Purpose: This Engineer Manual (EM) describes the Technical Project Planning (TPP) process for identifying project objectives and designing data collection programs at hazardous, toxic, and radioactive waste sites, The TPP process helps ensure that the requisite type, quality, and quantity of data are obtained to satisfy project objectives that lead to informed decisions and site closeout. The TPP process can be used from investigation through closeout at small, simple sites as well as large, complex sites. The TPP process is a critical component of the U.S. Army Corps of Engineers (USACE) quality management system that meets the American National Standard for planning the collection and evaluation of environmental data. This EM is intended for use by USACE project managers and both technical and contractor personnel for implementation of Engineer Regulation (ER) 5-1-11.