Water Environmental Soundness Index

Let's go to a river together!


of integrated index for evaluating water environment

Water quality standards have been used for evaluate water environment condition. Besides water quality, various factors are involved with soundness of water environment.

Therefore, the Ministry of Environment, Japan, developed an integrated index for evaluating river water environment. The integrated index can be used for comprehensive evaluation of all water environment factors. Water environment soundness is evaluated by (1)Natural state, (2)Rich plants and animals, (3) Clarity of water, (4) Pleasant waterfront environment, and (5) Regional culture on water, all of which come together to form the relationships between water environment and people.


of study river environment

1.What are the characteristics of rivers?

Rivers vary in size from large to small: a large river that we have to cross by boat and a small stream that is running near our houses.

A river condition varies from place to place: a river in a mountain and a river in a town.

Each river has a different characteristic according to flowing water, scenery, living things and relations with our life.

There are living things such as fish, crabs, insects, and aquatic plants in a river. Grasses and trees are growing in the riverside and birds are living there.

Rivers have long been used for various purposes, such as fishery, agriculture, and drinking water. And it is an important place for local festivals and traditions, for example the floating lantern ceremony.

2.How to investigate the river environment?

Five measures (indicators) are used to investigate the whole picture of the river environment, including river water, living things, scenery, its utilization for our daily life.

Each measure (indicator) has three to five items (called separate indicator) to investigate the river condition. Evaluate each separate indicator on a scale of 3 to 1 by observing the river condition. Write the reasons why you choose the scale, if possible.

You can start from any indicator that seems possible.