47 research outputs found
Dämpfung von Solitären Wellen und Seegang durch Küstenwälder
No full textBased on available knowledge and the field evidence from the latest extreme wave events, the interaction of coastal forests and tsunami as well as storm waves still needs further study directed towards an improved understanding of the attenuation performance of coastal forests and the development of reliable prediction models. The objective is to improve the understanding of the physical processes associated with the energy attenuation of tsunami and storm waves through coastal forests by developing a generic methodology for the parameterization of 3-D complex typical coastal forest vegetations and by performing physical laboratory experiment and numerical modelling. To achieve this objective, two typical coastal forest vegetations (mangroves and coastal pines) representing two different coastal habitats were selected. A physically-based parameterization using easily quantifiable parameters of the real tree was carried out and tested in a current flume for both stiff and flexible structure assumptions. Following the parameterization stage, large scale model tests with different model setups and wave conditions (solitary waves representing tsunami and regular/irregular waves representing storm waves) were simultaneously performed in the Twin Wave Flume of Leichtweiß-Instituts (LWI) to investigate the hydraulic performance and the hydraulic resistance characteristics of the coastal forest models. Furthermore, an empirical relationship (forest width factor) and a new procedure to assess tsunami attenuation by coastal forests have also been succesfully developed based on numerical simulation using the nonlinear shallow water equation model with hydraulic resistant coefficients obtained from the laboratory experiments. It can, therefore, be used as a practical tool in coastal zone management to evaluate feasible measures in mitigating and managing risks associated with tsunami and storm waves, particularly in the regions where coastal forests are favourable.Aus vielen Berichten nach dem Tsunami 2004 wurde die Schutzwirkung der Küstenwälder mehrfach bestätigt, obwohl bislang die Dämpfungsprozesse weitgehend unbekannt waren und hierfür kein verlässlicher Nachweis durch prozessbasierte Modelle vorlag. Vor diesem Hintergrund und dem Hintergrund des Wissensstandes besteht das Hauptziel dieser Studie darin, das Verständnis der Prozesse substantiell zu verbessern, die für die Dämpfung von Tsunami/Windwellen durch Küstenwälder verantwortlich sind. Den Schwerpunkt der Arbeit bilden die Entwicklung und systematische experimentelle Verifizierung eines neuen prozess-basierten Verfahrens zur Parametrisierung steifer und flexibler Walvegetation hinsichtlich des Strömungswiderstands. Mit den anhand dieses neuen Verfahrens ermittelten parametrisierten Modellbäumen wurden systematische Untersuchungen über die Dämpfungswirkung der o.g. zwei Waldtypen in den beiden Wellenkanälen des Leichtweiß-Instituts durchgeführt. Tsunami-ähnlichen solitären Wellen sowie regelmäßigem und unregelmäßigem Seegang wurden generiert. Berücksichtigt wurden sowohl globale Prozesse (hydraulische Wirksamkeit) als auch lokale Prozesse (z.B. Strömungswiderstand). Hinsichtlich der numerischen Modellierung wurde das nichtlineare Flachwasserwellen-Modell mit den aus den Experimenten gewonnenen Strömungswiderstandskoeffizienten implementiert und Daten erfolgreich validiert. Das validierte Modell wurde zur Durchführung einer systematischen Parameterstudie eingesetzt, die in die Entwicklung einer neuen Formel zur praktischen Ermittlung der hydraulischen Wirksamkeit von Küstenwäldern als Funktion eines dimensionslosen Parameters resultierte. Dieser Parameter fasst sinnvollerweise die Einflüsse der Breite und Dichte des Küstenwaldes sowie der Wellenhöhe und Wassertiefe am Vorlandfuß zusammen. Darüber hinaus wurden Empfehlungen für die praktische Bewertung der hydraulischen Wirksamkeit von Küstenwäldern zur Risikoreduzierung bei Tsunami und Sturmfluten ausgearbeitet
CHARACTERISTICS OF BREAKING WAVES AND ANALYSIS OF SEDIMENT TRANSPORT IN TELUK KENDARI
No full textOne of the problems that often occured in the bay area is a sedimentation process that occurred continuously, causing silting. The movement of sediment material in the process of sedimentation is influenced by the movement of the water flow like the tides, winds, currents and waves. The aim of this study was to determine the characteristics of the hydrodynamic conditions, particularly the distribution pattern and the capacity of the sediments in the Kendari Bay with oceanographic modeling approach. Bathymetry data measured at the site of the research conducted in August 2015. The analysis of distribution patterns of sedimentation, sedimentation capacity, wave hindcasting, wind data and tidal data using software, hindcasting results indicate the dominant wind direction coming from the east. Type tides in Kendari Bay is a mixed mainly semiurdunal tides. The concentration of suspended sediment at low tide is greater than at high tide. Keywords: sediment transport, wave characteristics, Kendari Bay, hydro - dynamics, mike21</jats:p
2D multichannel seismic reflection raw data (entire dataset) of RV SONNE during cruise SO299/2
No full textThe raw 2D multichannel seismic reflection data in this project were acquired during expedition SO299/2 offshore Krakatau using a single GI Gun. The data were recorded with a 48-channel streamer. The Krakatau survey aimed to shed light on the erupted volumes of the disastrous 1883 eruption and decipher the processes leading to a damaging tsunami. The data comprise 381 line kilometers and are provided in raw format (SEG-D) and associated standardized metadata. Detailed information on the acquisition can be found in the SO299/2 cruise report (https://doi.org/10.48433/cr_so299_2). In addition, a technical report is provided with this data set
WATER QUALITY OF POST CONTAMINATION OF MARINE DEBRIS IN THE KUTA BEACH OF BALI
No full textKuta Beach of Bali is one of the top tourist destination for a vacation in Bali Island. The beauty of the beach with white sand, ocean waves are excellent for surfing, sunset, and tourism infrastructure which detailed makes very famous Kuta beach to foreign countries. However, in recent years the beauty of Kuta beach which has become an icon of tourism in Bali began plagued by high levels of contaminant of the marine debris on the beach, mainly contamination of the marine debris that often accumulate in Kuta beach every season West. The purpose of this study was to determine the condition of water quality based the quality standards of sea water KMNLH Number 51 Years 2004 post contamination of the marine debris that occurred in the Kuta beach of Bali. The method used is to perform measurements using a "Water Quality Checker" at 8 measuring stations. Water quality parameters which measured, namely physical parameters (temperature, turbidity) and chemical parameters (pH, salinity, DO). The results showed a temperature with the range of value 29.10-29.40°C, turbidity with the value range 0.30-18.70 NTU, pH with the value range 8.10-8.15 DO with the value range 6.85-7.38 mg/L and salinity with the value range 30.60-30.90%o. Based on the measurement data obtained indicates conditions of the waters chemistry of still suitable and condition of the waters physical showed the value of the temperature is still suitable, except the turbidity value shows the value does not suitable in the station 1, 2 and 8. Keywords: Bali, water quality, Kuta Beach, marine debris</jats:p
Perubahan Garis Pantai di Pesisir Cirebon Berdasarkan Analisis Spasial
No full textABSTRAKInformasi kerusakan daerah Pesisir Utara Jawa bukan hal yang baru. Daerah pesisir Cirebon sebagai salah satu bagian Pesisir Utara Jawa mengalami permasalahan dinamika pesisir yang ditandai oleh erosi dan sedimentasi pantai. Erosi dan sedimentasi merupakan permasalahan mendasar dalam pengelolaan wilayah pesisir. Penelitian ini mengkaji kerusakan pesisir Cirebon ditinjau melalui perubahan garis pantai yang ditimbulkan oleh proses sedimentasi dan erosi yang terjadi secara alami ataupun akibat aktivitas manusia. Pengolahan data satelit Landsat tahun 1999 dan 2013 memberikan informasi sedimentasi dan erosi di sekitar pesisir Cirebon. Hasil perubahan garis pantai dari analisis satelit diverifikasi dengan pengamatan di lapangan dan wawancara dengan masyarakat pesisir yang dilakukan pada Juni 2013. Analisis memperlihatkan perubahan garis pantai di Pesisir Cirebon sangat dipengaruhi oleh aspek-aspek hidro-oseanografi, morfologi pantai, dan aktivitas manusia. Hasil ini diharapkan dapat menambah informasi mengenai kondisi pesisir di Cirebon yang dapat digunakan dasar dalam pengelolaan kerusakan wilayah pesisir sesuai dengan kondisi real di lapangan.Kata kunci: Cirebon, garis pantai, erosi, akresi, panturaABSTRACTThe damage of coastal area in Northen Java has been known for decades. As part of Northen Java Coastal, Cirebon coastal area suffered from severe damage due to erosion-abrasion phenomenon and turned to be a fundamental problem in coastal area management. This research analyses Cirebon coastal changes by analising shoreline changes induced by long term sedimentation and erosion processes. Landsat data in 1999 and 2013 are used in shoreline change analysis. The sattelite analysis results are verified by field observations and coastal communities interview in June 2013. The results show that the coastline dynamics of Cirebon are strongly influenced by hydro-oceanography aspects, coastal morphology and human activities. This result provides valuable information on the latest conditions of coastal area in Cirebon and this can be used as basis for land use management and future mitigation of costal areas.Keywords: Cirebon, coastlines, erosion, accretion, pantur
THE MODELLING OF SUSPENDED SEDIMENT DISTRIBUTION DUE TO TIN MINING IN BANGKA SEAS
No full textPulau Bangka merupakan penambangan timah lepas pantai terbesar di Indonesia yang dilakukan oleh perusahan dan masyarakat, baik legal maupun ilegal. Hal ini menjadi mengkhawatirkan terutama akan dampaknya terhadap peningkatan sedimentasi, seperti wilayah Teluk Kelabat yang direncanakan menjadi kawasan konservasi. Tujuan penelitian ini adalah mengetahui kondisi hidro-oseanografi dan sebaran Total Suspended Solid (TSS) akibat penambangan timah di perairan Bangka terutama di Teluk Kelabat. Metode yang digunakan adalah analisis pemodelan numerik dengan menggunakan software MIKE21 untuk memperoleh data hidro-oseanografi dan model sebaran TSS dengan sumber TSS dari tiap-tiap lokasi Izin Usaha Pertambangan (IUP) melalui modul Flow Model Flexibel Mesh (FM) dan Mud Transport (MT). Verifikasi hasil model diperoleh korelasi sebesar 0,9435 dengan Root Mean Squared Error (RMSE) sebesar 0,1611 untuk pasang-surut. Tailing penambangan timah lepas pantai akan menyebabkan tingginya sebaran TSS di perairan Bangka, terutama aktivitas penambangan di perairan yang dangkal (<10 m) dan dekat pesisir (<2 mil). Sebaran TSS di perairan Bangka akan dominan terbawa ke arah Selat Bangka. Pada Teluk Kelabat, TSS bernilai sekitar 0-25 mg/L dan menyebar ke seluruh wilayah yang dapat mencapai radius sekitar 16 mil. Hasil penelitian ini diharapkan dapat menjadi rekomendasi bagi stakeholder seperti penyusunan Rencana Zonasi Pesisir Dan Pulau-Pulau Kecil (RZWP3K) di Bangka Belitung.Bangka Island is the largest offshore tin mining in Indonesia conducted by companies and local communities, both legal and illegal. This could be alarming, for example Kelabat Bay which planned as a conservation area due to the impact of increase of suspended solid. This research aims to analyze the hydro-oceanographic conditions and Total Suspended Solid (TSS) distribution process due to tin mining in Bangka Waters, especially in Kelabat Bay. The method used was numerical modelling using MIKE 21 software to obtain hydro-dynamics data and TSS distribution due its sources from each mining spot with Flow Model Flexibel Mesh (FM) module and Mud Transport (MT) module. The model’s verification obtained 0.9435 correlation and 0.1611 Root Mean Squared Error (RMSE) for tidal data. The tailing will cause high TSS distribution in Bangka Waters especially for mining activities in shallow waters (<10 m) and nearby coast (<2 miles). The distribution of TSS in Bangka Waters will be dominantly carried towards the Bangka Strait. In Kelabat Bay itself, the TSS value is 0-25 mg/L and spread throughout the region with radius around 16 miles. The Bangka Waters, especially Kelabat Bay which planned as conservation area will be threatened by the increase of TSS due to offshore mining activities. It will become the recommendation for policy making in Bangka Belitung such as coastal and small islands zoning policy
Conditions of Kejawanan Beach Based on Standard Quality and Suitability for Pollution Index Marine Tourism Area
No full textKejawanan tourist beach is one beach which is located in West Java. This beach is located side to the Kejawanan fishing port. Kejawanan beach topography sloping beach with quiet waters and the waves are not too big. The dominant wind direction throughout the year that influencet the formation of ocean waves are heading toward the bay coast of Cirebon. The existence tourist beach that is located near to the fishing port crowded with activity interesting to known the conditions coast as marine tourism area based on Water quality standars according to Decree of The Minister of Environment Number 51 of 2004. Pollution indeks is based on Decree of The Minister of Environment Number 115 of 2003. Indication of biological contamination by Diversity index of makrobentic animal. The results of the research obtained Water quality standard for marine tourism area mostly exceeded. Pollution index is at the level Heavy pollution. Diversity index of macrobentic animal are at the level of Medium Pollution. Keywords : Kejawanan, standard quality, pollution index, diversity index Â
Identifying the effect of tides on groundwater level fluctuations on Gili Ketapang Island, Indonesia
No full textThis research aims to identify the effect of tides on groundwater level fluctuation in Gili Ketapang Island by using a combination of field monitoring and hydrodynamic modeling. Groundwater data were collected from 5 July to 17 August 2018 from two wells monitoring, while the hydrodynamic model was adopted to identify sea-level conditions. The result explains the sea level around the island is similar among extremely strong correlations between the points. The hydrodynamic model proves a standing wave due to tidal amplification in Madura Strait waters. The effect of tides on the groundwater level characterized by decreasing in amplitudes and time lags as increasing the distance from the coast
Status Baku Mutu Air Laut untuk Kehidupan Biota dan Indeks Pencemaran Perairan di Pesisir Cirebon pada Musim Kemarau [Water Quality Standards For Marine Life And Pollution Index In Cirebon Coastal Area In The Dry Season]
No full textCoastal land that is adjacent to the sea are still is influenced by the tide. Cirebon coast generally have ramps and high turbidity due to sediment supply and waste from the river that empties into the sea. Cirebon coast is divided into two areas, namely governance City of cirebon and Regency of cirebon. Coastal conditions closely related to river, estuaries, and the ocean in the region, the changing nature of the river caused by human activities will affect the water quality and coastal environment. Environmental pollution occurs mainly in the fisherman areas and industry. Determination of contamination status was determined using the pollution index according to equation 1 Sumiotomo and Nerow (1970) in the Minister of the Environment decree No. 115 of 2003 on Guidelines for Determination of Water Quality Status. Criteria for determining the level of water quality based on water quality standards for marine life by the Minister of Environment Decree No. 51 of 2004. The methods of research is done by the measuring of pH, dissolved oxygen, conductivity, turbidity, temperature, salinity, organic matter using Water quality Cheker along the coast cirebon within 500m - 1Km from the beach in June as a representation of the dry season. The results of the analysis addressed that in the dry season there are 10stations lightly polluted, 6 stationsare being polluted and heavily polluted 4 station
Hydrodynamics Banten Bay During Transitional Seasons (August-September) (Hidrodinamika Perairan Teluk Banten Pada Musim Peralihan (Agustus–September))
No full textPerairan Teluk Banten merupakan wilayah yang sibuk dengan aktivitas wisata bahari, industri, permukiman dan lain-lain. Kondisi tersebut dapat menimbulkan dampak-dampak negatif seperti pencemaran, erosi, dan masalah lingkungan lainya. Pemahaman mengenai kondisi hidro-oseanografi sangat penting sebagai langkah untuk pengelolaan dan perlindungan wilayah pesisir dan laut. Tujuan dari penelitian ini untuk mengetahui karakteristik hidrodinamika di Perairan Teluk Banten pada musim peralihan (Agustus - September) berdasarkan data primer (data satu bulan arus, pasang surut, suhu) dan data sekunder (batimetri, kualitas air dan nutrient). Simulasi model diolah menggunakan MIKE 21, didukung dengan penggunaan CD-Oceanography. Hasil pengolahan data menunjukkan bahwa pola arus di Perairan Teluk Banten didominasi arus pasut dengan kecepatan berkisar antara 0-0,41 m.s-1, ditunjukkan oleh hasil pengolahan dalam bentuk stick diagram dan scatter plot yang menunjukkan pergerakan arus cenderung teratur dan arah arus dominan menuju ke arah Tenggara dan Selatan, hal ini juga didukung dengan hasil Current rose dengan menggunakan software WR plot. Kecepatan arus di permukaan lebih besar dan menyebar dibanding kecepatan arus di dekat dasar perairan. Simulasi arus permukaan (nilai error MRSE 12,25 %) menunjukkan bahwa arus bergerak sesuai dengan pengaruh pasang dan surut dengan kecepatan berkisar antara 0-0,42 m.s-1. Simulasi juga memperlihatkan distribusi konsentrasi nutrient dan kualitas perairan dipengaruhi oleh karakteristik hidrodinamika Teluk Banten
