Lake Kasumigaura is the second largest lake in Japan, bringing boundless benefit to people’s lived including fishing and agriculture since the ancient times. It is an important and indispensable water source for Ibaraki Pref. and Tokyo metropolitan area, providing water for everyday life, industry, and agriculture. However, the bountiful nature around the lake including aquatic plants such as common reed and yellow floatinheart, good quality water and forests along the lakeside has been destroyed with the urbanization and industrialization of the surrounding towns. The lake spread over 23 municipalities, occupying a third of the prefecture’s total area. It is known as the treasure box of wild birds, and over 150 species of birds fly to the lake. In the summer tourists can enjoy sailing on a large sailing boat.