Abstract Ecological systems such as shallow lakes areusually non-linear and display discontinuitiesand hysteresis in their behaviour. Thesesystems often also provide conflicting servicesas a resource and a waste sink. This impliesthat the economic analysis of these systemsrequires to solve a non-standard optimalcontrol problem or, in case of a commonproperty resource, a non-standard differentialgame. This paper provides the optimalmanagement solution and the open-loop Nashequilibrium for a dynamic economic analysis ofthe model for a shallow lake. It alsoinvestigates whether it is possible to induceoptimal management in case of common use of thelake, by means of a tax. Finally, some remarksare made on the feedback Nash equilibrium.