STUDY OF THE IMPLEMENTATION OF INLETCONSTRUCTION AND METHODS OF OPERATION ANDMAINTENANCE IN CILIWUNG RIVER - EAST FLOOD CANAL(KBT) FLOOD DIVERSION TUNNEL

• Main Author: Kurnia Sari, Ika
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/71463
• Institution: Institut Teknologi Bandung

The Ciliwung River with springs from Mount Parangro has a length of 109 km and a watershed area of 347 km2 passing through Bogor, Depok and ends in the north coast of DKI Jakarta. Every year during the rainy season several sections of the Ciliwung River, especially the Cawang-Manggarai Water Gate section, experience flooding. So, flood control activities were carried out in Jakarta, one of them is diversion tunnel from the Ciliwung River to the East Flood Canal (KBT). This diversion tunnel is planned to channel some of the flood discharge of the Ciliwung River to the East Flood Canal (KBT) of 60 m3/s. Operation and maintenance is carried out in order to avoid or minimize the risk of decreasing performance and function, so that the function of the diversion tunnel can be sustainable and sustainable as expected. Therefore, a study will be carried out on the operation and maintenance methods of the Ciliwung River to the East Flood Canal (KBT) diversion tunnel and the implementation of the construction of the inlet. In this study, a hydrological analysis was carried out to obtain the planned flood discharge for the Ciliwung and Cipinang Rivers. Hydraulics analysis used the HEC-RAS software and the side spillway method to produce a discharge rating curve for the Ciliwung and Cipinang Rivers and diversion discharge for the tunnel. Sediment analysis was carried out in the Ciliwung River and in the diversion tunnel. The results of the analysis above are used to plan the operation of the gate and maintenance of the diversion tunnel. Then an analysis of the implementation of the construction at the inlet has been carried out in the field until this thesis was made. From the analysis that has been carried out, the maximum flood discharge that can be accommodated by the Ciliwung River before normalization is less than Q2, while after normalization it can accommodate ±Q70 flood discharge. The normalization of the Ciliwung River has reduced the flood level by up to two meters. From the HEC-RAS modeling of the diversion tunnel system, before normalizing the Ciliwung River, there was a decrease in elevation of up to 80 cm after construction of the diversion tunnel. In the condition of the Ciliwung River, after normalization, there is a decrease in elevation of up to 50 cm after construction of the diversion tunnel. Whereas in the condition of the Ciliwung River after construction of the diversion tunnel, the elevation decreased to 2.75 m after normalization was carried out. Using the side spillway method, a diversion discharge of 60 m3/s occurs when the water level elevation in the Ciliwung River is +12.5 with a discharge of 449.83 m3/s in the Ciliwung River under conditions after normalization. Whereas during conditions before normalization, at an elevation of +12.70. The results of the calculation of the flow profile method show that the difference in water level elevation in the upstream and downstream segments of the spillway shows that the downstream spillway experienced a water level rise of up to 30.35 cm. The results of the analysis of the amount of sediment (mass in) in the outlet pond that entered the tunnel before normalizing the Ciliwung River was greater than after normalization. In the condition of the Ciliwung River, after normalizing the incoming sediment, it was 32.73 tons in the planned Q2 flood discharge, while in the conditions before normalization it was 54.47 tons. Most of the sediment that enters the outlet pond is very fine sand with an average diameter of 0.088 mm. By analyzing the shield diagram and the Hjulström curve, the grains with a diameter of 0.088 mm do not settle. To fulfill the planned diversion discharge, it is necessary to open two doors with a height of 1.1 m to 2.1 m. In order to avoid serious damage, and to keep the building in accordance with the plan's age, it is necessary to carry out maintenance in the form of routine maintenance, periodic maintenance, emergency repair activities, and permanent repairs. The work that has been done at the inlet is jacking the concrete pipe on the driving shaft; installation of ground anchors, wire mesh, and shotcrete on open inlet channels; bore pile work for inspection bridge abutments; square pile work; beam capping work; crest dam work at the inlet mouth; sluice slab work; abutment installation work for inspection bridge. Keywords: diversion tunnel, diversion discharge, sediment, operation and maintenance