The purpose of this article is to explore some considerations based on the criterion of pure economic efficiency necessary to design efficient public policy for the allocation of public-interest environmental assets. A version of the Fisher and Krutillas’s model is proposed to study the problem of natural resources optimal allocation under conflicts of use between conservation and development. The model is a tool to determine the best use of an urban natural environment in Bogota, Colombia. Under the scenarios of conservation-passive use, conservation-active use and partial development, the major and the best use for the urban natural environment is the option of conservation-passive use. This option reports a cost benefit ratio of 3.44, estimated with the Contingent Valuation method of non-market values under this option. This information is useful for policy makers to choose the major and the best use for the urban natural environment.