Water / Soil / Ground Environment

Conservation of the Water Environment - Chapter 5

5. Securing a Sound Water Cycle

In the humid forest region of middle latitude nations like Japan, the water cycle is fundamentally represented by "rain → soil moisture → groundwater → surface water (lakes, marshes and rivers) → ocean." Most surface water of rivers, lakes, and marshes is also supplied by groundwater (or underground water), which spreads throughout the region. In addition, groundwater also plays an important role in the water cycle in the region because it becomes purified during the natural infiltrating process and contributes to the preservation of various species by supplying water in springs.

However, because of the progress of urbanization, the natural water cycle has been partially damaged. This has caused various problems to occur, e.g., instability of water flow in rivers, drying up of spring water, and deterioration of the ecosystem.

To solve these problems relating to water and to secure a sound water cycle, efficient planning should be developed, e.g. reviewing the regional situation based on local characteristics and creating a master plan for recovery of the water cycle by synthetic diagnosis and evaluation of water cycle.

As a result, it is expected that the water environment will be improved and contribute to the prevention of global warming caused by the drastic increase of energy consumption by air conditioners and by the increase in emissions of carbon dioxide.

Development of Planning to Secure a Sound Water Cycle

The "Meeting on Securing a Sound Water Cycle" consisted of scholars and NGO Representatives. It reviewed the basic ideology and planning aimed at securing a sound water cycle for the region based on groundwater, which plays an important role in the water cycle. Concrete planning for the recovery of water cycle can be considered for urban areas and would include not only the conservation of forest and paddy fields but also the establishment of storing and filtering equipment for rain water, the recovery and regeneration of wells and springs, and the conservation and upgrading of green zones. To promote the planning efficiently, it is important to synthetically diagnose and review water cycles in basins as units and to make a master plan for the recovery of the water cycle that calls for residents of the basin, related agencies, and scholars to cooperate with each other.

To secure a sound water cycle, the Environment Agency is (1) upgrading the cultivating equipment of groundwater and promoting "Well and Spring Recovery and Regenerating Program" to upgrade well and spring environments with the cooperation with the Ministry of Construction beginning in 1997 and (2) conducting case studies in the model basin for development of water cycle recovery plans for all basins in the country and is going to promote the survey and review to plan diagnostic and evaluating standards for the water cycle based on groundwater and guidelines for recovery.

Image of Measures for Recovery of Sound Water Cycle Present of Water Cycle

Current Condition of the Water Cycle
　　|
diagnosis and evaluation, creation of a master plan,
development of water cycle recovery planning
　　|
Recovery of Sound Water Cycle

[Poor Forest Management]

[Forest Conservation]

Changing Situation of Rain Water Infiltrating the Ground , Changing Situation of Surface Pavement and Covering, Changing Situation of Spring Dried and Disappeared

[Changing Situation of Rainwater Infiltrating the Ground , Changing Situation of Surface Pavement and Covering]

(Notes)
  1. "Infiltrating Rate of Rainwater" means the amount of rainwater
    infiltrating the ground compared to the amount
    of precipitation.
  2. "Pavement and Covering Rate of the Ground Surface"
    means the area of the ground surface paved and
    covered by concrete or other material compared to local area
    excluding mountainous areas
Authority:
Bureau of Environmental Protection, Tokyo Metropolitan
Government, "Survey Report on the Actual Situation of
Groundwater" (September 1992)

[Drying and Disappearing Springs]

Authority:
Bureau of Environmental Protection, Tokyo Metropolitan Government,
"Survey Report on the Actual Situation of Groundwater" (September 1992),
"Shimano, Original"

Examples for Water Cycle Recovering Planning

[Example for rainwater infiltrating equipment,Rain water infiltrating box]

[Utilization of Rainwater(Alley Patron Saint: Sumida Ward, Tokyo) ]

Rainwater on the roof flows down to the tank and stored for extinguishing fires.