Stormwater runoff can cause both flooding and the spread of pollutants, so it is important that it be managed effectively. This project investigates the watershed scale implementation of green stormwater infrastructure. The aim of the project is to create a modeling framework to be used in transportation planning. It will model the effect of green stormwater infrastructure on flooding and water quality, and assess their life cycle costs and environmental and health impacts. National Pollutant Discharge Elimination System (NPDES) regulates that transportation authorities are responsible for managing the stormwater runoff that carries pollutants from the land adjacent to road transportation systems. Green stormwater infrastructure (GSI) is a stormwater management approach with many economic and human health benefits. However, implementation and analysis of GSI at system level or urban watershed scale is generally lacking. As Roy et al. (2008) pointed out that “sustainable urban stormwater management must be planned and implemented at the watershed scale,” a framework is needed to design and evaluate the integration of GSI in transportations planning at system level. The overall goal of the proposed project is to develop a modeling framework integrating hydrologic simulation, water quality modeling, life cycle assessment (LCA) and cost analysis (LCCA) that can be used for design and planning for surface transportation with the spatial implementation of GSI. The objectives of the project include (1) developing a method for constructing an inventory of the implemented GSI using Tampa as a case study area; (2) integrating hydrologic modeling with water quality modeling for scenario analysis of GSI implementation at watershed scale; and (3) developing a spatial optimization model for GSI implementation based on the integrated LCA-LCCA-optimization framework. Corresponding to the set of objectives, the project is conducted in phases. Based on the completed Phases I and II, Phase III research will work on the development of a spatial optimization model. Furthermore, the trade-off between environmental, human health, and economic impacts will be investigated for the optimal and other scenarios of GSI implementation.