İzmit Körfezi Deniz Trafiğinin Iwrap Model Kullanılarak İncelenmesi

Abstract

Barındırdığı genel ve kendine has riskler ile denizyolu taşımacılığı, dünya ticaretinde çok önemli bir unsur olarak kabul edilmektedir. Ülkemiz ticaretine konu olan mal ve ürünlerin %87,6 sının deniz yolu ile taşındığı da göz önünde bulundurulduğunda, denizyolu taşımacılığının önemi çok daha net olarak anlaşılacaktır. Denizyolu taşımacılığındaki risk unsurlarının belirlenmesi ve bunlara karşı etkin önlemler alınması ile can ve mal kaybını en aza indirmek ve oluşabilecek muhtemel çevre felaketlerini önlemek, denizcilikte risk analizinin gerekliliğini açık bir şekilde ortaya koymaktadır. Denizcilikte, çok çeşitli alanlarda risk analizleri yapılmakla birlikte, deniz trafiğinin ve çevre şartlarının bir bütün olarak meydana getirdiği çatışma ve karaya oturma kazaları, temel risk unsurları olarak ilk sıralarda gelmektedir. Deniz trafiğinin barındırdığı bu risklerin belirlenmesi için çeşitli risk analiz metodları ortaya konmuştur. Deniz trafiğinin risk analizinin yapılabilmesi ve riskli bölgelerin belirlenebilmesi amacı ile 2004 yılında, International Association of Lighthouse Authorities (IALA) tarafından oluşturularak IMO’ya sunulan ve IMO tarafından da kabul edilen nicel bir deniz trafiği risk değerlendirme metodu olan IALA Waterways Risk Assessment Program (IWRAP) tanıtılmıştır. İlk sürümü IWRAP Mk1 adı ile oluşturulan bu sistemin, gerçekte olandan çok daha yüksek kaza oranları vermesi tatminkar bulunmamış ve 2008 yılında program güncellenerek IWRAP Mk2 adı ile yeniden oluşturulmuştur. IWRAP Mk2, seyir yardımcıları gibi kaza oranlarını doğrudan azaltabilecek sistemleri de göz önünde bulundurabilen ve tatminkar sonuçlar verebilen bir program haline gelmiştir. Su yollarının risk analizlerinin yapılması amacına yönelik IMO’nun kabul ettiği 2 metoddan biri olan IWRAP, diğer metod olan ve nitel özellikteki Ports and Waterways Safety Assessment (PAWSA) model ile birlikte birbirini tamamlayıcı özelliktedir. PAWSA çalıştayı, 2014 yılı içerisinde, uzman katılımcılar ile birlikte İzmit Körfezi’nde gerçekleştirilmiştir. Çalıştay sonunda elde edilen sonuçların geçerliliğinin tekrar değerlendirilmesi ve Türkiye için taşıdığı büyük öneme rağmen, deniz trafiği konusunda çok sınırlı çalışma bulunan İzmit Körfezi üzerinde nicel bir metod olan IWRAP ile çalışma yapılması, bir zaruriyet olarak görünmektedir. Bu çalışmada, Türkiye’nin önemli bir suyolu olan ve doğal liman konumundaki İzmit Körfezi’nde deniz ulaştırması ile ilgili risklerin temelini oluşturan çatışma ve karaya oturma frekansları ile bu kazaların gerçekleşmesi muhtemel bölgelerin, IALA’nın tavsiye ettiği ve IMO tarafından kabul edilmiş nicel bir deniz trafiği analiz metodu olan IWRAP model kullanılarak belirlenmesi amaçlanmıştır. Çalışmada, İzmit Körfezi’nin sahip olduğu boyutlar, dip yapısı, sıcaklık, rüzgarlar, akıntı, sis ve kısıtlı görüş şartları gibi genel özellikler incelenmiş, sonrasında ise deniz trafiğini meydana getiren, liman, tersane, marina ve balıkçı barınakları ile tarifeli yolcu taşımacılığı gibi ana etkenler ortaya konulmuştur. Deniz trafiğinde uygulanan risk değerlendirme metodlarına genel bir bakışdan sonra Izmit Körfezi’nde bu güne kadar uygulanmış modellere ve bu çalışmaların sonuçlarına değinilmiştir. Bu çalışmada tercih edilen metod olan IWRAP model detaylı olarak anlatılmış ve modelin İzmit Körfezi uygulama süreci ile elde edilen sonuçlar gösterilmiştir.

At present, a very large part of world trade is carried by maritime transportation. Hereby the commercial maritime transportation and ports consequently gained importance. According to statistical data, 87,6% percent of Turkey’s foreign trade is carried by maritime transportation. In 2010, the total cargo handled in Turkish ports was about 115 million tonnes with an increase of 83% compared to 2003 and significant amount of the total cargo handled was import – export goods. Moreover, Total amount of container transportation has increased up to 144% between 2004 and 2013 while the total amount in 2004 was 34.598.747 Tons and 84.656.192 Tons in 2013. Izmit Bay has a significant potential in terms of logistics sector due to its geographical position and the city Kocaeli is the leading industrial centre in Turkey. The bay is geographically located between Istanbul and Kocaeli, it is also the east part of the Marmara Sea. The city of Kocaeli has a fairly significant role in Turkey’s export and import because of the large hinterland in east and west directions which covers Kocaeli, Adapazarı and Istanbul. It is comprising various types of industries such as petroleum industry, automotive industry, clothing industry, pharmaceutical industry, chemical industry, cement industry, food industry and iron – steel industries etc. According to statistical data in 2013, 61 million tons of various types of cargo had been handled within 40 port facilities in Izmit Bay which corresponds %15,86 of total cargo handled in Turkish ports according to statistics of Turkish Chamber of Shipping, thus there is a significant amount of maritime traffic activities in Izmit Bay. Together with those statistics, Izmit Bay is the 11th largest port in EU with respect to EUROSTAT in 2011. In Izmit Bay, various types of cargo handled such as LPG, chemical tanker, container and the bay contains 50 ship yards, 8 fishing vessel shelter and 6 marina. Each year more than 10 thousand ships call the bay and 180 thousand ship movement with dense crossing local traffic creates high risk in terms of navigational safety. In this study, meteorological and oceanographic information of Izmit Bay has been given in the first chapter then statistical information and detailed overview of commercial structures affecting the maritime trade in Izmit Bay has been given in the second chapter. In general, marine accident probability models are based on the work of Fujii et al.(1974) and Macduff (1974). They described the accident frequency as: F = Na x Pc where F = Frequency, Na = Accident Candidates, Pc = Causation Factor. Accident Candidates are the ships which are on an accident course in the vicinity of a ground or another vessel. In other words, accident numbers would be Na if no evasive manoeuvres were made to avoid the accident. Causation factor is the probability of failing to take evasive action while being on an accident course. Today, most of the marine accident probabilty models are developed in accordance with this basic principle. Altough there are several models for calculating marine accident probabilities, the striking models in this area are Formal Safety Assessment (FSA), Iala Waterways Risk Assessment Program (IWRAP), Environmental Stress Model (ES Model), Ports and Waterways Safety Assessment (PAWSA), Pedersen’s Model, Model of Fowler and Sørgård, Macduff’s Model and COWI’s Model. In fourth chapter, detailed information about those models has been given. In fifth chapter, PAWSA and ES models which are applied to Izmit Bay in former studies have been discussed and the results were evaluated. According to Izmit Bay 2014 Ports and Waterways Safety Assessment (PAWSA) study which is an IMO approved qualitative risk assessment model, the area between Eskihisar – Topcular line is the most risky area in terms of collisions because the crossing of dense local trafffic and inbound – outbound traffic. Furthermore, the bottleneck areas such as Diliskelesi – Altınova and Derince – Golcuk are the most risky areas because of the narrowing waterway. Coming to the Environmental Stress (ES) model and its results, the model contains both mathematical equations and qualitative analyses of seafarers. Thus, ES model combines both qualitative and quantitative facts in one unique model. The study was conducted with 1210 ships and 564310 ship movement data of these ships collected from AIS. According to results of ES model, the entrance of Izmit Bay beginnig from a one mile distance from Darıca and Eskihisar – Topcular lines are the most risky areas due to the dense local traffic. Dilovası area has been found the third risky area due to the narrowing waterway caused by the Korfez Bridge construction. IWRAP is a quantitative safety assessment model which enables user to conceive yearly collision and grounding frequencies, risky areas and the risk distribution in terms of ship types in a selected waterway. IWRAP software is recommended by International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) and approved by IMO. While calculating these, IWRAP uses mathematical equations and Bayesian Belief Network (BBN). IWRAP calculates Crossing collisions, Head on collisions, Bending – Merging collisions and Overtaking collisions. To calculate Causation Factor, IWRAP uses Bayesian Belief Network rather than Scenario Approach because the Scenario Approach is based on past accident statistics and this is not always possible to have those statistics in all specific waterway. In sixth chapter, the IWRAP model is described in details. According to Izmit Bay IWRAP results, yearly collision frequency was found 0.3 and grounding as 1.937 which are about to coincide in statistical data. The most risky area is found as Eskihisar – Topcular line where is exposed to crossings of dense local traffic and inbound – outbound traffics. Yearly collision frequency in this specific area was found 0.171 and total groundings were 1.693. The results of this research has coincide with the results found in 2014 Izmit Bay Ports and Waterways Safety Assassment (PAWSA) model workshop which was utilized for identifying Vessel Traffic Service (VTS) control areas and also Environmental Stress (ES) model study. In this study, IWRAP model has been utilized 30 times with different leg distributions to find the true IWRAP results. In Izmit Bay area, IWRAP repeats itself and give same results after 30 different leg distributions. In seventh chapter, detailed information about the application process of IWRAP to Izmit Bay and the obtained results are shown. In the last chapter, general overview of the study has been given, results obtained from IWRAP were analysed and compared with the results of former PAWSA and ES model studies in Izmit Bay.