Johore Bahru is the fourth largest town in Malaysia. Situated on the north shore of the Johore Straits (Selat Johor) and linked to Singapore by a causeway, it has developed rapidly since 1965 as an economic region and service center for southern Peninsular Malaysia.

The study area extended from Kulai in the Skudai Valley north-west of Johore Bahre to the port and industrial area of Pasir Gudang to the south-east of Johore Bahru Town, and includes three sub-regions each having distinct natural features and population and physical characteristics.

Proposals were presented in three 10-year phases of implementation and investment each spanning two Malaysian Development 5-Year Plans.

Sewerage Studies
Pending introduction of sewerage, proposals made included temporary improvements to existing night soil collection system in central and some other urban area, reorganisation of septic tank emptying services and upgrading to pour, flush or septic tanks standards, properties with sub-standard pit latrines or direct stream discharge in areas of low density population.

Six sites for sewage treatment were proposed to serve first phase populations ranging from 3,000 to 48,000 rising to 16,000 to 210,000 by the end of the third phase (2010). Treatment will be in faculative or aereated ponds followed in some cases by maturation ponds, the process adopted being determined from a consideration of site areas and locations, nature and strength of existing predicted future waste-water flows, effluent standards, process reliability and capital and operating costs. In the design of sewers and choice of materials of construction particular consideration has been given to the need to minimize the risk of septicity with it's possible consequent harmful effects on the structure of the the sewerage system.

Much past development amploys small septic tanks receiving only toilet waste, sullage being discharge to road drains and water courses which are thereby seriously polluted. Proposals include for the trial of limited and relatively inexpensive in term measures to intercept flows at selected points in the drainage system and divert this to the new sewers via chambers design to past several dry weather flows but to restrict entry of large volume wet weather flow. Recognizing the problem involved in out-grading internal house plumbing, loans to assist property owners are proposed thus facilitating progressive conversion to full sewerage in the longer term.

First phase were includes construction of some 35 km of trunk sewer verying in diameter from 300mm to 1050mm, 10 km of rising mains in size up to 500mm, 11 submersible type pumping stations having installed capacity ranging from 20 to 1400 Liters per second (ultimate), and first phase development of five of the six proposed sewage treatment plant.

Drainage Studies
The study area topography is charecterize by well-defined catchments the mainstreams of which are becoming urban area trunk drains. Urban developments is increasing stormwater run-off, enchroaching on water waste and floodwaste and causing siltition of streams through erosion of cleared land. As a result the main streams no longer have sufficiantly capacity for peak flows and flooding is increasingly in freaquancy and severity in Johore Bahru Town and other urban areas.

The study covered both the situation in the existing built-up areas and that in areas not yet developed. In the former, channeling of streams and replacement of culverts and bridges have been proposed, the drains being designed to cope with storms likely to occur at periods of two to five years.

In new development areas developers must provide property, roadside and secondary drains. Channeling of streams is required to keep pace with the progress and location of new development. Where possible flood waste capable of containing the run off from a once in 100 years storm are reserved although these can be utilysed for access roads or public open spaces.

First phase work comprises replacement of structures and channel improvements on streams prone to frequent flooding and those serving existing and current development. A total length of 32 km will be improved.

Client : Government of Malaysia

Estimated Capital Costs (1982 prices):

Sewerage - RM 169.0 million

Drainage - RM 310.1 million

Consulting Services:

• Master Plan
• Preliminary Engineering
• Organisation, Management, Legal and Financial Studies.