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Surface Water Resources(9)Groundwater Resources(6)Environmental Hydraulics(15)

Surface Water Resources

9 Questions

GATE→2026→Water Resources and Environmental Hydraulics→Surface Water Resources

Q1

NAT[1 Mark]

A 6-hour rainfall of 6 cm at a station was found to have a return period of 40 years. The probability that a 6-hour rainfall of this or larger magnitude will occur at least once in 20 successive years at that station is _____ (rounded off to three decimal places).

Explanation

GATE→2026→Water Resources and Environmental Hydraulics→Surface Water Resources

Q2

NAT[2 Marks]

The mass curve of a rainfall event of $100\text{ min}$ duration over a catchment is given in the table. If the initial loss is $0.6\text{ cm}$ and $W$-index is $0.6\text{ cm/hour}$, the total surface runoff from the catchment is _____ cm (rounded off to one decimal place). Time (min): 0, 20, 40, 60, 80, 100 Cumulative rainfall (cm): 0, 0.5, 1.2, 2.6, 3.3, 3.5

Explanation

GATE→2024→Water Resources and Environmental Hydraulics→Surface Water Resources

Q3

NAT[1 Mark]

A Class-A pan was setup adjacent to a lake for measuring evaporation losses in the lake. The depth of water in the pan at the beginning of a certain week was $250\text{ mm}$. In that week, there was a rainfall event with $10\text{ mm}$ depth. Water depth in the pan at the end of the week was $240\text{ mm}$. The pan coefficient is $0.8$. The estimated lake evaporation during the week was _____ mm (an integer value).

Explanation

GATE→2024→Water Resources and Environmental Hydraulics→Surface Water Resources

Q4

NAT[2 Marks]

Consider a watershed and isohyets as shown in the figure. The average rainfall in the watershed is _____ mm (an integer value).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Surface Water Resources

Q5

NAT[1 Mark]

An S-hydrograph was prepared for a catchment of $240\text{ km}^2$ using 3-hour unit hydrograph ($1\text{ cm}$ rainfall excess). The equilibrium discharge for the S-hydrograph would be _____ (in $\text{m}^3/\text{s}$, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Surface Water Resources

Q6

NAT[2 Marks]

The following figure shows a catchment ($Q, S, U, T, Q$) and adjoining raingauge stations $P, Q, R, S, U$ and $V$. Due to a storm, $20\text{ mm}, 25\text{ mm}, 30\text{ mm}, 15\text{ mm}, 22\text{ mm}$ and $18\text{ mm}$ rainfall depths were recorded by raingauges at $P, Q, R, S, U$ and $V$, respectively. The corresponding mean rainfall over the catchment using Thiessen polygon method is _____ (in mm, rounded off to two decimal places).

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Surface Water Resources

Q7

MCQ[1 Mark]

Consider the following statements: Statement 1: Goodrich method for reservoir routing is based on hydrologic flood routing method. Statement 2: Muskingum method for channel routing is based on hydraulic flood routing method. Which one of the following is correct?

(A)

Statement 1 is false; Statement 2 is false

(B)

Statement 1 is true; Statement 2 is false

(C)

Statement 1 is true; Statement 2 is true

(D)

Statement 1 is false; Statement 2 is true

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Surface Water Resources

Q8

NAT[1 Mark]

The following figure shows a 2-hour unit hydrograph ($1\text{ cm}$ rainfall excess) for a catchment area of $540\text{ hectare}$. The peak discharge (in $\text{m}^3/\text{s}$, rounded off to one decimal place) of the above unit hydrograph is _____.

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Surface Water Resources

Q9

NAT[2 Marks]

An isolated storm of 3 hours occurred over a catchment area in the following manner: - Area 1 (15%): Rainfall (0.4, 2.5, 0.5 cm), $W$-index = 1.6 cm/h - Area 2 (35%): Rainfall (0.8, 3.0, 1.0 cm), $W$-index = 2.1 cm/h - Area 3 (50%): Rainfall (0.8, 0.6, 2.6 cm), $W$-index = 1.9 cm/h Total rainfall excess (in cm, rounded off to one decimal place) over the catchment for the above storm is

Explanation

Groundwater Resources

6 Questions

GATE→2026→Water Resources and Environmental Hydraulics→Groundwater Resources

Q10

NAT[2 Marks]

A well penetrates an unconfined aquifer. The water level (head) in the well prior to pumping is $25\text{ m}$. After a long period of pumping at a constant rate of $Q = 0.05\text{ m}^3/\text{s}$, the drawdowns at distances of $r_1 = 50\text{ m}$ and $r_2 = 150\text{ m}$ from the well are observed to be $s_1 = 3\text{ m}$ and $s_2 = 1.2\text{ m}$, respectively. The hydraulic conductivity of the unconfined aquifer is _____ $\times 10^{-4}\text{ m/s}$ (rounded off to two decimal places). ($\pi = 3.14$)

Explanation

GATE→2024→Water Resources and Environmental Hydraulics→Groundwater Resources

Q11

MCQ[2 Marks]

Consider two horizontal layers of an aquifer as shown in figure. Each layer is isotropic and homogeneous. Flow is parallel to the stratification. Thickness and horizontal hydraulic conductivity of layer-1 are $h_1$ and $K_1$, respectively. Thickness and horizontal hydraulic conductivity of layer-2 are $h_2$ and $K_2$, respectively. The equivalent horizontal conductivity $K_x$ for the aquifer system is given by

(A)

$K_x = \frac{K_1 h_1 + K_2 h_2}{h_1 + h_2}$

(B)

$K_x = \frac{K_1 + K_2}{2}$

(C)

$K_x = \frac{K_1 h_2 + K_2 h_1}{h_1 + h_2}$

(D)

$K_x = \sqrt{K_1 K_2}$

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Groundwater Resources

Q12

MCQ[1 Mark]

The kinematic viscosity of glycerin and kerosene are $1.2$ times and $0.95$ times of that of water, respectively. Glycerin and kerosene flow through two identical porous media having same hydraulic gradient. Assuming Darcy's law is valid for the porous media, the ratio of flow rate of kerosene to that of glycerin is

(A)

1.052

(B)

1.140

(C)

0.792

(D)

1.263

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Groundwater Resources

Q13

NAT[2 Marks]

A fully penetrating well is installed in a homogenous and isotropic confined aquifer. The aquifer has uniform thickness of $16\text{ m}$ and hydraulic conductivity of $25\text{ m/d}$. Water is being pumped out from the well at a constant rate of $0.1\text{ m}^3/\text{s}$ till steady state condition is reached. If a drawdown of $3.5\text{ m}$ is observed at a distance of $75\text{ m}$ from the well then the drawdown at a distance of $150\text{ m}$ from the well will be _____ (in m, rounded off to two decimal places).

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Groundwater Resources

Q14

MCQ[1 Mark]

The correct order of hydraulic conductivity for the geologic formations is

(A)

Aquifer > Aquitard > Aquiclude > Aquifuge

(B)

Aquifer < Aquitard < Aquiclude < Aquifuge

(C)

Aquitard > Aquifer > Aquifuge > Aquiclude

(D)

Aquifer > Aquiclude > Aquitard > Aquifuge

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Groundwater Resources

Q15

NAT[2 Marks]

Two reservoirs having a difference of $20\text{ m}$ in their water surface elevations are connected through a confined aquifer (thickness $= 5\text{ m}$, length $= 2\text{ km}$, hydraulic conductivity $K = 3 \times 10^{-3}\text{ m/s}$, and porosity $\eta = 0.3$) as shown in the following figure. If the Reservoir 1 is contaminated by a pollutant then the time (in days, rounded off to one decimal place) taken by the pollutant to reach to the Reservoir 2 under advection will be

Explanation

Environmental Hydraulics

15 Questions

GATE→2026→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q16

MCQ[1 Mark]

Consider the following statements regarding the pressure measured at a point in a fluid. S1: Absolute pressure is gauge pressure plus atmospheric pressure. S2: Gauge pressure is measured by considering absolute zero pressure as datum. S3: Absolute pressure is measured by considering atmospheric pressure as datum. S4: Vacuum pressure is negative pressure obtained by subtracting absolute pressure from atmospheric pressure. Which ONE of the following options lists all the TRUE statements?

(A)

S1 and S2

(B)

S2 and S3

(C)

S1 and S4

(D)

S1, S2, and S4

Explanation

GATE→2026→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q17

NAT[1 Mark]

Water is flowing at the rate of $15\text{ m}^3/\text{s}$ through a rectangular channel of $5\text{ m}$ width. If the acceleration due to gravity ($g$) is $9.81\text{ m/s}^2$, the critical velocity for the flow is _____ m/s (rounded off to three decimal places).

Explanation

GATE→2026→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q18

NAT[2 Marks]

A cylindrical roller gate of diameter $6.0\text{ m}$ and length $10.0\text{ m}$ is placed on a dam to store water behind it, as shown in figure. The magnitude of the resultant force due to water acting on that gate when the water is about to spill is _____ $\times 10^6\text{ N}$ (rounded off to two decimal places). (Consider $g = 9.81\text{ m/s}^2$, $\rho = 1000\text{ kg/m}^3$, $\pi = 3.14$)

Explanation

GATE→2024→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q19

MSQ[1 Mark]

In the context of fluid flow, which of the following statement(s) is/are correct?

(A)

Streamline is a line, tangent to which at any point gives the direction of the velocity vector

(B)

Streakline is the actual path traversed by a given fluid particle in an unsteady flow

(C)

Streakline and streamline are same for a steady flow

(D)

Pathline and streamline are same for a steady flow

Explanation

GATE→2024→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q20

MSQ[1 Mark]

In a rectangular open channel, the flow is critical, and the flow depth is $2\text{ m}$. Select the correct statement(s)

(A)

Specific energy for the flow is 3.0 m

(B)

Specific energy for the flow is 2.0 m

(C)

Froude number is 1.0

(D)

Froude number is 1.5

Explanation

GATE→2024→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q21

MSQ[2 Marks]

Water is flowing FULL through a rectangular tunnel of size $3\text{ m (width)} \times 2\text{ m (height)}$. The average velocity of flow is $1\text{ m/s}$. The frictional head loss is observed to be $1\text{ m per km}$. Consider acceleration due to gravity ($g$) as $10\text{ m/s}^2$. The correct statement(s) is/are

(A)

Hydraulic radius is 0.6 m

(B)

Darcy-Weisbach friction factor is 0.048

(C)

Hydraulic radius is 2 m

(D)

Darcy-Weisbach friction factor is 0.024

Explanation

GATE→2024→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q22

NAT[2 Marks]

With reference to the gate shown in the figure, the gate will start opening automatically when the water level '$h$' above the hinge is _____ m (rounded off to 2 decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q23

NAT[1 Mark]

The critical depth in a $2\text{ m}$ wide rectangular channel carrying a discharge of $10\text{ m}^3/\text{s}$ and taking value of acceleration due to gravity ($g$) as $9.81\text{ m/s}^2$ is _____ (in m, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q24

NAT[2 Marks]

A trapezoidal canal lined with cement concrete ($n = 0.01$) is designed to carry a discharge of $20\text{ m}^3/\text{s}$ at a bed slope $1$ in $400$. If the bed width is twice of the depth of flow and side slope of the canal section is $2$ ($1$ vertical : $2$ horizontal) then the corresponding depth of flow will be _____ (in m, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q25

NAT[2 Marks]

A plunger weighing $314\text{ kN}$ is balanced in a cylindrical vessel of diameter $1.5\text{ m}$ and filled with an oil (specific gravity $0.9$). If a pressure gauge is connected with the vessel using $1.5\text{ cm}$ diameter tube, the reading of the gauge will be _____ (in kPa, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q26

NAT[2 Marks]

A pipeline is designed to deliver $20\text{ L/s}$ of an oil (kinematic viscosity $= 6 \times 10^{-6}\text{ m}^2/\text{s}$ and specific gravity $= 0.9$) under the laminar flow condition. The minimum diameter of the pipe will be _____ (in m, rounded off to two decimal places).

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q27

MCQ[1 Mark]

Centrifugal pumps with suction pipe (shown by solid arrow) and delivery pipe (shown by dotted arrow) are shown in the figures. Choose the option that gives the correct connection

(A)

Option (A)

(B)

Option (B)

(C)

Option (C)

(D)

Option (D)

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q28

NAT[2 Marks]

A venturimeter along with a differential manometer was installed to measure flow in a water pipeline as shown in the following figure. Taking specific weight of water as $9810\text{ N/m}^3$, the pressure difference (in Pa, rounded off to one decimal place) between point Q and P is

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q29

NAT[2 Marks]

Two reservoirs having a difference of $10\text{ m}$ in their water surface elevations are connected by a pipeline (diameter $= 10\text{ cm}$, length $= 50\text{ m}$, and friction factor $f = 0.02$). If the last $25\text{ m}$ length of the pipeline is replaced by a same material pipe of diameter $20\text{ cm}$ then neglecting minor losses the discharge (in %, rounded off to one decimal place) will increase by

Explanation

GATE→2022→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q30

NAT[2 Marks]

The depth of flow (in m, rounded off to two decimal places) in a hydraulically efficient rectangular channel ($n = 1/80$) to carry a discharge of $64\text{ m}^3/\text{s}$ at bed slope $0.01$ is _____.

Explanation