This publication provides the results from Working Group 1, on Reference Methodologies for Controlling Discharges of Routine Releases, of the IAEA's EMRAS II (Environmental Modelling for Radiation Safety) programme, which ran from 2009 to 2011. This Working Group carried out an intercomparison of methods used for assessing radiological impacts to people and the environment due to authorized releases of radionuclides during normal operation of nuclear facilities. Three important types of exposure scenarios were considered, those related to atmospheric, marine and river releases. The publication describes the details of the hypothetical radioactive release scenarios, the environmental pathways considered, the environmental transfer models applied, the calculation methods and the results obtained. An analysis of the results and the main findings and conclusions relevant for the use of the described input data and methodologies in regulatory applications is included. The publication also presents considerations on selection of the 'representative person' and a summary of the different approaches in some States for the regulatory control of radioactive discharges. Input data is included in the annex.