Engineer Circular 1105-2-412, "Assuring Quality of Planning Models" , dated 30 December 2009, provides guidance for the certification/approval process of planning models.
EC 1105-2-412 defines a planning model as any models and analytical tools that planners use to define water resources management problems and opportunities, to formulate potential alternatives to address the problems and take advantage of the opportunities, to evaluate potential effects of alternatives and to support decision-making. It includes all models used for planning, regardless of their scope or source, as specified in the following sub-paragraphs. This EC does not cover engineering models used in planning which will be certified under a separate process.
These include but are not limited to models used to define the future without project condition, models used for plan formulation, models used to compute economic benefits, models used to assess the environmental impacts of alternatives, and any other models essential to the planning process and deifned in Paragraph of the EC.