River Basin Management in its implementation requires synergy between various sectors as a whole from the upstream, middle to downstream. The upstream watershed functions as a conservative zone, where as much as possible the ecosystem is maintained so that the availability of water remains stable to meet the water needs of the watershed below. The middle watershed functions as a transportation zone between the upstream and downstream sections, which usually functions as the utilization of managed river water to provide benefits for social and economic interests, related to irrigation infrastructure such as river, reservoir and lake management. The downstream part of the watershed is a sedimentation zone that functions as the use of river water in its use in agricultural activities.
The explanation this time tells about the use of the middle part of the watershed, specifically related to the function of irrigation infrastructure; reservoir.
Reservoirs or reservoirs are natural lakes or artificial lakes, reservoirs or river dams aimed at storing water.
Types of reservoirs
1. RESERVE VALLEY
Built using the valley topography so that reservoir water needs can be fulfilled. In some places, the construction of valley reservoirs involves the removal of residents and historic artifacts. The process of building valley reservoirs also involves breaking up rivers by building tunnels or special channels. In hilly areas, dams are usually built by expanding existing lakes. If the topography of the location is not suitable for large reservoirs, several small reservoirs are
usually built and made chains between reservoirs.
2. RESERVE RIVER SIDE
Built by pumping water from a river. Such reservoirs are usually built through excavation and construction on the embankment which usually covers more than 6 km. Water that is stored in reservoirs like this is usually deposited for several months so that contaminants and turbidity levels decrease naturally.
3. RESERVE SERVICES
Service reservoirs are reservoirs built close to the distribution point, with water that has been sterilized and cleaned. Service reservoirs are usually built in the form of water towers built on concrete pillars in a flat area. Others are built underground, especially for service reservoirs in countries filled with hills or mountains.
4. ARTIFICIAL RESERVOIR
The construction of homemade reservoirs is generally carried out on land that is free from the reach of residents or far from crowded areas. However, after completion, the reservoir function can be used to attract tourists or become a tourist attraction. This reservoir is usually built using semin on the side of the reservoir.
Some uses of the reservoir such as:
• Direct water providers: provide raw water through water pipes
• Hydroelectricity: power plant turbines
• Control of water resources: as water suppliers downstream, irrigation functions, flood control and water supply guarantees.
• Flow balancer: collect water when rainfall is high and drain it when rainfall is low.
• Recreation: facilitate fishing, boat and other activities.
In addition to the above uses, the reservoir also functions as a place / location for fish farming in floating nets (karamba), with the aim of providing opportunities or opportunities especially for communities affected by reservoir inundation or communities around the reservoir to have new livelihoods or additional livelihoods . Activities in karamba include: hatchery, provision of facilities and infrastructure for floating nets, transportation, trade, and others.
In some areas, reservoir management, especially fish farming in floating nets (karamba), has proven to have an economic impact on the surrounding community. However, in some areas, the socioeconomic impact of the reservoir has not been optimally utilized by the surrounding community.