Deformation of irregular waves due to river flooding and shoaling is examined experimentally. In designing port facilities in an estuarine area, not only wave shoaling but also interactions between surface waves and a river current must be considered. The present paper describes the two-dimensional experiemnts to investigate the wave deformation which propagates in a sloping beach with adverse current conditions.
　To investigate the influence of river currents on waves in Tottori Port area, beach profile in front of Sendai river is reproduced with the model scale 1/150. Two types of irregular waves are ussed for the experiment together with regular waves for comparison.
　Waves are measured at eight stations with resistance wave gauges from the deep water area to the river mouse.
　Deformations of wave heights and speactra including shoaling and breaking together with interactions with currents due to river flooding are investigated.
　The results are summarized as follows:
(1)Influence of currents on wave heights must be considered from the offshore to the breaking point.
(2)Modified Goda's formula for the wave breaking is presnted for the prediction of wave heights in adverse currents.