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PILOT PROJECT 3:

Detention Storage Cum Rainwater Harvesting System at DID

Headquarters, Kuala Lumpur

THE HEADQUARTERS OF DEPARTMENT OF

IRRIGATION AND DRAINAGE(DID), KUALA LUMPUR

Underground storage

tank underconstruction

MAIN COMPONENT OF RAINWATERHARVESTING SYSTEM

Gutter

Catchments area(roof)

Downspouts

and piping Underground Storage Tank

Underground

storage tank

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DEPARTMENT OF IRRIGATION

AND DRAINAGE (DID)

HEAD-QUARTERS COMPLEX

Storage tank

Roof as catchments area

Undergroundstorage tank

DID HEAD-QUARTERS COMPLEX

Consists of a block

of 4-storied which

is the standard

office building with

flat roof

Roof of this

building is attached

via central gutter

(size of 600 mm in

depth)

60% of the water

collected will flow

into central gutter

Collected water

will discharge to

the perimeter drain

at ground level

Rainwater flow

into two of 150

mm rainwater

downpipe.

Downpipe

Roof as catchments area

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The system uses

a header tank on

the roof of the

building

The water is

store in

underground

storage tank

Rainwater from downpipe

Header tank

Underground

storage tank

Tankinstallation

Toilet flushing

Main component of

rainwater harvesting system

Catchments system

Filtering system

pump

Header tank

Internal plumbingConveyance system

Storage tank

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Components of rainwater harvesting

system distribution network

Internal Plumbing (Diagrammatic)

Toilet flush

External

Installation ofInstallation of

Detention Storage Cum Rainwater Harvesting SystemDetention Storage Cum Rainwater Harvesting System

at DID Headquarters, Kuala Lumpurat DID Headquarters, Kuala Lumpur

JPSJPS HqHq. Building Roof Area:. Building Roof Area: 1,688.85 m1,688.85 m22 (calculated)(calculated)

Total JPSTotal JPS HqHq. staff:. staff: 250 (est.)250 (est.)

Average water use per person:Average water use per person: 25 liters/day.25 liters/day.

Total water use per day:Total water use per day: 250 x 25 = 6,250 liters/day.250 x 25 = 6,250 liters/day.

storage tank size:storage tank size:

(Say 3 days water storage):(Say 3 days water storage): 6,250 x 3 = 18,750 lit6,250 x 3 = 18,750 lit

Water for plants (25m.sq):Water for plants (25m.sq): 6.3 litres/m6.3 litres/m22/day(est.)/day(est.)

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Installation ofInstallation of

Detention Storage Cum Rainwater Harvesting SystemDetention Storage Cum Rainwater Harvesting System

at DID Headquarters, Kuala Lumpurat DID Headquarters, Kuala Lumpur

Tank Size (m3) Reliability (%)

40 57.53

50 60.74

60 63.64

70 66.31

80 67.95

90 69.67

100 70.93

110 72.02

120 72.98

Tank Size Vs Reliability

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140

Tank Size (cu. m)

Reliabilty(%)

Reliability (%)

Installation ofInstallation of

Detention Storage Cum Rainwater Harvesting SystemDetention Storage Cum Rainwater Harvesting System

at DID Headquarters, Kuala Lumpurat DID Headquarters, Kuala Lumpur

To determine the critical storm duration for Detention Storage Size RequiredCs = 1

td (min) I (mm/h) Runoff Coeff Area (m2) Qd (l/s)

Qbefore

(PSD)

T= 10 yr c d SSR (m3)

5 380 0.91 1688 162.2 41.1 124.94 6.09 40.81

10 263 0.91 1688 112.3 41.1 237.61 17.61 52.04

15 208 0.91 1688 88.8 41.1 340.61 33.39 57.46

20 175 0.91 1688 74.5 41.1 434.88 53.05 60.14

25 152 0.91 1688 64.7 41.1 520.94 76.33 61.26

30 135 0.91 1688 57.5 41.1 599.14 103.09 61.40

35 122 0.91 1688 51.9 41.1 669.75 133.20 60.88

40 111 0.91 1688 47.5 41.1 732.95 166.59 59.92

45 103 0.91 1688 43.8 41.1 788.90 203.18 58.66

50 95 0.91 1688 40.7 41.1 837.74 242.93 57.20

55 89 0.91 1688 38.0 41.1 879.56 285.77 55.61

60 84 0.91 1688 35.8 41.1 914.46 331.67 53.94

65 79 0.91 1688 33.8 41.1 942.52 380.60 52.25

Site S torage Requirement (SSR) = 0.06(Qdtd-c -d)

c= 0.675PSDtd(1-0.392PSD/Qd)

d= 0.117tdPSD2/Qd

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