A method of estimating water turbidity using image data, comprising: capturing underwater, by at least one imaging sensor a plurality of images; using at least one processor for: analyzing the plurality of images captured by the at least one imaging sensor to identify at least one object submerged at least partially in the water and distinguishable from its background, each of the plurality of images being captured from a respective one of a plurality of distances between the at least one imaging sensor and the at least one object ; calculating a luma value for each of a plurality of pixels along a corresponding at least one intensity gradient line across the at least one object in each of the plurality of images: calculating , for each image, a respective maximal intensity change between a lowest luma value and a highest luma value of the pixels along the at least one intensity gradient line in the respective image; evaluating a turbidity of the water based on mapping of the respective maximal intensity change to each of the plurality of distances; and initiating at least one action in case the turbidity exceeds a certain threshold. capturing underwater, by at least one imaging sensor a plurality of images; using at least one processor for: analyzing the plurality of images captured by the at least one imaging sensor to identify at least one object submerged at least partially in the water and distinguishable from its background, each of the plurality of images being captured from a respective one of a plurality of distances between the at least one imaging sensor and the at least one object ; calculating a luma value for each of a plurality of pixels along a corresponding at least one intensity gradient line across the at least one object in each of the plurality of images: calculating , for each image, a respective maximal intensity change between a lowest luma value and a highest luma value of the pixels along the at least one intensity gradient line in the respective image; evaluating a turbidity of the water based on mapping of the respective maximal intensity change to each of the plurality of distances; and initiating at least one action in case the turbidity exceeds a certain threshold. analyzing the plurality of images captured by the at least one imaging sensor to identify at least one object submerged at least partially in the water and distinguishable from its background, each of the plurality of images being captured from a respective one of a plurality of distances between the at least one imaging sensor and the at least one object ; calculating a luma value for each of a plurality of pixels along a corresponding at least one intensity gradient line across the at least one object in each of the plurality of images: calculating , for each image, a respective maximal intensity change between a lowest luma value and a highest luma value of the pixels along the at least one intensity gradient line in the respective image; evaluating a turbidity of the water based on mapping of the respective maximal intensity change to each of the plurality of distances; and initiating at least one action in case the turbidity exceeds a certain threshold. <EOS>