Generally Watershed (DAS) can be defined as an area, which is bounded by natural boundaries, such as a ridge or a mountain, or limit aid such as road or embankment, where the rainwater that fell in the region contributes flow to the control point (outlet ) (Suripin, 2002). Watershed is a geohydrology basin bounded by water and fishing area drained by a river and is the liaison body between the upstream area of land in the coastal area, so the conditions in the upstream region will have an impact on coastal areas.
DAS covers all the components of soil, water and biotic resources which is an ecological unit and has linkages between components. DAS has many sub-system which is also a function and part of a broader context (Clark, 1996 in Anna S, 2001). According Suranggajiwa (1978) in Anna S., 2001, the Watershed is an ecosystem Yag is a collection of various elements which are the main elements of vegetation, soil, water and human and all its resources are carried out in the area. Gunawan (1991) in Anna S 2001 split components
Watershed into 2 (two), namely:
1) Physical environment, including:
a) that the region (topology, shape and spacious DAS)
b) land (soil type, chemical properties fisk, class ability)
c) water (quality and quantity)
d) vegetation / forest (type, density, distribution)
2) Man, include:
a) The number of man
b) The need to live
The increase in the number of people especially those living in the basin will be followed by an increase in life needs to be met through the use of natural resources (which is part of the physical environment) will affect changes in human behavior, especially in an effort to make ends meet. Changes in behavior that is destructive / negative would be able to exert pressure on the physical environment, which has its limitations and is known as the carrying capacity of the environment (DDL).
If the pressure the greater the environmental carrying capacity will decline. River watershed as a major component has several definitions, namely: According to Haslam, 1992 (in Anna S., 2001) that:
1) river or stream flow is the amount of water that flows along the track on land towards the sea so that the river is a track where the water coming from upstream join and heading in a direction that is downstream (estuary).
2) River is a place of splitting mainland aquatic life. According Sulasdi, 2000 (in Anna S., 2001), the river has the potential balanced shown by the usability of the river, among others for the raw water, agriculture, energy and others, and the river is able to lead to flooding, sedimentation carrier, and the carrier of waste (pollutants from industrial, agricultural, residential and others).
Therefore, watershed management efforts intended to increase the utilization and simultaneously minimize its negative impact. Upstream region have an important role that is other than as a provider of water to flow into the downstream region for the benefit of agriculture, industry and housing also acts as a custodian for the ecological balance of the life support system (Supriya, 2000 in Anna S., 2001).
In economic terms, the uplands are the dominant production factor that often have conflicting interests of land use for agriculture, tourism, mining, housing and others. The ability of upstream land use is very limited, so the error will have a negative impact on the utilization of downstream areas. Conservation upstream areas need to cover all aspects related to the production and conservation of water itself.
Ecologically, it relates to the catchment ecosystem is a natural process of a series of hydrological cycle that produces water surface in the form of springs, streams and rivers.