craft afloat and automobiles in the flood area accounted for con- 

 siderable losses which were not included or included only in part, 

 because loss information in usable form was meagre or unavailable. 

 Available evidence indicates, however, that these losses were sub- 

 stantial in the 195^ and 1938 tidal flooding. Other unevaluated 

 losses include intangible damages such as loss of life, health, 

 security and menace to national defense. 



D-3« RECURRING DAMAGES 



a. General. Stage-loss curves, described in subsequent para- 

 graphs, indicate that a recurrence of the record flood of Septem- 

 ber 1938, under present economic conditions, would cause losses 

 estimated at $120,200,000 in the areas to be protected by the 

 plan. (All recurring losses are estimated at 1956 price levels.) 

 Tidal stages produced by a stonii of the 19^h magnitude would re- 

 sult in losses of $92,200,000. The design flood, which would 

 cause flood levels from 2 to 3 feet in excess of 1938 stages, 

 would cause an estimated total loss of approximately $2011,000,000. 

 Refer to Table D-5 on page D-l5 for a tabulation of recurring 

 losses of damaging hurricanes and storms which have occurred 

 within the last 50 years. 



As the basis of the economic analysis, stage-loss curves 

 referenced to the 19Sh flood level have been developed. These 

 stage-loss curves, based on data obtained by damage surveys made 

 subsequent to the 195U hurricane flood, provide a method by which 

 the magnitude of recurring losses at stages up to 3 feet above 

 the experienced 1951; stage may be determined. The difference be- 

 tween the losses experienced in the flood of 1951; and the recur- 

 ring losses used to develop the new stage-loss relationship re- 

 flects the economic and physical changes in the area since 195Il 

 which were revealed by the damage surveys initiated one year after 

 the hurricane flood. 



An additional analysis would be required in the final design 

 of the Lower Bay barriers to more accurately determine the effects 

 of wave action in the lower stages of the stage-damage curves for 

 controlling areas. 



A number of primary flood losses, both tangible and intangi- 

 ble, have not been included in the economic analysis of protective 

 measures, even though these losses may be substantial in a given 

 instance of tidal flooding. Tangible losses in this category are 

 made up of (1) damages to vehicles either underway or parked on 

 street or in public or commercial parking lots; (2) damages to 

 small craft and vessels afloat at shore facilities, or in open 



D-10 



