Accurate determination of evaporative flux from water surfaces and liquid containing porous media is critical for geotechnical and geoenvironmental applications. Laboratory simulations can isolate the various parameters influencing evaporative fluxes. However, most simulators capture selected surface and atmospheric conditions, and published literature generally provide limited information on the development and operation of the instruments. The new simulator adequately captures a wide range of relevant field parameters, maintains controlled conditions over the required testing time, utilizes readily available components for modular fabrication, and facilitates operational efficiency between individual modules.