Istanbul province is the largest city in Turkey and Europe. Istanbul is a city that has been the capital of many civilizations. The City of Istanbul served as the Capital of the Roman Empire, Byzantine Empire, the Latin Empire, and finally the Ottoman Empire as it is known. The geography of Istanbul is at such an important point that it constitutes the transition zone between many countries. Many civilizations have lived in the city of Istanbul so far. There are ruins from 5000 BC in Istanbul, which show how old its history is. Istanbul province is also one of the few cities in the world with a population of approximately 16 million. So do you know where is Istanbul located?
Istanbul is located between 280 01 ‘and 290 55’ east longitudes and 410 33 ‘and 400 28’ north latitudes. The provincial lands of Istanbul cover a total area of 5,512 km2. Istanbul is a city that acts as a bridge between the European and Asian continents and is built on the two ends where they are closest to each other. These ends are Çatalca in the European continent, Kocaeli in the Asian continent; It is surrounded by Marmara and Bursa from the south, Tekirdağ from the southwest, and Kırklareli from the northwest. The real Istanbul, which is located on the peninsula between the Golden Horn and the Marmara, from which the city is named, is 253 km², and the whole is 5.712 km². Islands in the Sea of Marmara are also included in the province of Istanbul.
The vegetation around Istanbul resembles the plants of the Mediterranean climate. The most common plant species in the region is “scrub”. These plants have adapted to a long dry summer. However, the hills are not bare due to the nature of the climate. The most important of the forested areas seen in patches is the Belgrad Forest, 20 km north of the city. There is no big river in Istanbul province. The largest stream is Riva Stream, which is also the largest water of the Kocaeli Peninsula. The 71 km Riva Stream takes its sources from Kocaeli province and flows in the southeast-northwest direction and flows into the Black Sea near Riva village.
The most important of the waters pouring into the Bosphorus are Küçüksu and Göksu streams. Apart from these, Kağıthane and Alibey Streams flowing into the Golden Horn, Sazlıdere flowing into Küçükçekmece Lake, Karasu Creek flowing into Büyükçekmece Lake, Trança Creek flowing into Terkos Lake are the main rivers of Istanbul. The water of the city is provided from here. The waters of Küçükçekmece (11 km²) and Büyükçekmece (16 km²) Lakes, which are located on the shores of the Marmara Sea, are salty due to their contact with the sea.
Although the summer months are generally hot and the winter months are not too cold due to the systems that affect the region, Istanbul seems to have the characteristics of the Mediterranean climate, but it has different characteristics with the influence of the Marmara Sea and the Bosphorus. During the winter months, the cold-dry air mass coming from the Black Sea and the cold-rainy air mass coming from the Balkans are especially under the influence of the warm and rainy southern air masses from the Mediterranean. The cold rainy (northeaster) weather of the Black Sea and the warm (southwester) air of the Mediterranean follow each other throughout the province. There are no big temperature differences between summer and winter and day and night in the province.
Geographical Location and Strategic Importance of Istanbul
The seas and lands divided the geography of Istanbul, which is embroidered like lace, into 4 parts. Old Istanbul and Galata are located on the shores of the Golden Horn, and on both sides of the Bosphorus, formerly separate villages, now united settlement areas. Inhabited areas along the shores of the Marmara Sea, the smallest sea in the world, show the size of the city has reached. The Old City is spread over the 7 hills of a triangular peninsula surrounded by 22 km of city walls. Located in the center of the Old World, Istanbul is a very important megalopolis with its historical monuments and magnificent natural landscapes. It is the only city in the world built on two continents where the Asian and European Continents are separated by a narrow sea passage.
Having a history of more than 2500 years, Istanbul became an important trade center following its establishment in this strategic region where sea and land meet. The historical city of Istanbul is located on a peninsula surrounded by the Marmara Sea, the Bosphorus, and the Golden Horn on three sides. Istanbul is located between 280 01 ‘and 290 55’ east longitudes and 410 33 ‘and 400 28’ north latitudes. While the Istanbul Strait connects the Black Sea with the Sea of Marmara; It separates the Asian Continent from the European Continent and divides the city of Istanbul into two. The province borders the Black Sea in the north, the high hills of the Kocaeli Mountain Range in the east, the Marmara Sea in the south, and the water divide line of the Ergene Basin in the west.
It is the fortune of Istanbul to be located at the crossroads where the main roads reach the sea, an easily defended peninsula, ideal climate, rich and generous nature, strategic control of the Bosphorus, and its geographical location in the center of the world. Istanbul has had a very important strategic importance throughout history due to its location at the confluence of two continents, being a gateway to hot climates and oceans, and being the gateway of the historical Silk Road to Europe. The city became the capital of 3 world empires, namely the Roman, Byzantine, and Ottoman Turks, and more than 120 emperors and sultans ruled here for more than 1600 years.
Istanbul is the only city in the world with these characteristics. During the development process, the city was expanded four times, each time building further west. There was Istanbul, surrounded by 5th-century Roman period walls and built on 7 hills. But the foundations of today’s Istanbul were laid in the 7th century BC. It was rebuilt by Emperor Constantin in the 4th century AD and made the capital city; After that day, it continued its title of capital during the Roman, Byzantine, and Ottoman periods for about 16 centuries. At the same time, Istanbul, which was one of the centers of Christianity with Emperor Constantine, was considered one of the most important cities of the Islamic religion after it was conquered by the Ottomans in 1453.
While it was the capital of the empires, it was the administrative center of the religions together with the state, the Eastern Christianity Patriarchate was based in this city since its establishment, and the first biggest churches and monasteries of the Christian world rose above the pagan temples here. After the conquest of Istanbul, in a century or so, artworks, mosques, palaces, schools, baths, and other facilities furnished the city and transformed it into an Islamic character, and some of the ruined churches were repaired and converted into mosques.
Istanbul Metropolitan is located on Kocaeli and Çatalca Peninsulas. Both peninsulas are eroded plateaus. While Istanbul and its surroundings were a gulf of the Sarmat inland sea at the end of the Miocene period of the III Period in geological times, in the Pliocene period the sea was withdrawn, lands emerged, and after a long erosion period with stream and wind erosion, the elevations disappeared, the abrasion-resistant quartzite hills remained and a peneplane has emerged. The valley at the place of the Bosphorus has also widened. Later, with the swelling of the northern part in the east of the Bosphorus Valley of the peneplain, and the swelling of the south part in the west, the water section lines changed, water erosion increased due to the increase in the slope of the river valleys, large streams on the east side of the Black Sea and on the west side the Marmara Sea was spilled into the seas.
As a result of the said geological movements, the area where the Metropolitan of Istanbul is located has gained the appearance of a plateau (peneplane) containing generally eroded landforms. Valleys, plains, heights (slightly wavy hilly areas), high areas, etc., which can be grouped as geomorphological units, do not have a sharp and striking appearance in the metropolitan area of Istanbul for the reasons explained. On the cold side (Kocaeli Plateau), there are quartzite hills (Aydos, Kayışdağı, Alemdağ, etc.) and high areas starting from the east of the Gebze – Ömerli Dam line and continuing to rise towards the east (350m +). In this peninsula, the “water section line” is closer to the Marmara shores. In the remaining parts of the peneplain, the flow direction of the streams is mostly the Black Sea and includes wide valley-based and slightly wavy areas.
On the west side (in Çatalca or Thrace Peneplane), apart from a few hills reaching and exceeding 200 m in places from the Bosphorus to Büyükçekmece – Karacaköy line, there is also a peneplane with wide base river valleys. However, in this peninsula, the “water section line” is closer to the Black Sea this time. Rivers mostly give water to the Golden Horn, Büyük and Küçükçekmece lakes and the Marmara Sea. Terkos lake, on the other hand, gets its main water from the Istranca Mountains in the northwest. Except for Istranca, which has heights above 350 m in places, it is located to the west of Çatalca, also to the west of the Kestanelik – Belgrad Villages line, their height is 200-350 m. varying hills and ridges are outstanding.
Climate and Vegetation of Istanbul
It is not possible to evaluate the climate type in the area where the entire province of Istanbul is located in a specific climate type. Due to its geographical location and physical geography features, it has different climatic characteristics than the climates of many settlements located at the same latitude. Istanbul within the low and high-pressure zones that start from the equator on the earth and repeat twice respectively (with 41 degrees north latitude, 29 degrees east longitude), is at the border of the western winds with subtropical high-pressure zone, and low pressures of the cold-warm region or terrestrial (humidity) low winds (humid and wet). Different climatic conditions occur in winter and summer seasons with the movements of the earth.
Three types of air are dominant throughout the year in Istanbul. These are air types introduced from the north and south and calm air types. Weather types depending on east and west winds are not important. Among the three types of air, it is the type of weather that shows the highest frequency (the most blowing number) when the northern winds are dominant. There are four periods according to the seasons; Two transition cycles, one long and one short, with cold and hot cycles. The metropolitan area of Istanbul consists of natural vegetation, forest, maquis (more woody maquis plant communities that have adapted to the Black Sea climate, changed, moist character) and coastal plants; Plant communities in Çatalca and Kocaeli Peninsula that adapt to the climatic conditions have developed “humid” in the north and “dry” in the south.
Kocaeli Peninsula has deciduous species such as cranberry, hazelnut, deer thistle, moth bush, medlar, wild plum, blackberry, rowan gorse, maple, elderberry, sumac, privet and bearberry, maple, arbutus, heather, laurel, mule, tar postman, and it also consists of elements such as kermes oak, laden and mastic. The tree species that characterize the humid forest are chestnut, beech, common hornbeam, and stalked oak, mostly seen in the north-east of the I. Strait, north of Alemdağ and around Polonezköy. In the region between Riva Stream and Gökdere in Ağva, stalked oak in the west and Hungarian oak in the east are the dominant species. Vegetation is related not only to climate but also to soil. While lime-free brown forest soils cover the areas where all beech troops are located, brown forest soils are seen in the areas of oak and chestnut species.
The General Location Information of Istanbul
Istanbul, Turkey’s most important province in many respects, is also one of the world’s most important points in terms of its location on earth. Istanbul has an area of 5.220 km in the Marmara Region, facing the Black Sea in the north and surrounded by the Marmara Sea and the Golden Horn in the south. Istanbul has gained a reputation as “the city with lands on two continents” due to its lands on both sides of the Bosphorus, which is one of the most important waterways of the world, which separates the Asian Continent from the European Continent. Istanbul is approximately at the intersection of 41.8 north latitude and 29th east longitude.
A large part of today’s Istanbul is on the European side and the other part is on the Asian continent. Istanbul is an important passage area between lands and seas. It has Anatolia and the Balkan Peninsula on one side and the Black Sea and the Aegean Sea on the other. It borders the Black Sea in the north, the high hills of the Kocaeli Mountain Range in the east, the Marmara Sea in the south, and the water dividing line of the Ergene Basin in the west. The provincial area is surrounded administratively in the east and southeast with Kocaeli’s Karamürsel, Gebze central and Kandıra districts, Bursa’s Gemlik and Orhangazi districts from the south, Tekirdağ’s Çerkezköy and Saray districts from the west and northwest, as well as the Vizne district of Kırıkkale.
Istanbul has the characteristic of a plateau with its general appearance. The high plains are divided by streams. 91% of the provincial land, 74.4% of which is covered by plateaus, is suitable for agriculture. The Bosphorus, which separates the Asian and European continents, turns from north to southwest and maintains its parallelism, even though the coasts are partially closer to each other. The distance between both coasts is 29.9 km on the line between Sarayburnu and Kızkulesi. The length of the coasts is 32.2 km from the Asian side between Ahırkapı Lighthouse and Kavak Cape, and 46 km between Rumeli Lighthouse and Ahırkapı Lighthouse (including the Golden Horn). There are eleven islands connected to Istanbul in the Sea of Marmara.
Landforms Located in Istanbul
Istanbul is composed of a plateau group, squeezed between two main peneplains located in the eastern Marmara part of the Marmara Basin, and fragmented by the strait and river valleys. The foundations of its soils consist of 1st-period old rocks. In later geological times, the rise and fall, erosion, sharp ridges, steep mountains, and very rugged topography disappeared, replaced by flat areas, round hills, and low ridges.
The place where today’s Bosphorus is located was the valley of two streams, one into the Black Sea and the other into the Sea of Marmara Region. During the compression and uplift that occurred between the 2nd and 3rd time, the Asian part located in the west of the valleys was hit to the south, and the Asian part located to the east of the valleys to the north. As a result of this incident, the current Bosphorus emerged with the breaking of the river valleys. The valleys formed by many streams and streams in the region and the small agricultural areas that emerged with the expansion of these valleys in places, the hills, and ridges that lost their steepness constitute the landforms of Istanbul.
It is a plateau community scattered between Istanbul, Thrace, and Kocaeli semi-plains. These plateaus are surrounded by seas from the north and south. Plateaus surrounded by seas generally extend in the west-northwest, east-southeast directions. 74% of its territory. The plateaus, which cover 4 of them and are divided into two parts by the strait, are not symmetrical in the east and west. While the plateaus to the west of the Bosphorus create a smooth and slightly wavy surface, the eastern ones are less developed and wavier. The most important plateaus in the province are Beyoğlu, Istanbul, and Üsküdar plateaus. The plateau that fills between the Bosphorus and the estuary in the province is called the Beyoğlu plateau. The plateau was largely removed by abrasion in both directions. For this reason, plateau depressions and valleys were formed by the combination of these depressions. The great ridge running in the direction of Galata-Beyoğlu-Şişli, Maslak-Darbent Büyükdere forms the waterline of the Beyoğlu plateau.
The triangle-shaped peninsula between the estuary where it was founded and the Marmara Sea is called the Istanbul plateau. It forms the highest city walls of Istanbul. The plateau of Istanbul starts from Saraburnu and extends by expanding in both directions. Beyazıt, Edirnekapı, Sarayburnu, Hagia Sophia constitute the higher parts of the Istanbul Plateau. The Istanbul plateau, like the Beyoğlu plateau, has been eroded from both sides. Although the shores of the plateau facing the Marmara are narrow and indented, it has become wider and flattened from Kum Kapı to Yenikapı.
The plateaus that fill the Asian side of Istanbul rise in steps starting from the Bosphorus and the Marmara shores. These steps end at Büyük and Küçük Çamlıca Hills. Big and Small Çamlıca Hills look like mountain peaks with their conical structures according to the flat shapes of the region. Another important plateau of Istanbul is the Üsküdar plateau. This plateau is divided into several sections with erosion grooves just like the Beyoğlu and Istanbul Plateaus. When going from Üsküdar to Ömerli and Şile direction, the plateau reaches the water section line in a short distance and loses its altitude and extends to the Black Sea.
Geographical Advantage: The Location of Istanbul Airport
Istanbul Airport serves as one of the most important aviation centers in the world with its strategic geographic location connecting the continents in Istanbul, at the crossroads of Asia, Europe, and the Middle East. The international air freight sector grew by 5.6% over the past 10 years worldwide, Turkey recorded 14% growth. Istanbul, which has become one of the most important flights and transfer hubs in the world, plays the leading role in this growth. According to the data of the Ministry of Culture of the Republic of Turkey, the number of foreign tourists coming to Istanbul increased by 17.8% in 2017 compared to the previous year. It is observed that a similar positive momentum continues in 2018 and it is predicted that the growth trend will continue.
According to the report published by the European Council of International Airports (ACI Europe), in February 2018, Istanbul Atatürk Airport was the one with the highest increase in the number of passengers among the top 5 airports in Europe, with an increase of 17.7%. Sabiha Gökçen took second place with the highest increase in passenger traffic among the airports in the Group 1 category with 15.5% after Istanbul Atatürk. In the Council’s 2018 Airport Industry Connection Report, Istanbul Atatürk Airport was ranked fifth with the number of direct connections and flight volume in flights between European airports.
In the same report, Atatürk Airport, which ranked fourth among the highest performing airports in Europe for the last 10 years, was announced as the fourth among the main flight centers with the highest connection volume. Istanbul Airport has made Istanbul, the center of wide geography stretching from the East to the West, stronger with its extremely high capacity, the rich variety of facilities, and solid infrastructure possibilities. With its strategic location on transfer routes, it operates as a center of attraction for transit flights between the USA and Europe and the Middle East, Central Asia, and Northern India via Istanbul.
Today, Istanbul Airport, which provides transportation to 120+ countries, 60+ capitals, 250+ international destinations, and 50 domestic destinations, flies to 146 destinations from different continents within 3 hours. When the airport is put into service at full capacity, flights will be arranged to more than 350 destinations. In addition to passenger transportation, Istanbul is also the hub between Asia and Europe in air cargo transportation. Cargo operations showed a significant increase of 18.7% compound annual growth rate (CAGR) between 2009-2017. Istanbul Airport also serves as a center with heavy traffic for air cargo transportation.
About the Valleys Located Near Istanbul
The valleys of the Istanbul region seem quite interesting in terms of the origin and evolution of the geomorphological forms in the region on the one hand, and the formation of the Bosphorus on the other. The main valleys in the region are İstranca Stream, Karasu Stream, Sazlı Stream, Şamlar Stream, Alibey and Kağıthane creeks, Göksu Stream, Riva Stream, Ulu Dere, Gök Dere, and Çatak Stream valleys. Most of these valleys lie in a rather northwest-southeast direction. Although the valleys on the Kocaeli peninsula generally flow towards the northwest and north, those on the Çatalca peninsula open towards the southeast.
However, the fact that the valleys run parallel to each other is seen as an important fact that draws attention. Furthermore, it is observed that the valleys extend parallel to the general direction of the Istanbul massif and its cover layers, on the one hand, and to the dissymmetric ridges formed on the cover layers with peaks on the other hand. These observations show that the great valleys were formed as tufts according to the Mesozoic and tertiary layers in the region and the relief that occurred above them. As explained by the general diving of the Mesozoic layers in this area, the south-west facing slopes of the Kocaeli peninsula valleys are more inclined than the slopes facing the northeast, as well as the dissymmetric slopes on the Çatalca peninsula are related to the general slope of the Eocene layers here.
As a matter of fact, the wide valley formed by the Alibey-Kâğıthane stream system, which runs parallel to the eastern edge of the Eocene strata, was formed as a result of the evolution of an old sub-secant valley, as in the other valleys of the region. It is understood that today’s valley bottoms and stream beds were formed over-the-counter, according to the quaternary and Pliocene archaea formations that were previously collected in the valley. As for the valleys around the Bosphorus, they are gathered in three main areas, in terms of their geomorphological status, around the southern part of the Bosphorus, the southern part of the Bosphorus, and the northern circumference of the Bosphorus.
Among those around the south mouth of the Bosphorus, Maltepe Creek, Bostancı Creek, Kurbağalı Creek, Yenikapı Creek, Çırpıcı Creek, Çavuşbaşı Creek, and Uzunca Dere valleys can be seen in particular. It is understood that these valleys are seen over the sea maps with medium micas, which do not contain much detail, and it is understood that they continue under the sea, which shows that they played an important role in the formation of the gulf here, together with the main valley located at a depth of 100 meters in the same place. The apparent expanse of the valleys and the gulf must be related to the presence of the less resistant Neogene land here. The relations of the native valleys in the southern part of the Bosphorus with the Bosphorus valley are also remarkable.
Most of these have a normal junction with the Bosphorus pivot, generally forming acute angles opening towards the north. Both this situation and the leveling patterns in this part of the Bosphorus and the ridges are generally inclined towards the south; In addition, the presence of epigenetic breaches corresponding to areas where hard devon lands such as siliceous schist, lumpy limestone, dense limestone emerged suggests that a valley previously opening towards the south may exist in this part of the Bosphorus. In the northern part of the strait, it is understood that a separate valley system has been formed. In this section, some eastern subordinates such as Kabakoz, Çakal, Poyraz, Keçilik and the western subordinates named Sazlı, Garipçe, Rumelikavağı, and Sarıyer merge with the axis of the Bosphorus, rather at acute angles to the south.
This situation reminds us that there may be an old valley opening towards the northeast in this part as well. The fact that this ancient valley is suitable for the coastal valleys between the mouth of the Riva valley and Kilyos in terms of extension and flow direction seems to be a remarkable geomorphological feature. Accordingly, this northern Bosphorus valley is perhaps one of the submerged natural valleys of the Riva valley. The northern Bosphorus valley, which can be followed up to the vicinity of Büyükdere in a fairly certain way, at a stage that has not yet been determined, perhaps extended to the present mouth areas of the Göksu and Küçüksu valleys and became a continuation of them.
It seems probable that the current subdivision lines passing over the peaks of the Kocaeli peninsula and the Çatalca peninsula with high relief and finally over the epigenetic breach areas once passed between the southern Bosphorus valley system and the northern Bosphorus valley system. If a comparison is made between the body and relief shapes of the Dardanelles region and those in the Istanbul Strait region, some important differences are immediately noticeable. A monoclinal structure is dominant in the Dardanelles region.