People without training and coordination with a larger system can cause problems, especially if he encourages other untrained people to do it.

It sucks but there’s billions of us so it’s gonna suck. At least that’s what my local councilman (and dad) said when I complained I needed to ask permission to change my deck.

Two years in prison is stupid though. Make him work with the groups who have approved plans.

And I hate that this is the answer I’m giving but honestly it’s the only thing keeping me from renting a bulldozer and making my neighborhood walkable.

Can't, since it doesn't 🤬

It's in the fine article:

The EA’s main complaint seems to be that the dredging was significant enough that it constitutes a flood risk.

I'm gonna lean on another commenter who made me realise the legitimate reasoning behind something like this (disregarding the fact that two years is absurdly high): If we permit anyone to do whatever "cleaning" they themselves deem reasonable without approval, we risk that unknowledgable people with good intentions cause serious damage. One reason could be that they create an acute flood risk (you're right: garbage shouldn't be flood protection, but the actual flood protection is built around existing circumstances, and if removing the garbage causes a major risk to people losing their homes, the correct approach is to first prepare the flood protection, then remove the garbage). Another is that people can unknowingly or unintentionally destroy habitats or otherwise damage the environment.

The point is: We have some very competent people that are capable of assessing the impact of various cleaning operations. We need to let those people do their job. There can be very complex interactions in play, that turn your good intentions into catastrophic consequences. Therefore, we cannot allow laymen to judge how large cleaning operations should be conducted.

Full disclaimer: While I think the above reasoning is sound, I think we should be very careful regarding how unauthorised cleaning operations are punished. For example, it seems absurd to me to give jail time for it. When the person in question is obviously acting with good intentions, it's much more reasonable to sentence them to take some course where they can learn about why what they were doing was potentially harmful, and perhaps sentence them to community service working on some authorised project. That way, you help them learn, let them work on something they want to contribute to, and get more resources for the authorised projects.