The Tersakan Stream, which brings life to the broad plains west of Amasya, is one of the left-bank tributaries of the Yeşilırmak. It leaves Lake Ladik in the Ladik district of Samsun, passes through Havza, cuts across the middle of the Suluova plain, bends eastward and joins the Yeşilırmak just as the river leaves the city of Amasya. Its length is given as 91.4 kilometres in some sources and 100 kilometres in others; its catchment covers 2,684 square kilometres. Compared with the other large tributaries of the Yeşilırmak its discharge is modest, yet the burden it carries in irrigating the Suluova and Merzifon plains far exceeds these small figures. Though its water no longer runs clear, it remains, through the abundance it brings, the main artery feeding one of Amasya's largest agricultural basins. The villages strung along its bed, the fields opened where marshes once lay, a town that grew up around a sugar factory and the dams built over the last forty years make the Tersakan basin one of the most transformed corners in the agricultural history of Amasya.

The Name and the Direction of Flow

The stream takes its name from the unusual course it follows. Leaving Lake Ladik, the water heads first west, then south, and after tracing a wide arc across the Suluova plain turns east and reaches the Yeşilırmak. To an observer who expects it to flow north toward the Black Sea, the water seems to be running the wrong way, and that is why the people of the region called it Tersakan, the "backward-flowing" stream. Residents of Havza, explaining that the water leaving Ladik passes through Havza, goes on to Amasya and joins the Yeşilırmak there, always trace the name to this winding course. Although the local press sometimes presents it as "Turkey's only river that flows backward", the description should be read as a popular epithet: the waters of the Tersakan do eventually reach the Black Sea at Çarşamba together with the Yeşilırmak, only they first make a great detour inland to get there.

Behind this arc-shaped course lies the geological past of the region. The present arrangement of the Tersakan is the result of a long process in which the Suluova plain was once an inland lake and north-flowing rivers gradually captured and drained it; this process is discussed in detail in the article İris'in Nabzı, which describes the hydrology of the Yeşilırmak. The source section of the stream lies within the zone of influence of the North Anatolian Fault Zone. A study by Serkan Gürgöze and Ali Uzun published in 2025 examined the section of the fault zone between the Kızılırmak and the Tersakan Stream, showing that tectonic activity in the drainage basins of this section is high and diminishes with distance from the fault zone. Both the source of the Tersakan and the shape of its valley bear the marks of this restless crust.

The Source Area: Lake Ladik and Akdağ

Sources place different emphases on where the Tersakan begins. Most encyclopaedic sources start the stream directly at Lake Ladik. Amasya's official geographical description and the Yeşilırmak Basin Flood Management Plan, however, state that the stream rises on the slopes of Akdağ at an elevation of 1,925 metres and passes through the Havza district after taking in the surplus water of Lake Ladik. A local description of Suluova, for its part, gives the Derinöz Stream as the source of the Tersakan. The difference depends on which of the several branches feeding the stream is counted as its main source: the lake provides a regular starting point, while the brooks descending from the slopes of Akdağ form the highest catchment area of the basin.

Lake Ladik is a lake of tectonic origin lying east of the town of Ladik at an elevation of about 950 metres; its surface area is given as about 8.7 square kilometres, or 870 hectares. It is known for its floating islets, and much of its shore is reed bed. The southern shore of the lake is identified as the epicentral area of the great earthquake of 1668 that shook northern Anatolia and is counted among the strongest earthquakes recorded in Turkey. Pike, roach, carp and rudd live in the lake; a bird survey carried out in 1997 found that species such as the black-crowned night heron, squacco heron, black stork and crane breed here.

Various works have been carried out since the 1930s to release the lake's water into the Tersakan in a regular way. The first surveys for the improvement of the lake bed were made in 1933, and as a result a regulator was built in 1951 between the villages of Mazlumoğlu and Kıranboğaz, at the starting point of the Tersakan. The Lake Ladik Improvement Plan prepared by the State Hydraulic Works (DSİ) was completed in 1973, the regulator was renewed in 1986, and the lake was turned into a reservoir for irrigation. The rise in water level caused by the embankment built on the north side of the lake also flooded some farmland along the shore and led to a decline in the lake's aquatic plants.

From Havza to Suluova: The Course of the Stream and Its Tributaries

Leaving the lake, the Tersakan descends westward to the Havza district. In this section the water is said to run clean, and its banks are used as a picnic spot in summer; older generations remember carpets and dishes being washed in the stream and children swimming in it. After Havza the stream turns south and enters the territory of Suluova district at Eski Çeltek. Known for its lignite pits, Çeltek is the point where the stream reaches the Amasya provincial boundary. The stretch of the Tersakan within the province of Amasya is about 41 kilometres long.

On the Suluova plain the stream curves to the right and here joins Gümüşsuyu, one of its most important tributaries. The main tributaries of the Tersakan are the Şeyhsuyu, Gümüşsuyu, Derinöz and Salhan streams; the Gümüşhacıköy, Merzifon and Suluova plains are the lowlands watered by these branches. The Derinöz brook is fed by the western slopes of Akdağ, which rise to 1,900–2,000 metres; at the gauging point in the village of Çatak its catchment reaches 120 square kilometres, and it joins the Tersakan downstream of Çatak. The Şeyhsuyu and Değirmendere are counted among the important sources of irrigation for the Suluova plain. Passing through the villages of the plain, the stream flows below the village of Saygılı, past the tomb (türbe) of Sheikh Abdülgani el-Halvetî, known as Gani Baba; according to local tradition Gani Baba was a ghazi dervish who came to Anatolia from Khorasan, and the surroundings of his tomb have today been laid out as a picnic area.

After Suluova the stream heads east and approaches the city of Amasya. On the western side of the city it passes near the Göllü Bağları, Bahçeleriçi and 55 Evler neighbourhoods, and at the exit from the provincial centre, around Kunç Köprü, it flows into the Yeşilırmak. This confluence is also a boundary separating two sections of the Yeşilırmak valley: the 8.5-kilometre stretch between Boğazköy and the mouth of the Tersakan is called the Beşgöz Valley, while the 20-kilometre stretch that begins at the mouth of the Tersakan and runs through Ziyaret and Yenice to the village of Kuzgeçe bears the name Onlukköprü Valley, where the Amasya apple is grown.

The Tersakan valley has also served as a passage throughout history. The chain of natural passes running from Samsun through Havza and Suluova into the Anatolian interior is one of the easiest routes linking the Black Sea coast to the inland regions. Suluova also lies on the old caravan route that ran through Taşova, Erbaa, Niksar, Reşadiye and the Kelkit valley all the way to Iran, and today on the E-80 international highway. The Samsun–Sivas railway also crosses the district. Mustafa Kemal Pasha used this road on 12 June 1919 on his way from Havza to Amasya; according to local records, when his car boiled over near the inns of Suluova he walked for a while with his companions, and the march "Dağ Başını Duman Almış" was sung here for the first time.

Flow Regime and Floods

The Tersakan carries the least water of the large tributaries of the Yeşilırmak. Its mean discharge has been measured at 3.96 cubic metres per second and its total annual flow at 125 million cubic metres. Behind this average lies an extremely irregular regime: the lowest recorded discharge fell to 0.021 cubic metres per second, while the highest rose to 317 cubic metres per second. In the dry late summer the stream shrinks almost to a brook, leaving stagnant pools here and there in its bed. Floods usually occur in March, April and May with snowmelt and spring rains, but also in summer with sudden downpours.

Because these floods threaten the farmland of the plain, they have long been a subject of research. In a study published in 2001 in the Journal of the Faculty of Agriculture of Gaziosmanpaşa University, Kadri Yürekli and Ahmet Kurunç calculated the return periods of the maximum daily flows causing floods in the Tersakan basin; the most frequently cited figures for the stream's length and catchment, 91.4 kilometres and 2,684 square kilometres, also derive from this study. The flood management plan prepared for the Yeşilırmak basin, on the other hand, classifies the Havza–Tersakan section among areas of very low flood risk. It is known that in the great floods that struck the Amasya area in the first decades of the Republic the Tersakan also overflowed its bed from time to time; today, however, the stream's real problem is less flooding than the shortage of water in summer and the pollution that this shortage aggravates.

The Geography of the Suluova Plain

The Suluova plain is a broad lowland covering the south and southeast of the district centre, with the Tersakan running right through its middle. With an area of about 40,000 hectares it makes up 7.3 per cent of the territory of Amasya province and lies at an average elevation of 550 metres. The plain stretches about 25 kilometres west of the provincial centre of Amasya, in the interior of the Central Black Sea Region. To the west it merges seamlessly with the Merzifon plain; the Merzifon plain, at an average elevation of 700 metres and with an area of 31,100 hectares the third largest plain in the province, also belongs to the Tersakan system through the Gümüşsuyu and Salhan streams. Together the Geldingen, Suluova, Merzifon and Gümüş plains cover nearly a quarter of the province's area and form the backbone of agriculture in Amasya.

The area of the district is given in sources as between 456 and 516 square kilometres, and the elevation of the town between 510 and 551 metres. Suluova is surrounded on three sides by mountains of no great height. The highest point is Akdağ to the southeast, whose height is given as 2,044 metres in some sources and 2,064 in others. The slopes of Akdağ are covered with forests of black pine, Scots pine, beech and oak, and the Kapaklı Forest Nursery, at 1,000 metres, lies on these slopes. In the mountains stretching to the northwest the forest grows steadily thinner, and on the mountains to the south there is almost no forest at all. The plain's own vegetation consists of orchards and rows of poplar and willow, most of them the product of the last seventy years.

The climate of the plain is transitional between the continental climate of Central Anatolia and the Black Sea climate. The mean annual temperature is about 12 degrees; the warmest month is July with an average of 21.5 degrees and the coldest January with 2.2 degrees. The first frosts come in November and the last in April. Precipitation falls mostly in spring and winter, while snow is rare on the plain and falls mostly on Akdağ. Annual precipitation totals around 430 millimetres, and July and August pass almost without rain. These dry summers explain why farming on the plain depends so heavily on irrigation.

The Name of the Plain and Early Settlements

The name Suluova comes from the abundance of its waters, and this abundance shows itself in every historical form of the name. According to local sources the area was known in the first centuries AD as Arguma, a name explained as "well-watered land"; Özhan Öztürk, however, proposes a different interpretation linking the name to the Hittite for "border settlement". In the late thirteenth century the name Alaflı appears. A small village where only a few families lived at the beginning of the twentieth century, the settlement became the seat of a subdistrict (nahiye) under the name Suluca in 1902. In 1946 it took the name Suluova and a municipality was established, and in 1957 it became a district. The Turkish name, meaning "watered plain", carries on the sense of the old Arguma.

Settlement on the plain is much older. Fragments of brick and stone found in excavations at the Kümbettepe mound in the Doğukent neighbourhood, today within the town centre, show that occupation goes back to the Chalcolithic Age and the Hittite period. The Devret Höyük mound in the village of Kanatpınar and the Yoğurtçu Baba Höyük in the village of Deveci are also counted among Amasya's Chalcolithic settlements. This open lowland between Merzifon and Amasya was also the scene of important events in the Middle Ages. In 1101 the crusader army that had entered Anatolia suffered a heavy defeat between Merzifon and Amasya at the hands of the forces of the Seljuk Sultan Kılıç Arslan I and Danishmend Gazi; local historiography places this battle at Arguma, that is, on today's Suluova plain. The region passed under Ottoman rule in 1386. In the Ottoman period one of Amasya's four subdistricts was the present-day village of Yolpınar, formerly called Hakala; to the east of the village stood the Kasım Bey Madrasa, whose remains survive today, and to its southwest the zaviye (dervish hospice) built in 1348 by Seyyid Necmeddin Yahya Rifaî.

The place of water in the life of the plain has also left its mark on local religious tradition. The person buried in the Erenler Türbesi, in the Erenler locality of the Hacı Hayta neighbourhood, is said to have built the irrigation channel known as the Alevi arkı, and water is still made to run through this channel in accordance with his will. Local sources link the tombs and shrines scattered across the plain to the people who first settled Suluova.

From Marsh to Field: The Transformation of the Plain

The Suluova plain, today one of the most fertile farming areas in Amasya, looked entirely different until the middle of the twentieth century. Before 1950 a large part of the plain was covered with marshes and standing water. Because drainage was poor, the water table in the fields was high and soil salinity was a widespread problem. These conditions spread malaria, and the plain became almost uninhabitable, especially in summer. Some families withdrew in summer to the upland pastures (yayla) on the slopes of Akdağ. Owing to the scarcity of fertile land and low yields, famine sometimes struck in dry years. The abundant water that gave the plain its name was, as long as it remained unregulated, its greatest problem.

The transformation began in the 1950s. In 1950 tractors and farm implements were distributed to farmers with Marshall aid, and in the same years the marshes were drained and poorly drained land was reclaimed, bringing new farmland into production. As the number of tractors grew, the unproductive meadows and pastures that had occupied much of the plain were also ploughed up and turned into fields. Even places known as marshland gradually became important farming and residential areas. This change combined with an industrial investment that would reshape the population and economy of the plain from the ground up.

The Sugar Factory and the Growth of the Town

The foundation stone of the Amasya Sugar Factory was laid on 13 September 1953, and the factory went into operation on 11 September 1954. Built under the Democrat Party government's programme to expand the sugar industry, it was Turkey's eighth sugar factory. At its foundation it could process 1,890 tons of beet a day; this capacity was raised to 2,400 tons a day in 1965 and to 4,800 tons in 1968. The Beet Growers' Cooperative, which held a 23 per cent share on behalf of the farmers in the founding years, gradually raised its stake to 71.5 per cent. Managed until 1991 by Türkiye Şeker Fabrikaları A.Ş., the factory became in that year the first sugar factory whose management was also fully privatised. Later modernisation brought its capacity to 5,500 tons a day, and some 30,000 farmers in about 400 villages came to grow beet for the factory on 200,000 decares. An alcohol plant to process the factory's molasses also went into production in 1996.

The factory's effect on the plain was not limited to beet. The company's agricultural engineers taught modern farming techniques to the farmers through intensive work, and with credits in kind added, agriculture on the plain developed rapidly. Wheat yields rose, fruit and vegetable growing spread, and orchards and poplar groves, previously almost non-existent, reached their present extent. The factory's by-products, beet pulp and molasses, together with beet leaves and tails, provided a strong source of fodder for animal husbandry, and above all for cattle fattening. Rapid urbanisation took place around the factory, and the centre of the town moved to its surroundings. Growing through migration from Taşova, Ladik, Gümüşhacıköy, Kavak, Zile and Vezirköprü, as well as from Kars, Erzurum, Gümüşhane and Sivas, Suluova's population rose from 19,538 in 1960 to 54,123 in 2000. The economic crisis after 1975, the privatisation of the Meat and Fish Corporation plant and of the sugar factory, and the inability of the coal pits to withstand foreign competition slowed this growth; the district's population today is around 47,000.

The Irrigation System: Yedikır, Derinöz and the Ponds

Farming on the plain today depends largely on water distributed from dams and ponds. The largest of these is the Yedikır Dam, fed by the water of the Tersakan. The construction dates of the dam, built by the State Hydraulic Works, are given differently in the sources as 1982–1985 or 1979–1986. The dam was formed by earth excavation at the Yedikır (Acıkır) locality from which it takes its name; it lies about 7.5 kilometres from the bed of the Tersakan, and the water it draws from the stream is carried to the reservoir by canals. According to the figures in the flood management plan, the reservoir covers 5.93 square kilometres and holds about 60 million cubic metres; with this volume it is regarded as the largest irrigation dam in the area and supplies water to about 7,400 hectares. In 1989 the reservoir was declared a first-degree natural protected site and a wildlife protection area and received the name Yedikuğular Bird Paradise. The lake's birds and the history of its protection are described separately in the article Yedikuğular Kuş Cenneti.

The water distributed from the dam to the plain is today managed by the Suluova Yedikır Irrigation Association, attached to the State Hydraulic Works. The association supplies water to about 154,000 decares of farmland, and the Eraslan and Saluca pumping stations supplement the dam's water. The irrigation season begins in June and lasts through the summer, together with the maintenance of the canals, hydraulic structures and pumping stations. In wet years the dam and ponds fill to the top, while in dry years the call to use water sparingly is the association's most frequently repeated warning.

The second large water structure of the Tersakan system is the Derinöz Dam, built on the Derinöz brook in the east of the district. The rockfill dam rises 74 metres above the stream bed, holds 18.9 million cubic metres at normal water level and forms a lake of 0.88 square kilometres. Its construction years are given in some sources as 1991–2000, while others give 2003 as its completion date; its irrigated area is likewise cited with different figures, between 4,490 and 6,500 hectares. The dam is used to irrigate the Ladik plain and part of the Suluova plain. In addition, there are irrigation ponds in the villages of Oğulbağı, Akören, Derebaşalan and Bayırlı; the Bayırlı Pond went into operation in 1994 and irrigates an area of 85 hectares. On the Merzifon plain the Yüzüncüyıl and Alala ponds supplement the water of Yedikır.

When classified as irrigation water, the water of the Tersakan is first class in terms of alkalinity and second class in terms of salinity; its average pH is around 8.5. With these properties the stream's water was used safely for many years to irrigate tens of thousands of decares on the plain, and most of the irrigated land in the basin still depends on it. As described below, however, pollution in the stretch below Suluova has changed this picture in recent years.

The Plain's Crops and Cattle Fattening

With its fertile alluvial soils and regular irrigation, the Suluova plain is one of the lowlands of Amasya with the widest range of crops. Cereals, sugar beet, onions, potatoes, sunflowers, silage maize, chickpeas, fodder crops, fruit and vegetables are grown on the plain. Among these, onions hold a special place: Suluova is counted among Turkey's largest producers of dry onions, and an onion growers' association has been founded in the district. Around 89,000 tons of wheat are reported to be produced on the plain each year and processed in the district's three flour mills; two feed mills also channel grain into animal husbandry. In local descriptions the district's livelihoods are listed simply as livestock, onions, sugar beet and coal mining.

What really sets Suluova apart from Amasya's other plains, however, is cattle fattening. The sugar factory's pulp and molasses, the fodder fields watered by the Tersakan and the grain of the plain laid a solid foundation for the growth of beef cattle fattening in the district. The district is reported to have some 51,000 cattle, 9,500 sheep and goats and about 925,000 poultry. The Suluova Specialised Agriculture-Based Fattening Organised Industrial Zone, founded in 2004, initially consisted of 32 fattening plots and 3 industrial plots on 90 hectares, with a capacity of about 10,000 cattle. Transferred to the Ministry of Agriculture and Forestry in 2012, the zone gained a 62.5-hectare expansion area within the boundaries of the village of Salucu in 2021, becoming, with a total of 152.5 hectares and a capacity of 17,850 cattle, the largest fattening organised industrial zone in Turkey. Two biogas plants in the zone generate a total of 7 megawatts of electricity from animal waste, and an integrated meat plant processes 200 tons of meat a day.

One of the reasons for concentrating cattle fattening in an organised zone is the Tersakan itself. Moving some of the stables in the town centre into the organised zone is regarded as a step taken to reduce the amount of animal waste reaching the stream directly. The same stream that carries the plain's abundance has also had to carry the residues of that abundance.

Water Quality and Pollution

One of the first studies to examine the water quality of the Tersakan scientifically is the master's thesis prepared by S. Tekin at Ondokuz Mayıs University in 1997, which dealt with pollution in the Amasya city section of the Yeşilırmak and in the Tersakan. A more detailed picture emerges from the monthly measurements made by Faruk Maraşlıoğlu, Arif Gönülol and Gonca Baş Pelit between June 2007 and May 2008 at four points from the stream's source to the Yeşilırmak. The first station was about 300 metres beyond the sluice gates at the outlet of Lake Ladik, the second at the sixth kilometre of the Havza–Merzifon road, the third under the bridge opposite a slaughterhouse five kilometres west of the Yedikır turn-off in Suluova, and the fourth at the confluence with the Yeşilırmak. Water temperature ranged between 2 and 24 degrees and pH between 7.8 and 9.8; dissolved oxygen averaged 9.9 milligrams per litre, with the lowest value measured in August at the third station.

The researchers identified 72 algal taxa in the stream and stated that both the physicochemical properties and the phytoplankton species showed the river to be mesotrophic, that is, moderately loaded with nutrients. At the third station, however, it emerged that the stream water was under threat of organic pollution because of slaughterhouse waste being discharged into it; the highest nitrite and phosphate readings were also recorded at this point. The fact that the first two stations below Lake Ladik showed similar seasonal patterns, while the two stations below Suluova followed a different course, clearly indicated that the source of the pollution was the plain section.

In the years that followed the problem grew worse. A study by Ayşe Yeşilyurt Alkan and Demet Erol published in 2023 lists climate change, agriculture, animal husbandry, urbanisation and industrialisation among the driving forces of environmental problems in the Tersakan sub-basin. According to the study, stables close to water sources, poultry farming, slaughterhouse waste and excess animal manure mix into the stream and pollute the Yeşilırmak as well; water pollution is concentrated particularly between the villages of Ayrancı, Kurnaz and Aşağıkarasu. The authors note that despite various improvement works the water and odour pollution in the basin has not been prevented, and that efforts are being made to improve the situation through increased inspections and new treatment plants. Biological treatment plants are located in Merzifon and Suluova.

The 2023 measurements cited by Prof. Dr. Cengiz Yıldırım, an ecologist at Amasya University, reveal the scale of the problem strikingly. According to these figures, the Tersakan enters Amasya at Çeltek as second-class water, usable for irrigation; at the point where it flows into the Yeşilırmak, however, pollution has increased seven- or eightfold and the water has fallen to the fourth class, the heaviest level in the surface-water classification, the category of water unusable for any purpose. Yıldırım stresses that it would be wrong to attribute the pollution to a single source, and that agricultural waste, industry, lignite extraction and domestic waste act together. People living along the stretch of the stream near the city of Amasya recall that twenty or thirty years ago its water could be drunk, fish lived in it and carpets were washed on its banks; they complain that as the water level drops in the dry summer months the stream runs black one day and grey the next, and that the smell reaches into their homes. The headman (muhtar) of the Göllü Bağları neighbourhood has proposed building a treatment plant at Boğazköy as a solution. The fact that the stream runs clean in its Havza section and deteriorates after Suluova shows that the present state of the Tersakan is a direct consequence of the production concentrated on the plain.

Chronology

1101: The crusader army that had entered Anatolia is defeated between Merzifon and Amasya by Seljuk and Danishmendid forces; local historiography places the battle on the Suluova plain.

1348: Seyyid Necmeddin Yahya Rifaî builds his zaviye in present-day Yolpınar (Hakala).

1386: Amasya and the Suluova area pass under Ottoman rule.

1668: The great North Anatolian earthquake, whose epicentral area is identified as the southern shore of Lake Ladik.

1902: Suluova becomes the seat of a subdistrict under the name Suluca.

1919: On 12 June Mustafa Kemal Pasha passes through Suluova on his way from Havza to Amasya.

1933: The first surveys for the improvement of the Lake Ladik bed are carried out.

1946: The settlement takes the name Suluova and a municipality is established.

1950: Tractor distribution with Marshall aid, the draining of the marshes and drainage improvement begin.

1951: A regulator is built at the outlet of Lake Ladik, at the starting point of the Tersakan.

1953–1954: The foundation stone of the Amasya Sugar Factory is laid on 13 September 1953; the factory goes into operation on 11 September 1954.

1957: Suluova becomes a district.

1965, 1968: The sugar factory's daily capacity is raised to 2,400 and 4,800 tons of beet respectively.

1973: The Lake Ladik Improvement Plan is completed.

1982–1985: The Yedikır Dam is built (1979–1986 in some sources).

1986: The Lake Ladik regulator is renewed and the lake is turned into an irrigation reservoir.

1989: The Yedikır reservoir is declared a first-degree natural protected site and a wildlife protection area.

1991: The management of the Amasya Sugar Factory is fully privatised.

1991–2000: The Derinöz Dam is built (completion given as 2003 in some sources).

1994: The Bayırlı Pond goes into operation.

2001: Yürekli and Kurunç publish the return periods of flood flows in the Tersakan basin.

2004: The Suluova Specialised Agriculture-Based Fattening Organised Industrial Zone is founded.

2007–2008: Monthly phytoplankton and water-quality measurements are made at four stations on the Tersakan.

2021: A 62.5-hectare expansion area for the fattening zone is confirmed in the village of Salucu.

2023: Measurements show that the Tersakan has fallen to fourth-class water quality where it flows into the Yeşilırmak.

Bibliography

Academic studies

  • Faruk Maraşlıoğlu, Arif Gönülol, Gonca Baş Pelit, "Tersakan Çayı (Samsun-Amasya, Türkiye) Fitoplanktonunun Mevsimsel Değişimi ve Kirlilik Düzeyinin Belirlenmesi", Sinop Üniversitesi Fen Bilimleri Dergisi 1(2), 2016, pp. 46-58: https://dergipark.org.tr/tr/download/article-file/269543
  • Ayşe Yeşilyurt Alkan, Demet Erol, "DPSIR Çerçevesi ile Ekosistem Hizmetlerinin Değerlendirilmesi", Kent Akademisi 16(1), 2023, pp. 260-275: https://dergipark.org.tr/tr/pub/kent/article/1086121
  • Serkan Gürgöze, Ali Uzun, "Tektoniğin Drenaj Havzalarına Etkisinin Morfometrik İndislerle İncelenmesi, Kuzey Anadolu Fay Zonu'nun Kızılırmak ile Tersakan Çayı Arası, Samsun", Coğrafi Bilimler Dergisi 23(1), 2025, pp. 151-178: https://dergipark.org.tr/tr/pub/aucbd/issue/88528/1613195
  • Kadri Yürekli, Ahmet Kurunç, "Tersakan Çayı Havzasında Taşkına Neden Olan Günlük En Büyük Akımların Tekrarlanma Sürelerinin Saptanması", GOÜ Ziraat Fakültesi Dergisi 18(1), 2001, pp. 119-123 (cited in Yeşilyurt Alkan and Erol 2023).

Official sources

  • Suluova District Governorate, "İlçemiz ve Tarihi" (name, history, geography, marshes, sugar factory, ponds, tombs): https://www.suluova.gov.tr/ilcemizin-tarihi
  • Amasya Governorate, "Yeryüzü Şekilleri" (plains, discharge figures of the Tersakan Stream, dams and ponds): https://amasya.gov.tr/yeryuzu-sekilleri
  • Ministry of Agriculture and Forestry, General Directorate of Water Management, Yeşilırmak Havzası Taşkın Yönetim Planı Yönetici Özeti (improvement of Lake Ladik, the Tersakan and the Derinöz brook, table of dams).

Other sources

Online sources