Kala duwanaansho badan oo ah ikhtiyaarada birta - bamgareynta gadaal iyo hore (mashiinnada xiran) waxay yareeyaan dib-u-wareejinta gudaha bamka, iyo caawinta kahortagga wasakheynta shaabadda - tuurista ikhtiyaarka ah ee Vanes toosan ama semi-Francis (laga bilaabo 2 ilaa 8 vanes ee cabbirro gaar ah) waxay bixiyaan fursadaha haydarooliga ballaaran ee hal cabbir.