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2 In classifying flood proofed structures, the classification is based on the level of protection (i.e, flood proofing) against the Base Flood, The Base Flood Elevation (BFE) is synonymous with Regulatory Flood (RF) and the 100'year flood event. The term Regulatory Flood Datum (RFD) refers to the Base Flood Elevation plus one foot freeboard as required for flood proof- ing by the Colorado Water Conservation Board (CWCB), Floodproofed structures are categorized into three classeS! completely dry Class A, essentially dry Class B, and wet Class C. Table 1.1 gives a summary of the classification of floodproofed structures, Table 1,1 - Classification of Floodproofed Structures Classification Definition Class B Completely Dry Structures designed to withstand all hydrostatic and hydrodynamic loads or elevated above the BFE. Walls and joints shall be impermeable to passage of water and water vapor or first floors cited above the BFE. Essentially Dry Structures designed to withstands all hydrostatic and hydrodynamic loads. A max- imum of four (4) inches of water depth may accumulate in a space during a 24 hour period. Wet Structures are allowed to fill with either clean or flood water to counter-balance outside hydros- tatic forces. Class A Class C Specific flood proofing measures are classified as permanent, contingent, or emergency. Per- manent measures are typically incorporated into the design of new structures and do not require any advance flood warning or availability of persons to initiate action. Permanent floodproofing, such as elevation on fill, is always in place and reduces the element of human error. Contingent or partial flood proofing measures, such as prefitted window and door closures, require some type of human action to make the flood proofing measures opera- tional at the time a flood warning is announced. Contingent measures require someone to be at the site during the flood warning and that an adequate flood- warning plan for the com. munity exists, Emergency flood proofing measures, such as sandbagging, are made operational during an actual flood event. Emergency measures are temporary and should be carried out according to a pre-arranged plan, Table 1.2 gives a summary of the classification of specific flood proofing measures. Table 1.2. Classification of floodproofed structures Classification Definition Examples Permanent Do not require any action to inititate. Usually incorporated into the design. - water closures - flood walls - levees - elevation - removable flood shields - watertight doors - movable flood walls - .sand bagging - temporary levees Contingent Require human action to initiate at time of flood warning. Emergency Measures used and initiated at the time of flooding.