Development Aspects Impressum Editors

Gully plug

A gully plug is a civil enginering technique of soil conservation for controlling sur- face water run-off by plugging the gully, at a specific location, with stones wrapped with wood and/or bamboo. The gully plug is also a soil conservation technique that serves to control a gully or valley by constructing a small, water-permeable dam across the gully made of rock gabions, wood/bamboo riprap or concrete structure. The gully plugs in this case were made from bamboo, as it is easy to find in the local area and is not expensive. Eight gully plugs were constructed in two gullies, each consisting of four gully plugs in series.

4. Regreening (afforestation) and reforestation

The purposes of afforestation and reforestation are to rehabilitate and to improve critical land conditions outside the forest area in order to improve water man- agement, to maintain and to improve land use. Regreening rehabilitates critical land outside the forest area by planting trees and establishing soil conservation structures so that the land is productive and at the same time serves as a hydro- logical control to maintain and improve land carrying-capacity in accordance with its function. The determination of critical land refers to the definition of a piece of land as severely damaged and as a result has reduced or lost its function beyond a tolerable limit. The locations of the afforestation and reforestation were in the dusuns of Cukal, Dadapan Wetan and Dadapan Kulon involving the planting of 8,000 trees on 20 ha.

4. Structural measures

Structural measures proposed are the construction or installation of eco-efficient modular/in situ structures to reduce pollution flow into the stream and to improve water quality. Eco-efficient development of sustainable infrastructure also aims to improve the quantity and quality of the river flow, with minimal waste of natural resources and within the stability and capacity of the environment’s carrying ca- pacity. The structures built were:

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  Riverbank protection (revetment): a structure placed on the surface of the slope of riverbanks or levees in order to improve their stability and prevent landslides which can lead to the collapse of riverbanks and/or leeves into the river. River- bank protection (revetment) can be made from woven bamboo that is placed on both sides of the riverbanks.
  
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  Drop structure: an in-stream structure constructed from stone, bamboo or wood and compacted grass (gebalan rumput) to reduce the energy of the water surface flow in an area with sufficient gravity drop. A drop structure is needed if the slope of the bottom surface of the river is too steep. It is usually necessary to build a series of drop structures to maintain the river slope.
  

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  Check dams: another structure that can provide riverbed or riverbank protection. Check dams were built across the river to reduce the flow velocity and capture sediments carried by the flow, so that the flow depth and slope of the riverbed can be reduced. These structures are usually made from locally available materi- als, such as wood, soil or stone. This structure has a high failure risk, but may provide temporary stabilization and can be combined with agronomic systems (using organic material).
  

A check dam, riverbank protection and a small drop structure were constructed in
Dusun Cukal of Bendosari Village.

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