Urban Stormwater Management Manual software Call 6012)710 2620

Urban Stormwater Management Manual software Call (6012)710 2620

http://msmaware.com/blog/msma-drainage-design-software/
Phone call (6012)710 2620

The Urban Stormwater Management Manual for Malaysia or the Manual Saliran Mesra Alam (MSMA) is the urban drainage design guideline first published by the Department of Irrigation and Drainage Malaysia in early 2000. Engineers in Malaysia are required by law to design drainage system to fullfil the requirements of MSMA. Eleven years after its first publication, DID has completely updated the first edition of MSMA (or MSMA1) with the publishing of the second edition (or MSMA2). There are a lot of differences in the second edition including (taken from case studies completed for Kuala Lumpur):

The design rainfall has gone up by up to 126% for ten out of the fourteen rainfall stations in Kuala Lumpur.
The design discharge using the Rational Method has gone up by up to 131% for commercial and city area.
For a factory lot in Kuala Lumpur the Site Storage Requirement for OSD has gone up by up to 234%.
The storage of a detention pond has gone up by up to 130%.

The rise in the values of the main design parameters as described above can be due to the differences between the first and the second editions of MSMA as follows:

Longer storm data covering 100 more stations in Peninsular Malaysia. This gives rise to in higher rainfall intensities for certain durations and Average Recurrence Intervals.

Compared to previously where it was divided into east and west coast of the Peninsula for the determination of the storm temporal pattern, Peninsular Malaysia is now separated into 5 regions. The differences in temporal patterns give rise to dissimilar hydrograph peaks and shapes.

The coefficient of runoff in the Rational Method is now fixed according to the types of landuse, and not dependent on rainfall durations and intensities, and whether a catchment is urban/rural in condition. Differences in the estimated peak discharge is observed .

The Time-Area Method in MSMA2 is affected by the differences in the rainfall intensites, temporal patterns and the loss model used. The rainfall intensities for Kuala Lumpur have increased and the storm temporal pattern is more peaky, giving rise to a more peaky discharge hydrograph.

The Approximate Swinburne Method in MSMA2 gives higher Site Storage Requirement (SSR) than the Swinburne Method in MSMA1. The second editon used the approximate method based on a set of approximation tables and this has resulted in an over estimation of the Site Storage Requirements.

Compared to MSMA1, the increase in the rainfall intensities, temporal patterns and the choice of loss rate have caused a rise in the storage of a detention pond using the second edition.

A software program Is developed to assist engineers to carry out the computations using both editions precisely and to allow comparison be made of their differences speedily, in view of the many differences in computational methods between the first and second editions of MSMA. A stormwater design software has been developed for MSMA. The software is programmed by Ir. Dr. Quek Keng Hong- a professonal engineer in Malaysia. MSMAware also contains more than a dozen rainfall stations and their temporal patterns in the Sarawak.





Urban Stormwater Management Manual software Call (6012)710 2620












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