Landscape Hydrology and Hydraulics 512/C23a LandscapeHydrology 2016.pdf · 2 1.Hydrological...

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Landscape Hydrology and Hydraulics

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1.Hydrological Analysis

2.Hydraulic Design of

Structures

Scope of Drainage Design and Construction

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HYDROLOGY – Factors affecting runoff

1. Catchment Area

2. Rainfall

3. Topography

4. Vegetation and Soil

5. Catchment Shape

6. Avaialable storage – lake/swamp

7. Degree of urbanisation

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Hydrology – Catchment area

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Hydrology – topography

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Hydrology – rainfall

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Major Waterway

Pond

Hydrology - storage

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Existing Landuse–vegetation/development/urbaniz

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HYDROLOGY – Rational Method

or

Q = CIA/360

A = area in hectare (ha)

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Rainfall intensity , I

Intensity

Intensity

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Runoff Coefficient C

Time of Concentration , Tc or Rainfall Duration

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Time of Concentration , Urbanizing area

1

10

100

1000

1 10 100 1000 10000

Inte

nsiti (m

m/h

r)

Duration (min)

ARI 2

ARI 5

ARI 10

ARI 20

ARI 50

ARI 100

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Hydraulic – Manning Eq

Hydraulic – Manning coeff