It is a freshwater lake located in the eastern half of a long trench connecting the Adapazarı Plain to the Izmit Bay trench in the east of the Marmara Region. Sapanca shores are Sakarya in the east and Kocaeli in the west. Its basin is 252 km2. Its area is 47 km2. Its east-west length is 17 km. The north-south width is 5 km, the height of the surface from the sea is 31 m. Its deepest point is 61 m. The lake takes its name from the town located on the south coast. It is mentioned as Lake Ayan in old Turkish sources. The lake, fed by the floods descending from the mountains in the south, empties its excess water into the Sakarya river with the Cark water from its eastern end. The streams feeding the lake are Karacay, Kurucay, Kurtköy, Mahmudiye, İstanbul, Karadere and Kaymakcı Streams. Partridge, snipe and rabbit hunting are practiced on the mountain foothills extending to the north and south. All kinds of freshwater fish are caught in the lake.
Evliya Celebi describes Sapanca as follows: “The circumference of Sapanca Lake is 24 miles. There are seventy-six villages around it, four of which are like towns. People in the sentence get angry because they drink the water of this Golden Horn. Although their products are many, they have no ties. The gardens are very crowded. Next to this lake will be some kind of melon and watermelon, but a donkey can pull both. There are eighty (piece) boats and gulets (grain boats) on this lake that buy men, timber and goods from the village. They make a profit by catching seventy or eighty kinds of fish in this lake. Freshwater fish such as trout, carp and pike are delicious. The depth of the lake is twenty fathoms in most places. The water is very pure and clear. The women of the coastal villages never use soap when washing clothes. Two hours east of this lake, Sakarya River passes. It pours into the Black Sea on the edge of Kocaeli Province Irva Town. With a little help, Sakarya can be poured into this lake.
History of Sapanca Lake
Since this lake is close to the Gulf of Izmit for three hours, its feet mingle with the sea in front of the Izmit Saltpan. Although hundreds of thousands of pickaxes and anchor capstans were gathered in a century to add this lake to the Gulf of Izmit, the people of Izmit needed many treasures and their slackness due to Noah’s life prevented the completion of the work. But if the Sakarya River had mixed with this lake and the Gulf of Izmit in this lake, five mansions would have been built up to Bolu. Istanbul Ships come to Bolu, a piece of wood costs three akces, a box of wood costs five akces and becomes a great charity.” According to the measurements made by the Electrical Works Survey Department, the water of the lake rises in winter and early spring and decreases towards autumn. There is a difference of 70-90 cm, sometimes 120-130 cm between two layers.
The E-5 Highway crosses the northern shore of the lake, while the TEM Highway and the railway pass through the southern part. Sapanca Lake and its surroundings, which were formed as a result of tectonic formations in Sakarya, are a center open to weekend rest and accommodation demands of the city center as well as the surrounding big cities, especially Istanbul, due to their characteristics. extremely striking natural beauty and location close to dense residential areas. . There are beautiful camping and picnic areas in the Arifiye Forest, at the height of Sapanca Lake. Sapanca Lake, where national and international surfing, sailing and rowing competitions are held, attracts many visitors for sportive purposes with these organizations.