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For Kuala Lumpur Referred To Table 13.A1

This document contains calculations for stormwater drainage design for Catchment A1, including: 1) Calculation of discharge for a 2.4 x 1.8 m proposed box culvert based on catchment area, drain dimensions, gradient and roughness. The culvert meets capacity requirements for 5, 10 and 100 year storms. 2) Calculation of discharge for a 2.1 x 1.8 m proposed box culvert for Catchment A2, also meeting capacity requirements. 3) Computation of upstream time of concentration, overland flow velocity and drain flow time to determine total time of concentration for the catchment.

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197 views24 pages

For Kuala Lumpur Referred To Table 13.A1

This document contains calculations for stormwater drainage design for Catchment A1, including: 1) Calculation of discharge for a 2.4 x 1.8 m proposed box culvert based on catchment area, drain dimensions, gradient and roughness. The culvert meets capacity requirements for 5, 10 and 100 year storms. 2) Calculation of discharge for a 2.1 x 1.8 m proposed box culvert for Catchment A2, also meeting capacity requirements. 3) Computation of upstream time of concentration, overland flow velocity and drain flow time to determine total time of concentration for the catchment.

Uploaded by

Anonymous O404LiV4C
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as XLS, PDF, TXT or read online on Scribd
You are on page 1/ 24

References : Urban Stormwater management manual

Table of Average Rainfall Intensity (mm/hr)


for Kuala Lumpur referred to table 13.A1

For Rainfall Duration > 30 minutes


referred to equation 13.2

Storm Duration , tc (mins)


ARI (year) 15 18 20 22 24 26 28 30 32 33 37 38 40 42 44 46 48 50 52 54 56 58
2 139.5 128.6 122.3 116.7 111.6 107.0 102.9 99.0 95.5 93.8 87.8 86.4 83.8 81.4 79.1 76.9 74.9 73.0 71.2 69.5 67.8 66.3
5 166.5 153.6 146.2 139.4 133.3 127.7 122.6 117.9 113.5 111.5 104.1 102.4 99.1 96.1 93.3 90.6 88.1 85.8 83.5 81.4 79.4 77.5
10 182.5 169.0 161.1 153.8 147.1 141.1 135.5 130.4 125.6 123.4 115.2 113.3 109.7 106.4 103.3 100.4 97.6 95.0 92.5 90.2 88.0 85.9
20 199.8 185.0 176.2 168.2 160.9 154.2 148.1 142.4 137.2 134.7 125.7 123.7 119.8 116.1 112.7 109.4 106.4 103.5 100.8 98.3 95.8 93.5
50 217.3 202.1 192.9 184.4 176.6 169.4 162.8 156.6 151.0 148.3 138.4 136.2 131.9 127.8 124.1 120.5 117.2 114.0 111.0 108.2 105.5 103.0
100 240.5 223.2 212.8 203.3 194.5 186.5 179.1 172.2 165.9 162.9 152.0 149.5 144.8 140.3 136.1 132.2 128.5 125.0 121.7 118.6 115.7 112.9

For Short Rainfall Duration < 30 minutes


referred to equation 13.3, 13.4 and table 13.3
value of 2P24h= 100 (KUALA LUMPUR).
Storm Duration , tc (mins)

ARI (year) 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
2 212.5 201.5 193.7 187.8 183.3 179.6 171.3 164.4 158.5 153.5 149.1 143.6 138.7 134.4 130.5 127.0 123.0 119.4 116.0 113.0 110.2 107.6

5 288.1 266.9 251.8 240.5 231.7 224.6 213.0 203.3 195.1 188.1 182.0 174.8 168.4 162.7 157.7 153.1 148.1 143.5 139.3 135.5 132.0 128.7

10 315.3 292.7 276.5 264.4 255.0 247.4 234.7 224.1 215.2 207.5 200.9 192.9 185.9 179.7 174.2 169.2 163.6 158.6 154.0 149.8 145.9 142.3

20 352.4 325.8 306.9 292.7 281.6 272.8 258.5 246.6 236.6 228.0 220.5 211.7 203.9 197.0 190.8 185.3 179.2 173.6 168.5 163.9 159.6 155.6

50 385.3 356.6 336.1 320.8 308.8 299.3 283.7 270.7 259.8 250.3 242.2 232.5 224.0 216.5 209.7 203.6 196.9 190.8 185.2 180.1 175.4 171.1

100 432.3 398.8 374.9 356.9 342.9 331.8 314.2 299.6 287.2 276.6 267.4 256.7 247.2 238.7 231.2 224.4 217.0 210.2 204.0 198.3 193.1 188.3
60
64.8
75.7
83.9
91.3
100.5
110.2

27 28 29 30
105.2 103.0 101.0 99.0

125.7 122.9 120.3 117.9

139.0 135.9 133.0 130.4

152.0 148.6 145.4 142.4

167.1 163.4 159.9 156.6

183.8 179.7 175.8 172.2


'file:///conversion/tmp/scratch/370956013.xls'#$MD (R

JURUTERA PERUNDING TEGAP SDN. BHD.

PROJECT : 06186 Designed :


page Main Drain A1 Compuation Date :
of post-development discharge computaion - Catchment A1 Checked :
REF. CALCULATION

0.3 FB TWL

Box Culvert
D

W
Pudu Cut Drain
Box culvert Capacity computation area,Ap =
perimeter, Pp =
depth, D= 1.35 m without FB
width, W= 1.20 m

Area, A = 1.78 m2
perimeter, P = 4.02 m
R= 0.44 m

drain gradient , S =1/ 300


n= 0.015 (for lined concrete drain)

discharge, Q = 3.98 m3/s > required. OK.


velocity, V = 2.24 m/s < 4.0 m/s. OK

top water lever TWL = 1.76 m 100 years storm Q100,post


top water lever TWL = 1.39 m 10 years storm Q10,post
top water lever TWL = 1.23 m 5 years storm Q5,post

Thus, Proposed 2.4 x 1.8 m PC Box Culvert


(include 0.3 free board)
'file:///conversion/tmp/scratch/370956013.xls'#$MD (R

JURUTERA PERUNDING TEGAP SDN. BHD.

PROJECT : 06186 Designed :


page Main Drain A2 Compuation Date :
of post-development discharge computaion - Catchment A2 Checked :
REF. CALCULATION

0.3 FB TWL

Box Culvert
D

W
Pudu Cut Drain
area,Ap =
Box culvert Capacity computation perimeter, Pp =

depth, D= 1.80 m without FB


width, W= 2.10 m

Area, A = 4.95 m2
perimeter, P = 4.65 m
R= 1.06 m

drain gradient , S =1/ 500


n= 0.015

discharge, Q = 15.39 m3/s > required. OK.


velocity, V = 3.11 m/s < 4.0 m/s. OK

top water lever TWL = 1.51 m 100 years storm Q100,post


top water lever TWL = 1.11 m 10 years storm Q10,post
top water lever TWL = 1.01 m 5 years storm Q5,post

Thus, Proposed 2.1 x 1.8 m PC Box Culvert


(include 0.3 free board)
'file:///conversion/tmp/scratch/370956013.xls'#$MD (RSD)

SDN. BHD.

signed : YauTY
e : Jun-06
ecked :
OUTPUT

0.16 m
1.17 m

= 8.82 m3/s
= 6.19 m3/s
= 5.27 m3/s
'file:///conversion/tmp/scratch/370956013.xls'#$MD (RSD)

SDN. BHD.

signed : YauTY
e : Jun-06
ecked :
OUTPUT

0.16 m
1.17 m

= 6.87 m3/s
= 4.63 m3/s
= 4.04 m3/s
'file:///conversion/tmp/scratch/370956013.xls'#$Catchm

JURUTERA PERUNDING TEGAP SDN. BHD.

d
PROJECT : 06186 Designed :
r
page Catchment Flow Compuation fora Main Drain A1 Date :
of Existing Catchment A1 i Checked :
REF. n CALCULATION
1.0 a
Post Development Catchment Area
Upstream Catchment Area gA1 A1=Forest Reserve = 33.23ac.
e

r
1.1 Determine of time of concentration, t
e up c (up stream)

for density grassed surface (n=0.060)


s
average surface slopes =5% e
Design overland flow distance = 50m r
v to =
chart 14.1
e
average velocity in open drain , assumed v = 2 m/s
natural channel, Ld =
drain flow time, td = Ld / (v x 60) =
thus, time of concentration, tc = t o+ t d =

1.2 Determine rainfall intensity and Runoff Coefficient


Referred to Table of Average Rainfall Intensity (mm/hr) for short rainfall
duration for tc = 22mins
thus,
rainfall intensity for 5 years storm I22
5
=
rainfall intensity for 10 years storm
10
I22 =
rainfall intensity for 100 years storm
100
I22 =

design chart Runoff Coefficient for Upstream catchment, C5 =


14.4 7 Park Lawns and Meadows C10 =
C100 =

1.6 Discharge flow computaion, Qpre , for Post-development


Q = (A1 x Cavg) x I22
Discharge flow for 5 years storm Q5,post =
Discharge flow for 10 years storm Q10,post =
Discharge flow for 100 years storm Q100,post =
JURUTERA PERUNDING TEGAP SDN. BHD.

d
PROJECT : 06186 Designed :
r
page Catchment Flow Compuation fora Main Drain A2 Date :
of Existing Catchment A2 i Checked :
REF. n CALCULATION
1.0 a
Post Development Catchment Area
Upstream Catchment Area gA2 A2=Forest Reserve = 33.23ac.
e

r
1.1 Determine of time of concentration, t
e up c (up stream)

for density grassed surface (n=0.060)


s
average surface slopes =5% e
Design overland flow distance = 50m r
chart 14.1
v to =
e
average velocity in open drain , assumed v = 2 m/s
natural channel, Ld =
drain flow time, td = Ld / (v x 60) =
thus, time of concentration, tc = t o+ t d =

1.2 Determine rainfall intensity and Runoff Coefficient


Referred to Table of Average Rainfall Intensity (mm/hr) for short rainfall
duration for tc = 25mins
thus,
rainfall intensity for 5 years storm
5
I25 =
rainfall intensity for 10 years storm
10
I25 =
rainfall intensity for 100 years storm
100
I25 =

design chart Runoff Coefficient for Upstream catchment, C5 =


14.4 7 Park Lawns and Meadows C10 =
C100 =

Rainfall Intensity Based on I25 from section 1.2


1.6 Discharge flow computaion, Qpre , for Post-development
Q = (A2 x Cavg) x I25
Discharge flow for 5 years storm Q5,post =
Discharge flow for 10 years storm Q10,post =
Discharge flow for 100 years storm Q100,post =
version/tmp/scratch/370956013.xls'#$Catchment(RSD)

YauTY
Apr-06

OUTPUT

13.45 ha

17 mins

600 m
5 mins
22 mins

143.50 mm/hr
158.57 mm/hr
210.18 mm/hr

0.53
0.56
0.63

2.84 m3/s

3.32 m3/s

4.95 m3/s
YauTY
Apr-06

OUTPUT

17.42 ha

17 mins

100 m
1 mins
18 mins

131.96 mm/hr
145.87 mm/hr
193.11 mm/hr

0.51
0.53
0.61

3.26 m3/s
3.74 m3/s
5.70 m3/s
'file:///conversion/tmp/scratch/370956013.xls'#$Ex

JURUTERA PERUNDING TEGAP SDN. BHD.

PROJECT : 06186 Designed :


page Existing Main Drain Capacity Checking Date :
of Checked :
REF. CALCULATION

0.3 FB TWL

Box Culvert
D

W
Pudu Cut Drain
Box culvert Capacity computation area,Ap = 0.16
perimeter, Pp = 1.17
depth, D= 3.10 m without FB
width, W= 3.10 m

Area, A = 9.77 m2
perimeter, P = 9.42 m
R= 1.04 m

drain gradient , S =1/ 600


n= 0.015 (for lined concrete drain)

discharge, Q = 27.25 m3/s > required. OK.


velocity, V = 2.79 m/s < 4.0 m/s. OK

Maximum Pond dischagre for 100 years storm = 15.204 m3/s


file:///conversion/tmp/scratch/370956013.xls'#$ExtMD

SDN. BHD.

YauTY
Jun-06

OUTPUT

m
m
'file:///conversion/tmp/scratch/370956013.xls'#$

JURUTERA PERUNDING TEGAP SDN. BHD.

PROJECT : 06186 Designed :


page Main Drain A1 Compuation Date :
of post-development discharge computaion - Catchment A1 Checked :
REF. CALCULATION

0.3 FB TWL

Box Culvert
D

W
Pudu Cut Drain
Box culvert Capacity computation area,Ap =
perimeter, Pp =
depth, D= 1.50 m without FB
width, W= 2.40 m

Area, A = 3.76 m2
perimeter, P = 5.52 m
R= 0.68 m

drain gradient , S =1/ 300


n= 0.015 (for lined concrete drain)

discharge, Q = 11.20 m3/s > required. OK.


velocity, V = 2.98 m/s < 4.0 m/s. OK

top water lever TWL = 1.24 m 100 years storm Q100,post


top water lever TWL = 0.93 m 10 years storm Q10,post
top water lever TWL = 0.82 m 5 years storm Q5,post

Thus, Proposed 2.4 x 1.5 m PC Box Culvert


(include 0.3 free board)
'file:///conversion/tmp/scratch/370956013.xls'#$

JURUTERA PERUNDING TEGAP SDN. BHD.

PROJECT : 06186 Designed :


page Main Drain A2 Compuation Date :
of post-development discharge computaion - Catchment A2 Checked :
REF. CALCULATION

0.3 FB TWL

Box Culvert
D

W
Pudu Cut Drain
area,Ap =
Box culvert Capacity computation perimeter, Pp =

depth, D= 1.50 m without FB


width, W= 2.10 m

Area, A = 3.15 m2
perimeter, P = 5.10 m
R= 0.62 m

drain gradient , S =1/ 300


n= 0.015

discharge, Q = 8.79 m3/s > required. OK.


velocity, V = 2.79 m/s < 4.0 m/s. OK

top water lever TWL = 1.24 m 100 years storm Q100,post


top water lever TWL = 0.92 m 10 years storm Q10,post
top water lever TWL = 0.83 m 5 years storm Q5,post

Thus, Proposed 2.1 x 1.5 m PC Box Culvert


(include 0.3 free board)
'file:///conversion/tmp/scratch/370956013.xls'#$MD

SDN. BHD.

signed : YauTY
e : Jun-06
ecked :
OUTPUT

0.16 m
1.17 m

= 8.82 m3/s
= 6.19 m3/s
= 5.27 m3/s
'file:///conversion/tmp/scratch/370956013.xls'#$MD

SDN. BHD.

signed : YauTY
e : Jun-06
ecked :
OUTPUT

0.16 m
1.17 m

= 6.87 m3/s
= 4.63 m3/s
= 4.04 m3/s

xx
'file:///conversion/tmp/scratch/370956013.xls'#$C

JURUTERA PERUNDING TEGAP SDN. BHD.

d
PROJECT : 06186 Designed :
r
page Catchment Flow Compuation a Date :
of post-development discharge computaion
i - Catchment A1 Checked :
REF. n CALCULATION
1.0 Post Development Catchment a Area
Upstream Catchment Area g(A1-A1b) A1a=Forest = 35.2ac.
e
Project Site (A1b) ( developed area ) = 17.2ac.
r Overall Catchment, A1 =
1.1 Determine of time of concentration, t
e up c (up stream)

for density grassed surface (n=0.060)


s
average surface slopes =5% e
Design overland flow distance = 50m r
v to =
chart 14.1
e
average velocity in open drain , assumed v = 2 m/s
natural channel, Ld =
drain flow time, td = Ld / (v x 60) =
thus, time of concentration, tc = t o+ t d =

1.2 Determine rainfall intensity and Runoff Coefficient


Referred to Table of Average Rainfall Intensity (mm/hr) for short rainfall
duration for tc = 22mins
thus,
rainfall intensity for 5 years storm I22
5
=
rainfall intensity for 10 years storm
10
I22 =
rainfall intensity for 100 years storm
100
I22 =

design chart Runoff Coefficient for Upstream catchment, C5 =


14.4 7 Park Lawns and Meadows C10 =
C100 =
1. 3 Determine of time of concentration, t
dn c (down stream)

for bare soil surface (n=0.0275)


average surface slopes =0.5
Design overland flow distance = 50m
chart 14.1 to =
average velocity in open drain , assumed v = 0.8 m/s
natural channel, Ld =
drain flow time, td = Ld / (v x 60) =

thus, time of concentration, tc = to+ td =

1.4 Determine rainfall intensity and Runoff Coefficient


Referred to Table of Average Rainfall Intensity (mm/hr) for short rainfall
duration for tc = 16mins
thus,
rainfall intensity for 5 years storm I16
5
=
rainfall intensity for 10 years storm
10
I16 =
rainfall intensity for 100 years storm
100
I16 =

design chart Runoff Coefficient for Upstream catchment, C5 =


14.4 3 Semi-Detached Houses on Bare Earth C10 =
C100 =
1.5 Determine Average Runoff Coefficient
C5 =
avg
Cavg = Ci Ai C 10 =
avg

Ai avg
C 100 =
Rainfall Intensity Based on I22 from section 1.2
1.6 Discharge flow computaion, Qpre , for Post-development
Q = (A1 x Cavg) x I22
Discharge flow for 5 years storm Q5,post =
Discharge flow for 10 years storm Q10,post =
Discharge flow for 100 years storm Q100,post =
JURUTERA PERUNDING TEGAP SDN. BHD.

d
PROJECT : 06186 Designed :
r
page Catchment Flow Compuation a Date :
of post-development discharge computaion
i - Catchment A2 Checked :
REF. n CALCULATION
1.0 Post Development Catchment a Area
Upstream Catchment Area g(A2-A2b) A2a=Forest = 42.12ac.
e
Project Site (A2b) ( developed area ) = 7.1ac.
r Overall Catchment, A2 =
1.1 Determine of time of concentration, t
e up c (up stream)

for density grassed surface (n=0.060)


s
average surface slopes =5% e
Design overland flow distance = 50m r
v to =
chart 14.1
e
average velocity in open drain , assumed v = 2 m/s
natural channel, Ld =
drain flow time, td = Ld / (v x 60) =
thus, time of concentration, tc = t o+ t d =

1.2 Determine rainfall intensity and Runoff Coefficient


Referred to Table of Average Rainfall Intensity (mm/hr) for short rainfall
duration for tc = 25mins
thus,
rainfall intensity for 5 years storm
5
I25 =
rainfall intensity for 10 years storm
10
I25 =
rainfall intensity for 100 years storm
100
I25 =

design chart Runoff Coefficient for Upstream catchment, C5 =


14.4 7 Park Lawns and Meadows C10 =
C100 =

1. 3 Determine of time of concentration, t


dn c (down stream)

for bare soil surface (n=0.0275)


average surface slopes =0.5
Design overland flow distance = 50m
chart 14.1 to =
average velocity in open drain , assumed v = 0.8 m/s
natural channel, Ld =
drain flow time, td = Ld / (v x 60) =

thus, time of concentration, tc = to+ td =

1.4 Determine rainfall intensity and Runoff Coefficient


Referred to Table of Average Rainfall Intensity (mm/hr) for short rainfall
duration for tc = 16mins
thus,
rainfall intensity for 5 years storm I16
5
=
rainfall intensity for 10 years storm
10
I16 =
rainfall intensity for 100 years storm
100
I16 =

design chart Runoff Coefficient for Upstream catchment, C5 =


14.4 3 Semi-Detached Houses on Bare Earth C10 =
C100 =
1.5 Determine Average Runoff Coefficient

Cavg = Ci Ai C5 =
avg

Ai
C 10 =
avg

avg
C 100 =
Rainfall Intensity Based on I25 from section 1.2
1.6 Discharge flow computaion, Qpre , for Post-development
Q = (A2 x Cavg) x I25
Discharge flow for 5 years storm Q5,post =
Discharge flow for 10 years storm Q10,post =
Discharge flow for 100 years storm Q100,post =
///conversion/tmp/scratch/370956013.xls'#$Catchment

YauTY
Apr-06

OUTPUT

14.09 ha
6.89 ha
20.98 ha

17 mins

600 m
5 mins
22 mins

143.50 mm/hr
158.57 mm/hr
210.18 mm/hr

0.53
0.56
0.63

12 mins

200 m
4 mins

16 mins

174.77 mm/hr
192.93 mm/hr
256.66 mm/hr

0.84
0.89
0.90

0.63
0.67
0.72

5.27 m3/s
6.19 m3/s

8.82 m3/s
YauTY
Apr-06

OUTPUT

16.85 ha
0.00 ha
16.85 ha

17 mins

1000 m
8 mins
25 mins

131.96 mm/hr
145.87 mm/hr
193.11 mm/hr

0.51
0.53
0.61

12 mins

200 m
4 mins

16 mins

174.77 mm/hr
192.93 mm/hr
256.66 mm/hr

0.84
0.89
0.90

0.51
0.53
0.61

3.15 m3/s
3.62 m3/s
5.51 m3/s

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