Step one:
First draw a semicircle.
Step 2:
Then draw some long shapes on it, paying attention to symmetry.
The third step:
Draw an arc below to connect it.
Step 4:
Then draw sections of double arcs between the long strips.
Step 5:
Below, use arcs to draw the feeling of a small river.
Step 6:
Finally, apply a nice color, and the bridge is finished.