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<br />Flood Plain Regulation.--Flood plain regulation is the zoning of the <br />flood plain to restrict encroachment by major damageable land uses. hope- <br />fully resulting in minimizing future damages. This usually means that if <br />a damageable land use is placed within the flood plain. fill or some other <br />means must be used to raise the ground floor elevation above the flood <br />plain elevation. It is. therefore. desirable to evaluate the effect flood <br />plain regulation has on potential flood damage reduction. The effectiveness <br />of flood plain regulation in reducing potential damage is determined by con- <br />structing an aggregate elevation-damage curve for each index location for <br />the future land use pattern. and then reconstructing the aggregate elevation- <br />damage curves again. but with the regulatory policy in effect. These <br />aggregate elevation-damage curves are then used as the basis 'to make the <br />comparisons. <br /> <br />To subject a land use pattern to flood plain regulation. the analysis <br />makes use of the reference flood to determine the flood plain of interest. <br />The elevation of the regulatory flood at the index location is determined <br />similar to that for flood proofing damage reaches to a uniform protection <br />level. If the computed regulatory flood event water surface elevation is <br />higher than the topography elevation of the grid cell. the elevation damage <br />function for the grid cell is elevated so that the ground floor 'is the same <br />as the event water surface elevation. ' . <br /> <br />The corresponding change in the elevation damage function is shown in <br />Fig. 8 Grid Cell Elevation-Damage Function Adjustment for Flood Plain <br />Regulation. based on the grid cell example used in Fig. 6. For a regulatory <br />elevation of 423.0 feet. the elevation-damage function must be raised 3 <br />feet to reflect the placement of the ground floor above the regulated <br />flood plain. <br /> <br />4lb <br />427 <br />42b <br />42:; <br />'424 <br />423 <br />422 <br />421 <br />420 <br />419 <br />418 <br /> <br /> <br />428 <br />427 . <br />426 <br />425 - <br />424 <br />423 <br />422 <br />421 <br />420 <br />419 <br />418 <br />$ Damage $ Damage <br />A) Elevation-Damage Function B) Elevation-Damage Function After <br />Before Flood Plain Regulation Flood Plain Regulation <br />Grid Cell Elevation - Damage Function Adjustment for Flood Plain <br />Regulation. <br /> <br />- - Ref. Flood Elev. <br /> <br /> <br />- -- Ref. Flood Elev. <br /> <br />- -Flood Plain Elev. <br /> <br />Flood Plain and Modified <br />Ground Floor Elev. <br /> <br />- - - Original Ground Floor <br />E1ev. <br /> <br />16 <br /> <br />Fig:. 8. <br />