The Canadian Environmental Assessment Act (CEAA) defines the federal environmental assessment (EA) process for evaluating the likelihood that development projects (e.g., roads, buildings, factories) will have impacts on the environment. Environmental effects monitoring (EEM) programs for mining and pulp and paper mills under the Federal Fisheries Act, define the process that is to be used to evaluate existing effects caused by liquid effluents discharged by operating facilities. The EA process occurs before a project is approved, and involves predicting whether the project is going to cause significant environmental impacts. The EEM process occurs after a project is operational, and involves determining whether an existing project has had or is continuing to have significant impacts on the environment. Ideally, the processes are complimentary, with the EA process identifying environmental attributes considered important, and the EEM process demonstrating whether predicted or unpredicted impacts occurred. The two processes are usually done in isolation so potential synergies are lost. The point of this manuscript is to justify bridging the two processes. We use the aquatic environment as the example, and briefly describe the EEM process, aquatic environment indicators, experimental designs, and typical environmental thresholds, to illustrate how the EEM and EA processes link.