# Flood Routing and Flood Control

 Question 1
Superpassage is a canal cross-drainage structure in which
 A natural stream water flows with free surface below a canal B natural stream water flows under pressure below a canal C canal water flows with free surface below a natural stream D canal water flows under pressure below a natural stream
GATE CE 2020 SET-2   Engineering Hydrology
Question 1 Explanation:
Cross-section of a super passage Question 2
Muskingum method is used in
 A hydrologic reservoir routing B hydrologic channel routing C hydraulic channel routing D hydraulic reservoir routing
GATE CE 2020 SET-2   Engineering Hydrology
Question 2 Explanation:
Muskingum method is used in hydrological channel routing
 Question 3
In a homogeneous unconfined aquifer of area 3.00 $km^2$, the water table was at an elevation of 102.00 m. After a natural recharge of volume 0.90 million cubic meter ($Mm^2$), the water table rose to 103.20 m. After this recharge, ground water pumping took place and the water table dropped down to 101.020 m. The volume of ground water pumped after the natural recharge, expressed (in $Mm^2$ and round off to two decimal places), is ______.
 A 0.5 B 1 C 1.5 D 2.5
GATE CE 2020 SET-1   Engineering Hydrology
Question 3 Explanation: \begin{aligned} V_R&=0.9Mm^3\\ V&=3 \times (103.2-102)\\ y_s \; \text{or}\; y_R&=\frac{VR}{V}=\frac{0.9}{3.6}\\ \text{Now,}\;\; y_s&=\frac{V_D}{V}\\ V_D&=\frac{0.9}{3.6}[3 \times (103.2-101.2)]\\ V_D&=1.5Mm^3 \end{aligned}
 Question 4
The probability that the annual maximum flood discharge will exceed 25000 $m^3/s$, at least once in next 5 years is found to be 0.25. The return period of this flood event (in years, round off to 1 decimal place) is ____
 A 12.2 B 16.4 C 17.9 D 20.6
GATE CE 2019 SET-1   Engineering Hydrology
Question 4 Explanation:
\begin{aligned} \text{Risk} &=1-q^n \\ 0.25&=1-q^5 \\ q&=0.944087 \\ 1-p&=0.944087 \\ 1-\frac{1}{T}&=0.944087 \\ T&\simeq 17.9 \; \text{years} \end{aligned}
 Question 5
A culvert is designed for a flood frequency of 100 years and a useful life of 20 years. The risk involved in the design of the culvert (in percentage, up to two decimal places) is______
 A 9.45 B 18.21 C 27.47 D 36.36
GATE CE 2018 SET-2   Engineering Hydrology
Question 5 Explanation:
Risk = The probabality of a flood to occur at least once in n-successive years.
\begin{aligned} \therefore \;\; \text{Risk }&=1-q^{n} \\ &=1-\left ( 1-P \right )^{n} \\ &=1-\left ( 1-\frac{1}{T} \right )^{n} \\ &=1-\left ( 1-\frac{1}{100} \right )^{20} \\ &=1-\left ( 0.99 \right )^{20} \\ &=0.18209=18.209\% \end{aligned}
 Question 6
For routing of flood in a given channel using the Muskingum method, two of the routing coefficients are estimated as $C_{0}=-0.25$ and $C_{1}= 0.55$. The value of the third coefficient $C_{2}$ would be ______
 A 0.2 B 0.5 C 0.7 D 0.9
GATE CE 2018 SET-1   Engineering Hydrology
Question 6 Explanation:
In Muskingum flood routing method
\begin{aligned}C_{0}+C_{1}+C_{2}&=1 \\ \Rightarrow \;\; C_{2}&=1-\left ( -0.25 \right )-0.55=0.7 \end{aligned}
 Question 7
The type of flood routing (Group I) and the equation(s) used for the purpose (Group II) are given below. The correct match is
 A P - 1; Q - 1, 2 & 3 B P - 1; Q - 1 & 2 C P - 1 & 2; Q - 1 D P - 1 & 2; Q - 1 & 2
GATE CE 2016 SET-1   Engineering Hydrology
 Question 8
The Muskingum Model of routing a flood through a stream reach is expressed as $O_{2}=K_{0}I_{2}+K_{1}I_{1}+K_{2}O_{1}$, where $K_{0}$, $K_{1}$ and $K_{2}$ are the routing coefficients for the concerned reach, $I_{1}$ and $I_{2}$ are the inflows to reach, and $O_{1}$ and $O_{2}$ are the outflows from the reach corresponding to time step 1 and 2 respectively. The sum of $K_{0}$, $K_{1}$ and $K_{2}$ of the model is
 A -1 B -0.5 C 0.5 D 1
GATE CE 2014 SET-2   Engineering Hydrology
 Question 9
In reservoirs with an uncontrolled spillway, the peak of the plotted outflow hydrograph
 A lies outside the plotted inflow hydrograph B lies on the recession limb of the plotted inflow hydrograph C lies on the peak of the inflow hydrograph D is higher than the peak of the plotted inflow hydrograph
GATE CE 2014 SET-1   Engineering Hydrology
Question 9 Explanation: Question 10
A conventional flow duration curve is a plot between
 A Flow and percentage time flow is exceeded B Duration of flooding and ground level elevation C Duration of water supply in a city and proportion of area receiving supply exceeding this duration D Flow rate and duration of time taken to empty a reservoir at that flow rate
GATE CE 2014 SET-1   Engineering Hydrology
There are 10 questions to complete.