List of top Water Resources and Environmental Hydraulics Questions on Hydrology asked in GATE ES

Which one of the following gases is primarily responsible for the formation of photochemical smog?
Which of the following is the first step in Environmental Impact Assessment (EIA)?
Water from a hand pump located near a landfill has 1 mg/L arsenic (oral carcinogenic potency factor = 1.75 (kg-day)/mg). A person who lives nearby drinks 2 L/day of water from this hand pump for 10 years. Assume a body weight of 70 kg and an average life duration of 70 years. The chances of this person getting an excess risk of cancer is ________ $\times 10^{-3$ (rounded off to three decimal places).}

A particle dispersoid has 1510 spherical particles of uniform density. An air purifier is proposed to be used to remove these particles. The diameter-specific number of particles in the dispersoid, along with the number removal efficiency of the proposed purifier is shown in the following table:

The overall mass removal efficiency of the proposed purifier is ________% (rounded off to one decimal place).

A circular sewer pipe, having Manning’s coefficient (n) of 0.01, is laid at a bed slope of 1:100. If it is flowing 80% full for a discharge of 2 m\(^3\)/s, then its diameter is ________ m. (rounded off to three decimal places)
Diameter ($d$) and length ($l$) of each pipe are as presented in figure and all pipes are of same material having friction factor ($f$) of 0.02. Assume acceleration due to gravity ($g$) as 10.0 m/s$^2$. If the head difference between $P$ and $Q$ is 10 m, then the head loss between $Q$ and $R$ is ________ m. (rounded off to two decimal places)

The following table and figure (not to scale) show characteristics of a catchment

The hyetograph resulting from a storm that occurred uniformly over the catchment, is as follows

Assuming a constant base flow of 40 m$^3$/s, the peak of the runoff hydrograph produced by storm for the catchment at the outlet $O$ is ________ m$^3$/s. (rounded off to two decimal places)

An unconfined aquifer of areal extent 20 km × 20 km has hydraulic conductivity of 4 m/day, porosity of 0.32, and storage coefficient (specific yield) of 0.18. If the initial saturated thickness of the aquifer is 30 m, and 4×10^8 m\(^3\) of water is extracted from the aquifer, then the decline in the saturated thickness is ____________ m.
An incandescent light bulb operated for two hours per day uses 12.2 kWh of energy per month. Burning of one kg of coal generates 2 kWh of electrical energy and releases 7 g of PM10. The reduction in PM10 emitted per month, if this incandescent bulb is replaced with a light emitting diode (LED) bulb which consumes 1/6th of energy, is ________ g (rounded off to one decimal place).
Length of the streets, in km, are shown on the network. The minimum distance travelled by the sweeping machine for completing the job of sweeping all the streets is ________ km. (rounded off to nearest integer)
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If the storm produced a direct runoff of 12.5 mm, then the $\phi$-index of the storm for the catchment is ________ mm/hour. (rounded off to two decimal places)
A homogeneous isotropic confined aquifer of uniform thickness 30 m has hydraulic conductivity of 5 m/day and porosity of 0.3. There are two observation wells X and Y along a radial line from a fully penetrating pumping well at 100 m and 200 m distance, respectively. The well is pumped at a uniform rate to produce steady drawdown of 5 m at X and 3 m at Y. If a non-reactive pollutant enters at the observation well Y, then the time taken by the pollutant (under advection) to reach the observation well X is ________ days. (rounded off to two decimal places)
You conducted a batch experiment in the lab for 10 minutes to degrade a toxic compound, which follows first-order kinetics. The compound degrades from \( 2 \times 10^{-3} \, {M} \) to \( 2 \times 10^{-4} \, {M} \). The information from the lab experiment will be used to design a plug flow reactor in field conditions.
Given field conditions:
• Flow rate of contaminated water to be treated: 1 m\(^3\)/hour
• Concentration of toxic compound in contaminated water: \( 5 \times 10^{-1} \, {M} \)
• Target concentration of toxic compound in treated water: \( 1 \times 10^{-4} \, {M} \)
• Temperature is the same in lab and field conditions.
The required volume of the plug flow reactor is ________ m\(^3\). (rounded off to two decimal places)
Water from a hand pump located near a landfill has 1 mg/L arsenic (oral carcinogenic potency factor = 1.75 (kg-day)/mg). A person who lives nearby drinks 2 L/day of water from this hand pump for 10 years. Assume a body weight of 70 kg and an average life duration of 70 years. The chances of this person getting an excess risk of cancer is ________ × 10-3 (rounded off to three decimal places).

Length of the streets, in km, are shown on the network. The minimum distance travelled by the sweeping machine for completing the job of sweeping all the streets is ________ km. (rounded off to nearest integer)


 

An incandescent light bulb operated for two hours per day uses 12.2 kWh of energy per month. Burning of one kg of coal generates 2 kWh of electrical energy and releases 7 g of PM10. The reduction in PM10 emitted per month, if this incandescent bulb is replaced with a light emitting diode (LED) bulb which consumes 1/6th of energy, is ________ g (rounded off to one decimal place).

A particle dispersoid has 1510 spherical particles of uniform density. An air purifier is proposed to be used to remove these particles. The diameter-specific number of particles in the dispersoid, along with the number removal efficiency of the proposed purifier is shown in the following table:

The overall mass removal efficiency of the proposed purifier is ________% (rounded off to one decimal place).

A circular sewer pipe, having Manning’s coefficient (n) of 0.01, is laid at a bed slope of 1:100. If it is flowing 80% full for a discharge of 2 m\(^3\)/s, then its diameter is ________ m. (rounded off to three decimal places)
Diameter ($d$) and length ($l$) of each pipe are as presented in figure and all pipes are of same material having friction factor ($f$) of 0.02. Assume acceleration due to gravity ($g$) as 10.0 m/s$^2$. If the head difference between $P$ and $Q$ is 10 m, then the head loss between $Q$ and $R$ is ________ m. (rounded off to two decimal places)

The following table and figure (not to scale) show characteristics of a catchment

The hyetograph resulting from a storm that occurred uniformly over the catchment, is as follows

Assuming a constant base flow of 40 m$^3$/s, the peak of the runoff hydrograph produced by storm for the catchment at the outlet $O$ is ________ m$^3$/s. (rounded off to two decimal places)

The following figure (not to scale) depicts a rainfall hyetograph for a storm over a catchment

If the storm produced a direct runoff of 12.5 mm, then the $\phi$-index of the storm for the catchment is ________ mm/hour. (rounded off to two decimal places)

Choose the correct option(s) from the following regarding the solubility in water:
Consider the following figure of an activated sludge process (ASP), depicting the flow (Q), substrate (S), and microorganism concentration (X) at various points in the system, where subscripts “0”, “r”, “w”, “e”, and “i” indicate influent, recycle line, wastage, effluent, and flow from aeration tank to settling tank, respectively. Note that influent to the ASP has microbes too. V is volume of aeration tank. Choose the correct option for net rate of formation of microorganisms in the system at steady state, from the following
An unconfined aquifer of areal extent 20 km × 20 km has hydraulic conductivity of 4 m/day, porosity of 0.32, and storage coefficient (specific yield) of 0.18. If the initial saturated thickness of the aquifer is 30 m, and 4×10^8 m\(^3\) of water is extracted from the aquifer, then the decline in the saturated thickness is ____________ m.
Multiple effect evaporator is commonly used, in the zero liquid discharge (ZLD) scheme, for ________