THE STUDY OF LAKE LIMBOTO CONSERVATION IN GORONTALO REGENCY

• Main Author: Firman (NIM 95004009), Mohammad
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/8644
• Institution: Institut Teknologi Bandung

ABSTRACT: <br /> <br /> <br /> Lake Limboto is the largest lake in Gorontalo Province. It is a natural lake with a flow area of approximately 890 km (including the lake area) and considered unique due to its proximity to the city cntre and Gorontalo Regency. At present, Lake Limboto may be categorized as acritical lake. The sedimentation process and the peoples pressures on land ownership around the lake for farming and housing activities cause the lake to experience a decrease in area and depth from year 1934 with the lake reaching approximately 70 km2 and a depth of 14 m, and now the area is approximately 30 km2 with a depth of 2,5-4 m. <br /> <br /> <br /> The purpose of this study is to determine the parameter that influence the preservation of Lake Limboto, either technical or non-technical. <br /> <br /> <br /> The goal expected is formulating conservation/preservation activities of Lake Limboto, from the aspect of area, flood and sedimentation control, and the benefit of Lake Limboto. <br /> <br /> <br /> The result of the calculation of flood rate with a repeated period of 100 years was 2377.94 (m3/sec). The result of calculation using USLE method was 1.506.155.51 m3/year for sedimentation volume, thus the lake productive age is approximately another 32 years. From the result offlood routing with a flood rate of Q100 year plan, with the outlet existing condition, an outflow rate of 152,93 m3/sec was obtained, which is able toincrease the water surface elevation reaching +6,03 mdpl at the 37th hour. To decrease the flood peak rate, Topadu River expansion is planned with a width of 70 m, an outflow rate of 651,74 m3/sec at 16,5th hour and highest water surface elevation of +5,29 m was obtained. <br /> <br /> <br /> From the result of flood routing with a flood rate of Q100 year plan for rate of flow passing though 10 controlling doors width of 6 m each, an outflow rate 575,82 m3/sec at 17,5th hour was obtained and the highest water surface of +5,57 m was also obtained. With the condition of the plan, it can be observed that the river retainingcapacity after expansion is able to accomodate the outflow rate passing through the plan control door. From the result of daily operation simulation conducted of the lake, it can be observed that the inflow rate which always met to accommodate the lake volume and area to be maintained at +4 m elevation. <br /> <br /> <br /> To maintain the existence and preservation of Lake Limboto, conservation plans need to be conducted, among others, water surface level control, up stream area conservation, water plants clearing at Lake Limboto, addition of chek dam structure and lake dredging, also determining lake conservation area which covers maintained lake area of approximately 2800 ha at +4 m elevation and supporting area approximately 500 ha.