The River Function Questionnaire (Questionnaire) is a series of questions designed to help stakeholders determine the impacts of hydropower on a series of environmental indicators, i.e. river functions, that may need to be understood or addressed through additional field studies or environmental assessments. In order to provide a platform accessible to many users, the questionnaire was developed in Microsoft Excel with convenient macro-enabled interactive features. The Questionnaire was developed under the Department of Energy (DOE)-funded Environmental Metrics for Hydropower (EMH) project in FY 2018. This document provides an instruction manual that provides overall guidance and step-by-step instructions for use.