Central-upwind scheme for two-layer shallow water equations
 

I am having trouble implementing the 1-D central-upwind scheme as proposed by Kurganov and Petrova (see reference, available for free if you google the paper). The scheme presented in section 2.2 is used to discretize and solve the system 2.1. I am trying to familiarize myself with the handling of nonconservative and geometric source terms so that I can apply it to my own work.
Basically, since I can't seem to pinpoint where my mistakes are, I am wondering if anyone has solved the shallow water equations using this scheme and is willing to share their code with me.

References

Kurganov, Alexander, and Guergana Petrova. "Central-upwind schemes for two-layer shallow water equations." SIAM Journal on Scientific Computing 31.3 (2009): 1742-1773.