Japan Geoscience Union Meeting 2021

Presentation information

[E] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-HW Hydrology & Water Environment

[A-HW22] Material transportation and cycling in watershed ecosystems; from headwaters to coastal areas

Fri. Jun 4, 2021 9:00 AM - 10:30 AM Ch.12 (Zoom Room 12)

convener:Morihiro Maeda(Okayama University), Tomohisa Irino(Faculty of Environmental Earth Science, Hokkaido University), Shin-ichi Onodera(Graduate School of Advanced Science and Engineering, , Hiroshima University), Adina Paytan(University of California Santa Cruz), Chairperson:Morihiro Maeda(Okayama University)

9:30 AM - 9:45 AM

[AHW22-03] How should we manage a watershed for sustainable water environment?

★Invited Papers

*Hiroaki Somura1, Slamet Budi Yuwono2, Rahmah Dewi Yustika3 (1.Okayama University, 2.University of Lampung, 3.Indonesian Soil Research Institute)

Keywords:Water quality, Land use, Coffee plantation, Mountainous area

Land use management in a watershed has large influences against downstream lake / reservoir water environment. Eutrophication has many negative effects on aquatic ecosystems. Also, large sediment loadings from upstream will cause capacity decrease of lakes and reservoirs, and then affect the potential availability of water resources such as irrigation water. In a mountainous region, the introduction of social forestry leads to changes in land use. The pattern and composition of land use could affect the water quality characteristics of a river and downstream water bodies. Their primary products in the region are export crops like coffee beans. After that, these products are imported to other countries. This means that the degradation of the water environment has happened outside consumers and it is difficult to know the local situation. It is therefore very important to consider sustainable land use management within the area by beneficiaries.
In the Batutegi Dam watershed, located in Tanggamus region, approximately 60 km north-west of Bandar Lampung City in Sumatra, Indonesia, social forestry policies were applied in the protected forest areas. Two rivers of upper Sekampung and Sangharus were selected as target sites for discussing sound utilization and conservation ways of the dam reservoir. It was concluded that land uses and land management in the watershed had a major impact against water qualities because adjacent target two rivers showed different characteristics on water quality and may have different problem points. Thus, it is considered that different approaches should be executed against the two rivers to conserve the downstream dam reservoir water environment. In order to find out the approaches, it is necessary to analyze them, including socio-economic aspects for realistic activations with local people.