Lake Kasumigaura
WEPA Water Environment Partnership in Asia
Lake Kasumigaura
1. Outline of Lake Kasumigaura
(1) Lake Kasumigaura
(2) Kasumigaura basin
2. The Use and Management of Lake Kasumigaura
(1) Lake Kasumigaura and human life
(2) Floods and salt damage
(3) Overall development system for Lake Kasumigaura
(4) Management of water levels
(5) Water Utilization at Kasumigaura
3. Causes of Water Pollution in Lake Kasumigaura
(1) The quality of water in Lake Kasumigaura
(2) Present water quality
(3) Obstacles on water utilization
(4) The primary factors in lake water pollution
4. Measures to Improve Water Quality
(1) Environmental standards
(2) Locale effluent standards more stringent than the national uniform standards
(3) Ibaraki Prefectural Ordinance for the Prevention of Eutrophication
(4) The Basic Plan to Prevent Eutrophication
(5) Special Measures Act for the Preservation of Lake Water Quality
(6) The Plan for Conservation of Lake Water Quality
5. Further Issues on Water Quality Management

1. Outline of Lake Kasumigaura

(1) Lake Kasumigaura

Lake Kasumigaura is located about 60~90 kilometers northeast of Tokyo, in the southeast of Ibaraki Prefecture, and it is Japan’s second largest natural freshwater lake. Lake Kasumigaura covers an area of approximately 220 square kilometers, and averages 4 meters in depth, with a maximum depth of 7 meters. Its capacity is about 85 million cubic meters. The shoreline is 250 kilometers. The lake is long, Y-shaped, and narrow, so those living nearby call Lake Kasumigaura “kawa” (meaning river).

Because Lake Kasumigaura used to be an inland sea, it lies a mere 16 centimeters (Y.P.+1.0m see Fig.4) above sea level. While 56 rivers now into Lake Kasumigaura, the lake discharges into just one river, the Hitachi River, which later joins with the Tone River (at a point about 18 kilometers from the river mouth), and with the Pacific Ocean. Lake Kasumigaura became a freshwater lake around the year 1638, during the Edo Period (1600-1868).

Lake Kasumigaura is comprised of three lake regions (Lake Nishiura, Lake Kitaura and Lake Sotonasakaura), and three river regions (the Kitatone River, the Wani River and the Hitachi River) (Figure 1). Lake Nishiura is commonly called Kasumigaura.

Figure 1 Region of Lake Kasumigaura


Okada M, Peterson SA. (2000): “Water Pollution Control Policy and Management: the Japanese Experience”. Gyosei, Japan, 287pp.

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