Which of the following can not be legally prepared by a professional planner?

The ability for a professional planner to engage in various planning activities is often delineated by their scope of practice, which is influenced by legal and professional standards. The correct answer highlights that drainage facilities involving storm water detention typically require specialized training and knowledge that go beyond the general purview of a professional planner.

While professional planners may certainly play a key role in land use planning and site design aspects, the specifics of engineering designs for stormwater facilities—such as detention basins—usually fall under the domain of civil engineers or trained professionals with specific expertise in hydrology and engineering principles. This role requires an understanding of complex hydrological processes, engineering calculations, and regulatory compliance that professional planners may not typically possess or be licensed to perform.

On the other hand, the other options outlined involve activities that are generally within the purview of a professional planner. For instance, general floodplain determination, site circulation planning, and landscaping design can be effectively handled by planners, as these tasks align more closely with land use, site planning, and design principles that focus on usability, accessibility, and aesthetic considerations rather than the technical engineering aspects required for stormwater management systems. Thus, the choice regarding drainage facilities is accurate in distinguishing the boundaries of professional planner responsibilities.