July 16, 2004
The nationwide survey on aquatic life forms for FY 2003 was conducted through the efforts of approximately 86,000 participants. According to the survey results, which were compiled by the Ministry of the Environment and the Ministry of Land, Infrastructure and Transport:
| - | Water quality evaluations were conducted at 5,042 survey points nationwide by means of surveys of aquatic life forms found in rivers. Survey points deemed to have clean water comprised 60% of the total. |
| - | The survey had participatory support from a large number of schools and civil groups, with most participation taking place during summer vacation. (74% of participants were affiliated with elementary or junior high schools and 23% of participants were affiliated with local children's organizations or civil groups.) |
Insofar as river water quality is reflected in the population status of aquatic life forms such as sawagani freshwater crabs, kawagera water flies, and other river dwellers, it is possible to determine water quality by using these creatures as indicators. One benefit of this kind of survey is that it is simple to understand and no expensive equipment is required, making it easy for anyone to participate. Furthermore, becoming closer to nature through this survey enhances people's interest in environmental issues, and thus the Ministry of the Environment and the Ministry of Land, Infrastructure and Transport have been conducting this nationwide survey on aquatic life forms annually since FY 1984.
Overview of the FY 2003 Survey Results
1. Survey methodologies
Thirty species of river-dwelling aquatic life forms were selected as target creatures for this study. Criteria for selection were that (i) the creatures are found throughout Japan; (ii) the creatures are easy to classify; (iii) the creatures have a high degree of usefulness as indicators of water quality.
Creatures were collected from various rivers and identification and classification was conducted for creatures selected as water quality indicators. Each survey point was assigned a rating on a four-tiered scale, with a rating of "I" indicating "clean water," "II" indicating "slightly dirty water," "III" indicating "dirty water," and "IV" indicating "extremely dirty water."
2. Survey results
(1) Number of participants
FY 2003 saw the participation of 85,907 people (compared to 91,649 people in FY 2002).| Number of participants |
Number of participating groups |
Number of survey points |
|
| Total | 85,907 | 2,479 | 5,042 |
| Class 1 rivers*1 | 16,010 | 560 | 664 |
| Other rivers*2 | 69,897 | 1,919 | 4,378 |
| Notes: | 1. | Class 1 rivers in areas under the direct administration of the Ministry of Land,Infrastructure and Transport. |
| 2. | Class 1 rivers under the administration of the prefectural government, Class 2 rivers, etc. |
(2) Water quality assessment results
In FY 2003, 60% percent of survey points were evaluated as having clean water, representing a increase of 4 percentage points from FY 2002, when 56% were judged as having clean water.
| Total | Class 1 rivers | Other rivers | |
| I Clean water | 60% | 58% | 60% |
| II Slightly dirty water | 24% | 32% | 22% |
| III Dirty water | 12% | 7% | 13% |
| IV Extremely dirty water | 2% | 2% | 2% |
| Note: | Numbers may not add up to 100% due to rounding. |
| 3. | Aggregation and viewing system of the survey results via Internet |
Ministry of the Environment developed an aggregation and viewing system for participants of the survey to view the result right after they put the data. This system has launched its operation under the name of the Nationwide Survey on Aquatic Life Forms (in Japanese only).
| 4. | Contact point for the prospective participants of the survey |
To participate in the survey, conducted by the Ministry of the Environment every year, contact the environmental division of each local government. For further information, please visit the Nationwide Survey on Aquatic Life Forms page on the web.
[LINK]
| * | Nationwide Survey on Aquatic Life Forms |