The catchment area of the Klang River basin is 1,288 square kilometers (km2), and it is
the most urbanized region in Malaysia, encompassing the Federal Territory of Kuala Lumpur
and includes part of the state of Selangor. It has an estimated population of 4.4 million (16% of
the national population) that is growing at a rate of 5% annually. The basin spreads over nine
local government authorities and faces serious environmental degradation and flooding
problems from urbanization, industrialization, and population growth. More than half of the basin
has been urbanized, and much of this continuing urban development has taken place on land
that is prone to flooding. Construction has caused soil erosion and huge discharges of
sediments into waterways. The increase in impervious surface area in the watershed causes
flooding. The water quality in the basin has declined due to high sediment loads from
construction and deforestation, large quantities of litter and rubbish, and untreated sewage and
industrial and commercial effluents. The ecology of the river has suffered from the removal of
vegetation from the riparian corridor and removal of snags from the watercourses, diminishing
habitats for a variety of riparian and aquatic fauna. This has also reduced pollutant filtration
capacity and increased the nutrients and other pollutants going into the rivers. The combined
effect of poor water quality, high sediment load, and the removal of vegetation from the river
corridor has caused a decline in the number and diversity of native flora and fauna.