- Authors: Sudarmadji
- From: Faculty of Geography, Gadjah Mada University
Abstract:
Volcanic lakes in the Dieng Plateau offer some unique phenomena which are interested for tourists to visit and scientists to study. They also have some specific ecosystem which differs to other lakes. However as land use changes in the surrounding area the lakes is now facing to environmental degradation. The land use in the surrounding area is for intensive agricultural which main crops are vegetable, especially potato (Solanum tuberosum L) This research aims to study the impacts of the agricultural practices to the environmental degradation of lakes which could be give farther impact to the sustainability of the lakes. One among lakes in Dieng Plateau was selected in this research, it was Merdada Lake . The field survey was conducted to collect some data on lakes characteristics (morphometry of lake, water quality, sediments) and agricultural activities. Some interviews to local people were also conducted. Some secondary data from previous study was also collected. Data analysis was conducted based on qualitative and quantitative techniques. The study found that agricultural practices of potato plantation uses water from lake to irrigate the plant by pumping out the water using water pump and distribute the water over the plantation area. The volume of water pumped out of the lake was so high that gradually decrease the water level of the lake, especially during dry season. Agricultural practices lead to soil erosion, which contribute sediment to the lake brought by surface runoff. The use of fertilizer in the agricultural practice contribute nutrient into the lake brought by surface runoff, leading to the eutrophication of the lake, due to the excess used of fertilizer. The study concludes that agricultural practices have some adverse affects on volcanic lakes. Quantitatively the volume of lakes is gradually decreasing due to rapid sedimentation; water level of the lake has been lowering due to high rate of pumping. Water quality of lakes is getting worse, leading to eutrophication. In the long terms the sustainability of the lake is threatene.
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