Water for people.pdf - WHO Thailand Digital Repository

G R E A T E R T O KY O , J A P A N / 4 9 3For watershed management, water information such as drainageand basin groundwater needs to be kept updated. People needhigher quality services for river administration: downsizingadministrative services, making river administrative services moreefficient with proper information updating, privatizing some parts ofservices and simplifying contract procedures. In addition, riverinformation, such as water quality and ecosystem data, has becomemore useful in education systems.In ‘the water-aware country’, information technology is used tomanage and share information efficiently. For example, when anarea’s flood safety degree can be calculated more precisely byinformation technology, human losses will be reduced through thecombination of people reaching suitable refuge under properguidance, and the river administrator’s efficient operationalfacilities. River GIS also attempt to deal rapidly with water-relateddisasters, through such measures as structure maps, waterwayfigures, maps showing the placement of dangerous objects and awater database. To these ends, super-high-speed, big-capacityoptical fibre networks are connected to the related organs in orderto make the latest data in emergency situations available (Sato,2002).Fitting the Pieces TogetherIn densely populated Greater Tokyo, the water management policycan be considered a success in providing the population andindustries with water, and many years of flood control efforts havereduced the total inundated area. Water resource development hasfocused on stabilizing river flow and meeting new water demands.However, the high concentration of people and industry makes thissuccess fragile and risky. Flood damage has only slightly decreased,due to a higher concentration of population and property: access toa stable water supply has accelerated the rate of concentration andcreated a new demand for water. The need for water resourcemanagement has become more diversified. People are moreconcerned with the environment and nature. In addition to thewater resources policy, it is necessary to establish more integratedriver management suitable for sharing risk information and copingwith this risk. The concept of risk management is consistent withthe revised 1997 River Law, which calls for public participation andenvironmental consideration. The various policies relating to efficientwater use will be evaluated, easily comprehensible water qualityindicators developed, and a commitment will be made and enforcedto restore the natural environment and to make information public.These are highly related to the participation of citizens and nongovernmentalorganizations (NGOs) in water policy.Managing risksAs a countermeasure to the high flood damage in Greater Tokyo, aneasily comprehensible indicator showing the degree of risk of flooddamage was developed and made public (Yasuda and Murase,2002). The safety degree against flood damage can be expressedthrough a combination of the flood frequency and the inundationlevel. This two-dimensional aspect of floods renders it difficult todevelop a single-dimensional indicator by which the risk can beexpressed.Figure 22.5 shows that the frequency of floods and theinundation level can be expressed by a colour and a height,respectively. The green represents low flood frequency while the redrepresents high flood frequency. Comparing the flood levels withthe height of people and houses directly indicates a degree ofsafety against flood damage. Inter-temporal changes in the safetydegree can also be expressed, as shown in figure 22.6.Based on this, flood risk expression has been developed inTokyo region. The index in the legend is the Flood Risk Indicator(FRICAT) employed in Japan for policy evaluation. The FRICATrepresents how often the expected annual damage by flood ishigher than that of fire. The average expected annual fire damagein Japan between 1998 and 2001 was 1,165 yen (approximatelyUS$9.3) per person.Improving water resource managementThe tight water resources in Greater Tokyo must be carefullymanaged, as they have to meet the competing demands of a largepopulation. It has become difficult to develop new water resourcesfacilities such as dams. To further improve the water resourcemanagement system, an evaluation of the various policies forefficient use of the limited water resources is being carried out.Integrated Water Resources Management (IWRM)The combination of an increased concentration of population andindustries, the expansion of urban areas, changes in industrial andsocial structures and changes in the climate, have all given rise to avariety of water-related problems in Japan. These include watershortages in rivers and groundwater and deterioration of the qualityof water, as well as an increase in urban flood damage. The problemsoriginate from changes to the hydrological cycle, such as a lack ofinfiltration or continuity between surface water and groundwater.Water authorities in Japan are divided among several institutions. In1998, they reached an agreement on fundamental policy for restoringa healthy hydrological cycle. The policy advocates adopting anintegrated water basin approach and sharing knowledge about thehydrological cycle, and encourages efforts to improve the situation ineach basin. In addition, case studies were conducted in some riversaround Tokyo and Osaka to monitor and analyse problems.