The concept of Lomaya and Pilohayanga weir rehabilitation based on technical and economic aspects

摘要

Lomaya and Pilohayanga Weirs are located in Limboto-Bone- Bolango River, Bone Bolango District, and Gorontalo Province. Pilohayanga Weir is located at 1,500 meters downstream of Lomaya Weir, it has 1,045 hectares of irrigation services area while also serving as a supplier of raw water requirements. The damage that occurred in Pilohayanga Weir resulted in its decreasing function, and also resulted in unmet irrigation and raw water needs. Meanwhile, Lomaya Weir has 3,148 hectares of irrigation services area. The aim of this research is to find the optimal solution among several alternative design concepts to meet Pilohayanga Weir’s water needs by supplying water from Lomaya Weir, considering both the technical aspects of hydraulic and the cost of implementation which must be within the economical boundary. In conclusion, the exact solution required is by the addition of several designs, these include: a) creating a new intake area on the right side of Pilohayanga Weir; b) creating an additional channel, flushing out sediment from Lomaya Weir; c) creating sand trap; and d) creating a carrier which will be channelled to Pilohayanga Irrigation Area.