Abstract
Alternate bar is common bed form and closely associate with flood disasters and natural environment, it is important to elucidate its formation condition and formation mechanism. However, the formation mechanism of alternate bar is not well understood. As a factor to that, measurement method for water and bed surfaces when developing alternate bar in either flume experiments and actual rivers may not be established yet. We developed a new simultaneously measurement method for water and bed surfaces in evolution process of alternate bar without stopping supply water. We verified accuracy of the measurement method in fixed bed and movable bed condition. The result showed that accuracy of measured bed shape was several percent of wave height of alternate bars at 1cm square resolution in flowing water. The method can be completed simultaneously measurement in about 10 seconds in experimental flume of 10 meter length.
