Section 4(2)(ii) in The Bihar Irrigation and Flood Protection, (Betterment Contribution) Rules, 1961
(ii)In the case of a work which is ancillary to the main flood protection work such as a sluice on a flood protection embankment, no betterment contribution shall be leviable in respect of the irrigational facilities it may incidentally provide to any land which has been benefited by the flood protection work.