By Esty Siske Setioriny – (Thesis M.Si Sriwijaya University, 2012), Supervised by Prof. Bart Schultz, PhD, MSc; Prof. Ir. Robiyanto H. Susanto, PhD, M.Agr.Sc; F.X. Suryadi, PhD, MSc.

High demand for paper in Asia led to an overall increase in the global pulp market. Indonesia has a great potential to become the producer in the pulp and paper industry. The products of forest industry have contributed to generating the Indonesian economic growth and development. Being located in a strategic location, tropical area that is good for the growth of plants, and availability of productive human resources make Indonesia a preferred choice for pulp and paper production. To guarantee wood-based industries including paper pulp and to run sustainable plantations; support is required because it is not possible to depend on natural forests as sustainable source of raw materials for the industry. Hence, plantation forests are very essential to safe the sustainability of wood-based industries. The areas of plantation forests are made up of both mineral soils and marginal soils such as peatland areas. Improved water management is an essential step to support the management of peatlands. Water is probably the most essential part of a peatland, with most them containing almost 90% water. Drainage has enhanced the ability to farm peatlands, but it leads to oxidation and subsidence of peat soils. A balance between drainage and conservation is needed in order to protect peatland soils. Excessive drainage of peatlands can also cause the shrinkage or loss of wetland area, as well as the reduction of water levels in nearby wetlands and mineral soils. Therefore, to optimize the wood production of forest plantation and also to conserve peatlands, water management is needed.

On Sumatra island, the spread of peatlands is generally found in lowland areas along the east coast, namely in the provinces Riau, South Sumatra, Jambi, North Sumatra and Lampung. In South Sumatra Province, there are 20 forest concessionaires for plantation forest with a total area of 1,4 million ha and some of them are on peatlands.

This research is on Improvement of water management in a plantation forest in Sembilang area, Banyuasin District, Indonesia. The analyses focused on the main system to identify whether the water management applied in the study area at the present is appropriate to support pulpwood growth and also conserve the peatland. The software that is used in this study is DUFLOW for hydraulic analysis. The DUFLOW simulation is carried out in the rainy and in the dry season. The result of the simulation shows that there inundation in some places in the rainy season while the dryness of the drainage canal in the dry season. It is indicate that water management needs to be improved.

In order to manage water table in the field, water level in the drainage canal should be maintained as high as possible especially in the dry season to sustain peatland by making hydraulics structures. Stoplogs can be installed to raise the water level in the canal and dikes/embankments can be made to avoid inundation in the field. Water management is very important for plantation forest located in reclaimed peatland area to reach high production of pulpwood and on the other hand to minimize the effect of the drainage.

Keywords: water management, plantation forest, peatland management, DUFLOW modelling