The drainage system assessment shall be based on Manual Saliran Mesra Alam Malaysia (MSMA) 1st Edition, year 2000 published by Jabatan Pengairan Dan Saliran, Malaysia.
The concept in the storm water management is to impose the control of both runoff quantity and quality. The establishment of a storage-oriented approach is for controlling runoff quantity from the development site.
In general, a major and minor system approach shall be adopted for the planning and design of drainage system. The minor system shall be designed to collect and convey runoff from relative frequent storm events to minimize inconvenience and nuisance flooding. The major system shall be designed to safely convey runoff in excess of minor drainage system to waterways of rivers. The major system shall protect the development area from the consequence of large, reasonably rare events, which could cause severe flood damage.
The drainage system shall be designed for water quantity controls. The final outflow from the drainage system after development shall not exceed pre-development discharge.