The flow in a suddenly expanding rectangular channel with movable bed comprised of 0.28 mm diameter material is studied using expansion ratios up to 4.5. The longitudinal velocity distribution is found to follow cosine law for small expansion ratios, which gradually changes to Gaussian distribution for expansion ratio of 4.5. The scour depth profiles are found to follow cosine law. The other characteristics studied include shape of separating stream lines and average height of longitudinal deposition bar.