PERENCANAAN BENDUNG AMOHALO DI KECAMATAN BARUGA KOTA KENDARI

Bendung Amohalo berlokasi di Kecamatan Baruga Kota Kendari. Dengan luasan DAS (daerah aliran sungai) 38,63 km2. Adapun sungai yang dibendung adalah sungai Amohalo. Alasan yang mendasari perlunya dibangun bendung tersebut antara lain tingginya elevasi sebagian area sawah yang ada di DAS sungai Amohalo, sehingga tidak dapat langsung diairi. Maka dalam hal ini dengan adanya bendung tersebut, diharap areal sawah seluas 577 ha dapat terairi. Dampak sebelum adanya bendung berakibat buruk terhadap pertanian dan kondisi ekonomi penduduk. Perencanaan bendung didasarkan pada debit banjir rencana dengan periode ulang T=100 tahun. Dalam hal ini, pembahasan meliputi analisa hidrologi, perhitungan kebutuhan air sawah, perencanaan teknis tubuh bendung, dan perhitungan stabilitas bendung Dari perhitungan digunankan metode Nakayasu yang kemudian didapat besar debit banjir periode ulang 100 tahun (Q100) = 149,368 m3/dtk, elevasi muka air banjir pada ketinggian +17,686 m, elevasi mercu bendung pada ketinggian +16,7 m, elevasi dasar sungai pada ketinggian +13,45 m, pola tanam lahan padi-palawija-bero, kebutuhan air untuk lahan sebesar 1,0187 m3/dtk. Mercu bendung direncanakan tipe bulat, kolam olak tipe ambang ujung dan bangunan ukur yang digunakan adalah ambang lebar. Dari analisis stabilitas tubuh bendung dalam kondisi stabil terhadap geser, guling, retak dan bangunan tidak turun

PERENCANAAN BENDUNG AMOHALO DI KECAMATAN BARUGA KOTA KENDARI

Bendung Amohalo berlokasi di Kecamatan Baruga Kota Kendari. Dengan luasan DAS (daerah aliran sungai) 38,63 km2. Adapun sungai yang dibendung adalah sungai Amohalo. Alasan yang mendasari perlunya dibangun bendung tersebut antara lain tingginya elevasi sebagian area sawah yang ada di DAS sungai Amohalo, sehingga tidak dapat langsung diairi. Maka dalam hal ini dengan adanya bendung tersebut, diharap areal sawah seluas 577 ha dapat terairi. Dampak sebelum adanya bendung berakibat buruk terhadap pertanian dan kondisi ekonomi penduduk. Perencanaan bendung didasarkan pada debit banjir rencana dengan periode ulang T=100 tahun. Dalam hal ini, pembahasan meliputi analisa hidrologi, perhitungan kebutuhan air sawah, perencanaan teknis tubuh bendung, dan perhitungan stabilitas bendung Dari perhitungan digunankan metode Nakayasu yang kemudian didapat besar debit banjir periode ulang 100 tahun (Q100) = 149,368 m3/dtk, elevasi muka air banjir pada ketinggian +17,686 m, elevasi mercu bendung pada ketinggian +16,7 m, elevasi dasar sungai pada ketinggian +13,45 m, pola tanam lahan padi-palawija-bero, kebutuhan air untuk lahan sebesar 1,0187 m3/dtk. Mercu bendung direncanakan tipe bulat, kolam olak tipe ambang ujung dan bangunan ukur yang digunakan adalah ambang lebar. Dari analisis stabilitas tubuh bendung dalam kondisi stabil terhadap geser, guling, retak dan bangunan tidak turun

PERENCANAAN BENDUNG AMOHALO DI KECAMATAN BARUGA KOTA KENDARI

Bendung Amohalo berlokasi di Kecamatan Baruga Kota Kendari. Dengan luasan DAS (daerah aliran sungai) 38,63 km2. Adapun sungai yang dibendung adalah sungai Amohalo. Alasan yang mendasari perlunya dibangun bendung tersebut antara lain tingginya elevasi sebagian area sawah yang ada di DAS sungai Amohalo, sehingga tidak dapat langsung diairi. Maka dalam hal ini dengan adanya bendung tersebut, diharap areal sawah seluas 577 ha dapat terairi. Dampak sebelum adanya bendung berakibat buruk terhadap pertanian dan kondisi ekonomi penduduk.Perencanaan bendung didasarkan pada debit banjir rencana dengan periode ulang T=100 tahun, Dalam hal ini, pembahasan meliputi analisa hidrologi, perhitungan kebutuhan air sawah, perencanaan teknis tubuh bendung, dan perhitungan stabilitas bendung.Dari perhitungan digunankan metode Nakayasu yang kemudian didapat besar debit banjir periode ulang 100 tahun (Q100) = 149,368 m3/dtk, elevasi muka air banjir pada ketinggian +17,686 m, elevasi mercu bendung pada ketinggian +16,7 m, elevasi dasar sungai pada ketinggian +13,45 m, pola tanam padi-palawija-bero, kebutuhan air untuk lahan sebesar 1,0187 m3/dtk. Mercu bendung direncanakan tipe bulat, kolam olak tipe ambang ujung dan bangunan ukur yang digunakan adalah ambang lebar. Dari analisis stabilitas tubuh bendung dalam kondisi stabil terhadap geser, guling, retak dan bangunan tidak turun

2D Modeling of Flood Propagation due to the Failure of Way Ela Natural Dam

A dam break induced-flood propagation modeling is needed to reduce the losses of any potential dam failure. On the 25 July 2013, there was a dam break generated flood due to the failure of Way Ela Natural Dam that severely damaged houses and various public facilities. This study simulated the flooding induced by the failure of Way Ela Natural Dam. A two-dimensional (2D) numerical model, HEC-RAS v.5, is used to simulate the overland flow. The dam failure itself is simulated using HECHMSv.4. The results of this study, the flood inundation, flood depth, and flood arrival time are verified by using available secondary data. These informations are very important to propose mitigation plans with respect to possible dam break in the future

Analysis of flood propagation and its impact on Negeri Lima Village due to the failure of Way Ela Dam

Way Ela dam is a dam to be built in the Negeri Lima village. In the negeri lima village there was also a dam that formed naturally by landslide due to high rainfall on 13 July 2012. A year after it was formed, on 25 July 2013 flooding occurred due to an extreme rainfall that caused the failure of the natural dam. The event of the failure on 2012 generated flood that severely damaged houses and various public facilities to negeri lima village down toward to the coast. As a result of this event, a small-scale reservoir is formed. The Government plans to utilize the established reservoir to build the new Way Ela Dam. This study was conducted to analyze floods with scenarios in the event of a failure in the new Way Ela Dam. The overland flow is simulate with two dimensional numerical model HEC-RAS v.5. Determining strategies for mitigation needs to be assessed comprehensively, by simulating disaster scenarios on the dam, analyzing the impacts and then planning recommendations for disaster risk. The results are expected to be a reference for mitigation plans for the new Way Ela Dam

Prediction of shoreline change using a numerical model: case of the Kulon Progo Coast, Central Java

Kulon Progo Airport is an airport development project located in the coastal area near Yogyakarta, Indonesia, which is expected to complete in 2019. With the increase in population, huge land acquisition will be difficult, so the development of coastal areas for the airport became inevitable. Kulon Progo is located in the disaster-prone zone area of the earthquake and tsunami, the airport design must consider the risk management and mitigation from tsunami and earthquake disaster. Although the airport is already calculated the danger of earthquake and tsunami, the development of the coastal area also needs to consider the danger of the natural coastal process itself such as sedimentation and erosion. Shoreline changes due to the new infrastructure in the coastal area can disrupt the equilibrium of coastal process especially the longshore sediment transport. A satellite image shows that Kulon Progo shoreline retreats over 60 meters due to the heavy sediment longshore transport in the past 10 years. Breakwaters in Tanjung Adikarto fishing port also made a great contribution in huge sedimentation behind the infrastructure up to 90 meters. This research will conduct an analysis trough satellite and numerical model to observe the shoreline changes along Kulon Progo Coast. A numerical model shows a high erosion rate along the coast. High sedimentation also observed at the river mouth of Bogowonto and Serang Rivers

Development of FTCS Artificial Dissipation for Dam Break 2D Modelling

AbstractDam is a useful infrastructure for human life. It helps supporting social and economic development. Damages to dams may cause negative impacts such as casualties and destruction.  Thus, mitigation for dam related disaster has to be performed. This study uses derivatives of 1D and 2D shallow water wave equations.  This equation is based on the principle of mass and momentum conservation. Furthermore, it is discretized using finite difference Forward Time Center Space (FTCS) scheme. Hansen's filter is used to reduce oscillation and maintain the stability of the calculation. The filter serves as an artificial dissipation to filter each point for each time step. Based on the analysis, simulation of 1D dam break using FTCS numerical scheme shows a similar flow pattern to the analytical solution. But, it is not stable and still shows a quite big oscillation. Hansen Filter can significantly reduce oscillation and increase accuracy. However, its application shows a less accurate wavefront and moveable bed situation. Overall it can be concluded that FTCS numerical scheme with numerical filter can be used to solve 2D shallow flow problems such as circular dam break simulation. AbstrakBendungan adalah infrastruktur yang bermanfaat bagi kehidupan manusia untuk mendukung pembangunan sosial dan ekonomi. Selain bermanfaat, bendungan juga bisa berdampak negatif yaitu menyebabkan korban jiwa dan kerusakan. Oleh karena itu, mitigasi bencana terkait kegagalan bendungan perlu dilakukan. Penelitian ini dilakukan menggunakan turunan dari persamaan gelombang air dangkal 1D dan 2D. Persamaan ini merupakan gabungan dari prinsip konservasi massa dan momentum. Persamaan tersebut kemudian didiskritisasi menggunakan skema beda hingga Forward Time Center Space (FTCS). Filter Hansen digunakan untuk mengurangi osilasi dan menjaga stabilitas perhitungan. Filter berfungsi sebagai disipasi buatan untuk menyaring setiap titik pada setiap langkah waktu. Berdasarkan hasil analisis, dapat disimpulkan bahwa simulasi dam break 1D menggunakan skema numerik FTCS menunjukkan pola aliran yang mirip dengan solusi analitik tetapi tidak stabil dan masih menunjukkan osilasi yang cukup besar. Hansen Filter secara signifikan dapat mengurangi osilasi dan meningkatkan akurasi. Akan tetapi, aplikasinya menunjukkan muka gelombang dan situasi lapisan dasar yang kurang akurat. Secara keseluruhan dapat disimpulkan bahwa skema numerik FTCS dengan filter numerik dapat digunakan untuk menyelesaikan masalah aliran dangkal 2D seperti simulasi dam break.

Application of Finite Difference Schemes to 1D St. Venant for Simulating Weir Overflow

Depth averaged equations are commonly used for modelling hydraulics problems. Nevertheless, the model may not be able to accurately assess the flow in the case of different flow regimes, such as hydraulic jump. The model requires appropriate numerical method or other numerical treatments in order to simulate the case accurately. A finite volume scheme with shock capturing may provide a good result, but it is time consuming as compared to the commonly used finite difference schemes. In this study, 1D St. Venant equation is solved using Artificial Viscosity Lax-Wendroff and Mac-Cormack with TVD filter schemes to simulate an experiment case of weir overflow. The case is chosen to test each scheme ability in simulating flow under different flow regimes. The simulation results are benchmarked to the observed experimental data from previous study. Additionally, to observe the scheme efficiency, the simulation time between the models are compared. Therefore, the most accurate and efficient scheme can be determined

Application of Finite Difference Schemes to 1D St. Venant for Simulating Weir Overflow

Depth averaged equations are commonly used for modelling hydraulics problems. Nevertheless, the model may not be able to accurately assess the flow in the case of different flow regimes, such as hydraulic jump. The model requires appropriate numerical method or other numerical treatments in order to simulate the case accurately. A finite volume scheme with shock capturing may provide a good result, but it is time consuming as compared to the commonly used finite difference schemes. In this study, 1D St. Venant equation is solved using Artificial Viscosity Lax-Wendroff and Mac-Cormack with TVD filter schemes to simulate an experiment case of weir overflow. The case is chosen to test each scheme ability in simulating flow under different flow regimes. The simulation results are benchmarked to the observed experimental data from previous study. Additionally, to observe the scheme efficiency, the simulation time between the models are compared. Therefore, the most accurate and efficient scheme can be determined

2D Modeling of Flood Propagation due to the Failure of Way Ela Natural Dam

A dam break induced-flood propagation modeling is needed to reduce the losses of any potential dam failure. On the 25 July 2013, there was a dam break generated flood due to the failure of Way Ela Natural Dam that severely damaged houses and various public facilities. This study simulated the flooding induced by the failure of Way Ela Natural Dam. A two-dimensional (2D) numerical model, HEC-RAS v.5, is used to simulate the overland flow. The dam failure itself is simulated using HECHMSv.4. The results of this study, the flood inundation, flood depth, and flood arrival time are verified by using available secondary data. These informations are very important to propose mitigation plans with respect to possible dam break in the future