1D_Shallow Water Equation_Dam-Break Problem using Lax-Wendroff method

How to formulate these equations using Lax-Wendroff method ?

For burger's equation both temporal and spatial terms are same, here they differ, so got struck in formulating Lax-Wendroff for these equations......

dH/dt + d UH/dx = 0, d UH/dt + d ( U^2 H + 1/2 g H^2 )/dx = 0

Any explanations on how to program these equations ?

Thank you.