drainage design guideline Ph 6012)710 2620

http://ift.tt/1RH3cu1 Ph 6012 710 2620 Manual Saliran Mesra Alam Malaysia (MSMA), also known as the Urban Stormwater Management Manual for Malaysia is the stormwater drainage design procedure first issued by the Department of Irrigation and Drainage Malaysia (D.I.D) in 2000. It is compulsory for all engineers in Malaysia to design drainage system to comply with the requirements of MSMA. 11 years after its first publication, DID has completely updated the first edition of MSMA (MSMA1) with the publication of the second edition (MSMA2). There are a lot of differences in the second edition including (based on case studies carried out for Kuala Lumpur): 1. The design storm has risen by up to 126% for 10 out of the 14 rainfall stations in Kuala Lumpur. 2. The design discharge using the Rational Method has risen by up to 131% for commercial and city area. 3. The Site Storage Requirement for On-Site Detention for a factory site in Kuala Lumpur has risen by up to 235%, 4. The storage of a detention basin has risen by up to 130%. The hike in the magnitudes of the main design parameters as outlined above can be due to the differences between the first and the second editions of MSMA as follows: 1. Longer storm data covering 100 more rainfall stations in Peninsular Malaysia. This results in higher rainfall intensities for certain durations and ARI's. 2. Peninsular Malaysia is now separated into 5 regions for the determination of the storm temporal pattern, compared to previously where it was divided into east and west coast of the Peninsula. The differences in temporal patterns give rise to dissimilar hydrograph peaks and shapes. 3. The coefficient of runoff in the Rational Method is now determined according to the types of landuse, and not dependent on storm durations and intensities, and whether a catchment is urban/rural in condition. This resulted in differences in the estimated peak discharge. 4. The Time-Area Method in MSMA2 is affected by the differences in the storm intensites, temporal patterns and the loss model used. For Kuala Lumpur it is noticed that the storm intensities have increased and the storm temporal pattern is more peaky, thus resulting in a more peaky discharge hydrograph. 5. The Site Storage Requirement (SSR) based on the Approximate Swinburne Method in MSMA2 is higher than that using the Swinburne Method in the first edition. The second editon used the approximate method based on a set of approximation tables and this has resulted in an over estimation of the SSR's. 6. The storage of a detention basin has risen using MSMA2 compared to the first edition because of the increase in the storm intensities, temporal patterns and the choice of loss rate. In view of the many differences in computational methods between the first and second editions of MSMA, a tool is developed to help engineers to perform the computations using both editions accurately and to allow comparison be made of their differences quickly. The tool is a stormwater design software designed for MSMA. The software is written by Ir. Dr. Quek Keng Hong- a practising professional engineer in Malaysia. MSMAware also covers the East Malaysian state of Sarawak where more than a dozen storm stations and their temporal patterns are programmed into the software. DRAINAGE DESIGN GUIDELINE : 00:00:05 drainage design guideline 00:00:06 Manual Saliran Mesra Alam Malaysia 00:00:07 Urban Stormwater Management Manual for Malaysia 00:00:08 Urban Stormwater Management Manual 00:00:10 Department of Irrigation and Drainage Malaysia drainage design guideline Ph (6012)710 2620
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