1. Overview of water supply services
(1) Geomorphology and Hydrology in Japan
Japan is an archipelago, made from four large islands and many other small islands. Among them, 6,852 islands have more than 100 m of coastline, and around 400 islands are inhabited. The length of Japanese archipelago is over 3,000 km. The highest mountain is Mt. Fuji (3,776m) located at the border of Shizuoka Prefecture and Yamanashi Prefecture. The longest river is Shinano River (367km) meandered from Gumma Prefecture, Nagano Prefecture to Niigata Prefecture. The largest lake is Lake Biwa (671km2), located in Shiga Prefecture.
Since Japan lies from north to south, covering a wide range of latitude, the climate varies from cold zone (northern area), temperate monsoon zone (central area), to subtropical zone (southern area). The average temperature in Tokyo, located in central area, is 15 degrees Celsius (ranging from 5 degrees Celsius at the lowest to 27 degrees Celsius at the highest). In Sapporo, located in cold zone, the average temperature is 8 degrees Celsius (ranging from -5 degrees Celsius to 21 degrees Celsius). In Naha, located in subtropical zone, the average temperature is 22 degrees Celsius (ranging from 16 degrees Celsius to 28 degrees Celsius). This diverse climate range results in rich natural environment and ecosystem. Also, because of the diverse climate and topology, every region has different water environment.
The average precipitation in Japan is 1,718 mm/year, higher than the world average (880 mm/year). Again, precipitation in Sapporo, Tokyo, and Naha is 1,029 mm/year, 1,322 mm/year, and 2,816 mm/year, respectively. Recently, local heavy rain and torrential shower have been occurring frequently.
Diagram 1 shows the gradient of major rivers all over the world. Comparing to the rivers in the continents, the rivers in Japan are short and steep, so rain fallen in the watershed flows out rapidly. In cold zone, dams are constructed to capture snow melt.
Diagram 1. Rivers around the world
Additionally, the population in Japan is around 128 million. Eleven cities have population exceeding 1 million people. The average density is 319 persons/km2. The highest density is 5,750 persons/km2 in Tokyo Metropolitan Area, and the lowest density is 72 persons/km2 in Hokkaido Prefecture.
(2) Development of Modern Waterworks
In 1854, around 200-year period of isolation was ended by the Japan-US Treaty of Amity. After the treaty, active trading with foreign countries had caused Japan to experience epidemics of water-borne diseases such as cholera, typhus, etc. The number of patients in the 20 years from 1868 was approximately 410 thousands, and half of them lost their lives. Since then, to address water-borne diseases, related authorities started to emphasize the importance of modern waterworks construction. Port cities were especially motivated to introduce waterworks since these cities were at high risk of outbreaks.
First, Kanagawa Prefecture asked a British Engineer, Henry Spencer Palmer, to investigate and design water supply system in Yokohama City, one of the port cities in Japan. In this water supply system, completed in 1887, water was taken from Sagami River, filtered with sand, and supplied using iron pipes with pressure. By 1900, water supply systems were constructed in Hakodate City (1889), Nagasaki City (1891), Osaka City (1895), Tokyo (1898), Hiroshima City (1899), and Kobe City (1900), one after the other.
After the introduction in ports and large cities, water supply systems had spread all over Japan. Despite the expansion of modern water supply systems, the number of patients suffering from water-borne diseases such as cholera, dysentery, typhoid, and paratyphoid, was not reduced until 1940s. The decrease in patient number was brought by the introduction of disinfection, which was strengthened under American control after World War II. In 1957, disinfection was required by the newly implemented Waterworks Act. After the new regulation started, the number of patients suffering from water-borne diseases decreased significantly. The coverage of piped water supply as of 2006 is more than 97% with very few patients.
Diagram 2 Development of modern waterworks
(3) Administration System concerning Water
The Japanese administration system has three layers: state, prefectures, and municipalities. Both prefectures and municipalities, including cities, towns, and villages, are considered as local governments. Among 47 prefectures, the largest prefecture in terms of population is Tokyo Prefecture (12.8 million) and the smallest is Tottori Prefecture (0.6 million). The number of municipalities had been reduced from 3,232 (as of 1999) to 1,810 (as of 2008) by around 1400. This reduction was resulted from municipality merge promoted by the national government.
The national government is constituted from 1 office and 11 ministries. Among them, the ministries in charge of water-related affairs are as follow:
Water Supply - Ministry of Health, Labour and Welfare
Water Environment - Ministry of the Environment
River Control, Water Resource, and Sewage System - Ministry of Land, Infrastructure and Transport
Industrial Water - Ministry of Economy, Trade and Industry
Agricultural Water - Ministry of Agriculture, and Forestry
(4) Administration System concerning Water Supply Services
a. Role of Ministry of Health, Labour and Welfare
-Governance of Waterworks Act
-Approval of business license
-Structure and material standards of water service installation
-Drinking water quality standards
-Supervision of Laboratory
-Supervisory guidance and on-site inspection
-Promotion of research and development
b. Role of Water Utilities
With the compliance of the requirements of the Act including Facility Standards, Drinking Water Quality Standards, etc., water utilities must supply water to their consumers at all times. Because water is indispensable for daily life, water should be available from taps 24 hours a day. However, when consumers fail to pay tariff, water utilities can suspend the supply to them according to rules of supply. Also, in case of drought or destruction of facilities caused by national disaster, the obligation can be exempted. On the contrary, in the case that water has possibility to harm human health, water utilities must suspend the supply immediately and notify their consumers.
It is important to clarify the rules of supply between water utilities and their consumers. Therefore, water utilities have to set the contracts concerning tariff and cost allocation of water service installation in advance, and let them be publicly known. The rules of supply are usually implemented as a bylaw, when public utilities provide services. Generally speaking, water service installation before the meter is a property of water utilities, and service installation after the meter until the tap is a property of consumers.
To supply safe water, water utilities have to assure hygiene as well as comply with Drinking Water Quality Standards. Water utilities have to keep water supply facilities clean and take measures to prevent contamination, such as cleaning and locking water treatment plants, reservoirs, etc.
Furthermore, the Act requires health check-ups for workers in treatment plants every six months, to prevent the contamination of water from the workers infected with water-borne diseases.
Also, drinking water utilities are required by the Act to provide the consumers with information pertaining to the results of water quality inspections and related information. The implementing regulation of Waterworks Act defines contents of information, which water utilities are expected to make available as the following.
- Plan / Results of water quality inspections
- Implementation system of waterworks
- Cost of business/water charge
- Water supply equipment / facilities
- Sanitary management plan of water tank
- Results of extra water quality inspections
- Crisis management
(5) Types of Water Supply Services
a. Water Supply Business (1,572 businesses as of March 31,2007)
Water supply business provides water to more than 101 people according to general needs. In principle, water supply businesses are managed by municipalities. Business license is approved by the Ministry of Health, Labour and Welfare or Prefecture Governor depending on the population served.
b. Bulk Water Supply Business (102 businesses as of March 31,2007)
Bulk water supply business is a business that provides treated water to water supply businesses. Most of the bulk water supply businesses are managed by either prefecture or a group of municipalities. Business license is approved by the Ministry of Health, Labour and Welfare or Prefecture Governor depending on the volume served.
Diagram 3 Bulk Water Supply Business
c. Private Water Supply (7,737 systems as of March 31,2007)
Private water supply system supplies water in dormitories, company residences, and sanatoriums for private use. The population served is more than 101 persons or the capacity of the facility is more than 20 m3/day. The confirmation of the design of facilities by the governor is required before construction.
d. Private Water Supply Facility
Private water supply facility has more than 10 m3 of tank, and provides only received water from water supply business.
Diagram 4 Private Water Supply System and Private Water Supply Facility
|No||Name of Water Supply Business||Design maximum daily supply|
|2||Osaka City||2,430,000 m3/day|
|3||Yokohama City||1,800,000 m3/day|
|4||Kanagawa Prefecture||1,588,000 m3/day|
|5||Chiba Prefecture||1,440,000 m3/day|
|6||Nagoya City||1,244,000 m3/day|
|7||Kyoto City||1,050,000 m3/day|
|8||Kawasaki City||1,026,000 m3/day|
|9||Sapporo City||958,000 m3/day|
|10||Hiroshima City||811,000 m3/day|
|No||Name of Bulk Water Supply Business||Design maximum daily supply|
|1||Kanagawa Water Supply Authority||2,535,000 m3/day|
|2||Saitama Prefecture||2,433,000 m3/day|
|3||Osaka Prefecture||2,160,000 m3/day|
|4||Aichi Prefecture||1,740,000 m3/day|
|5||Hanshin Water Supply Authority||1,289,000 m3/day|
|6||Hyogo Prefecture||750,000 m3/day|
|7||Okinawa Prefecture||602,000 m3/day|
|8||Miyagi Prefecture||553,000 m3/day|
|9||Kitachiba Water Supply Authority||534,000 m3/day|
|10||Nara Prefecture||484,000 m3/day|
In Japan, 124 million people use tap water, constituting 97.3% of total population (2006). Major portion of the rest, around 3.7 million people, use their own wells or unregulated small scale water supply services without the access to tap water from water supply businesses regulated by the Act. Diagram 6 shows that the coverage is different in each prefecture, and six prefectures have coverage less than 90%. Also, it shows a gap between urban areas and rural areas. Unlike the high coverage in cities (98%), the coverage in towns and villages are relatively low (91% and 88% respectively).
Therefore, the national government is continuing to promote the expansion of water supply businesses so that these people can have access to water that satisfies Drinking Water Quality Standards.
Diagram 5 Coverage of water supply
Diagram 6 Coverage of water supply by prefecture
(7) Water Sources
Surface water (including dam, river and lake) consists 72% of total annual intake, and ground water (including river-bed, shallow and deep well) consists 26% (2006). Therefore, most of the water supply sources can be easily influenced by pollutions such as eutrophication, oil spill accidents, etc.
Diagram 7 Water source
(8) Types of Treatment Plants
Water utilities select the type of treatment plants according to the quality of source water. Rapid sand filtration is most commonly used (76%), while 20% of water utilities only have the process of disinfection without filtration. Recently, more and more water utilities (22%) have adopted advanced water treatment method such as activated carbon, ozonization, biological treatment, air stripping, prechlorination, etc., to cope with the deterioration of source water quality. Advanced water treatment plants can reduce odor, iron/manganese, trihalogenerated methanes, ammonium, free carbon dioxide or volatile organic carbon.
Diagram 8 Type of water treatment
(9) Leakage Control
Leakage affects the management of water supply businesses since the process of water treatment requires huge costs. Therefore, water utilities have made great efforts to reduce leakage. In 1970s, only 78% of water distributed reached taps, but in 2006, more than 92% of water distributed reached taps (This ratio is called effective water ratio). Therefore, leakage had improved down to only 8%. The goal of effective ratio is set to be 98% for large water utilities and 95% for small water utilities by the national government.
Leakage is caused by some sort of pipe damages. Pipes could have cracks caused by load or vibration from traffic, or pipes might be corroded by acidic soil. When leakage appears on the ground, it is easily detected and pipe can be rehabilitated immediately. However, when leakage occurs underground, its detection is not easy. Therefore, leakage control survey, rehabilitation and renewal of old pipes should be conducted according to plans made by water utilities.
Diagram 9 Effective water ratio
The average cost of supplying 1 m3 of revenue water is approximately 180 yen/m3 in 2005. Recently, depreciation and purchase of water from bulk water supply businesses have occupied more than before because of the rehabilitation of old facilities and the increasing usage of bulk water supply businesses, to secure water quality and quantity.
Diagram 10 Cost
As opposed to the cost (179.74 yen/m3), the unit price of water, calculated by dividing revenue by total revenue water, is 175.21 (yen/m3).
Diagram 11 Trend of cost and price of water
(11) Subsidy from National Treasury
The Act allows the national government to subsidize part of their business costs to local governments, when local governments manage water supply business or bulk water supply business. Subsidy is classified into two categories. One is the subsidy of water source development or advanced treatment plants construction by water utilities. The other is the subsidy of the facility construction by small water supply businesses (Population served is less than 5,000). This subsidy system has contributed greatly to the expansion of water supply services and the control of the local gap among water supply businesses. The budget of subsidy from National Treasury in 2009 is around 96 billion yen.
(12) Guidelines for the Management and Assessment of a Drinking Water Supply Services
In 2005, guidelines for the management and assessment of a drinking water supply services (JWWA Q 100) were developed by Japan Water Works Association, based on the basic concept of ISO/TC 224, to improve the service of drinking water supply by the quantification of waterworks. These guidelines include a performance indicators system, comprised of a set of performance indicators (PI), context information and variables.
(13) The guideline of asset management of water supply businesses
The current generation is responsible for the deliberate renewal of water supply facilities and the succession of sound asset to next generation. In this context, the role of water supply utilities, in charge of the management of water supply businesses, is especially important.
In Japan, water supply facilities were constructed rapidly during the high-growth period in 1970’, and these facilities are now facing the aging problems and are about to reach the peak of renewal demand. Therefore, the same imminent problem and the necessity of deliberate renewal of aged water supply facilities are shared among all of the water supply utilities.
In 2004, Ministry of Health, Labour and Welfare, announced the Waterworks Vision and showed “Stability” and “Sustainability” as one of the long-term goals. In order to strengthen the foundation of the water supply management, the Ministry emphasized the importance of deliberate maintenance and renewal of water supply facilities, based on mid-long term financial balance. However, the approaches for the renewal of water supply facilities and the assurance of finance by water supply utilities have not been sufficient.
In July of 2008, the Ministry reviewed and revised the Vision. In the revised Vision, it is described that the deliberate rebuilding or renewal of water supply facilities, their efficient maintenance and operation, and the assurance of finance will be promoted based on the technical platforms, from a medium and long term perspective, with the introduction of asset management. Also, in order for consumers to understand necessary cost share for the renewal of facilities, the detailed study for public relations will be promoted.
The asset management is systematic activities conducted by water supply utilities to realize efficient and effective management of water supply facilities, considering their life-cycle, from the long-term viewpoint. Therefore, the Ministry issued the guideline to promote the implementation of asset management among water supply utilities, through thorough understanding of its importance.