WorksheetsDay 48-Nov 8-worksheet-Diploma-Rainfall data & mean precipitatio
Total questions: 15
Worksheet time: 11mins
Arithmetic mean method for estimating missing rainfall is preferred only when —
Rainfall intensities vary significantly between stations
Normal annual precipitation differs by more than 10%
Normal annual precipitation differs within 10%
Only two rain gauges exist
A mass curve represents —
(a)
The area under a hyetograph gives —
(a)
In a DAD curve, for constant duration, increasing area causes —
Depth to increase
Depth to decrease
Duration to increase
Intensity to increase
Thiessen polygon method assumes —
Equal distribution
Polygon area irrelevant
Each gauge represents nearest area
Rainfall decreases with duration
Which method does NOT involve catchment area?
Isohyetal method
Thiessen polygon method
Arithmetic mean method
None of these
Point rainfall does not represent areal rainfall.
True
False
For constant frequency, IDF curves show intensity decreases with decreasing duration.
True
False
Daily rainfall is measured over how many hours?
(a)
The slope of a mass curve indicates what characteristic of a storm?
(a)
IDF curves relate rainfall intensity with which variable?
Duration
Temperature
Elevation
Wind speed
In the isohyetal method, the area between isohyets is measured using which instrument?
(a)
The rainfall cycle period used in India lies in which interval?
5–10 years
15–20 years
30–35 years
60–70 years
Use missing Rainfall (Normal Ratio Method). Normal annual rainfall: N1 = 80 cm, N2 = 95 cm, N3 = 110 cm, N4 = 90 cm. Recorded annual rainfall: P1 = 72 cm, P2 = 88 cm, P3 = 105 cm, P4 = 84 cm. Target station Nx = 100 cm.Find the missing annual rainfall at the target station.
(a)
Thiessen Weighted Rainfall. Station rainfall & areas: 1: 42 cm, 3 km²; 2: 55 cm, 4 km²; 3: 38 cm, 2 km²; 4: 60 cm, 5 km²; 5: 48 cm, 6 km². Weighted rainfall = 1010. Total area = 20 km². Compute the average basin rainfall.
(a)
