wetlands

A wetland is a distinct ecosystem that is flooded by water, either permanently or seasonally. Flooding results in oxygen-free processes prevailing, especially in the soils

https://www.environment.nsw.gov.au/topics/water/wetlands/plants-and-animals-in-wetlands

the wetland habitat is home to many animals and plants like frogs, fish, freshwater crayfish and more animals and with plants like reeds, watercress, lily pads and more

Although some wetlands can form relatively quickly, many others took thousands of years to develop. Here are some of the processes that form or modify wetlands:

• Flooding of coastal lowlands from rising sea levels has created broad coastal marshes that are protected from wave action by barrier islands or reefs. Coastal wetlands also form when rivers deposit sediment as they reach the ocean. Plants then take root and hold the soil firm against the forces of tides and waves.

• River floodplains develop through erosion processes and through deposition of sediment on adjacent lands during floods. Wetlands form on floodplains where periodic flooding or high water tables provide sufficient moisture. These "riparian" wetlands may undergo constant change as rivers and streams form new channels and when floods scour the floodplain or deposit new material.