273:, the Economic Stabilization Board's consultative flood prevention committee proposed the construction of a reservoir as the pillar of a cumulative plan for developing flood prevention infrastructure. The Ministry of Construction's Kantō Regional Development Bureau drafted the "Tonegawa River Repair and Improvement Plan" in response to this proposal; the plan was based on the construction of (originally) 9 multi-purpose dams on the Tonegawa River system. These eventually became the Tonegawa River 8 Dam Cluster, with one of the dams on the main Tonegawa River—
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impoundment (in which the dam is partially filled to test for abnormalities), leakage through the bedrock on the left bank was discovered, and Gunma
Prefecture requested repairs from the Ministry of Construction. That same year, concrete work was started to enable seepage control on the left bank. Repairs were completed three years later in 1959, and construction was finalized. Aimata Dam was placed under the direct management of the Ministry of Construction, and became the second of the Tonegawa River 8 Dam Cluster.
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irrigation water (with unspecified usage permissions) to the city of Kuki in
Saitama Prefecture, and also creates energy via the Aimata electricity generation plant, with a permitted output of 7,300 kW, and the Momono electricity generation plant, with a permitted output of 6,200 kW. Afterward, the #2 Aimata electricity generation plant (120 kW) was added, to make use of the sustained effluent. Each generation plant is independently run at the prefectural level by the Gunma Prefecture Public Enterprise Bureau.
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droughts had begun to occur at a rate of once every two-to-three years, accompanied by a lack of rainfall, both attributed to the effects of global warming. To secure enough water to meet demand, the
Ministry of Construction implemented the "Emergency Water Supply-Countermeasure Dam Project" to retain water in reservoirs during droughts.
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The population of the
Capital region exploded after the completion of Aimata Dam; to meet demand, the Ministry of Construction and the Water Resources Development Organization (renamed as the Japan Water Agency) energetically continued development of the Tonegawa River system. However, in the 1980s,
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dam's purposes are flood prevention at the point where the Akaya River merges with the
Tonegawa River in the former city of Tsukiyono, and energy generation via the Gunma Prefecture-operated hydroelectricity facilities, making it a multi-purpose dam. The artificial Akaya Lake was created by the dam.
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It is a gravity dam made of concrete, operated by the
Ministry of Land, Infrastructure, Transport and Tourism's Kantō Regional Development Bureau, built to a height of 67.0 metres. As a member of the upstream Tonegawa River dam cluster, it supplies water to Tokyo and the Japanese capital region. The
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A construction feasibility study was carried out in 1990, after which the initial plans were altered to increase the height of the dam to 160.0 meters and the flood control storage to 76,000,000 tons. However, water demand from the
Capital region continued to increase, and as public projects at the
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The Akaya River and
Kawafuru Hot Springs upstream of Aimata Dam were singled out, and plans were brought forth for the newer "Kawafuru Dam" on the Akaya River. The concrete gravity dam was to be built at Kawafuru to a height of 131.0 meters, with flood control storage of 46,000,000 tons of water,
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The famous
Sarugakyou hot springs are located adjacent to the lake created by the dam—Akaya Lake. The hot spring facilities were originally located adjacent to the Akaya River, but submerged as a result of the dam's establishment, similar to Yanba Dam and the Kawarayu hot springs. However, in the
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Aimata Dam provides flood control from the Akaya River to the bank of the merged
Tonegawa River, rated to cut a (1947) Typhoon Kathleen-level design flood of 650 tons per second to 330 tons per second (cutting 320 tons per second). It maintains customary water rights of 140 tons per second for
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Route 17, which passes nearby, is more commonly known as the Mikuni Kaidō highway, and drivers continuing along toward Niigata go through the Mikuni Touge mountain pass. This road historically linked the former Echigo province and the former Kouzuke province, and was used several times by the
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Preliminary studies for dam construction were begun on the Akaya River in 1948. Afterward, the dam project's operation was turned over to Gunma Prefecture, rebranded as the auxiliary "Akaya River Cumulative Project"; construction began in 1952, and completed in 1956. However, during initial
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Currently, the dam functions as a valuable source of water for the capital region, and is controlled via the Tonegawa River Integrated Dam Group Operation Office in the city of Maebashi. The dam site itself is cut into a large "V" shape, and is fairly tall in proportion to its length.
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time were all being put under review, the dam project was scheduled for further reevaluation. Water demand eventually shrank, and as the necessity of Kawafuru Dam was called into question the construction project was put on hold for an indefinite period of time.
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case of Sarugakyou, the source of the hot spring was preserved, allowing for the development of a new hot spring resort area, and many hotels and inns sprung up around the shores of Akaya Lake, drawing numerous hot spring tourists to Gunma Prefecture.
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In 2005, it was designated by the Water Resources Environment Engineering Center as one of Japan's "Selected 100 Dam Lakes" after recommendation from the city of Minami.
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period. Featuring attractions like the Minakami Hot Springs, Mount Tanigawa, and the city of Yuzawa's ski area, the area features several touristic points of interest.
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appropriating water to municipal and industrial water systems and helping to alleviate water shortages in the Capital region.
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system at Aimata in the city of Minakami (the former village of Nīharimura), in the Tone District of
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Purposes: Flood control, unspecified water use, hydroelectricity
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http://www2.river.go.jp/dam/summary/?damCode=10301044700000
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Ministry of Land, Infrastructure and Transport Web Site -
378:建設省 河川局 監修・全国河川総合開発促進期成同盟会編 「日本の多目的ダム」1963年版：山海堂。1963年
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Aimata Secondary Electrical Generation Plant: 120 kW
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225:Aimata Electrical Generation Plant: 7,300 kW
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163:63,000 m (2,200,000 cu ft)
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194:110.8 km (42.8 sq mi)
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139:Akaya River, Tonegawa River system
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374:Aimata Dam Sightseeing (Japanese)
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1093:Kanna Lake (Okinawa Prefecture)
16:Dam in Gunma Prefecture, Japan
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905:Takase Dam Adjustment Lake
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1119:Dams in Gunma Prefecture
435:Dams in Gunma Prefecture
381:群馬県土木部河川課 「ぐんまのダム」：2000年
221:Installed capacity
155:80 m (260 ft)
147:67 m (220 ft)
103:Construction began
1124:Dams completed in 1959
1068:Takashima Sea-Dam Lake
693:Selected 100 Dam Lakes
87:36.71222°N 138.89306°E
125:Type of dam
732:Sasanagare Reservoir
451:Akasan Choseichi Dam
400:at Wikimedia Commons
190:Catchment area
181:Total capacity
92:36.71222; 138.89306
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986:Tsubayama Dam Lake
976:Nunobiki Reservoir
854:Kanna Lake (Kantō)
788:Shichikasyuku Lake
353:2014-02-22 at the
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1073:Kitagawa Dam Lake
981:Ikehara Reservoir
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396:Media related to
369:Damnet (Japanese)
318:Kawafuru Dam Plan
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199:Surface area
119:Dam and spillways
111:Opening date
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1017:Honjyō Reservoir
773:Nanatsumori Lake
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1042:Sameura Lake
1037:Asagiri Lake
1007:Yachiyo Lake
1002:Shinryū Lake
966:Amawaka Lake
956:Eigenji Lake
949:Kinki region
930:Agigawa Lake
910:Okugiso Lake
900:Arimine Lake
888:Chūbu region
879:Tanzawa Lake
869:Okutama Lake
843:
829:Okutone Lake
778:Asahina Lake
646:Yagisawa Dam
631:Terazawa Dam
626:Tamahara Dam
621:Takenuma Dam
606:Sonohara Dam
571:Sakamoto Dam
541:Narusawa Dam
536:Naramata Dam
531:Nakanojo Dam
516:Marunuma Dam
486:Kirizumi Dam
466:Hayakawa Dam
461:Fujiwara Dam
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275:Fujiwara Dam
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241:(相俣ダム) is a
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1083:Ōtsuru Lake
1063:Minagi Lake
1022:Yasaka Lake
971:Chimyō Lake
961:Nijino Lake
940:Mikawa Lake
935:Sakuma Lake
915:Takatō Lake
895:Kurobe Lake
859:Sayama Lake
849:Kusagi Lake
839:Nozori Lake
803:Hatori Lake
798:Gassan Lake
768:Kinsyū Lake
611:Sudagai Dam
596:Shinsui Dam
591:Shinaki Dam
471:Hiraide Dam
212:Operator(s)
90: /
78:138°53′35″E
66:Coordinates
1113:Categories
1012:Ryūki Lake
844:Akaya Lake
793:Hōsen Lake
758:Gosho Lake
753:Gandō Lake
727:Lake Jōzan
556:Ohnita Dam
546:Nozori Dam
526:Nakagi Dam
521:Mozawa Dam
511:Makabe Dam
506:Kusaki Dam
496:Komori Dam
481:Kazawa Dam
446:Aimata Dam
398:Aimata Dam
363:References
298:Akaya Lake
239:Aimata Dam
176:Akaya Lake
75:36°42′44″N
22:Aimata Dam
920:Miwa Lake
864:Tama Lake
763:Tase Lake
651:Yamba Dam
566:Ohtsu Dam
561:Ohsio Dam
168:Reservoir
1027:Ono Lake
705:Hokkaidō
636:Ueno Dam
351:Archived
136:Impounds
48:Minakami
36:Location
551:Nyu Dam
285:Purpose
265:History
173:Creates
130:Gravity
1051:Kyūshū
925:Enakyō
152:Length
144:Height
822:Kantō
697:ダム湖百選
335:Notes
255:Japan
60:Japan
114:1959
106:1952
243:dam
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695:(
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413:v
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