How do Salva and Nya demonstrate kindness in A Long Walk to Water?

Salva shows kindness by working hard to provide the people of Nya's village with a regular supply of clean, safe, drinkable water. This is something that most of us in the developed world take for granted, but in South Sudan, where Salva and Nya live, it's a completely different story. Here, people must trek long distances to draw water from a brown, muddy pond that's also used by animals.
Nya shows kindness by embarking on the long, arduous trek to the pond every day to fetch water for her family. This journey covers several miles each day, there and back, across harsh and potentially dangerous terrain. And yet Nya is so utterly devoted to the welfare of her family that she makes this journey without complaint or hesitation.