STORM WATER MANAGEMENT REPORT
Hydraulic Design Calculation
CADANGAN PEMBANGUNAN FASA 1 YANG MENGANDUNGI 1 BLOK
BANGUNAN PENTADBIRAN 2 TINGKAT, SEBUAH DEWAN SERBAGUNA, 2
BLOK BANGUNAN ASRAMA KANAK-KANAK TERENCAT AKAL, SEBUAH
DEWAN MAKAN DAN SEBUAH PENCAWANG TNB 'SINGLE CHAMBER' DI
ATAS SEBAHGIAN LOT 1648, MUKIM TANJUNG 12, DAERAH KUALA
LANGAT,SELANGOR DARUL EHSAN UNTUK TETUAN PERSATUAN
PENJAGAAN KANAK-KANAK TERENCAT AKAL JOHOR BAHRU, JOHOR.
Date: September 2010
Table of Contents
3. Project Description...3
4. Previous Submission Approval...4
5. Objective of Submission...4
6. The earthwork platform design criteria...4
7. Stormwater Management For Whole of Lot 1648...4
8. Storm Water Management For Old Folks’ Home...4
9. Silt trap...5
10. Design Guidelines and Criteria...5
9.1 Design Average Recurrence Intervals (ARI)...5
9.2 The Rational Method...5
9.3 Runoff Coefficient...6
9.4 Rainfall Intensity-Duration-Frequency Relationship...6
9.5 Flow Computation...6
9.6 Velocity of Flow...6
Appendix 1 – Key Plan and Location Plan
Appendix 2 - Overall Planning Layout Plan (Plan No.SAMP/LION/MDKL-SA/TG12/04-7(043)
Old Folk’s Home Layout Plan (Plan No. PR1005/ARC/DO/SP/01-01)
Appendix 3 - Authorities Approval Letter For Original Earthwork Layout & Details
Appendix 4 – Catchments Area for Main Drain And Detention Ponds
Appendix 5 - Hydraulic Calculation for Sediment Basins and Detail Drawing
Appendix 6 - Table of Rainfall Intensity At Kuala Lumpur for Various Return
Period And Duration
Appendix 7 - Hydraulic Design Charts and Tables from Urban Storm Water
Chen Fook Yew
Checked & Approved
Ir. Teoh Yong Hoee
A mix development project, which is named Bandar Baru Brookland (2), was proposed by Messrs. Andalas Development Sdn. Bhd. ( a member of Lion Group of Company ). The land for development involves lot 707, 1644, 1645, 1647 and 1648 local at Mukim Tanjung Dua Belas, Daerah Kuala Langat, Selangor Darul Ehsan. A development plan had been drawn-up in the early 90’s and approved by all relevant authorities. The layout plan has been revised several time since then.
In year 2009, the developer revised the layout by converting some of the terrace house at Lot 1648 to Old Folk’s Home. The revised layout was approved by Majlis Daerah Kuala Langat on 12th February 2010 via planning layout plan SAMP/LION/MDKL-SA/TG12/04-07(043). The approved layout is attached in appendix.
The proposed development is located along Jalan Banting, approximately 4 km of Banting town as shown in the key plan. The Key plan and Location plan of the proposed site is shown in Appendix 1.
The proposed site is situated at Lot 1648 (Brookland 2) occupied an area of 4.11 acres. Please refer to planning layout plan: SAMP/LION/MDKL-SA/TG12/04-07(043) in Appendix 2 for the composition of the overall development. The Old Folk’s Home planning layout with plan no. PR1005/ARC/DO/SP/01-01 is as shown in Appendix 2 and its composition of development is as follow:
a) Dining area b) Multipurpose Hall c) Guard house
d) 2 storey admin block
e) Mentally impair male children hostel f) Therapy pool
g) Mentally impair female children hostel h) Old folks and orphanage home
This report illustrated
storm water management system and design of silt trapfor Old Folk’s Home on part of Lot 1648 on south of Persiaran Brookland.
Previous Submission Approval
4.1 The original earthwork layout and details for the Lot 1648 of Brookland 2 had been approved by the relevant authorities as following:
a) Jabatan Pengairan Dan Saliran Negeri Selangor dated 6 April 1999 with reference no. Bil(14)dlm.JPS Sel 012C/5/2/163.
b) Majlis Daerah Kuala Langat dated 21 November 2000 with reference no. Bil(13)dlm.MDK.Lgt.4//PL/4/467(K/T).
The above-mentioned letters are attached in Appendix 4.
Objective of Submission
The objective of this submission is to seek the approval from relevant authority on the:
Storm water management system for predevelopment and post
Detail design of sediment basin.
The earthwork platform design criteria
The earthwork planning is designed in accordance to JPS requirement which as following: 1) +4.5 LSD at downstream of Brookland 2
2) +5.4 LSD at upstream of Brookland 2
3) The platform level in between the upstream and downstream of Brookland 2 along the “Sungai Langat” is determined by linear interpolate method
Stormwater Management For Whole of Lot 1648
Two centralize detention pond (detention pond “E” and “D”) was provided for the whole development in Lot 1648, storm water from all parcel of development in Lot 1648 shall be channel to these two detention pond before discharge into existing river. The detention ponds will attenuate storm water discharge into the existing river as according to MASMA requirement.
Storm Water Management For Old Folks’ Home
This Old Folk’s Home development with 4.11 acres is a parcel of development in Lot 1648. The proposed Old Folk’s Home development has been included in Detention Pond
“E” catchment. There is no change in storm water discharge eventually. The development has changed from terrace house to Old Folk’s Home development. As such, the storm water management system for whole of Lot 1648 previously approved remain valid. Therefore, no storm water detention within Old Folk’s Home site is required.
Nevertheless, proper lined concrete drain will be constructed within the site to channel storm water discharge to existing detention pond.
A silt trap also provided during the construction to ensure that quality of storm water discharge during the construction process is up to the D.O.E. requirement. The calculation and the detail drawing are as shown in appendix.
Design Guidelines and Criteria
The hydraulic and hydrology calculation for the main drainage system and detention pond is generally designed in accordance to Urban Stormwater Management Manual for Malaysia, 2000 published by the Drainage and Irrigation Department (DID).
9.1 Design Average Recurrence Intervals (ARI)
The Design Average Recurrence Intervals (ARI) adopted for the planning and design of stormwater systems shall be in accordance with Table 4.1 of Urban Stormwater Management Manual for Malaysia, 2000 as attached in Appendix 12.
9.2 The Rational Method
The Rational Method can provide satisfactory estimates of peak discharge on small catchments of up to 80 hectares. The development area has been divided in small catchments area of individual drainage system of less than 100 acres each. Hence, the method is used for the runoff discharges.
Assumptions used in Rational Method are as follows:
1. The peak flow occurs when the entire catchments is contributing to the flow 2. The rainfall intensity is the same over the entire catchments area
3. The rainfall intensity is uniform over a time duration equal to the time of concentration, tc
4. The ARI of the computed peak flow is the same as that of the rainfall intensity, i.e. 5 year ARI rainfall intensity will produce a 5 year ARI peak flow.
The formula is : Qy = C . y It.A 360
Where Qy = Y Year ARI peak flow (m3/s)
C = dimensionless runoff coefficient
yIt = y year ARI average rainfall intensity over time of concentration, (mm/hr)
A = drainage area (ha)
9.3 Runoff Coefficient
The runoff coefficient, C adopted depends on rainfall intensity and duration as well as on the catchment characteristics. Recommended runoff coefficient values for rainfall intensities of up to 200mm/hr can be obtained from Design Chart 14.3 (urban areas) or Chart 14.4(rural areas) respectively as attached in Appendix 12.
9.4 Rainfall Intensity-Duration-Frequency Relationship
The derivation of the IDF curves for the development is based on Chapter 13 of the Urban Stormwater Management Manual on Design Rainfall. The IDF curves for Kuala Lumpur is attached in Appendix 12.
9.5 Flow Computation
Manning’s formula is adopted for uniform flow computation. The formula is : V = R 2/3 S ½ and Q = AV
Where, Q = flow in cumecs
n = Manning’s roughness coefficient
A = drain cross sectional area in square meters R = hydraulic radius in meters
S = slope in meters/meter
The n value is depends on the type of materials used for the drain lining construction as recommended at Chart 28.1 as attached in Appendix 12.
To minimize the deposition of grit and sand in stormwater drains and scouring of drain linings, the recommended minimum and maximum velocities for various types of drains are indicates in Table 4.3 as attached in Appendix 12.