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. IDENTIFICATION OF THE FLOODPLAIN The starting point of any floodplain management program is identification of the floodplain. This chapter discusses the reasons for identifying floodplain areas. the engineering methods used for delineating the floodplain. and the CWCB's designation process for floodplain studies performed in the state. It was written for an administrator who needs to know the procedures and language of the professionals who will assist in or actually perform the technical work associated with identifying a floodplain. . The Role of Floodplain Identification in a Local Floodplain Management Program The identification of floodplains in a community begins with acknowledging the hazard, describing the characteristics of the problem, and formulating solutions.' Acknowledging the hazard The extent of a community's drainage and flooding problems can be ascer. tained through good documentation of historical flood events or through a flood hazard analysis or both. Describing the Flood Characteristics The hydrologic and hydraulic parameters of each flood problem can be quantified through engineering principles and procedures. A floodplain study provides community officials with Information to describe flooding and drainage problems. Officials will find out how high the water might rise. which structures and dwellings might be damaged, and which areas would be safe. Formulating Solutions Basic engineering information is necessary to formulate solutions to com- munity floodplain problems. Engineering Information helps In three ways. 1) It can help a community select a regulatory or structural improvement plan; the community's flood and drainage problems will be addressed and expenditures prioritized. 2) It can show the limits of the regulatory floodplains on the zoning map. (Showing the floodplain limits and water su,tace elevations makes implementation of regulations more feasible.) 3) It will help the community to comply With Colorado Statutes. by deter' mining a legally enforceable floodplain boundary delineated by: an acceptable hydrologic and hydraulic investigation conforming to CWCS standards and guidelines; and an official deSignation by the CWCS and adoption by the local government. . Procedures and Methods Those uSing floodplain information should be aware of the accuracy and the limitations of "app,oximate" and "detailed" study methods. Many com- munities have floodplains which have been identified by both methods. Development pressures, study costs, and the community's adopted manage- ment procedures for the floodplain wlil determine an identification procedure and method.