A floodplain is land near a river. It may be covered with water after a heavy rain.
Floodplains are dry most of the time, and often go years without being flooded.
The land is nearly flat, but it slopes gently down to the river on your left.
To the right, the land rises steeply from the floodplain up to the road.
During a rain, excess water runs off the higher land and onto the floodplain. Instead of going directly into the river, the floodplain holds the water like a sponge, slowly letting it seep into the ground. It acts as a buffer and reduces erosion. Sediments settle on the floodplain instead of entering the river directly. The floodplain filters out impurities which would otherwise pollute the river.
Sometimes people make buildings on floodplains. Then they put up barricades to keep floodwater from entering the floodplain and ruining their structures. But the water has to go somewhere -- so the river overflows its banks and floods someplace else instead. The new area may not be as well suited to store the excess water as the original floodplain. Instead of filtering out impurities, the newly flooded area may actually add impurties to the river. For example, if a parking lot is flooded, grease and oil from the cars are washed into the water supply.
Nearby on the trail you can find bittersweet vines.