The development and use of web-enabled tools for watershed modeling and decision-making have gained popularity lately with the increase in internet speed and accessibility. Most of the web-enabled tools available today address the watershed problems related to a narrow discipline like hydrology, or ecology etc. This thesis presents the work done in the development of a web-enabled integrated system, named WebL2W, which can address watershed problems in a more holistic approach.

WebL2W integrates models from hydrology, economics, and biology in a single shell. The integration is performed using GIS as a common platform for database and interface management. A user accesses the system over the web and chooses pre-selected land development patterns to create a 'what if' scenario. The hydrologic model simulates effects of the scenario on annual runoff volume, flood peaks of various return periods, and ground water recharge. The economics model evaluates the changes in land value, tax revenue, and government expenditures as a result of the new land development scenario. The biology model evaluates effects of new land uses to fish habitats in the watershed. The design of the system is based on current software engineering practices such as object oriented programming (OOP) and relational database management system (RDBMS). The implementation uses the Visual Basic programming environment and Active Server Pages.