One of the key components to achieving a high level of realism in today's training simulations is the ability to dynamically interact and manipulate the synthetic environment utilized by the simulation. Whether the interaction is the result of naturally occurring environmental effects, such as flooding and erosion, or simulation driven events, such as bomb craters, dynamically manipulating the synthetic environment provides critical feedback to the warfighter that is representative of real world engagements. In recent years, many research efforts have been undertaken to support the correlated representation of dynamic terrain in a federated simulation environment. However, much of those research efforts have focused entirely on the dynamic manipulation of the underlying terrain polygons and associated visual representation without considering the dynamic modification of the original source data or other derived datasets that are utilized by client devices participating in the training event. In today's Modeling and Simulation (M&S) environment, there are a wide number of applications and client devices that utilize native GIS source data at run-time and require more than just updated terrain polygons and visual images. In order to support dynamic modifications to the synthetic environment applicable to a full range of M&S applications, a comprehensive approach must be taken to ensure that multiple data types and formats can be dynamically modified and updated at run-time. In this paper we will provide an overview of the current approaches for achieving dynamic terrain and present a proposed method for the dynamic run-time modification of synthetic terrain data to support correlated visual, sensor, and SAF devices. The approach presented will utilize event-driven changes to dynamically modify and manipulate multiple data sources in a central repository with the use of an event notification mechanism to ensure all client devices are updated to reflect the latest changes to the environment at run-time.