We present a method for modeling and separation of waterlayer- related multiples in towed streamer acquisitions. Our method models accurately the kinematics of multiples with bounces in the water layer, both on the source and receiver sides, and extends the capabilities of previous methods in particular for the cases with complex topography on the sea bed. We illustrate the method with synthetic data and with field data from a shallow-water 3D towed-streamers marine survey.