[Japan Water Agency / JWA] Water resources development of seven river systems.

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Outline of JWA

Outline of JWA

[1]Stably supplying safe and quality water

Stable water supply (Water supply from dams)

The stream flow changes depending on the rainfall. When it decreases due to poor rainfall, for example, JWA supplies water that has been stored in the dam reservoir to the river downstream so as to ensure that necessary amount of water can be taken stably from the river. JWA also supplies necessary amount of water to facilitate water transportation, fisheries, and conserve the river environment.
Water supplies to water users from the Hinachi Dam
Water supplies to water users from the Hinachi Dam
(Water Supply for different purposes from canal facilities) JWA meticulously operates, maintains and manages its canals that extend approx. 3,030 km in total length.
An operator at Gunma Canal facilities
An operator at Gunma Canal facilities
Taking water from the Tone River at the Tone Barrage
Taking water from the Tone River at the Tone Barrage

Safe and quality water supply

JWA conducts water quality surveys and facility patrols to monitor day-to-day water quality. It also addresses eutrophication and water turbidity with effective use of its facilities. In the event of pipeline leakage or a water quality hazard due to an oil spill in a river or canal, JWA takes prompt action to prevent the damage from spreading and notify water users for information sharing.
Water survey above the Nunome Dam
Water survey above the Nunome Dam
An oil fence is installed across the Kisogawa Canal to address a water quality hazard
An oil fence is installed across the Kisogawa Canal to address a water quality hazard
Removal of volcanic ashes from Mt. Ontake (Makio Dam-Aichi Canal)
Removal of volcanic ashes from Mt. Ontake (Makio Dam-Aichi Canal)

[2]Preventing and mitigating flood hazards

Flood control with dams

Dams perform an important function of storing river water that increases rapidly in volume due to heavy rain and regulate discharges downstream (flood control function). Weirs and barrages raise water levels with their gate shut down in normal times. At the time of flood, however, the gate is opened to allow excessive river water to flow downstream safely. When a heavy rain that may cause floods is expected, JWA accurately assess weather information and streamflows and operate its dams, weirs/barrages, and facilities accordingly.
Conceptual rendering of flood control
Conceptual rendering of flood control
Flood control at the Shorenji Dam
Flood control at the Shorenji Dam
Facility patrol at the Takizawa Dam
Facility patrol at the Takizawa Dam
The gate at the Nagaragawa Estuary Barrage is widely opened to discharge flood water
The gate at the Nagaragawa Estuary Barrage is widely opened to discharge flood water

[3]Preparing for crises

Better seismic performance

JWA keeps improving the seismic performance of its facilities, thereby enhances public confidence in their security. To this end, JWA checks their performance and assess their risks in relation to major earthquakes. Based on the findings of such checks and assessment, JWA is conducting seismic measures to its facilities systematically.
Checking seismic performance(Resources Engineering Department)
Checking seismic performance
(Resources Engineering Department)
Seismic engineering (replacing a flexible pipe)(Fukuoka Headrace)
Seismic engineering
(replacing a flexible pipe)
(Fukuoka Headrace)
Bracing for an possible major earthquake(Inserting a steel pipe into the existing siphon)(Toyogawa Canal)
Bracing for an possible major earthquake
(Inserting a steel pipe into the existing siphon)
(Toyogawa Canal)

Routine training for major disasters

JWA works with the central government, water users, the police, fire and disaster management authorities and other institutions concerned to conduct flood response exercises and earthquake and disaster management drills regularly to prepare for floods, major earthquakes and other natural disasters, as well as water quality hazards. JWA also has a stockpile of steel pipes, pump trucks and other equipment and materials in preparation for any contingency on its canal facilities.
Earthquake and disaster management drill(Headquarters)
Earthquake and disaster management drill
(Headquarters)
Installation practice for central disaster emergency communications network equipment (Headquarters)
Installation practice for central disaster emergency communications network equipment
(Headquarters)
Water quality accident response drill(Gunma Canal)
Water quality accident response drill
(Gunma Canal)
Pump truck water-supply drill(Tone Canal)
Pump truck water-supply drill
(Tone Canal)

[4]Ensuring facility integrity

Facility inspection and maintenance

JWA works to conserve and manage its facilities through routine patrol, inspection and maintenance. On dam reservoirs, it collects driftwood and solid waste using work boats. JWA also strives to find any malfunction of its canal facilities and leakage from them as early as possible. It promptly repairs any leak from such facilities so that water supply can be smooth without interruptions.
Measuring the leakage inside the dam body (Shimokubo Dam)
Measuring the leakage inside the dam body
(Shimokubo Dam)
Routine patrol of canal facilities (Tone Canal)
Routine patrol of canal facilities
(Tone Canal)
Inspecting the inside of a tunnel (Kasumigaura Canal)
Inspecting the inside of a tunnel
(Kasumigaura Canal)
Facility operation support, using a head-mounted tablet display (Trial run) (Lake Biwa Development)
Facility operation support, using a head-mounted tablet display (Trial run) (Lake Biwa Development)

Stock management of canals and other facilities

JWA conducts routine inspection, maintenance and regular functional diagnostic study to accurately assess the state of each facility and share the information on their risks and their effects to water users so as to take necessary measures appropriately to extend the facility life and reduce its life-cycle costs.
Replacing a branch pipeline at the Kisogawa Canal
Replacing a branch pipeline at the Kisogawa Canal
Stock management of canals and other facilities
*1 Continual facility monitoring as part of the routine management
(The resulted data are used for functional analysis and planning of functional security.)
*2 Facility monitoring regularly conducted to enhance the quality of functional security plan and to find the right timing of remedial work

Extending the life of dams

To secure the safety and long life of functions of dams, JWA conducts periodical inspections every three years and for the dams with 30 years services since the start of management, JWA implements the comprehensive inspection of each of them. Based on the result of that inspection, it makes the plan to extend the life of the dam, in which a medium and long-term maintenance and management policy of individual facilities comprising the dam is formulated and systematic maintenance and management work for them are carried out.
Equipment check as part of dam's regular inspection(Muroo Dam)
Equipment check as part of dam's regular inspection
(Muroo Dam)
Inspection of the hydropower plant(Hitokura Dam)
Inspection of the hydropower plant
(Hitokura Dam)

[5]Developing facilities in a systematic and appropriate manner

Construction and reconstruction of dams, canals and other facilities

JWA constructs and reconstructs dams, canals and other facilities systematically so that water resources can be used stably.
Oyama Dam construction project (completed in 2012)
Oyama Dam construction project
(completed in 2012)
Musashi Canal reconstruction project(Change to double-way canal)
Musashi Canal reconstruction project
(Change to double-way canal)
Toyogawa Canal Project Stage II(Renewal of the canal)
Toyogawa Canal Project Stage II
(Renewal of the canal)
Ryochiku-heiya Canal Stage II(Reinforcement of inner tunnel surface)
Ryochiku-heiya Canal Stage II
(Reinforcement of inner tunnel surface)

[6]Conserving natural environment

Conservation of the natural environment

JWA engages in environmental survey, revegetation, and vibration and noise pollution control to conserve the natural environment, including the local flora and fauna, ecosystems and landscapes. In addition, as a member of the local community, it engages in environmental conservation activities proactively.
Environmental Survey Installation of dormice(Koishibaragawa Dam)
Environmental Survey Installation of dormice
(Koishibaragawa Dam)
Participation in floating hearts preservation activities (Lake Biwa  Development)
Participation in floating hearts preservation activities
(Lake Biwa Development)
(Reinforcement of inner tunnel surface)

Improvement of environment of downstream river

We are working on the improvement of river environment for the fish and other river creatures, providing a large amount of sand and gravel to the downstream rivers of the dams and flashing discharge within a short time to flash away the mud and mosses adhered to the gravel in the river and refresh them. As a result of such measures, in the case of Hitokura Dam of kawanishi City, Hyogo Pref., there were increasing number of small creatures on the bottom of the river such as may-fly, stone –fly, and caddis –fly, etc. and clean-water fish by about 5 times compared with the days before such river refreshment measures.
1
1. In 1976, when the river condition was good.
(Gravel and sand spread on the surface.)
2
2. In 2002, about 20 years passed since management start.
The river condition was bad. Gravel and sand are gone and grasses and bushes were growing.
3
3. In 2003, gravel and sand were thrown in with a heavy machine
4
4. In 2015, when the river condition is good. (Coming closer to the condition before dam construction)
An example of improvement work of downstream river environment of Hitokura Dam

[7]Promoting international cooperation

Network of Asian River Basin Organizations (NARBO)

[Other Works]
Strengthening Coordination with Local Municipalities Concerned and Local People

JWA strives for the social exchanges between the people of upstream and downstream areas to deepen the coordination with the water source areas where they show deep understanding and cooperation in organizing and managing the dam facilities and also with the water users downstream.
Safety inspection with local municipality staff (Muroo Dam)
Safety inspection with local municipality staff
(Muroo Dam)
Underbrush clearing activity with people of upstream and downstream areas (Oyama Dam)
Underbrush clearing activity with people of upstream and downstream areas
(Oyama Dam)
Facility site tour (Musashi Canal)
Facility site tour
(Musashi Canal)
A lecture at the local high school (Tokuyama Dam)
A lecture at the local high school
(Tokuyama Dam)
Gate inspection discharge-opening to the public (Shimokubo Dam)
Gate inspection discharge-opening to the public
(Shimokubo Dam)
“Dam Curry and Rice” served at a diner near the dam (Left: Shimokubo Dam, Right: Yagisawa Dam)
"Dam Curry and Rice" served at a diner near the dam
(Left: Shimokubo Dam, Right: Yagisawa Dam)

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