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<br />litigation before any Federal, State, or <br />local court or administrative agency and, <br />If so, the purpose of the litigation <br /> <br />6. Statement of whether the community <br />has previously requested a <br />determination concerning the same <br />subject and, if so, the disposition of that <br />req u est <br /> <br />General Technical Guidance <br /> <br />When developing technical supporting data, <br />requestors should consider the following points: <br /> <br />. <br /> <br />Unless Map Revision requests are based <br />on indisputable and clearly defined <br />mathematical or measurement errors in <br />the original FEMA analyses, the requests <br />must be accompanied by all the data <br />that FEMA needs to revise the FHBM or <br />the FIRM, FBFM, and FIS report. The <br />requestor should therefore be prepared <br />to perform new hydrologic and <br />hydraulic analyses and delineate new <br />floodplain and floodway boundaries as <br />necessary. <br /> <br />In addition, new flooding information <br />cannot be added to an NFIP map in such <br />a way as to create mismatches with the <br />flooding information shown for <br />unrevised areas. Therefore, in <br />performing new analyses and <br />developing revised flooding <br />information, the requestor must tie the <br />new flood elevations, floodplai n <br />boundaries, and floodway boundaries <br />into those shown for areas not affected <br />by the revi si on. <br /> <br />When requests involve new flood <br />discharge values, extensive changes in <br />hydraulic conditions, or complex <br />situations in which changes made to the <br />flooding information developed for one <br />flooding source will affect that <br />developed for others, the requestor may <br />be required to provide new information <br />for a large portion of the map. <br /> <br />24 <br /> <br />. <br /> <br />All analyses and data submitted by the <br />requestor, including those that show <br />mathematical or measurement errors <br />must be certified by a registered <br />professional engineer or licensed land <br />surveyor, as appropriate. <br /> <br />. <br /> <br />Revisions, except for those based on the <br />effects of flood protection systems under <br />construction that meet the previously <br />listed requirements, cannot be made <br />based on the effects of proposed <br />projects or future conditions; therefore, <br />any maps, plans, drawings, <br />measurements, or ground elevation data <br />submitted by the requestor must be <br />certified as representing existing, or as- <br />built, conditions. <br /> <br />. <br /> <br />NFIP maps may be revised when flood <br />discharges change as a result of <br />structural improvements, such as dams <br />or other significant retention facilities. <br />However, NFIP maps will not be revised <br />when discharges change as a result of <br />the use of an alternative methodology <br />or additional data unless the change is <br />statistically significant. <br /> <br />The criteria that the requestor must use <br />in determining whether a change is <br />statistically significant are discussed in <br />Section 2-6, "Hydrologic Analyses," of <br />Flood Insurance Study Guidelines and <br />Specifications for Study Contractors, <br />dated September 1985. When <br />requesting a Map Revision based on new <br />flood discharges, the Tequestor should <br />determine the significance of the change <br />before proceeding with new hydraulic <br />analyses. When the statistical <br />significance test does not apply, a <br />determination by a Federal or State <br />agency that the change is significant <br />may be accepted as the basis for a <br />revision. <br /> <br />. <br /> <br />Generally, when a requestor is required <br />to submit hydrologic or hydraulic <br />analyses for flooding sources studied by <br />detailed methods, those analyses must <br />be performed for the same floods <br />studied for the preparation of the <br />effective NFIP map. <br />