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The principal conclusions from this analysis are that the relative differences between expected annual damage computed using different depth-damage data decreases significantly when the event at the first floor goes to 25 year and beyond, and that annual damage is particularly sensitive to the assumed distribution of damage below the first floor. Because damage occurring below the first floor is weighted with a higher frequency of occurrence than damage above the first floor, the total expected annual damage is particularly sensitive to assumptions made about the distribution of damage and the physical feasibility of damage actually occurring below the first floor. Sensitivity to Management Adjustments Five flood plain management adjustments were simulated and damage reduced computed. These adjustments were: raising a structure three feet and five feet; protecting a structure to three feet and five feet above the first floor; and removing both structure and contents from the flood hazard area. Damage reduced by each adjustment is presented graphically and in tabular form in the Figures and Tables which follow. Table A-3 is an index to these data. Damage reduced data follow the same trend as total damage data with respect to location in the flood plain. The damage reduced is greatest where the 2 year event is at the first floor and the reduction decreases rather sharply from the 2 year event to the 15 year event. 8eyond the 15 year event damage reduced decreases with less frequent events, however the reduction is significantly less. These trends exist for all types of adjustments. The influence of flood hazard factor varies depending upon the adjustment, type structure, and location in the flood plain. The amount of damage reduction achieved by the different adjustments varied depending upon the type of adjustment, type of structure, flood hazard factor and event at the first floor. Removing both structure and contents from the flood plain reduced damage 100 percent. Data plotted in Figures A-39 through A-42 and tabulated in Table A-8 are the total damage for the type struCture, flood hazard factor, and event at the first floor indicated. The damage reduction for raising or prqtecting a structure 5 feet varies from 80 to 100 percent for flood hazard factors less than or equal to 4.0 feet. This is true for all type structures and for the full range of events at the first floor. Generally, as the event at the first floor becomes less frequent the percent reduction increases. When the flood hazard factor is greater than 4.0 feet (4.0 to 20.0) the percent reduction decreases from a minimum of 80 percent to a minimum of 22 percent. A 3 foot adjustment (raising or protecting) reduces damage 59 to 100 percent for flood hazard factors less than or equal to 4.0 feet and a minimum of 11 percent for flood hazard factors greater than 4.0 feet. Once again the specific amount of reduction depends upon type structure, flood hazard factor, and location in the flood plain. Removal of structure and contents is, of course, the most effective of the five adjustments for reducing damage. Since it was assumed that damage with the structure and contents removed is zero, the damage reduced (without - with) is equivalent to total damage (without condition). Next comes raising or protecting a structure 3 feet. Raising reduces damage the most for one and two story structures without basements. The reduction may be the same for low flood hazard factors, but as the flood hazard factor increases raising becomes more effective. The principal reason is that when the elevation raised is exceeded damage increases gradually, whereas, when protection is exceeded damage jumps from zero to a significant amount because immediate inundation to the protection level is assumed. Protection is the most effective A-11