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<br />shown. This indicates that protecting to 3 .feet above the first floor will generally ~e <br />economically feasible for this type structure. Naturally, if significant additional cost are incurred <br />above those assumed, it may become infeasible. A two story, no basement structure (Figure 3-3) <br />shows damage reduced roughly 50 percent of that for a single story structure. This reduction <br />causes economic feasibility to be somewhat marginal for conditions with a flood hazard factor <br />of twelve or greater and located with the 20 year event at the first floor. Because of the closeness <br />of the values in this range it is difficult to draw definite conclusions from the analyses since a <br />change of anyone of several factors could make up the difference. <br /> <br />Advantages and Disadvantages <br />Table 3-2 summarizes the advantages and disadvantages of this measure as an adjustment <br />tool. <br /> <br />TABLE 3-2 <br /> <br />ADVANTAGES AND DISADVANTAGES <br />OF TEMPORARY OR PERMANENT CLOSURES FOR EXISTING STRUCTURES <br /> <br />Advantages <br /> <br />Flood proofing may be done on a selective <br />basis to only those openings through which <br />water enters and only to the height desired. <br /> <br />Easy and quick to implement. <br /> <br />For large commercial and industrial type <br />structures, this. may be the most important <br />nonstructural means of flood damage reduc- <br />tion. <br /> <br />Disadvantages <br /> <br />Applicable only to structures with brick or <br />masonry type walls, without basements, <br />which can structurally withstand the hydro- <br />static and uplift pressure of the design flood <br />and which are generally watertight. <br /> <br />Reduced likelihood of effective closure at <br />nights and during vacations with temporary <br />closures. <br /> <br />May create a false sense of security and <br />induce people to stay in the structure longer <br />than they should. <br /> <br />References <br /> <br />1. Anderson, Charles M. et ai, "Manual for the Construction of Residential Basements in Non- <br />Coastal Flood Environs", National Association of Home Builders Research Foundation Inc., July <br />1976. <br /> <br />2. Black, Richard D., "Flood Proofing Rural Residences," Department of Agricultural <br />Engineering, Cornell University, May 1975. <br /> <br />3. Vierling, Steve, "Report on the Initial Costs of Nonstructural Alternatives for the Protection <br />or Evacuation of Existing Structures Withi", a Flood Plain," Louisville District, Corps of Engineers, <br />Unpublished Report, January 1976. <br /> <br />17 <br />