All four wetlands (Upo, Mokpo, Sajipo, and Jjokjibeol) are about a meter in depth and surrounded by an embankment. Seasonally, some parts of the wetland floors are exposed, revealing the variety of ecological conditions favorable to plants like willow colony, reed, great duckweed, and Canada parrot feather. Numerous flowers blossom in spring and the area becomes greener with yellow water snowflake, water chestnut, and pickerelweed floating on the water during summer. In August and September, the rare thorn lotus wrapped in thorns blossom their purple flowers and the reeds swaying in the wind create a picturesque scene. When the wind blows colder in winter, water plants sink under the water and go into hibernation until spring. This is the time for migratory birds to pick their fruits and stems.
Uponeup Wetland offers a place of respite for migratory birds traveling between South and North. Winter is the best time to observe migratory birds as approximately 30,000 of them fly 4,300 km to 6,000 km to Uponeup Wetland in October to escape the cold of the North Polar regions. These include wild geese, swans, mallards, and auks. In summer, such birds as the common kingfisher, bush warbler, and common heron visit the area to lay and hatch eggs. Birds such as titmouse, flycatcher, and magpie live there year-round, and some endangered species like kestrel, stork, and whooper swan are also found there, too.