Normally, currents in the Gulf carry water from the muddy Mississippi River from the coast of Louisiana all the way down to the upper Texas coast and Galveston. This is why the surf in Galveston is usually a bit brown. It's healthy for fish and marine life, but not as pretty as we humans sometimes like.
Every now and then, the currents shift. A central gulf counter current expands. The flow down the coast from the Mississippi stops. The water clears up and man is it a treat. I don't know know much longer this phenomenon will last, but I'm heading down to the water this weekend to see for myself. Cheers Galveston!
