Bartın River is a stream located in the Western Black Sea Region and forming an important river system within the borders of Bartın Province. Known in ancient times as Parthenios, it is also the river that gave its name to the city of Bartın. The river, which has a length of approximately 15 kilometers, flows through the center of Bartın Province and empties into the Black Sea. The most distinctive feature of the Bartın River is that it is one of the rivers in Turkey suitable for transportation. In particular, the river, which was used for commercial and transportation purposes in the past, is currently also utilized for tourism and recreational activities.
In terms of its basin, the Bartın River is fed by numerous streams and small waterways. Among its main tributaries are the Kocaçay and the Kocanaz River. Although its flow regime shows seasonal variations, a significant rise in water level is observed in the spring and autumn months depending on the precipitation regime. From an ecological standpoint, the Bartın River is of great importance, forming a unity with the surrounding agricultural areas and forest ecosystems, and contributing to the region’s biodiversity.
Bartın River flowing beside Bartın Port (Photo: Batı Karadeniz)
Stratigraphy
Because the Bartın River is located in the Western Black Sea Region, it possesses a geological structure related to the North Anatolian Fault and the Western Black Sea Geological Zones. The stratigraphy of the basin consists of various rocks belonging to the Paleozoic, Mesozoic, and Cenozoic eras. These formations are represented by different lithological units along the river’s flow direction.
Paleozoic Period
The oldest units in the Bartın River basin consist of Paleozoic-aged metamorphic and sedimentary rocks. These units, extending to the Devrekani Massif and the Zonguldak Coal Basin, particularly contain coal-bearing schists and limestone levels from the Carboniferous (359 – 299 million years ago). These rocks, belonging to this period, are observed in the upper basin section of the Bartın River and have generally undergone low-grade metamorphism.
Mesozoic Period
During this period, the region’s geological structure underwent significant changes. Marine sedimentary rocks from the Triassic and Jurassic (252 – 145 million years ago) periods are especially widespread in Bartın and its surroundings. Limestone, sandstone, and shale formations cover most of the area through which the river flows. Black Sea Limestones from the Cretaceous (145 – 66 million years ago) period are commonly found on the valley slopes of the Bartın River.
Cenozoic Period
Cenozoic-aged units are quite common in the Bartın River basin. During the Paleogene (66 – 23 million years ago), the region was shaped by tectonic movements and marine transgressions. Eocene-aged volcanic rocks and flysch formations are found in the lower sections of the river basin. In the Miocene (23 – 5 million years ago) and Pliocene (5 – 2.5 million years ago) periods, terrestrial sediments accumulated, particularly in alluvial plains. Today, the youngest rocks forming the bed of the Bartın River belong to the Quaternary (2.5 million years ago – present) period. These units generally consist of alluvium, clay, sand, and gravel. These alluvial plains form the river’s floodplains and provide suitable areas for agricultural activities.
Geomorphological Characteristics of the Bartın River
Bartın River, one of the major rivers in the Western Black Sea Region, has a geomorphological structure shaped by climate, tectonic movements, and fluvial dynamics. From its source to the point where it discharges into the sea, the river exhibits different geomorphological features, boasting a rich structure in terms of valleys, floodplains, alluvial areas, and coastal morphology. The river regime and the geological history of the region have directly influenced the riverbed characteristics and led to the formation of various geomorphological forms.
The source of the Bartın River is located on the northern slopes of the Ilgaz Mountains. This upper basin region is characterized by narrow and deep valleys. Especially near the source, the river flows through steeply sloped and narrow incision-type valleys. Because the water velocity is high in this area, erosional processes are predominant, and the river transports and erodes stone and rock fragments. Geologically, Paleozoic-aged metamorphic rocks and Mesozoic-aged limestone formations are common in the upper basin. These rocks limit the lateral erosion of the river, contributing to the formation of steep valleys.
In the lower basin, before reaching the sea, the Bartın River forms wide delta-like alluvial plains. At the Boğaz location, where the river empties into the Black Sea, the sediments it carries have accumulated to form lagoons, coastal barriers, and deltaic structures. This area is shaped by both the sediments brought by the river and the wave actions of the Black Sea. In particular, changes in sea level and coastal currents can cause channel shifts where the river meets the sea.
Geomorphologically, the lower basin of the Bartın River is quite prone to flooding. This is because the wide alluvial plains in the region provide a favorable environment for water levels to rise rapidly during sudden rainfall events, leading to floods. During flood periods, the flow velocity of the river increases, resulting in erosion and channel changes along the shores and valley floors.
Tectonic Characteristics of the Bartın River
The Bartın River and its basin hold an important position within the tectonic structure of the Western Black Sea Region. The area has been influenced by the North Anatolian Fault (NAF) and the Western Black Sea Geological Zones, shaped as a result of ongoing tectonic processes from the past to the present. Particularly during the Neotectonic Period (Pliocene–Present), active tectonic movements have significantly affected the river’s channel morphology and drainage system.
Because the region where the Bartın River is located is close to the northern branch of the NAF, it has been influenced by secondary fault zones. Although the main fault line does not lie directly along the river’s route, subsidiary faults and fracture lines have markedly affected the geomorphological structure in the area. These tectonic movements have caused the formation of valleys that determine the river’s flow direction, as well as local uplifts and depressions regulating water flow. Through such tectonic movements, the Bartın Plain has expanded by filling with alluvium, becoming one of the region’s most fertile agricultural lands.
The Bartın River displays a fluvial system oriented along fault zones and folded structures formed by tectonic movements. While narrow and deep valleys dominate in the upper sections of the basin, wider and less steep valleys become prominent toward the middle and lower basin. These differences indicate the active role of fault lines and fracture systems in the region. Additionally, at the Boğaz location, where it drains into the Black Sea, coastal plains formed by the alluvium carried by the river can be observed.
Bartın River (Photo: Anadolu Agency)
Flow Regime of the Bartın River
The flow regime is determined by the region’s climatic characteristics, geomorphological structure, and seasonal precipitation variations. Originating from the Ilgaz Mountains, the river flows northward, passing through Bartın city center and emptying into the Black Sea at the Boğaz location. The flow regime is directly related to the seasonal distribution of precipitation and the hydrological processes in the drainage basin.
The flow regime of the Bartın River increases in the spring and autumn months, while it tends to decrease in the summer. During winter and spring, particularly between October and April, the river discharge rises due to increased precipitation and snowmelt. In this period, the discharge of the river reaches its maximum level, and the risk of flooding increases. Especially during intense downpours, floods are observed in Bartın city center and the surrounding plains.
In the summer months (June–August), the water level in the Bartın River shows a significant decrease. Reduced precipitation during the summer season and increased evaporation rates cause the flow regime to trend downward. This process is especially important for agricultural irrigation needs and water resource usage. However, in extremely dry years, more pronounced reductions in water volume can be observed in some sections of the river.
The river’s flow regime is also shaped by the geological structure in the basin and the valley floors covered with alluvium. Particularly in the Bartın Plain, the river’s flow over alluvial deposits can lead to ponding or channel shifts in certain areas. Moreover, the feeding influence of its tributaries, such as the Kocaçay and the Kocanaz River, is among the important factors determining the total discharge of the Bartın River.
In general, the Bartın River has a semi-irregular flow regime, dependent on climatic and geomorphological factors. The river’s discharge is sensitive to seasonal variations, rising in spring and autumn while decreasing in summer. Considering climate change scenarios for the region, it is predicted that the flow regime may change further in the future, with increased severity of summer droughts and a rise in the frequency of floods.
Bartın River (Photo: Batı Karadeniz)
