For the wave, I used a Image from one of our CD, we use @ work (I asked my Boss if it's ok):
step 4 of 7
I choose the one which suites the best:
step 5 of 7
For more details, I modified the mask by brushing parts of the bridge, so the wave go over it:
step 6 of 7
To get a better transition from one image to the other, I put an Selective Color Correction as a single layer, brush the bottom of the wave image, and play around with "Cyan" and "Blue" to get a satisfying result.