Portal:Rivers/Did you know

Instructions
These "Did you know..." subpages are randomly displayed using Random portal component.
 * The layout design for these subpages is at Portal:Rivers/Did you know/Layout.
 * 1) DYKs at this list must have successfully already appeared at Template:Did you know.
 * 2) Add a new DYK set to the next available subpage.(Only include completed sets of 3 with a picture)
 * 3) Update the max value at the portal main page - Portal:Rivers