This paper presents a prototype software system for integrated environmental modeling that provides interoperability between the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) Hydrologic Information System (HIS) and the Open Modeling Interface (OpenMI). The primary motivation for making these two systems interoperable is that the CUAHSI HIS has a primary focus on hydrologic data management and visualization while the OpenMI has a primary focus on integrated environmental modeling. By combining the two systems into a single software application, it is possible to create an integrated environmental modeling environment that scientists and engineers can use to understand and manage environmental systems. Using standards to achieve the steps required to find, gather, integrate, and analyze hydrologic data allows for a wide community of groups to participate because it establishes key rules and protocols that must be followed in order to add to the overarching system. The key contribution of this work, therefore, is an investigation of two standards in the community and exploring ways to provide interoperability between them. HydroModeler is a software implementation of our work and provides an OpenMI-compliant modeling environment embedded within the CUAHSI HIS HydroDesktop software system. We describe the design and implementation of this prototype software system, and then present an example application in which evapotranspiration is modeled using OpenMI components that consume HIS time series data for input. Finally, we conclude with a summary of our experience exploring the potential for interoperability between data and modeling systems, and suggest ways in which future development can better facilitate connections between the various subsystems needed within an integrated environmental modeling system. (C) 2012 Elsevier Ltd. All rights reserved.