1. Recreational use of River Terraces 2. Revetment Harmonious with a River's Environment 3. Improvement of Reservoir Water Quality 4. River Purification Projects 5. Water Quality Improvement Vessel 6. Biological Index of Water Quality in Japan [video cd] 

 - Japan  [date of publication not identified] 
 - 1 video cd 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Ricers--Japan.<br/>Water quality--Japan.