In rational method, the peak runoff is given by Q =
Cf. C. i. A. The...
In rational method, the peak runoff is given by Q =
Cf. C. i. A. The intensity i can be obtain
from IDF curves. Discuss why a duration equal to time of
concentration is used to determine the intensity
In the Rational Method the peak runoff resulting from a
rainfall event depends on which of the following
factors
The frequency and duration of the rainfall
event.
The size of the area on which the rainfall
lands.
The characteristics of the surface over which the
rainwater flows.
The time that has elapsed since the last rainfall
event.
I, II, III and IV.
I, II and III only.
I and III only.
II and III only.
Which of the following are...
Describe briefly the principle of the Rational method and the
limitation of this method for runoff estimation. A sub-catchment of
area 0.1km2 is built on gently sloping land. The average
slope of the land is 0.001. The length of the longest natural flow
path L is 276.3m. The flow time tf in the drainage
system is 3min. Determine the 50yr design discharge for the
subdivision using the rational method, given that the average
runoff coefficient of the subdivision is C=0.7....
short answers
T
F When using
the runoff coefficient, c, the Rational Method assumes that land
uses are uniformly distributed within a drainage
area.
What is the overland flow travel time for a hydraulic
path 140 ft long through dense grass at an average slope of
1.0%?
1 minute
4 minutes
21 minutes
25 minutes
The rational method assumes rainfall duration equal to
the time of concentration. If an estimated time of concentration is
larger than the actual time of...
You are using the rational method for calculating the surface
runoff in a rural area. The area is flat, permeable grassland.
Calculate the runoff coefficient (C).
Using the rational method, determine the amount of runoff that
would occur for a paved parking lot that is 100m * 50m and is
uniformly sloped from one long edge to the other long edge at a
rate of 2%. The time of concentration for this parking is 4
minutes. The five-year storm with duration of 4 minutes has an
intensity of 10 mm/hr. The runoff coefficient for this parking lot
is 0.80.آ [Q=0.166 CIA]
The runoff from part (a)...
Using the rational method, determine the amount of runoff that
would occur for a paved parking lot that is 100m * 50m and is
uniformly sloped from one long edge to the other long edge at a
rate of 2%. The time of concentration for this parking is 4
minutes. The five-year storm with duration of 4 minutes has an
intensity of 10 mm/hr. The runoff coefficient for this parking lot
is 0.80.آ [Q=0.166 CIA]
The runoff from part (a)...
22a. What would be the
peak runoff rate by the NRCS Soil-Cover-Complex method for a 100
year return period for a watershed in coastal South Carolina with
the following practices? Use the NRCS curve number
method to find the time of concentration.
Acres
Land use
Soil quality
Soil Class
Length ft
Slope %
50
Small grain, contoured,
Good
A
1000
4
50
Golf course, with 80% grass cover
Good
C
1500
4
Followings are given for a watershed:
Rational method coefficient C = 0.35
Time of concentration = 60 min
Area A = 4.2 km^2
Rainfall intensity is 1.7 cm/hr
Part A: If rainfall duration is 60 min, determine the peak
discharge in m^3/s.
Part B: If rainfall duration is 90 min, determine the peak
discharge in m^3/s.
I
used my catchement area to calculate my runoff using the national
method.
how will i go on calculating the volume needed for
storage?
which equations will i use ?
i want to have a storage tank that is pumped to the wetland.
how will i distribute the volume and calculate the sizing for
each.
Can you explain with an example if you can?
The time area method is often used to estimate catchment runoff
process. In this method, the catchment of concern is split into
several sub-areas where runoff generated from each sub-area is
thought to take the same amount of time to travel to the outlet of
the catchment. Suppose a catchment can be split into M
sub-areas. For the i-th sub-area (i=1,2,…, M),
the size of the area is Ai km2 and it
takes i-th hours for the runoff generated to...