Abstract
Coarse woody debris (CWD) is an important material for providing habitats for aquatic organisms. In this study, pieces of CWD of different sizes were artificially installed in a creek and their effects on the physical and biological environments were investigated. The flow velocity decreased and the water depth increased near the CWD. The streambed sediment was composed of sand in the upstream of the CWD and gravel in the downstream of the CWD. Fish were abundant near the CWD, and aquatic insects increased in number. It is postulated that the water flow changed due to the topographic alteration caused by the CWD, and that the CWD had some role in providing habitats for various aquatic organisms, resulting in their increased abundance. The effects did not significantly vary depending on the size of CWD, and even a small piece of CWD had a significant effect.
https://ror.org/05f8a4p63 
