Tidal marshes are that part of the river bank that overflows with every tide. Only few plants last here. The mud however is brimming with micro-organisms such as worms, crabs, small crayfish, ideally suited for ducks and stilt-walkers. With each tide a small layer of sediment is left behind, thus raising the level of the flats and causing them to gradually rise above the waterline. As a result they are no longer submerged with each and every tide, causing them to become mudflats.
Mudflats are only submerged during springtide. Tides cause water levels to rise on some and drop on other spots. Mudflat borders can be caved and in the centre gullies appear and new tidal marsh areas. This dynamic environment is populated with specific fauna and flora. Plants sustaining temporal flooding by freshwater and seawater start to appear. (source: Agency for Nature and Forest)