Recent questions and answers in Water Resources Engineering

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1

GATE2020-CE-1-12
Velocity of flow is proportional to the first power of hydraulic gradient in Darcy’s law. This law is applicable to laminar flow in porous media transitional flow in porous media turbulent flow in porous media laminar as well as turbulent flow in porous media

asked Feb 28, 2020 in Hydraulics by jothee (2.7k points)

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2

GATE2020-CE-1-14
Uniform flow with velocity $U$ makes an angle $\theta$ with $y$-axis, as shown in the figure The velocity potential $(\phi)$, is $\pm U(x\sin\theta+y\cos\theta)$ $\pm U(y\sin\theta-x\cos\theta)$ $\pm U(x\sin\theta-y\cos\theta)$ $\pm U(y\sin\theta+x\cos\theta)$

asked Feb 28, 2020 in Hydraulics by jothee (2.7k points)

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3

GATE2020-CE-1-15
The data for an agricultural field for a specific month are given below: ... $mm$) to be applied to the field in that month, is $0$ $20$ $40$ $80$

asked Feb 28, 2020 in Irrigation by jothee (2.7k points)

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4

GATE2020-CE-1-16
During chlorination process, aqueous (aq) chlorine reacts rapidly with water to form $Cl^-,HOCl$, and $H^+$ as shown below $Cl_2(aq)+H_2O\:{\large\rightleftharpoons}\:HOCl+Cl^-+H^+$ The most active disinfectant in the chlorination process from amongst the following, is $H^+$ $HOCl$ $Cl^-$ $H_2O$

asked Feb 28, 2020 in Water Resources Engineering by jothee (2.7k points)

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5

GATE2020-CE-1-17
An amount of $35.67\:mg\:HCl$ is added to distilled water and the total solution volume is made to one litre. The atomic weights of $H$ and $Cl$ are $1$ and $35.5$, respectively. Neglecting the dissociation of water, the pH of the solution, is $3.50$ $3.01$ $2.50$ $2.01$

asked Feb 28, 2020 in Water Resources Engineering by jothee (2.7k points)

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6

GATE2020-CE-1-24
A $4\:m$ wide rectangular channel carries $6\:m^3/s$ of water. The Manning’s ‘$n$’ of the open channel is $0.02$. Considering $g=9.81\:m/s^2$, the critical velocity of flow (in $m/s$, round off to two decimal places ) in the channel, is ____________.

asked Feb 28, 2020 in Water Resources Engineering by jothee (2.7k points)

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7

GATE2020-CE-1-36
Water flows at the rate of $12\:m^3/s$ in a $6\:m$ wide rectangular channel. A hydraulic jump is formed in the channel at a point where the upstream depth is $30\:cm$ (just before the jump). Considering acceleration due to gravity as $9.81\:m/s^2$ and density of water as $1000\:kg/m^3$, the energy loss in the jump is $114.2\:kW$ $114.2\:MW$ $141.2\:h.p.$ $141.2\:J/s$

asked Feb 28, 2020 in Hydraulics by jothee (2.7k points)

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8

GATE2020-CE-1-37
A water supply scheme transports $10\:MLD$ (MIllion Litres per Day) water through a $450\:mm$ diameter pipeline for a distance of $2.5\:km$. A chlorine dose of $3.50\:mg/litre$ is applied at the starting point of the pipeline to attain a certain level of disinfection at ... the chlorine dose (in $mg/litre$) to be applied at the starting point should be $3.95$ $4.40$ $4.75$ $5.55$

asked Feb 28, 2020 in Fluid Mechanics by jothee (2.7k points)

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9

GATE2020-CE-1-49
Three reservoirs $P,Q$ and $R$ are interconnected by pipes as shown in the figure (not drawn to the scale). Piezometric head at the junction $S$ of the pipes is $100\:m$. Assume acceleration due to gravity as $9.81\:m/s^2$ ... height of water level in the lowermost reservoir $R$ (in $m$, round off to one decimal place) with respect to the datum, is ______.

asked Feb 28, 2020 in Hydrology by jothee (2.7k points)

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10

GATE2020-CE-1-51
A circular water tank of $2\:m$ diameter has a circular orifice of diameter $0.1\:m$ at the bottom. Water enters the tank steadily at a flow rate of $20\:litre/s$ and escapes through the orifice. The coefficient of discharge of the orifice is $0.8$. ... losses. The height of the water level (in $m$, round off to two decimal places) in the tank at the steady state, is ______.

asked Feb 28, 2020 in Hydrology by jothee (2.7k points)

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11

GATE2020-CE-1-52
Surface Overflow Rate (SOR) of a primary settling tank (discrete settling) is $20000\:litre/m^2$ per day. Kinematic viscosity of water in the tank is $1.01\times10^{-2}\:cm^2/s$. Specific gravity of the settling particles is $2.64$. Acceleration due to ... $80\%$ efficiency in the tank, is ______.

asked Feb 28, 2020 in Water Resources Engineering by jothee (2.7k points)

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12

GATE2020 CE-2-12
Muskingum method is used in hydrologic reservoir routing hydrologic channel routing hydraulic channel routing hydraulic reservoir routing

asked Feb 13, 2020 in Hydrology by jothee (2.7k points)

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13

GATE2020 CE-2-13
Superpassage is a canal cross-drainage structure in which natural stream water flows with free surface below a canal natural stream water flows under pressure below a canal canal water flows with free surface below a natural stream canal water flows under pressure below a natural stream

asked Feb 13, 2020 in Irrigation by jothee (2.7k points)

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14

GATE2020 CE-2-14
A triangular direct runoff hydrograph due to a storm has a time base of $90$ hours. The peak flow of $60\: m^3/s$ occurs at $20$ hours from the start of the storm. The area of catchment is $300\: km^2$. The rainfall excess of the storm (in cm), is $2.00$ $3.24$ $5.40$ $6.48$

asked Feb 13, 2020 in Hydrology by jothee (2.7k points)

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15

GATE2020 CE-2-15
The velocity components in the $x$ and $y$ directions for an incompressible flow are given as $u = (-5 + 6x)$ and $v = -(9+6y)$, respectively. The equation of the streamline is $(-5+6x)-(9+6y) = \text{constant}$ $\dfrac{-5+6x}{9+6y}= \text{constant}$ $(-5+6x)(9+6y) = \text{constant}$ $\dfrac{9+6y}{-5+6x}= \text{constant}$

asked Feb 13, 2020 in Water Resources Engineering by jothee (2.7k points)

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16

GATE2020 CE-2-36
Crops are grown in a field having soil, which has field capacity of $30\%$ and permanent wilting point of $13\%.$ The effective depth of root zone is $80\ cm$. Irrigation water is supplied when the average soil moisture drops to $20\%.$ ... of water for the crops is $2\ mm$, the frequency of irrigating the crops (in days), is $7$ $10$ $11$ $13$

asked Feb 13, 2020 in Irrigation by jothee (2.7k points)

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17

GATE2020 CE-2-37
Alkalinity of water, in equivalent/litre (eq/litre), is given by ${\{HC{O_3}^-}\} + 2{\{C{O_3}^{2-}}\} + {\{OH^-\}}\ -\ {\{H^+\}}$ where, $\{\ \ \}$ represents concentration in $\text{mol/litre}$ ... and $H^+$ are NEGLECTED, the alkalinity of the water sample $\text{(in mg/litre as}\: CaCO_3),$ is $130.4$ $100.0$ $50.0$ $65.2$

asked Feb 13, 2020 in Water Resources Engineering by jothee (2.7k points)

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18

GATE2020 CE-2-49
A cast iron pipe of diameter $600\: mm$ and length $400\: m$ carries water from a tank and discharges freely into air at a point $4.5\: m$ below the water surface in the tank. The friction factor of the pipe is $0.018$. Consider acceleration due to gravity as $9.81\: m/s^2$. The velocity of the flow in pipe (in $m/s$, round off to two decimal places) is ________.

asked Feb 13, 2020 in Water Resources Engineering by jothee (2.7k points)

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19

GATE2020 CE-2-50
A hydraulic jump occurs in a triangular $\text{(V-shaped)}$ channel with side slopes $1:1$ (vertical to horizontal). The sequent depths are $0.5\: m$ and $1.5\: m$. The flow rate (in $m^3/s$, round off to two decimal places) in the channel is ________.

asked Feb 13, 2020 in Water Resources Engineering by jothee (2.7k points)

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20

GATE2020 CE-2-52
The ion product of water $(pK_w)$ is $14$. If a rain water sample has a $pH$ of $5.6$, the concentration of $OH^-$ in the sample (in $10^{-9}\: \text{mol/litre}$, round off to one decimal place), is ________.

asked Feb 13, 2020 in Water Resources Engineering by jothee (2.7k points)

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21

GATE2017 CE-2-7
If a centrifugal pump has an impeller speed of $N$ (in rpm), discharge $Q$ (in $m^3/s$) and the total head $H$ (in $m$), the expression for the specific speed $N_s$ of the pump is given by $N_s = \dfrac{NQ^{0.5}}{H^{0.5}} \\$ $N_s = \dfrac{NQ^{0.5}}{H}\\$ $N_s = \dfrac{NQ^{0.5}}{H^{0.75}} \\$ $N_s = \dfrac{NQ}{H^{0.5}}$

asked Aug 7, 2019 in Hydraulics by gatecse (3.9k points)

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22

GATE2017 CE-2-46
A $1$ m wide rectangular channel carries a discharge of $2 \: m^3 /s$. The specific energy-depth diagram is prepared for the channel. It is observed in this diagram that corresponding to a particular specific energy, the subcritical depth is twice the supercritical depth. The subcritical depth (in meters, up to two decimal places) is equal to ________

asked Aug 7, 2019 in Water Resources Engineering by gatecse (3.9k points)

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23

GATE2017 CE-2-47
A catchment is idealized as a $25 \: km \times 25 \: km$ ... . The average precipitation (in mm, up to one decimal place) over the catchment during this month by using the Thiessen polygon method is ___________

asked Aug 7, 2019 in Hydrology by gatecse (3.9k points)

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24

GATE2017 CE-2-48
The culturable command area of a canal is $10.000$ ha. The area grows only two crops - rice in the Kharif season and wheat in the Rabi season. The design discharge of the canal is based on the rice requirements, which has an irrigated area of $2500$ ha, ... The maximum permissible irrigated area (in ha) for wheat, with a base period of $120$ days and delta of $50$ cm, is __________

asked Aug 7, 2019 in Irrigation by gatecse (3.9k points)

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25

GATE2017 CE-2-49
Water is pumped at a steady uniform flow rate of $0.01 \: m^3/s$ through a horizontal smooth circular pipe of $100$ mm diameter. Given that the Reynolds number is $800$ and $g$ is $9.81 \: m/s^2$, the head loss (in meters, up to one decimal place) per km length due to friction would be _______

asked Aug 7, 2019 in Hydraulics by gatecse (3.9k points)

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26

GATE2017 CE-2-51
For a given water sample, the ratio between BOD$_{\text{5-day, 20}^{\circ} C}$ and the ultimate BOD is $0.68$. The value of the reaction rate constant $k$ (on base $e$) (in day$^{-1}$, up to two decimal places) is ________

asked Aug 7, 2019 in Water Resources Engineering by gatecse (3.9k points)

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27

GATE2017 CE-2-52
A municipal corporation is required to treat $1000 \: m^3/day$ of water. It is found that an overflow rate of $20 m/day$ will produce a satisfactory removal of the discrete suspended particles at a depth of $3 m$. The diameter (in meters, round to the nearest integer) of a circular settling tank designed for the removal of these particles would be ___________

asked Aug 7, 2019 in Water Resources Engineering by gatecse (3.9k points)

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28

GATE2017 CE-2-53
The analysis of a water sample produces the following results: ... $CaCO_3$) of the water sample is _______

asked Aug 7, 2019 in Water Resources Engineering by gatecse (3.9k points)

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29

GATE2019 CE-1: 13
In a rectangular channel, the ratio of the velocity head to the flow depth for critical flow condition, is $\dfrac{1}{2}\\$ $\dfrac{2}{3} \\$ $\dfrac{3}{2} \\$ $2$

asked Feb 14, 2019 in Hydraulics by Arjun (2.8k points)

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30

GATE2019 CE-1: 14
If the path of an irrigation canal is below the bed level of a natural stream, the type of cross-drainage structure provided is Aqueduct Level crossing Sluice gate Super passage

asked Feb 14, 2019 in Water Resources Engineering by Arjun (2.8k points)

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31

GATE2019 CE-1: 15
A catchment may be idealised as a rectangle. There are three rain gauges located inside the catchment at arbitrary locations. The average precipitation over the catchment is estimated by two methods: Arithmetic mean $(P_A)$ Thiessen polygon $(P_T)$ Which one of the ... greater than $P_T$ $P_A$ is always equal to $P_T$ There is no definite relationship between $P_A$ and $P_T$

asked Feb 14, 2019 in Water Resources Engineering by Arjun (2.8k points)

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32

GATE2019 CE-1: 22
A circular duct carrying water gradually contracts from a diameter of $30 \: cm$ to $15 \: cm$. The figure (not drawn to scale) shows the arrangement to differential manometer attached to the duct. When the water flows, the differential manometer shows a ... Assuming frictionless flow, the flow rate (in $m^3/s$, round off to $3$ decimal places) through the duct is ________

asked Feb 14, 2019 in Water Resources Engineering by Arjun (2.8k points)

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33

GATE2019 CE-1: 28
A rectangular open channel has a width of $5 \: m$ and a bed slope of $0.001$. For a uniform flow of depth $2 \: m$, the velocity is $2 \: m/s$. The Manning’s roughness coefficient for the channel is $0.002$ $0.017$ $0.033$ $0.050$

asked Feb 14, 2019 in Water Resources Engineering by Arjun (2.8k points)

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34

GATE2019 CE-1: 49
The hyetograph of a storm event of duration $140$ minutes is shown in the figure: The infiltration capacity at the start of this event $(t=0)$ is $17 \: mm/hour$, which linearly decreases to $10 \: mm/hour$ after $40$ minutes duration. As the event ... of the storm event. The value of the infiltration index, $\phi$ (in $mm/hour$ round off to $2$ decimal places), is _____________

asked Feb 14, 2019 in Water Resources Engineering by Arjun (2.8k points)

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35

GATE2019 CE-1: 50
Two water reservoirs are connected by a siphon (running full) of total length $5000$ m and diameter of $1.10$ m, as shown below (figure not drawn to scale). The inlet leg length of the siphon to its summit is $2000$ m. The difference in the water surface ... of the summit of siphon from the water level of upper reservoir, $h$ (in m, round off to $1$ decimal place) is ______

asked Feb 14, 2019 in Hydrology by Arjun (2.8k points)

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36

GATE2019 CE-1: 51
Consider a laminar flow in the x-direction between two infinite parallel plates (Couette flow). The lower plate is stationary and the upper plate is moving with a velocity of $1 \: cm/s$ in the x-direction. The distance between the plates is $5 \: mm$ and the dynamic viscosity ... $\dfrac {\partial p}{\partial x}$, (in $N/m^2$ per $m$, round off to $1$ decimal place) is _________

asked Feb 14, 2019 in Fluid Mechanics by Arjun (2.8k points)

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37

GATE2019 CE-2: 12
A solid sphere of radius, $r$, and made of material with density, $\rho_s$, is moving through the atmosphere (constant pressure, $p$) with a velocity, $v$. The net force ONLY due to atmospheric pressure $(F_p)$ acting on the sphere at any time, $t$, is $\pi r^2 p$ $4 \pi r^2 p$ $\dfrac{4}{3} \pi r^3 \rho_s \dfrac{dv}{dt}$ zero

asked Feb 12, 2019 in Water Resources Engineering by Arjun (2.8k points)

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38

GATE2019 CE-2: 13
The velocity field in a flow system is given by $v=2\textbf{i}+(x+y) \textbf{j} + (xyz) \textbf{k}$. The acceleration of the fluid at $(1,1,2)$ is $2 \textbf{i}+ 10 \textbf{k}$ $4 \textbf{i}+ 12 \textbf{k}$ $ \textbf{j}+ \textbf{k}$ $4 \textbf{j}+ 10 \textbf{k}$

asked Feb 12, 2019 in Water Resources Engineering by Arjun (2.8k points)

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39

GATE2019 CE-2: 14
An inflow hydrograph is routed through a reservoir to produce an outflow hydrograph. The peak flow of the inflow hydrograph is $P_I$ and the time of occurrence of the peak is $t_I$. The peak flow of the outflow hydrograph is $P_O$ and the time of occurrence of the peak is $t_O$. ... $P_I <P_O$ and $t_I > t_O$ $P_I >P_O$ and $t_I < t_O$ $P_I >P_O$ and $t_I > t_O$

asked Feb 12, 2019 in Hydrology by Arjun (2.8k points)

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40

GATE2019 CE-2: 15
An earthen dam of height $H$ is made of cohesive soil whose cohesion and unit weight arc $c$ and $\gamma$ respectively. If the factor of safety against cohesion is $F_c$, the Taylor’s stability number $(S_n)$ is $\dfrac{\gamma H}{cF_c} \\$ $\dfrac{cF_c}{\gamma H} \\$ $\dfrac{c}{F_c \gamma H} \\$ $\dfrac{F_c \gamma H}{c}$

asked Feb 12, 2019 in Water Resources Engineering by Arjun (2.8k points)