is an

artificial lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

located in Midori-ku, Sagamihara,

Kanagawa is a Prefectures of Japan, prefecture of Japan located in the Kantō region of Honshu. Kanagawa Prefecture is the List of Japanese prefectures by population, second-most populous prefecture of Japan at 9,221,129 (1 April 2022) and third-dens ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Kantō region The is a geography, geographical region of Honshu, the largest island of Japan. In a common definition, the region includes the Greater Tokyo Area and encompasses seven prefectures of Japan, prefectures: Chiba Prefecture, Chiba, Gunma Prefe ...

. Created in 1947 after the

Sagami River The is a river in Kanagawa and Yamanashi Prefectures on the island of Honshū, Japan. The upper reaches of the river in Yamanashi prefecture are also sometimes known as the , and the portion near the river mouth as the . The river overall was ...

was

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...

med, it serves as use for

recreation Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for happiness, enjoyment, amusement, ...

al and

hydroelectric Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

purposes. The lake also served as venue for

canoeing Canoeing is an activity which involves paddling a canoe with a single-bladed paddle. In some parts of Europe, canoeing refers to both canoeing and kayaking, with a canoe being called an 'open canoe' or Canadian. A few of the recreational ...

events at the

1964 Summer Olympics The , officially the and commonly known as Tokyo 1964 (), were an international multi-sport event held from 10 to 24 October 1964 in Tokyo, Japan. Tokyo had been awarded the organization of the 1940 Summer Olympics, but this honor was subseq ...

held in

Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...

, located from the lake.1964 Summer Olympics official report Volume 1, Part 1.
p. 131. Accessed September 11, 2008.

Water and land usage surrounding the lake

Typical lake flows (in m³/s) are 85 hydroelectric, 10.34 domestic, 4.16

irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...

, and 2.15 industrial. Land usage is 87.5% natural, 4.6%

agricultural Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created f ...

, and 7.9% other.

Eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

issues have been a serious issue of the lake that was first observed in 1967. The main issue was microcystis

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

bloom and reached its highest cell count of 2,500,000 cells/mL in July–October 1979 (data from 1985). Most vegetation grown around the lake are grassland and

weed A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

s while most crops grown are

rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...

and

vegetable Vegetables are edible parts of plants that are consumed by humans or other animals as food. This original meaning is still commonly used, and is applied to plants collectively to refer to all edible plant matter, including edible flower, flo ...

Fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...

application for crops near the lake is moderate.

Recreational uses

Because of the lake's creation in 1947, it displaced the

career A career is an individual's metaphorical "journey" through learning, work (human activity), work and other aspects of personal life, life. There are a number of ways to define career and the term is used in a variety of ways. Definitions The ...

s of many local fishermen in the area.Green Gables information on Lake Sagami
. Accessed September 9, 2008. In return for their livelihood being taken away, many of these families were offered rental boats in the new lake. No private boats are allowed on the lake as a result. To compensate for the loss of the smelt, black bass from the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

was imported to the lake as was Prussian

carp The term carp (: carp) is a generic common name for numerous species of freshwater fish from the family (biology), family Cyprinidae, a very large clade of ray-finned fish mostly native to Eurasia. While carp are prized game fish, quarries and a ...

. Because of the bass, the lake is a popular

recreational fishing Recreational fishing, also called sport fishing or game fishing, is fishing for leisure, exercise or competition. It can be contrasted with commercial fishing, which is occupational fishing activities done for profit; or subsistence fishing, ...

area. The lake is also used for couples

dating Dating is a stage of Romance (love), romantic relationships in which individuals engage in activity together, often with the intention of evaluating each other's suitability as a partner in a future intimate relationship. It falls into the cate ...

for boat rides and families. Row boat standard daily rental rates are ¥3000 for one person, ¥4500 for two people, and ¥6000 for three people.

Water treatment

In 1984, there were 170 industrial and four municipal

sewage treatment Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water p ...

plants surrounding the lake.

References

External links

{{Authority control Venues of the 1964 Summer Olympics Olympic canoeing venues Sagami Sagamihara Lakes of Kanagawa Prefecture