Hydrograph MCQ Quiz in తెలుగు - Objective Question with Answer for Hydrograph - ముఫ్త్ [PDF] డౌన్లోడ్ కరెన్
Last updated on Mar 9, 2025
Latest Hydrograph MCQ Objective Questions
Top Hydrograph MCQ Objective Questions
Hydrograph Question 1:
A 8 hours unit hydrograph of catchment is triangular in shape with base width of 64 hours and peak ordinate of 20 m3/s. the equilibrium discharge of S-curve obtained by using this 8-hour unit hydrograph is-
Answer (Detailed Solution Below)
Hydrograph Question 1 Detailed Solution
Let us assume the area of the catchment is A, then the area of triangle (from the shape of unit hydrograph) is equal to the volume of the water accumulated in the catchment area.
\(\frac{1}{2} \times {Q_{Peak}} \times Base\;width = Area\;\left( A \right) \times depth\;of\;water\)
\(\frac{1}{2} \times 20 \times 64 \times 3600 = A \times \frac{1}{{100}}\)
\(A = 230.4 \times {10^6}\;{m^2} = 230.4\;k{m^2}\)
Therefore, the equilibrium discharge of S-curve obtained by using this 8-hour unit hydrograph will be
\({Q_s} = 2.778\frac{A}{{{T_0}}}\)
where A is in km2 and T0 is in hours
\({Q_s} = 2.778 \times \frac{{230.4}}{8}\)
\({Q_s} = 80\;{m^3}/s\)Hydrograph Question 2:
If the base period of a 6 hr. unit hydrograph of a basin is 84 hr. then, the base period of a 12 hr. unit hydrograph of the same basin will be
Answer (Detailed Solution Below)
Hydrograph Question 2 Detailed Solution
Explanation:
Unit hydrograph:
A unit hydrograph is a direct runoff hydrograph resulting from one unit (one cm) of constant intensity uniform rainfall occurring over the entire watershed.
Base period of 12 hr unit hydrograph = Base period of 6 hr unit hydrograph + 6
Base period of 12 hr unit hydrograph = 84 + 6 = 90h
Hydrograph Question 3:
Basin lag in hydrology is the time difference between the ______.
Answer (Detailed Solution Below)
Hydrograph Question 3 Detailed Solution
Explanation:
Basin lag or Basin lag time:
- It is defined as the measurement of the time between the center of mass of the precipitation (or rainfall excess) to the center of mass of the runoff (on the hydrograph) in the basin.
- Basin lag is not only a function of basin characteristics but also of storm intensity and speed.
- It also defines as the interval from the center of mass of precipitation to the hydrograph crest.
Hence basin lag in hydrology is the time difference between the centroid of rainfall excess and the centroid of surface runoff.
Hydrograph Question 4:
Cumulative frequency curve that shows the percent of time specified discharge was equalled or exceeded during a given period is known as:
Answer (Detailed Solution Below)
Hydrograph Question 4 Detailed Solution
Explanation:
Flow duration curve:
- Flow-duration curve is a cumulative frequency curve that shows the percent of time specified discharges were equaled or exceeded during a given period.
- It is a graphical method to present the discharge data of a river or a stream.
- it represents flow characteristics of a river for a particular region subjected to recorded flows in the river.
Mass duration curve:
- It is a plot between the stored volume of water in a stream and time in days.
- The curve represents the reservoir capacity.
Hydrograph:
- It is the graphical representation between discharge (rate of flow) and time in a particular river channel.
- it is used in various engineering applications such a estimation flood water and risk analysis of dam etc.
Hydrograph Question 5:
A unit hydrograph for a watershed is triangular in share with a base period of 20 hours. The area of the watershed is 500 ha What is the peak discharge in m3 /hr?
Answer (Detailed Solution Below)
Hydrograph Question 5 Detailed Solution
Explanation
Unit hydrograph (UH) is a hydrograph that resulted from 1 cm of rainfall excess depth
We know that
∴ \(rainfall\;excess = \frac{{Volume\;of\;direct\;runoff}}{{Catchment\;area}}\)
The area under triangle = Volume of direct runoff
\(\frac{1}{2} × {q_p} × Base\;period = Area\;of\;catchment × 1\;cm\;runoff\;\;\)
Where qp is peak discharge of unit hydrograph
Given,
Base period = 20 hours, Area of catchment = 500 ha = 50 × 104 m2
\(\frac{1}{2} × {q_p} × Base\;period = Area\;of\;catchment × 1\;cm\;runoff\;\;\)
\(\frac{1}{2} × {q_p} × 20 = 500 \times 10^4m^2 × 1\;cm\;runoff\;\;\)
qp = 5000 m3/hr
∴ Peak Discharge = 5000 m3/hr
Hydrograph Question 6:
If the base period of a 4-hour unit hydrograph is 48 hours then for a storm of 8 hour, derived from this unit hydrograph, will be having a base period of
Answer (Detailed Solution Below)
Hydrograph Question 6 Detailed Solution
Explanation
Given,
The base period of 4 hr UH is 48 hr
for 8 hr Unit Hydrograph i.e. lag by 4 Hr
Hence, the base period of 8 hr storm hydrograph = 48 + 4 = 52 hr
Hydrograph Question 7:
A triangular direct runoff hydrograph due to 6 hour storm in a catchment has a time base of 100 hour, and peak of flow of 40 m3/s. The catchment is 180 km2. Determine the peak flow value of 6 hour unit hydrograph of this catchment? (in m3/s units)
Answer (Detailed Solution Below)
Hydrograph Question 7 Detailed Solution
Concept:
Volume of rainfall = Area of hydrograph
Depth of rainfall = Volume of rainfall/Area of catchment
Calculation:
Duration of Storm = 6 hr
Base period = 100 hr = 100 × 3600 sec
QP = 40 m3/s
Area of catchment = 180 km2
The volume of rainfall = Area of Hydrograph \( = \frac{1}{2} \times 100 \times 40 \times 3600 = 72 \times {10^5}{\rm{\;}}{{\rm{m}}^3}\)
Depth of rainfall \( = \frac{{72 \times {{10}^5}}}{{180 \times {{10}^6}}} = 4{\rm{\;cm}}\)
So, from the property of the Hydrograph, peak discharge for unit hydrograph can be calculated.
For runoff of 4 cm, QP = 40 m3/s
So, for a depth of 1 cm, QP = 40/4 = 10 m3/s
Hydrograph Question 8:
Hydrograph is the graphical representation of
Answer (Detailed Solution Below)
Hydrograph Question 8 Detailed Solution
Hydrograph: It is a continuous plot of instantaneous discharge (runoff) v/s time.
It results from a combination of physiographic and meteorological conditions in a watershed and represents the integrated effects of climate, hydrologic losses, surface runoff, interflow, and groundwater flow.
Detailed analysis of hydrographs is usually important in flood damage mitigation, flood forecasting, or establishing design flows for structures that convey floodwaters.
Factors that influence the hydrograph shape and volume
i. Meteorological factors
ii. Physiographic or watershed factors and
iii. Human factors
Example of a Hydrograph
Hydrograph Question 9:
Dalton's law is given as:
Answer (Detailed Solution Below)
Hydrograph Question 9 Detailed Solution
Explanation:
Evaporation:
- The process of transformation of liquid water into a gaseous form is called evaporation.
Dalton's law:
- It gives the relationship between the rate of evaporation and the difference between the saturation vapour pressure and existing vapour pressure, by the following expression
EL = C(es - ea)
Where, EL = Rate of evaporation (mm/day), C = Constant, es = Saturation vapour pressure in mm of mercury, ea = Existing vapour pressure in mm of mercury
Dependency of the rate of evaporation on various factors:
- Increases with an increase in vapour pressure at the water surface and air above it.
- Increases with increases in Air and water temperature.
- Increases when wind speed is above critical Wind speed.
- Decrease with the increase in Atmospheric pressure.
Additional Information
Instrument name | Used for measuring |
Psychrometer | Relative humidity |
Anemometer | Wind velocity |
Pluviometer | Rainfall depth |
Lysimeter | Evapotranspiration |
Atmometer | Evaporation |
Phytometer | Transpiration |
Hygrometer | Relative humidity |
Hydrograph Question 10:
If the peak ordinate of a 4 h unit hydrograph of a basin is 270 m3/s, then the peak ordinate of a 8 h unit hydrograph of the same basin will be:
Answer (Detailed Solution Below)
Hydrograph Question 10 Detailed Solution
Concept:
Hydrograph:
- A hydrograph is a plot between discharge and time at any given section of a river, channel, etc.
- It is a response of a given catchment to the rainfall input.
Unit hydrograph (UH):
- A unit hydrograph can be defined as the hydrograph of direct runoff resulting from one unit depth (1 cm) of rainfall excess occurring uniformly over the basin for a specified duration.
- A unit hydrograph is based on the principle of linearity and the principle of superposition.
- If a D-hr unit hydrograph is available, a unit hydrograph with other duration such as 2D, 3D, etc. can be obtained easily from the principle of superposition. As the duration of the unit hydrograph increases, the base period also increases, and consequently, the peak ordinate decreases.
Hence, If the peak ordinate of a 4 h unit hydrograph of a basin is 270 m3/s, then the peak ordinate of an 8 h unit hydrograph of the same basin will be Less than 270 m3/s.