| "The river incision has been decreasing gravel and sandy riverbed and deteriorating floodplain ecosystem in Japan. However, the academic research of nationwide river incision is quite scarce yet. The purpose of this paper is to examine the long-term trend of the riparian landcover changes and the channel changes (river incision) such as river width, water depth, and riverbed level at seven rivers in Japan. Both B/H (river width/water depth) and riverbed level has been declining since 1970. The gravel and sandy riverbed has been proportionally diminished at the rate of 5,000 to 40,000 (m2/year) at five rivers. On the other hand, the area of vegetation and artificial landcover has been expanding since 1970." |
