What is the depth of the water?
The water is shallow.
    src        edge_attr  dst
0     0  to the right of    3
1     1   to the left of    6
2     1   to the left of    5
3     3   to the left of    0
4     3   to the left of    8
5     5  to the right of   12
6     5  to the right of    1
7     5   to the left of    9
8     6  to the right of    1
9     8  to the right of    3
10    8  to the right of   10
11    9  to the right of    5
12   10   to the left of    8
13   12   to the left of    5