A river is define as any natural stream of water that flows in a channel with defined banks (Encyclopedia Britannica). The source of a river may be a lake, a spring, or a collection of small streams, known as headwaters. From their source, all rivers flow downhill, typically terminating into the sea/ocean as sketched in Figure 1. In some cases a river flows into the ground or dries up completely before reaching another water body. River is a component of the water cycle. Most rainfall on land passes through a river on its way to the ocean. Smaller side streams that join to a river are tributaries. Usually larger streams are called rivers while smaller streams are called creeks, brooks, rivulets, rills, and many other terms, but there is no general rule that defines a river. Locally, besides sungai, there are also many other terms refering to river; including alor (Kelantan), carok (Kedah), parit (Johor), batang (Sarawak) and terusan.

Overall, rivers in Malaysia starts from rain and generally, rivers come from surface runoff, groundwater recharge that flows into the rivers (especially during dry season) and water release from man made or natural 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 and start to form loops and snake through the plain by eroding the riverbanks

Oxbow lakes occur when the flow of river water does not pass through a bend and makes the river channel shorter.  A large amount of sediment in a river will develope a complex delta at the mouth of the river with saline tidal waters forming estuaries.

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

Uses of Rivers

Rivers have been used as a source of water, for food, for transport, as a defensive barrier and as a source of power to drive machinery. For thousands of years rivers have been used for navigation.

Riverine navigation provides the cheapest means of transport and is still used extensively in Sarawak and Sabah. In the forest logging areas, timber loggers use the river to float felled trees downstream to lumber camps for further processing, saving much effort and cost by transporting the huge heavy logs by natural means. Rivers have been a source of food since pre-history. Apart from being a rich source of fish, prawns, shells and crabs, rivers indirectly aid cultivation by supplying water for crops. Rivers sustain their own food chain. They are a major source of fresh water; hence, it is no surprise to find most of the major towns and cities situated on the banks of rivers. Unfortunately, rivers readily provide an easy means of waste disposal and a source of gravel and sand generated and moved by rivers and used for construction. Rivers should be enjoyed not for their capacity for waste disposal, but rather for the beauty of rivers and their surroundings, which contributes to recreation as well as tourist income.

Integrated River Basin Management (IRBM)

On the other hand, Integrated River Basin Management (IRBM) is the process of coordinating conservation, management and development of water, land and related resources across sectors within a given river basin, in order to maximize the economic and social benefits derived from water resources in an equitable manner while preserving and, where necessary, restoring freshwater ecosystems ([1] GWP, 2002).

River Management Vision

IRBM is thus a subset of IWRM and is the effective approach or tool to achieve IWRM objectives on the river basin basis. In simple terms, it is the management of a river basin as an entity, not as a series of individual, unconnected pieces. It is geared towards integrating and coordinating policies, programmes and practices. It addresses water and water related issues. It requires improved professional capacity and increased financial, legislative, managerial and political capacity.