers based on the topography of river basin. ,. (1 6)
(c) Define s1n~osity._ Based ·on sinuosity classify the channel oatterns and write.,,~;~ the (08)
values of s1nuos1ty for each. · · · , , .-
(d) What_are the primary causes for the braided condition of a riJ~r? (04}

2. (a) Deduce the expression for fall velocity of a spherical sediment particl~_.,,•,. -. (iO}
(b) Define sediment· flux. Show that the vertical distribution of suspended sediment (16) - .:.
concentration ean be- express~d a~
• 4• • • ,_., ;,,,.~ ;

Where the symbols bear their usual meanings

(c) Why some particles stay in suspension in a stream? "The sediment particles are found (09)
In suspension even the flow is steady and Uniform•-explain briefly.

3. (a) What are the common bed forms found in river bed? Expl~ifl .with neat sketches, the (14)
change in bed forms with increasing flow velocity from I01Nerflow regime to upper flow
regime.
(b) What are the approaches for predicting bed forms? Explain ~~e,6-~them. -·_ (07)
(c) Classify the sediment transport formula based on the mode of sediment transport. (08)
Write down the name of formulas under each class.
(d) Explain the Colby formula to determine the total bed material load. (06)

4. (a) How can you mathematically express the aggradation and degradation of a river bed by (10)
applying the principle of continuity? Explain with neat sketches.
(b) What is river navigation? Explain its importance in the modem system of transport. (08)
(c) Write down the conditions to be satisfied for improving the navigability by open d1annel {17)
method? Describe briefly the different techniques which are involved in improving the
navigability by this method.

Pam: l of2
 5.

(06)
(16)

,.=; \, '. , •,1r•1• ' •: : • :

·:
f
.-'.'' .
•
,:- ·: .; ,• • .
• .~.),· .. :;.: -..::· •~
I
.
, 1' • ' t.

(08)
6. (a) What is cut-off? Explain'brieflY how·is it used.as a method o~F!v~r training?
(07)
(b) Describe the functions of guide banks.arid as'river training measures. lir~y~es
(20)
(c) Write short notes on the following:
(i) Aggrading and Degrading rivers
(ii) T-headed and Hoc,kev: t:!~q~} ivers •
(iii) Sphericity and sha·p·e factor of a sediment particle
(iv) Deltas and .Alluvial fans.

; :. : . ,· ' .: ,. . ·.

·'i: .') a) What' are· ttie'\1enerai' te'at'Gres 'oi·a meanderin~{ ·riv~r? Explain .'the meandering (12)
parameters of a river meander with neat sketches. ·· ·· ·
(b) Differentiate be'tween · · .' ·. ··, ,.:;•. 'I ,: · -·; ., ·,. .;. · . . · (06)
(i) Suspended load and vrosh load.
(ii) Bed load and bed material load.
• •.· I • • \ • ,• f ~ ,:•1 l : •:. ; • J• • ~ ,' ,

:-:., :(~) .:~h~t do you mean ~Y initia~\?n of mo~io~ ~fa sedimer.{ P.~.rtic/e? From .~h~ balance of (12)
forces acting on a sediment · particle lying on a hQ~zpntal, river ·.bed, ... deduce the
conditions for the initiation of motion. ·· · -· · · ·"· · · · · · ·
(d) Draw a qualitative sheild diagram for initiation of motion and explain its different (05)
regions. :·• ·

~. ;; ·. , ' . ::-· • . -:"· .. · ,·:.,;;i..":,' ' i •!:1•·.~,'./•·~ ·..· .'.·-)

8. (a) What are the:purposes of temporary river improveinent?-What are the commonly used (08)
methods for it?
(b) What are the v,arious methods which are generally adopted for bank protection? (05)
(c) . The fol/oW,ing,~ydraulic
.
d~ta pertains to.a bridge site qf. a river:
. . . . •, .. (22)
Maximum discharge'= 12000 curryecs .·-•:: .,,·; ;c·r: · '· ... . ....., .
-:--

Highest flood level= 106.0 m

River bed level= 100.0 m · . .: . ·. ;··· · · ,..:-;
Average diameter of river bed material := 0:10 mm.·Design and sketch Bell's bunds
including the launching apron to .train--the riv.er,-'.-· ·· · ·. . · · ·- · ...
:: Ii · j , • , ' · , '
 a University of Eng_in,eering. & Technology
,<httlnoepart!ne~ht of ~~~•I Eng,ne~rir:19
,..._ Engineering 4 year, Term Examination 200S
fJ, __,..,. CE 4261 '
(River Engineering)

pull Marl<S: 210 . . Time: 3 hrs

N .B . n Answer any three C1uestions from each section in separate script.
ii) Fi9ures in the ri9ht margin indicate full marks.
Iii) Necessary chart and qraphs will be supplied.

Section -A

1. (a) What is mean~ by the term "River Training"? What are the d ifferent ob_iectives (08)
5erved by it?
(b) What are the different mett:,ods that are generally adopted to train a river (12)
permanently? Explain any three methods of the same vvitt-, neat 5ketches.
(c) The following hydraulic cat~ pertains to a bridge side of a river: (15)
iviaxlmum discharge - .10,000 m 3/sec
Highest fiood level= 110m

Average diameter of river bed materiel = 0.10mm

Design and sketch a guide bank including th2 /a:..;nchir,g apron to train the
river.

2. (a_i Classify rivers according to different criteria. (10)

(b) Exnl2:n the fluvial system of a river with neat sketches. (10_)
(c) oesr;nbe different stage or a rive,. Write cown the dIscnarg.2 behavior of (15)
Ganges and Brahmaputra river. .

3. (a) Exp!ain 'Constriction scour' and 'Confluence scour' with sketches. (08)
(bl Define local scour. What are the factors that affect the magnitude of locel scour (12)
depth ~t piers & abutments?
(c) Determine the magnitude of the contraction ~cour depth for both live-bed & (15)
clea~ ·vvata; scou; condition from ttia follo-.,ving data. -
The upstream chann~I width= 9Q.5m: dept~ ~ ?:§¥p:,. The discharge is . 752
m~'/s and ls all contained within the channel. Channe: slope= 0.0045m/m. The
bridge abutments consist of vertical war:~ with wing wa!ls. Bridge \Vidth = 36.2;
with 4 ~et~ of pir-r5 consisting of 4 columns 0 .3Sm in diamet\=-;r.
The bed material size df.o is 0. 75mm with a fall velocity of 0 .12 ·m /s. Original
depth at brldge is e5timated as 2.16 m .

4. (a) What are the forces acting on a sediment oarticle? Under what conditions a (10)
particle on a river bed will be set in motion. .
(b) Derive an expression for two dimensional vertical diffusion equation for (15)
sediment
 (c) State and explain Engelund and Hansen total load formula.

Section - B

5. (a) What are the purposes of bank protection? What are the various methods (17)
avaflable for it? E:..:plain any three methods of the same.
(b) When do you suggest a temporary river Improvement rather than a (18)
penY,ai,ent improvement? What are the different methods available for
temporary river improvement? Explain anyone method of the same with neat
sketches .

..6. (a_) What is meant by the term fall velocity? Explain the ·influence of Reynold;s (08)
" number on it. ·
. . .
(b) State and explain PuBoy's bed load formula.
.., (15)
':., (c_)
- Determine the total sediment load. of a river frP,m ·the data qiven beiow by (12)
r--'b·
\JVI Y· '-'-I vv •-r--u
~V~O lo=--! IUI I I I
1a _ _ . .
I • . -
Width of river= 2 mile
.A verage deptll of flow= 20 ft
Mean velocity =- 0 ft/sec
Median particle size= 0.50 mm ·
V'v'ater t~mperature =- ·70°F
Concentration of fine sediment= 80,000 ppm
[ Use suppi\ed figs. E-nclc,se]'

7. (a) Describe the following t\,vo methods adopted for improvin9 river navigation. (10)
Loc.k Et:ld Dam arrangements
Canalizc:tion
(b) Exolain the idealized bed forms 1n alluvial channel .according to Simon et. al. (1 O)

(c) Explain Van Ri_in approach for prediction of bed form. (15)

...
8. (a) \/\'hat is Groyr:e? Mention its functions in river' training works. Distinguieh {1.5)
between ''Ri:;peHlng" and "Deflecting" groyne~ explaining the!r action in river
training.
(b) Expiain the principle of dredging · operation. Dii;cuss about the working (12)
principle of main f\1ur types of dredgers.
(c) \/./hat is Cutt-off? Explain how a cLrtt-off may be us•Jd. as a river training (OB)
mea5ure.
 ----= £xpfanot,o
· on available _
ea·sed data
_ -
.
Ex trapo toted - •
Ocplh ·
1. 0 rt
D tplh
10ft /
Dtpth
100,,
I
I
II
I I 11
II /I
100
en
"C
C
ro

-0
en

a, 10 r7r---r--;¥1---1--+1--At--+.-J.--Lt.::-.--J
I

....C)
ro
.c
u
CfJ
·-
Cl

0 .1 .......__~_._.........U..UU..UL.L!.....J..."-'-.1..L.1.UUU-IIJ~L-L....i.+.U...U...&.....1~.L..L...&..1.~
1 10 1 10
Cl
1 10 I 10· u.
Mean velocity (ft/sec)

(1)
N
'iii
(1)
u
t
ro
a.
C:
ro
1oo'g
.,,
'
-E
C:
(1)
.....
(1)
~
"O
.....
.E
·1 0 u
&Q)
(1)
0)
ro
c
Q)
~
1-----.......................... 1 Q)
a..
0 .1 1
0 .1 1 10 . 100 Median diameter of
Depth (ft) bed ,:naterial (mm)

Fig. Approximate effect of.water temperature and concentration of fine sediment

on the relationship of discharge of sands to mean velocity (after Colby, 1964).

'