CSIR-NET
90. The total observed runoff volume during a
storm of 5-hr duration with a uniform
intensity of 16 mm/hr is 20 *10^6 m3
. If the area
of the basin is 400 km^2
, then the infiltration
(mm) is
1. 15
2. 20
3. 25
4. 30
Answer: 4
Solution:
1. Infiltration loss (Fp)= Rainfall (P) - Runoff(R)
2. Rainfall intensity = total amount of rain water (mm)/ Duration of the rain water (hours)
3. Total amount of rain water or Rainfall (P) = Rainfall intensity * Duration of the rain water (hours)
Rainfall (P) = 16 mm/h * 5 h
= 80 mm
Runoff length(R) = Volume /unit Area
1. Infiltration loss (Fp)= Rainfall (P) - Runoff(R)
2. Rainfall intensity = total amount of rain water (mm)/ Duration of the rain water (hours)
3. Total amount of rain water or Rainfall (P) = Rainfall intensity * Duration of the rain water (hours)
Rainfall (P) = 16 mm/h * 5 h
= 80 mm
Runoff length(R) = Volume /unit Area
Runoff (R) = 20 *10^6 m^3 / 400 km^2
= (20 / 400 ) * 1000 mm
= 50 mm
Therefore
Infiltration loss (Fp) = Rainfall (P) - Runoff (R)
= 80 -50
= 30 mm
Any doubt please refer this below sites:
https://www.esciencecentral.org/ebooks/handbook-of-hydrologic-engineering-problems/handbook-of-hydrologic-engineering-problems.php
http://www.fao.org/docrep/r4082e/r4082e05.htm#TopOfPage
mega metre^3 to millimetre^3
ReplyDeleteRunoff (R) = 20 Mm^3 / 400 km^2
= 20* 10^6 * 10^9 mm^3/ 400 * 10^12 mm^2
= (20/ 400) *10^3 mm
Nice explanation sivan.thank you
Deletei cant understand the conversion. how 10^6 is coming???
DeleteThat's due to Maga meter^3
DeleteOne mega meter = 10^27 milometer .
ReplyDeleteSo how can u multiply 10^6
yes correct...i think question they give little bit confuse better to write 10^6 m^3 instead of Mm^3 .
Delete