Design of object-oriented water quality software system

Software models are important for the evaluation and management of environm ental resources. This paper presents a framework for developing a software system for water quality analysis of river ecosystems. A major component of the system is a database that permits inclusion of analytical water qualit y and sediment data, river geometry and sampling site characteristics, hydr ologic measurements, and reference information on water quality parameters and criteria. Associated with the database is software for managing, analyz ing, and representing the information in the database. An abject-oriented s trategy is applied to derive a model of the software system. The resulting object-oriented design is then translated into an entity-relationship model , which is in turn translated into a relational model. The formality of thi s translation process ensures consistency among the successive design stage s. The overall development approach to system design and implementation is described, and an application for evaluating water quality conditions in th e lower Mississippi River is presented.