NEPA requires that sponsors of transportation projects consider the impacts of those projects on water quality and water resources. There are numerous methodologies available to perform these analyses; however, there is little or no guidance on the appropriate method for a NEPA analysis versus other purposes. This study reviewed currently available water quality models / methodologies used for analyzing potential impacts of transportation projects, provided a description and assessment of each model/method and a determination of whether the model/method is out-dated or valid. When valid, the study identified the type of project or level of analysis the model/method is best suited to as well as any limitations to the model's use.
