Wetlands form in any depression where water collects. They may be spring fed, run-off ponds, bays or backwaters, glacial pot holes, or old river bends now separated from the main stream.
Wetlands are very important for many reasons. They hold water on the land so it can seep down and recharge the aquifer. They are important in flood control and they filter out contaminants and sediment. Wetlands produce the greatest food biomass of any environment and provide habitat for waterfowl and many other kinds of wildlife.
Large numbers of insect larvae develop in water then crawl up the stems of aquatic vegetation and emerge as flying adults. These larvae provide abundant food for growing ducklings, turtles, fish, and many other water creatures. Numerous species of birds, not normally considered water birds, nest near wetlands because of the wonderful supply of insect foods for their young. Watch for swallows swooping over the water catching flying insects.
Like streams, wetlands usually have lush sub-irrigated plant life along their shores. Aquatic vegetation can get a foothold directly in the still waters and include plants with a variety of strategies. Cattails and rushes, called emergents, are rooted near shores and grow up out of the water. Water weeds are mostly under water with their roots in the silt at the bottom of the pond and their blooms on the water surface. Plants such as duck weed float on the surface with roots that hang down, drawing all their nutrients from the water alone. These tiny leaved plants are the green vegetative cover you see on the ponds.