I wonder if you have a "swivel bucket" (a wider bucket for gravel)?? I'm pretty sure that the excavator is heavy and strong enough to work with a bigger bucket. Do you have biological hydraulic oil in your machine? In Germany where I worked we had few machines specific for working in water areas like in this video. If there is a leak it's not a problem because the biological hydraulic oil can decay biological and isn't dangerous for the environment 👍❤️