Unmanned Aerial Vehicles (UAV) are being increasingly utilized by the geophysical community for large-scale surveys of environments that are challenging to reach (e.g. volcanoes, glaciers). Some of these natural systems include large bodies of water such as oceans, lakes and rivers. Here, we propose to employ a specifically-developed UAV system to remotely and safely gain high-resolution images of the water surface. Application of Particle Image Velocimetry (PIV) algorithms allow for the complex two-dimensional flow fields of the water surface to be accurately resolved. Specifically, we present details of a Scale Invariant Feature Transform (SIFT) that permits accurate rectification of the images. These data are key to informing and calibrating predictive tools that can reconstruct potential emergency scenarios. Here, we discuss the concept and technology employed to render these measurement systems effective, and provide examples of applications that show the fidelity of the data that can be extracted from aerial images, and thus the vast potential of this technology.