#storm temporal pattern

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storm temporal pattern Phone 6012)-7102620

http://msmaware.com/blog/enquiry-about-msmaware-software/ Phone 6012-710-2620

Manual Saliran Mesra Alam Malaysia (MSMA), or the Urban Stormwater Management Manual for Malaysia is the urban drainage design guideline first produced by the Department of Irrigation and Drainage Malaysia (D.I.D) in 2000. It is required by law for all engineers in Malaysia to build drainage works to comply with the requirements of MSMA. 11 years after its first publication, DID has completely revised the first edition of MSMA (MSMA1) with the release of the second edition (MSMA2). There are many alterations in the second edition including the following (taken from case studies done for Kuala Lumpur):

1. The design storm has risen by up to 126% for ten out of the 14 storm stations in Kuala Lumpur.

2. The design flow using the Rational Method has gone up 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 volume of a detention basin has gone up by up to 130%.

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

1. Longer rainfall data covering 100 more storm 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 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 different hydrograph peaks and shapes.

3. The coefficient of runoff in the Rational Method is now fixed according to the types of landuse, and not influenced by storm durations and intensities, and whether a catchment is urban/rural in condition. This gives rise to changes in the estimated peak flow.

4. The Time-Area Method in the second editon is affected by the changes 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 giving rise to a more peaky flow hydrograph.

5. The Site Storage Requirement (SSR) based on the Approximate Swinburne Method in the second editon is higher than that using 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.

6. The volume of a detention basin has risen using the second editon compared to MSMA1 because of the increase in the storm 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 perform the computations using both editions precisely and to allow comparison be made of their changes quickly. The tool is a stormwater design software created for MSMA- 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 storm stations in the state and their temporal patterns are programmed into the software.

STORM TEMPORAL PATTERN : 00:00:05 storm temporal pattern 00:00:05 Rational Method 00:00:06 Time-Area Method 00:00:07 culvert design 00:00:08 culvert analysis