The second step of the planning process is "to develop an inventory and forecast of critical resources... relevant to the problems and opportunities under consideration in the planning area. This information is used to further define and characterize the problems and opportunities. A quantitative and qualitative description of these resources is made, for both current and future conditions, and is used to define existing and future without-project conditions." (ER 1105-2-100 :page 2-3). Chapter 7 of the Planning Guidelines addresses this step (page 132 of the Planning Manual).
The inventory is to collect sufficient information to plan and present the project. Information is needed on relevant historic conditions and current conditions. Forecasting is done to describe future conditions with and without the project so the effects of putting the project in place can be estimated. Page 139 of the Planning Guidelines includes Table 21 with a list of topics that may be relevant, and Table 22 illustrates the next level of detail using a problem of flood damages.