Amber is not a good swimmer. 

At all. 

In her normal life, her family would travel to a lake every other weekend, and they would all go swimming and have one big picnic.

Amber hated the fact that she couldn't see what lay underneath the surface of the murky lake water, and so developed a slight fear of swimming in the lake. She would always think of an excuse not to go swimming, such as "I have cramps" or "It's that time of the month" or something  like that.

The only reason she is able to swim at all, even though she's quite terrible, is because of the few times when she went to a pool and was able to practice her swimming in the clear water