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Japan, located just north-east of Kyoto and Osaka in Shiga Prefecture. Because of its proximity to the ancient capital Biwako is often referenced in literature, poetry, and historical accounts of battles.
The area of this lake is about 670 km², the same size as Awaji Island. Rivers from various other prefectures drain into Lake Biwa, which in turn provides drinking water for about 15 million people in the region.
Lake Biwa is the world's third oldest lake (after Lake Baikal and Lake Tanganyika), dating to almost 4 million years ago. This long uninterrupted age has allowed for a notably diverse ecosystem to evolve in the lake. Naturalists have documented about 1100 kinds of living things in the lake, including 58 species found nowhere else on earth. Lake Biwa is important place for water birds. About 5 thousand water birds visit Lake Biwa every year. Recently the biodiversity of the lake has suffered greatly due to the invasion of a foreign fish, the black bass.
Various environmental laws cover Lake Biwa:
This was enacted in 1981 and first enforced on July 1, 1982; therefore, this day is called “the day of Lake Biwa”. The characteristic of the treaty is that local government established standards for the nitrogen and phosphorus levels for agricultural, industrial, and household water sources emptying into the lake. They also banned from people using and selling synthetic detergents that included phosphorus.
The lake was designated as a Unesco Ramsar Wetland and World Heritage site at the Ramsar Convention held in Ramsar, Iran in 1971. The object of this treaty is to plan the protection and sensible use of internationally precious marsh. The Kushiro marsh in Japan is under this treaty now.
The reed colony on shore forms the scenery in Lake Biwa and has been used as bamboo blind. It is said that the reeds play an important role in purifying water as well as providing habitat for birds and fish. At one time there was a large reed colony along the shores of Lake Biwa, which local government surveys found were recently decreased by half due to encroaching development. This ordinance was established to protect, grow, and utilize the reed colony. It has been in force since 1992.