storm temporal pattern Phone 6012)-7102620

storm temporal pattern Phone (6012)-7102620

http://msmaware.com/blog/enquiry-about-msmaware-software/


Phone (6012)-7102620





Manual Saliran Mesra Alam Malaysia (MSMA), or the Urban Stormwater Management Manual for Malaysia is the stormwater drainage design standard first produced by the Department of Irrigation and Drainage Malaysia (D.I.D) in 2000. It is compulsory for all engineers in Malaysia to build drainage structures to comply with the requirements of MSMA. Eleven years after its first publication, DID has completely updated the first edition of MSMA (MSMA1) with the publishing of the second edition (MSMA2). There are a lot of alterations in the second edition including (based on case studies done for Kuala Lumpur):





1. The design rainfall has risen by up to 126% for 10 out of the fourteen storm stations in Kuala Lumpur.





2. The design discharge using the Rational Method has increased by up to 131% for commercial and city area.





3. The Site Storage Requirement for OSD for a factory lot in Kuala Lumpur has risen by up to 235%,





4. The storage of a detention pond has increased by up to 130%.





The hike in the values of the main design parameters as outlined above can be attributed to the changes between the first and the second editions of MSMA as follows:





1. Longer storm data covering 100 more stations in Peninsular Malaysia. This results in higher storm intensities for certain durations and Average Recurrence Intervals.





2. West Malaysia is now separated into 5 regions for the computation of the 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 established according to the types of landuse, and not affected by rainfall durations and intensities, and whether a catchment is urban/rural in condition. This resulted in changes in the estimated peak discharge.





4. The Time-Area Method in MSMA2 is affected by the changes in the rainfall intensites, temporal patterns and the loss model used. For Kuala Lumpur it is noted that the rainfall intensities have increased and the temporal pattern is more peaky, thus giving rise to 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. MSMA2 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 pond has risen using MSMA2 compared to the first edition because of the increase in the rainfall intensities, temporal patterns and the choice of loss rate.





In view of the many changes in computational methods between the first and second editions of MSMA, a tool is developed to help engineers to carry out the computations using both editions precisely and to allow comparison be made of their changes speedily. The tool is a drainage design software created for MSMA- which is known as the MSMAware. The software is created by Ir. Dr. Quek Keng Hong who is a professonal engineer in Malaysia. MSMAware also covers the East Malaysian state of Sarawak where more than a dozen rainfall stations in the state and their temporal patterns are included into the software.

















storm temporal pattern Phone (6012)-7102620










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