Where Is Uluabat Lake Connected? How did Uluabat Lake come about? How Much Depth?

how much is the depth of how it is formed
Photo: wikipedia

Uluabat Lake, formerly known as Apolyont Lake, is a lake in Bursa province. Uluabat lake is located between 15 ° south of the Sea of ​​Marmara and 30 km west of the city of Bursa, east of Mustafakemalpaşa district and 40 ° 12 ′ north, 28 ° 40 ′ east coordinates to the south of Bursa Karacabey highway. Altitude is 7 meters. The lake was accepted as Ramsar Area by the Turkish Ministry of Environment in April 1998. Lake Uluabat should plankton and bottom organisms, both aquatic plants, fish and bird populations in terms is one of Turkey's richest lake. The lake was also included in the Living Lakes network, which was an international non-governmental partnership project in November 2000 and incorporated 2001 world-renowned lakes as of 19.

It is Eskikaraağaç, Gölyazı and Kirmik in the north, Mustafa Kemalpaşa in the west, Akçalar in the east, Akçapınar, Fadıllı and Furla in the south. The northern shores of the lake have a highly indented structure. Eskikaraağaç and Gölyazı (Apolyont) villages are located in both peninsulas in this section. Uluabat Lake is a very large and shallow fresh water lake. There are 0,25 islands within the lake, ranging in size from 190 ha (Heybeli Island) to 11 ha (Halilbey Island). These islands; Terzioğlu (Süleyman Efendi) Island, Monastery (Nail Bey Island, Happy Island) Island, Arif Molla (Molla Efendi Island), Devil Island, Big and Small Crayfish Islands, Cloud Island, Maiden's Island It is the Heybeli Islands. These islands consist of the Jura limestone. Especially in stormy weather, these islands act as a breakout.


It was developed as an alluvial embankment lake in a plain opened under the control of tectonism. Lake; It is bordered by low hills formed by Neogene period embankments in the north and the Jura period low mountains in the south. There are different interpretations about the geological evolution of Uluabat Lake. Based on geological and paleontological findings, Pfannestiel suggests that the Manyas, Apolyont (Uluabat) and Sapanca lakes, located on the south and southwest coast of the Marmara Sea, are the remnants of the ancient Sarmastic sea. In the works of Artüz and Korkmaz (1981), Sapanca, Iznik, Apolyont and Manyas depression pits were formed as a result of the strong collapse tectonics (Graben) events in the region stretching from the Uluabat lake to the present Saros Gulf, Central Marmara, Karacabey and Bursa plain. It is a period of sweet and slightly brackish water before Mindel and there is an old cox basin formation. In the pre-Riss period, Thrace rose. Pfannenstiel, Deveciyan and Kosswig state that during the transition period of the Marmara Sea from fresh water to salt water, many elements of the Sarmatik sea, which has fresh and slightly brackish waters and suitable fauna elements, migrated to the sheltered areas fed by the rivers, and that the fish species with Sarmatic relics of the lake are evidence of this situation. express. Dalkıran (2001) and Demirhindi (1972) also support the same formation and show that there are several sea fishes and brackish water forms adapted to the fauna of the Uluabat and Manyas lakes. the water lake is formed; He stated that as a result of the movements at the end of Neogene or Kuvarter, 4 small bathtubs were formed in this lake area, the other two bathtubs (Bursa and Gönen) were filled with alluviums and Uluabat and Kuş lakes remained. (Karacaoğlu 2001)

The oldest unit observed around Uluabat Lake is the Paleozoic metamorphic series.

The building, which started with gneiss at the base, then continues with the schists containing marble lenses.


The average depth of the lake is 2,5 meters. Most of them are quite shallow, and the depth in these sections varies between 1-2 meters. The deepest place is the pit up to 10 meters in Halil Bey Island.

Length and width

It is 23-24 km long and 12 km wide in the east-west direction.


Ulubat Lake is a lake with a surface area of ​​136 km². After the rains on the splayed lake, there will be floods and floods to the hollow places, during which the surface area of ​​the lake exceeds 160 km².

There are some islets and cliffs in the lake. The most important of these limestone islets are Halil Bey Island, Heybeli Island and Kız Island.

The lake, which gets shallow from day to day, has a dirty white color. It has a muddy structure at the bottom, it becomes cloudy in windy weather.

Climate features

The Marmara climate is dominant in and around Uluabat lake. Although generally there is precipitation in all seasons, summer months are hot and little rainy, winter months are cold and rainy, and spring months are warm and rainy. According to the data of Bursa Meteorology Station's average temperature of 1929 years between 1986-57, the average annual temperature of the lake and its surroundings is 14 ° C. According to the data of 1929 years between 1978-49, the highest temperature belongs to August with 42.6 ° C and the lowest temperature is February with 25.7 ° C. The average annual precipitation in the region is 650 mm, and as a result of the 33-year measurements, it was determined that the least precipitation occurred in August with 10,6 mm and the most precipitation in December with 104,9 mm. Although there is not a single dominant climate in the Uluabat lake basin, the fact that the precipitation hits the winter and spring months is the common character of the entire basin. While in the lower basin there is rain and dominant precipitation, in the upper parts precipitation returns in the cold seasons. Although it is not possible to talk about the effect of a wind active in the whole basin, the most effective wind of the lower basin is the lodos and the most continuous wind is the north wind.

Threats to the lake system

Despite its international importance, the lake ecosystem is under the threat of eutraphication caused by overfishing, land reclamation in coastal development and agricultural industrial and domestic waste discharges. Some of these threats:

  • Industrial and domestic waste discharges and chemicals from agriculture
  • Land reclamation up to 25 ha in the last 2000 years in coastal development
  • Heavy hunting pressure on fish and birds
  • Forest destruction in the basin
  • Wrong agricultural practices and wastes of mines and water shots for the irrigation of the lake.
  • Water level regulations with regulators
  • 4 hydroelectric energy projects planned in the basin
  • Generally interventions on lake hydrology
  • Narrowing the floodplain of the lake through the stretches drawn to the southwestern shores of the lake
  • Opening parts protected from flood to agriculture.

Biodiversity in Uluabat Lake

Uluabat Lake is one of our eutrophic (abundant food) lakes in terms of biological production. Being rich in plankton and bottom creatures, it has created an ideal environment for the breeding and feeding of many different species. Both plants need in terms of animal species is the most rich lake in Turkey. The ecological features of Uluabat lake and its surroundings cause the formation of plant species unique to this area. Uluabat Lake is a typical shallow lake. As a typical feature of shallow lakes, it is fully mixed with the effect of the wind, the littoral region where the light accessibility is determined is wide. Alternative steady-state theory explaining the state of shallow lakes seems to be valid in Uluabat Lake as well. According to this theory, shallow lakes can be in two stable states. The first is the clear water state in which the aquatic plants predominate over the algae, and the second is the turbid water state, where the algae are dominant over the aquatic plants. Lake Uluabat should live plankton and bottom, both in terms of both aquatic plants and fish and bird populations it is one of Turkey's richest lake.

Organizations that pollute Lake Uluabat and its surroundings

  • Bursa Organized Industrial Zone
  • Etibank Emet Boron Salt Deposits
  • Turkey Coal Enterprises (TKI) Tuncbilek of Western Lignite Corporation
  • Turkey Electricity Authority (TEK) Tunçbilek Thermal Power Plant
  • Etibank Kestelek Boron Salt Enterprises
  • Turkey Coal Enterprises (TKI) Keles Lignite Plant
  • Irrigation water
  • Food businesses

Efforts to protect Lake Uluabat

Uluabat Lake, is one of nine Ramsar Site in Turkey, despite its importance in the international level is significantly below the lake environmental threats. Its Ramsar status cannot provide legal protection to sustain biodiversity in the lake. Collective treatment facilities should be established for waste water of settlements such as Mustafa Kemalpaşa, Orhaneli, Harmancık and Akçalar in the Uluabat lake basin and discharging sewage to the lake, the islands in the lake and the lake environment should not be opened for construction, the facilities around the lake should not be allowed to be built, Purification facilities in the flow basin of Mustafa Kemalpaşa stream, which brings a large amount of water, should be established in industrial establishments, almost all of which are public, and technical measures to reduce eutrophication in the lake should be prevented, excessive hunting in the lake should be taken, technical measures should be taken to reduce eutrophication in the lake, accelerating erosion in the region and accelerating the filling of the lake by sedimentation, other agricultural lands Activities such as disposal for purposes should not be allowed, the use of chemical fertilizers in agricultural areas irrigated with lake water should be limited, the use of pesticides should be taken under control and irrigation water returned to the lake should be protected from harmful substances. technical infrastructure for breastfeeding should be provided.

Water entry into the lake and water loss of the lake 

While there are some small streams that feed into the lake from the sources that feed the lake, the most important foot that feeds the lake is Mustafakemalpaşa Creek.

Water inlet into the lake
Kaynak Minimum hm³ / year Maximum hm³ / year Average hm³ / year
Mustafakemalpaşa Tea 25,14 2413,45 1550,68
Rain falling on lake mirror 71,65 120,32 92,72
Coming from the lake foot 25,14 227,31 97,58
Waters from Lake Uluabat
Kaynak Minimum hm³ / year Maximum hm³ / year Average hm³ / year
Lake foot 392,37 2531,8 1553,2
Evaporation 162,56 195,48 176,2
Uluabat Irrigation 6,5 17,78 11,53

Bird species 

In the census conducted in January 1996, 429.423 water birds were counted. This is the highest number of waterfowl counted in a lake since 1970.

Some of the bird species observed according to the 1996 Census
Bird species Number of birds
Cormorant 300 pairs
Pied Heron 30 pairs
spoonbill 75 pairs
Little cormorant 1078
Crested pelican 136
Elmabaş path 42.500
Crested path 13.600
coot 321.550

The area around the lake is the home of small cormorant, crested pelican, mustache terns and pasbaş patka, which are in danger on a national and global scale. The lake, where the otter also lives, contains the endemic and globally threatened freshwater sardine (Clupeonella abrau muhlisi)..


Günceleme: 04/01/2023 09:13

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