section_path: Topography/The terminus
section_name: The terminus
paragraph_text: The terminus
  
  While rivers may flow into lakes or man-made features such as reservoirs, the water they contain will always tend to flow down toward the ocean. However, if human activity siphons too much water away from a river for other uses, the riverbed may run dry before reaching the sea. The outlets mouth of a river can take several forms. Tidal rivers (often part of an estuary) have their levels rise and fall with the tide. Since the levels of these rivers are often already at or near sea level, the flow of alluvium and the brackish water that flows in these rivers may be either upriver or downriver depending on the time of day.
  
  Rivers that are not tidal may form deltas that continuously deposit alluvium into the sea from their mouths. Depending on the activity of waves, the strength of the river, and the strength of the tidal current, the sediment can accumulate to form new land. When viewed from above, a delta can appear to take the form of several triangular shapes as the river mouth appears to fan out from the original coastline.