Unwrap Curved Flat Stripe How to unwrap this curved flat surface? 

How to unwrap such mesh properly? I want to fix texture mapping on the curved part of the mesh. My plan is to make smth like river animation(U coordinate animation).

Wireframe and texture:
 

Thank you!
start with a shape like this and unwrap it.



then add an array modifier and a curve modifier to control the array.



Blend file here