That is 330 million not billion. This is about 1/30 of the total flow of the Gulfstream. Also, since the flow is going in the same direction as the gulfstream we only have to account for a one mile per hour loss af speed of the water going through the tunnel due to frictional and verticle lift losses through the tunnel. Only 1/30 of total amout of the Gulf stream is flowing through the tunnels at any given time.There are more frictional losses in the Gulfstream due to ships traveling through it every day. So little effect if any to the Gulfstream will occur . This is well worth the investment if it can save lifes and 200 billon in damages per storm. The tunnels restore the balance to planets warming problem caused by greenhouse gasses and at the same time privide power to 22 million people and sealife loves them.