Dam break analysis using 1D geometry at Jatigede Dam, Sumedang

Dam breaks can result in flash floods which have enormous destructive power. This destructive force becomes even more significant when the dam break occurs in a dam with a large capacity. An example is the Jatigede Dam, which has a capacity of 1,060 million m3. To determine the flash flood characteristics and potential impact of the collapse of the Jatigede Dam, an analysis of the dam break was carried out using HEC-RAS software. The dam break scenario uses a Probable Maximum Flood (PMF) inflow with the partial opening of two spillway gates in the middle, which causes the dam overtopping. The Froehlich and Von Thun, and Gillette regression methods were used to defining the breach parameters. Based on the dam break analysis, the simulated flash flood of the Von Thun-Gillette method resulted in a higher velocity and lower water surface elevation than the Froehlich method. The difference in the velocity, dimension of the breach shape, water surface elevation, and discharge is caused by the breaching shape and breach formation time.

Estimation of Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF) Using GSSHA Model (Case Study Area Upper Citarum Watershed)

Probable Maximum Flood (PMF) used in the design of hydrological structures reliabilities and safety which its value is obtained from the Probable Maximum Precipitation (PMP). The objectives of this study are to estimate PMP and PMF value in Upper Citarum Watershed and understand the impact from different PMP value to PMF value with two scenarios those are Scenario A and B. Scenario A will calculate the PMP value from each Global Satellite Mapping of Precipitation (GSMaP) rainfall data grid and Scenario B calculate the PMP value from the mean area rainfall. PMP value will be obtained by the statistical Hershfield method, and the PMF will be obtained by employed the PMP value as the input data in Gridded Surface Subsurface Hydrologic Analysis (GSSHA) hydrologic model. Model simulation results for PMF hydrographs from both scenarios show that spatial distribution of rainfall in the Upper Citarum watershed will affect the calculated discharge and whether Scenario A or B can be applied in the study area for PMP duration equal or higher than 72 hours. PMF peak discharge for Scenario A is averagely 13,12% larger than Scenario B.

Evaluasi Kinerja Tampungan Waduk Selorejo Menggunakan Perangkat Lunak HEC-HMS

[ID] Permasalahan banjir merupakan permasalahan pengelolaan air yang sering terjadi di Indonesia. Untuk mengatasi permasalahan tersebut dibuat sebuah struktur yaitu waduk yang berfungsi sebagai pengendali banjir. Namun seiring waktu tampungan waduk akan semakin menurun akibat adanya akumulasi sedimen yang terbawa oleh air sungai yang masuk ke dalam waduk dan mengendap. Sehingga diperlukan evaluasi kinerja tampungan waduk tersebut, Permasalahan ini juga dialami oleh Waduk Selorejo yang terletak di Kabupaten Malang. Untuk melakukan evaluasi kinerja tampungan waduk digunakan bantuan perangkat lunak HEC-HMS yang dapat mensimulasikan debit banjir yang masuk beserta elevasi tampungan waduk. Berdasarkan hasil analisis tampungan Waduk Selorejo mampu untuk mengendalikan banjir periode ulang desain awal nya yaitu periode ulang 1000 tahun. Selain itu Waduk Selorejo juga mampu menampung debit banjir Probable Maximum Flood (PMF) apabila muka air awal waduk diturunkan sampai elevasi +605 m. [EN] Flood problem is a water management problem that often occurs in Indonesia. To overcome this problem, a structure is created, namely DAM that functions as a flood controller. However, over time the reservoir storage will decrease due to the accumulation of sediment carried by river water that enters the reservoir. So it is necessary to evaluate the performance of the Rervoir storage. This problem is also experienced by the Selorejo DAM which is located in Malang Regency. To evaluate the performance of the reservoir storage, the help of HEC-HMS software is used which can simulate the incoming flood discharge along with the elevation of the reservoir. Based on the analysis, the Selorejo DAM is able to control the flood of its initial design period which is the 1000-year return period. In addition, the Selorejo Reservoir is also able to accommodate the Probable Maximum Flood (PMF) flood discharge if the initial water level of the reservoir is lowered to an elevation of +605 m.

Using Multiple Objective Calibrations to Explore Uncertainty in Extreme Event Modeling

Deterministic watershed models are often used to estimate the probable maximum flood (PMF). An approach for investigating the uncertainty in extreme flood modeling is proposed. Using different calibration objectives, several automatic calibrations of the University of British Columbia Watershed Model (UBCWM) are conducted and the resulting collection of optimal combinations of parameter values are used to simulate the extreme event. An application to the Coquitlam River watershed above Coquitlam Dam in southwestern British Columbia shows that the variability amongst the PMF estimates is relatively small in comparison with the potential uncertainties in estimating extreme events, with coefficient of variation values for peak flow, event volume, and time to peak of 4%, 1%, and 1%, respectively. The PMF-based simulations

The Flood Analysis of Karadere Stream in the Mustafakemalpaşa District of Bursa Province and Determination of Its Effect on the Sünlük District Settlement

Floods shows an increase both in number and in terms of damages they cause in tropical climates as well as in Turkey which is not located in tropical region. With the increasing population density and unplanned urbanization, life and property losses become inevitable as a result of these floods. In this study, the flood analysis of the section between the beginning and the end of the Sünlük District settlement located on the border of Karadere Stream in the Mustafakemalpaşa District of Bursa Province was assessed. The planning works of the Sünlük Dam on the Karadere Stream, which is intended to provide drinking water and industrial water to the Mustafakemalpaşa and Karacabey Districts of Bursa Province, are continuing by the 1st Regional Directorate of State Hydraulic Works of Turkey (DSI). Flood areas were determined with the help of the HEC-RAS (Hydrologic Engineering Centers River Analysis System) software and applying the Q1000, Q10000 and QMMF (probable maximum flood) flood return period flow rates at the Karadere Stream which obtained from the dam planning studies. It was concluded that the damage caused by QMMF can reach up to 1000000 TL once flood occur.

The Usage of Agent Based Modelling in Flood Evacuation during Dam Failure

With the advent of latest technology has enabled disaster management related efforts to be more efficient and effective. Agent based modelling has been utilized in crowd management context especially related to simulation of evacuation passage during the outbreak of any untoward incidents. In dam safety assessment, the number of loss of life during the flood indicates the severity of the catastrophe. Therefore, it is important for any dam owners to estimate the required warning time to ensure minimization of fatalities in the event of a disaster. The objective of the research is to estimate the loss of life at the downstream area of the Sultan Abu Bakar Dam when Probable Maximum Flood (PMF) scenario occurs. The adopted model is known as Life Safety Model (LSM), which is an agent-based model that uses the concept of dynamic interaction between the 2d-hydraulic and the receptor. A case study has been conducted focusing the population of Bertam Valley in Cameron Highlands, Pahang, West Malaysia. The outcome of this modelling has indicated that successful evacuation depends on the response rate of the victims towards the given warning prior to the disaster. It is shown that the response time might affect the fate of people during the evacuation. The application of Life Safety Model in this simulation proves its capability in estimating the loss of life as a planning measure to face the actual events.