The Archimedes screw turbine has rapidly become the most popular turbine in the UK for micro hydro projects. Even H.m. Queen Elizabth II has decided to get one (made in Holland by a German company, SEPEL installed). The PR departments spin the turbines (ouch!) as Dutch..... not that it matters. What is worth noting though - is that the turbines couldn't be built in the U.K. because no bank would lend the Queen the money - can you believe that?
As waterpower installations increase it's only normal that people seek to improve the efficiency, environmental impact and reliability of Archimedes turbines and there's a few variations on the theme out there.