Since the humans started settling and performing agriculture, they started to have a big impact on the marshes. People started to drain the marshes when they came to a situation to be able to perform that. This was done for multiple reasons:
- the marshes had lots of insects that were transmitting diseases, so the humans wanted to remove the danger;
- a typical marsh is in a lowland region, it is shallow, and has relatively flat floor, so humans saw an opportunity to use that land for agriculture;
- because of the shape of the floor of the marshes, the humans also saw a potential in them as places for inhabiting, were building was going to be easy because of the flat surface.
In the modern time, the marshes are also heavily impacted by pollution from multiple sources caused by the humans, and that damages their ecosystems and even totally destroys them.