This paper presents a cost-benefit analysis for alternative programs intended for the control of the nuisance growth of an attached alga (Cladophora). Such analyses require that changes in water quality be quantitatively related to the cost of implementation for specific management strategies. In this study, a mathematical model for Cladophora growth provided the link between management strategy and water quality. Credibility of the model as a management tool was established through a program of model development, calibration and verification at a site on Lake Huron. The modeling program was complemented by an extensive field monitoring effort and comprehensive scientific studies defining the processes of nutrient uptake and algal growth. Cost-benefit analyses were prepared for three general control strategies.