1. A method of detecting structural changes to underwater structures comprising: directing an acoustic sonar wave toward an underwater structure; receiving the acoustic sonar wave reflected from the underwater structure, obtaining 3D data points from the acoustic sonar wave reflected from the underwater structure, the 3D data points are configured to provide a three-dimensional image of the underwater structure; aligning a sample of the data points obtained to the pre-existing three dimensional model of the underwater structure; generating a change detection model based on the aligned sample; comparing the change detection model to the pre-existing three dimensional model of the underwater structure; and based on the comparison, detecting whether a structural change in the underwater structure has occurred.