Drainage Case

8.0 DRAINAGE DESIGN:

8.1 References:

The designs of the drainage system are based in accordance with Department Irrigation And Drainage Malaysia (DID) of Urban Stormwater Management Manual For Malaysia (Manual Saliran Mesra Alam Malaysia).

8.2 General:

The first urban drainage manual, ‘Planning and Design Procedures No. 1: Urban Drainage Design Standards and Procedures for Peninsular Malaysia’ was published by DID in 1975. This manual was prepared as a guideline for engineers in designing drainage system and had been referred to by various agencies at federal and state level for the drainage requirements needed for any development in urban areas. The manual has been in used as a guideline for more than twenty five years and since its publication, changes have not been made although there have been many new technological developments in urban drainage.

Stormwater management within a catchment is often undertaken by a number of organisations. The challenge is to ensure that the administration of the planning, design and maintenance of stormwater management systems is consistent across the relevant Local, State and Federal Authorities and the professions of planning, environmental and civil engineering, and landscape architecture.

Under this new direction, stormwater management will have multiple objectives, including to:

• Ensure the safety of the public

• Control nuisance flooding and provide for the safe passage of less frequent and larger flood events

• Protect property

• Stabilise the landform and control erosion

• Optimise the land available for urban development

• Minimise the environmental impact of urban runoff on water quality

• Enhance the urban landscape

These objectives will be seen as being achieved when:

• the planning, design and construction of new stormwater facilities is adequate to service the requirements of new and future developments

• there is compatibility with existing stormwater facilities, operational methods and maintenance techniques

• Stormwater facilities provide adequate environmental, community and asset protection consistent with acceptable planning, design and construction requirements and the principles of ecologically sustainable development.

8.3 Rational formula:

The Rational Formula is one of the most frequently used urban hydrology methods in Malaysia.