Definitions of River

Section 5 (Interpretation) of the National Land code: “River” means any stream, creek or other natural watercourse, and any tributary, distributary or artificial deviation thereof.

In Malaysia, the water within a river generally originates from precipitation through surface runoff, groundwater recharge (as seen at base flow conditions / during periods of lack of precipitation) and release of stored water in natural or man-made reservoirs, such as wetlands, ponds or lakes. A river conveys water by constantly flowing perpendicular to the elevation contours, thereby converting the potential energy of the water into kinetic energy. Where a river flows over relatively flat areas, the river will meander, start to form loops and snake through the plain by eroding the riverbanks.

Sometimes the river will cut off a loop, shortening the channel and forming an oxbow lake from the cut off section. Rivers that carry large amounts of sediment develop complex deltas at their mouths, with saline tidal waters forming estuaries.

Definitions of River Basin

"River basin" is an area of land from which all surface run-off flows through a sequence of streams, rivers and, possibly, lakes into the sea at a single river mouth, estuary or delta.

Table 5.1 River Basins in Malaysia

Area

No. Of Basin

Main Basin (>80km2)

Small Basin (2)

Peninsular Malaysia

1,235

74

1,161

Sabah

1,468

75

1,393

Sarawak

283

40

243

Total

2,986

189

2,797

Total Area

327,897.031

312,863.713

15,033.858

% Total Area

-

95%

5%