Monitoring of solitary wave on water surface is introduced. For this purpose, a water basin for a hydraulic modeling is used. Under a given boundary condition of a hydraulic model, a sinusoidal wave is propagates to pass a slit to diffract just like a case of Fresnel diffraction of optical ray. A specific linkage of boundary conditions, bathymetry, and a generated sinusoidal wave with a specific period is found for producing a solitary water wave in the basin. Some experiments are helpful for basic understanding of a process of solitary wave formation at a generated sinusoidal wave. Then, the author tends to consider whether this solitary wave might suggest that the strange peak observed during the monitoring tsunami waves accompanied by the 2011 earthquake in the northwest Pacific.