A trimatrix approach is proposed for evaluating the impacts of technological alternatives on different urban uses of water and related land areas and, in turn, the impacts of these uses on urban goals and values. This provides a systematic accounting system for mapping the interrelationships of the decision criteria of the research planner, the water resources planner, and the urban planner. This analytical tool is quite useful to the process of technology assessment which is receiving increased emphasis nationally and internationally in making new technologies more responsive to social needs as reflected in the desire to protect and enhance the quality of the environment and the quality of urban living. The trimatrix method was applied to contrasting case studies of the urban water and related land uses and potential technological developments affecting the Phoenix and Baltimore metropolitan areas. The case studies revealed the highly complex nature of the technology assessment process and the difficulty of evaluating impacts on urban goals and values. Numerous information deficiencies need to be surmounted in refining the methodology and developing more socially optimal planning decisions affecting water resource utilization in achieving urban goals. (Author)