Water Resources Management of Lake Tondano in North Sulawesi Province

Lake Tondano is a lake that is used for various purposes. On the other hand, this lake is a source of germplasm, a site where life cycle of important flora and fauna takes place, and water source that isused for agriculture, livestock production, home industry, and domestic use. Water from Lake Tondano also produces energy through hydropower plant and maintain microclimate. Therefore, lake Tondano is experiencing problems as indicated by the fast growth and wide distribution of water hyacinth that can have a negative impact for the lake itself. The objectives of this research were to identify problems caused by the spread of water hyacinth and to identify water resources management plan for Lake Tondano preservation. This study used primary datasuch as concentration of nitrat, nitrit, and ammonia in lake Tondano, nitrogen ballance in inlet and outlet of the lake Tondano and flow rate of river Leleko and river Panasen, including map or spatial data of Lake Tondano (secondary data) which describe the extent of cover and distribution of water hyacinth in the lake, the negative impact of water hyacinth distribution in the lake, and the utilization of water hyacinth. Secondary data was also used and obtained from various related institutions as well as from the community and other stakeholders. The results show that 88.17% - 99.83% of the lake area was covered by water hyacinth. The biomass growth rate was 9.78-13.39 kg within 7 weeks (Tampi, 2001). Data from BAPPEDA of North Sulawesi province shows that the extent of water hyacinth spread in Lake Tondano in 2014 had reached 277 ha or 5.92% of the lake area. The management of the lake can be performed by controlling the growth of water hyacinth through the utilization of water hyacinth systematically and structurally so that it directly controls the rate of increasing covered area by water hyacinth. Water hyacinth can be utilized as raw material to produce various economic value products, such as organic fertilizer and biogas.