MATEC Web of Conferences 147, 03006 (2018) https://doi.org/10.1051/matecconf/201814703006 SIBE 2017 Diversion Canal to Decrease Flooding (Case Study : Kebon Jati- Kalibata Segment, Ciliwung River Basin) Dian Indrawati1,*, Iwan K. Hadihardaja2, M. Bagus Adityawan2, Syambali F. Pahrizal1 and Fajar Taufik1 1Faculty of Engineering, Jenderal Achmad Yani University, Jalan Terusan Jenderal Sudirman, PO BOX 148, Cimahi, West Java, Indonesia 2Faculty of Civil and Environmental Engineering, Institut Teknologi Bandung, Jl. Ganesha No.10 Bandung 40132, West Java, Indonesia Abstract. The flood in Jakarta has become a national concern in Indonesia. It is a haunting disaster, with a high probability to happen when heavy rainfalls in Jakarta and/or its upstream area. Based on data that was provided by Public Work Agency of DKI Jakarta, there are 78 vulnerable points of inundation in which, most of them are located in Ciliwung river basin, commonly in the meandering segments. One of the worst flooding occurs in Pancoran, at Kebonjati to Kalibata segment in particular. The river discharge in this segment is much higher as compared to the carrying capacity. In addition, this area has a high density of population and thus, difficult to increase the *river capacity* by enlarging the river dimension. In this research, a closed diversion canal is proposed as a solution. The effectiveness of the solution is evaluated using a numerical model, HEC-RAS 4.1. The diversion canal is designed as two culverts, with 2.0 m in diameter. Nevertheless, hydraulic jump may occur at the outlet of the canal due to the relatively steep slope. Therefore, the canal outlet should be designed accordingly. A Hydraulic structure such as a stilling basin can be employed to reduce the energy. The results show that the diversion canal has a good performance in decreasing water level and flood discharge in the study area. The canal has the capacity of 17,72 m3/sec and succesfully decreases the water level by 4.71 – 5.66 m from flood level for 2 – 100 years returned period. 1 Introduction for Ciliwung river flood based on FESWMS modelling, Emam [2] using HEC-HMS modelling in order to Based on data from Indonesian National Board for analyse land-use changes and assesment of climate in Disaster Management (BNPB), since 1815, flood upper Ciliwung river basin, and Murniningsing [3] become the most frequently disaster with 31.5% of shows that the developing of Ciawi, Sukamahi and events compare to others such as puting beliung, Katulampa weir DAM takes less significant values terorism, fire and earthquake. Specially for DKI Jakarta, compared to its huge cost. during period 2011-2015, there are 98 flood events occur This study will analyze the effectiveness of diversion and most of them were happened on Ciliwung river canal in order to decrease the flooding specially in basin and make these a national concern in Indonesia. It Kebonjati- Kalibata segment which indicated as the is a haunting disaster with a high probability hazard in source of problem in Pancoran area. every heavy rainfall occurs in DKI Jakarta area and/or its Although in some of researches show lackness of this upstream of river basin. method because of its impacts regard to sedimentation Flood in the Ciliwung river basin had presented annually [4] and [5], the river diversion recomended for river on since the 1600’s and in order to manage its disaster, flattened area [6] with dense population. several projects have been developing such as Amanus straits digging in North Bandengan in 1647, Bageracht 2 Literature Study and Mookervart from 1678 to 1686, and The Jakarta The flow in diversion chute canal should be occoring in Flood Canal i.e. West Flood Canal (KBB) and East supercritical scheme as the result of the deployed flow Flood Canal (KBT) recently. on the upstream structure which is requiring quick Furthermore, a numerous sources of this disaster had acceleration. So in the design flow, its depth in this been identifying, and one of them is the insufficient of section should be in uniform depth. Thus, it is necessary the carrying capacity of the river specially in meandering to define which condition the flow occur along the canal. segments. One of the worst flooding occurs in Pancoran Also whileas a possibility of occuring the hydraulics area whileas in a year several spots in this area reach 2 jumps inside, if it is happen, the location of it should be meter-height. determined. The last thing, back water curves probably Several studies related to this flood had conducted i.e occur inside and need to be analyzed along the canal [7]. Formanek [1] studied about Regional Flood Map Index * Corresponding author: [email protected] © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). MATEC Web of Conferences 147, 03006 (2018) https://doi.org/10.1051/matecconf/201814703006 SIBE 2017 n EC-R 8], the diersion chute cana is modeing diersion cana which ocated on 615'16.99" - as the culvert condition. hich is the assumption of inet 615'11"S and 1065137.6"E - 10651028"E contro is that the ow asses through critica deth near descries on igure 1 eow: the inet and transiting to supercritica ow. f the hydraics ump occured in this arre, it is assumed its Kaliba cause the ie to pressuirie aong the ength and fow (outlet) wi act ie an orriice type f this occurs, then the outet contro wi ecome the answer. or computing inet contro headwater with submerged inet, the euation are : 2 HW Q i 1) c 0.5 Y 0.5S D AD Whereas wi is the headwater energy deth aove the invert of the clvert inet m), is the interior height of the culvert barre (m), is the discharge through the Ke ati clvert m3s), is the ull cross sectiona area of the (inlet) clvert arre (m2), is the slope of clvert barre (m/m) and ,,c, is euation constants, which vary deending on culvert shae and entrance conditions. On contrary, for the outlet control flow using Bernoulli’s Fig. 1. Diversion na Location Kebon ti nd libata segment euation in order to compute the change of energy through the barre under outet condition is foowing: The diersion, which ocated beore the anggarai water 2 2 a V a V gate, is a subsystem of ood management in aarta Z Y 3 3 Z Y 2 2 H (2) 3 3 2g 2 2 2g L province and eing a part of B. Where Z3 is the upstream invert eeation of the culvert (m), is the deth of ater aove the upstream culvert EAST FLOOD CANAL (KBB) KBT INLET - CAKUNG inet m), V3 is the aerage eocity pstream of the KBT INLET - JATIKRAMAT KBT INLET - BUARAN clvert (m2/s), a is the veocity weighting coeficient KBT INLET - SUNTER KBT INLET - CIPINANG upstream of the clvert (dimensioness), g is the EAST KALI BARU acceeration of graity m/s2), 2 is the downstream MANGGARAI WATER invert eevation of the clvert (m), is the deth of GATE CILIWUNG RIVER water aove the downstream clvert inet m), V2 is the KEBON JATI – JAVA SEA KALIBATA SEGMENT aerage veocity downstream of the culvert m2/s), a is WEST FLOOD the veocity weighting coeficient downstream of the CANAL (KBB) KRUKUT RIVER clvert (dimensioness) and is the tota energy oss KRUKUT SUB RIVER PESANGGRAHAN RIVER through the clvert m). The head oss is computed using the formua : SEPAK MERUYA ANGKE RIVER (3) H h h h MOOKERVART L en f ex Which hen is the entrance oss m), hf is the friction oss Fig. 2. Schematization f he ersion na of bon – (m) and hex is the exit oss m). he friction oss in the Kaliba Segmen on lood Managemen in Jakarta culvert is computing using Manning’s formula derived as oow : 2 3.2 Methodology Qn h L (4) f 1.486AR 2 / 3 This stdy consists of hydroogica and hydrauics mode which are hydroogica mode was sed to obtain ood Where hf is the friction oss (m), is the culvert ength hydrograh and hydrauics mode was used to simuate (m), is the fow rate in the clvert (m3/s), n is the the fow on the river. n order to estimate severa rainfa Manning’s roughness coefficient (dimensionless), A is retrned eriod, the data was etraoated sing anaysis the fow area m2) and is the hydralic radis m). freqenc method. or the hydrauics mode, its een cairated y 3 Study Site and Methodology comparing ear food retrn eriod with capacity of rier ankfull in the inet of diersion cana nd SS aayashu has cosed enough alues compares to 3.1 Study Site Rationa, aspers and SS nyder-Aexje. oreover, In order to manage the food in ancoran area, speciay the schematication of the modeing shows in igure 3 at eonjati to aiata segment, Pubic ork egiona beow. Office of KI aarta Province wi deeop the 2 MATEC Web of Conferences 147, 03006 (2018) https://doi.org/10.1051/matecconf/201814703006 SIBE 2017 Data Collecting : Flood Table 1. nfluence surfaces of ainfall tation in iliwung Climatology, Hydrograph Hydrological Frequency Start Hydrology, on Several iver Basin Analysis Analysis Long&Cross, Returned Infuence Area Land-Use Period Stations (km2) Bendung og 89.61 Flood Modelling of Bankfull Cawang 64.10 Designed of Modelling in Hydraulics Diversion Capacity Diversion Canal Existing Analysis FT 114.04 Canal Analysis Condition Gunun as 101.61 Effectiveness Analysis of Diversion Canal for Several Finish Flood Returned Periods Fig.