On literature we had Two modified Thornthwaite-Mather Water Balance (TMWB) models were calibrated using historic rainfall and discharge data and shown to reproduce dry-season flows with NashSutcliffe efficiencies between 0.86 and 0.91 for a especific area, wher you can take details at: http://www.geo.mtu.edu/rs4hazards/Project%20resources/theses/fish_thesis.pdf