Environmental planners take advantage of Spatial Decision Support Systems (SDSS) to deal with data and models for problem solving. However, these kinds of software usually provide generic models, which require considerable effort to be specialized to fit particular situations. This paper explores a solution which couples Case-Based Reasoning (CBR) to an existing SDSS, named WOODSS, to help planners to profit from others' experiences. WOODSS is based on a Geographic Information System, and interactively documents planners' modeling activities by means of scientific workflows, that are stored in a database. This paper describes how CBR has been used as part of WOODSS' retrieval and storage mechanisms, to identify similar models to reuse in new decision processes. This adds a new dimension to the functionality of available SDSS. (c) 2004 Elsevier Ltd. All rights reserved.206689704