Drainage System of Tegalsari Polder for Handling Flood and Tide in Tegal City Indonesia

Although in 2019 the local government of Tegal city Indonesia had constructed a retention basin at drainage system of Siwatu, Tegal Barat, Tegal city with a catchment area of 226 ha, the areas around the system still experienced flood and inundation. This study belonged to a descriptive qualitative research aimed to evaluate the performances of Siwatu drainage system and Tegalsari retention basin. Data of the study included field data and technical data from institutions. Based on the 15-year rainfall data (2014 – 2018) from Pemali - Comal PSDA Office, Central Java Province, Indonesia, the statistical parameters of Cs: 0.0027, Ck: 1.904, Sd: 15.91, Cv: 0.144 were obtained and so Gumbel method distribution was applied in the study, the return period rainfall of 10 years was 138 mm, the flood discharge for Qr.10 years was 9.63 m3/sec., the addition of long storage was 8×2,50×500 m, and the combination of pump addition was of 1 m3/sec. with the long storage of 8×2.00×500 m. By implementing one of the alternative choices, either flood or inundation could be resolved.

Analysis of Ciliwung river flood debit and city flood anticipation using floods early detection system (FEDS)

This research is based on flood conditions that often occur in lowland areas such as Jakarta and Semarang. The problem faced is that the notification and early detection of floods is often late, done manually so that it cannot be anticipated by areas downstream of the river. Therefore, it is very important to be able to develop an IoT-based early warning tool so that floods can be detected early in a fast, real time, and immediately anticipated in the upstream area of the river. This research method uses design methods and experiments carried out in the field and laboratory. This research will present a prototype of the FEDS (Floods Early Detection System), based on the Blynk application. The results showed that the calculation of planned flood discharge with a return period of 2, 5, 10, 25 and 50 years can provide an overview of the ability of an area to face the maximum possible rainfall. The FEDS prototype tool, with the Blynk application, can work well using a microcontroller, ultra sonic sensor, and a rainfall sensor. This system is suitable for use in the community to determine rain conditions and water level conditions used at river water level conditions, for early notification of floods.

Hydrological Analysis In Selecting Flood Discharge Method In Watershed Of Kelara River

For Engineers involved in planning and construction of water resources building, hydrology becomes very important data. In terms of planning stage in water resources especially waterworks, it is known that design flood discharge closed to field realistic conditions is often needed in order that a planned construction is able to control flood discharge. Several previous researches in choosing flood discharge selection method have diverse depending on observed watershed. One method in determining selected flood discharge by verification using Creager diagram, by comparing discharge calculation results of several Synthetic Unit Hydrograph (SUH) with infrastructure flood discharge (AWLR result) in observation point. This research aims to obtain the most suitable synthetic unit hydrograph and close to analysis result of measured discharge frequency, and Creager diagram in Kelara watershed (DAS). Based on the calculation of design flood discharge according to rainfall data using synthetic unit hydrograph of Nakayasu, ITB I, ITB II, and SCS (HEC-HMS) as well as the calculation of design flood discharge according to collected data, it is concluded that the synthetic unit hydrograph method closest to design flood discharge with measured discharge rate and Q1000 rate of Creager diagram is SCS. Flood discharge rate obtained according to HSS SCS method using HEC-HMS 4.8 application in period of 2 years is 658,40 m3/s, 25 years is 682,70 m3/s, 50 years is 787,00 m3/s, 100 years is 885,70 m3/det, and 1000 years is 1202,60 m3/s

ANALYSIS AND EVALUATION OF THE DRAINAGE NETWORK SYSTEM IN THE HOUSING AREA OF VILA RIZKI ILHAMI 2 SAWANGAN, DEPOK-WEST JAVA

<p>The impact that occurs from the rampant development of residential areas will certainly make the volume of surface water flow or run off become large. Drainage is a system created to deal with the problem of excess water flow that is above the surface of the earth, some of the things that cause excess water are caused by high water intensity and the long duration of rain. In this study, the problem that occurred was in the drainage network in the residential area of Vila Rizki Ilhami 2 Sawangan, which was a transfer of land functions from infiltration land into a residential area. Evaluation that must be done is covering hydrological analysis and hydraulics analysis to get the amount of flood discharge plan that will be used to analyze the capacity of the planned channel so that no flooding occurs at the location of the settlement area when the settlement is built, recommendations for drainage system design and determine the size of the river dimension / size / times that should be made when accommodating water discharge during maximum rain so that the flood control system can be well integrated. With 3 methods of calculating rainfall, the method of calculation is selected using the gumbel method which is SNI (Indonesian National Standard) with a return period of 2 years, 5 years and 10 years. From the evaluation obtained is to add height height or free board to accommodate flood discharge plan.</p>

Research on Flood Discharge and Energy Dissipation of a Tunnel Group Layout for a Super-High Rockfill Dam in a High-Altitude Region

Under the condition of a large dip angle between the flood discharging structure axis and the downstream cushion pool centerline, the downstream flow connection for the discharging tunnel group is poor, and the lower air pressure in high-altitude areas increases its influence on the trajectory distance of the nappe, further increasing the difficulty of predicting the flood discharge and energy dissipation layout. Based on the RM hydropower project with the world’s highest earth-rockfill dam, this paper studies the problem of a large included angle flip energy dissipation layout of a tunnel group flood discharge using the method of the overall hydraulic physical model test. The test results show that the conventional flip outlet mode has a long nappe falling point, a serious shortage of effective energy dissipation space, a large dynamic hydraulic pressure impact peak value on the bottom slab and side wall of the plunge pool, a poor flow connection between the outlet of the plunge pool and the downstream river channel, and a low energy dissipation rate. Considering the influence of a low-pressure environment, when the “transverse diffusion and downward incidence” outflow is adopted, the nappe falling point shrinks by 11 m, the energy dissipation form of the plunge pool is greatly improved, the effective energy dissipation space is increased by 159%, the RMS of the maximum fluctuating pressure is reduced by 74%, the outflow is smoothly connected with the downstream river, the energy dissipation rate is increased by 0.8%, and the protection range of flood discharge atomization is significantly reduced. This effectively solves the safety problems of large included angle discharge return channels and the energy dissipation and erosion prevention of super-high rockfill dams.

Increasing Effectiveness of The Urban Artificial Reservoir Trough Cross Section Improvement

Situ Ciledug is an artificial reservoir located at Tangerang Selatan, Indonesia. In 1950 known as one of the largest lakes with total area of 32.806 hectares. As time goes by, due to the construction of housing and land use around the area, the catcahment area was reduced about 19.3 hectares in 2013 and by the end of 2020 the surface area was become 16.2 hectares. Urbanization is the main factor that makes the area of Situ Ciledug’s narrower. The second impact was flooding, as a result, the flood inundates the cities around the reservoir. This study aims to increase the storage capacities by normalizing the reservoir using SWMM 5.1 software. Hydrological analysis was carried out in the first stage to find the maximum rainfall using a 100-year return period. Then result intensity of rainfall used to analyze the hyetograph as input for rainfall data in SWMM 5.1. The modeling uses a maximum of rainfall about 107 mm with a reservoir depth of 1.3 meters. The large inflow that enters the reservoir is 87.504 m3/second aand the volume is 30.145 m3/second. Therefore, it is necessary to normalize the reservoir by increasing the depth of the reservoir by 0.7 meters. Normalization is carried out to accommodate flood discharge as a solution to flood mitigation due to the overflow.