FLOOD07385

• County: Statewide
• Community: Statewide
• Basin: Statewide
• Title: National Flood Insurance Program Administrative Procedures Manual
• Date: 10/1/1987
• Prepared For: City, Town and County Administrators
• Prepared By: CWCB
• Floodplain - Doc Type: Educational/Technical/Reference Information

E. Revisions Based On The Effects Of Physical Changes
That Have Occurred In The Floodplain
1, Changes Affecting Hydrologic Conditions. The following data
must be submitted:
a General description of the changes (dam, diversion channel.
detention basin, etc,)
b, Construction plans for as.built condition. if applicable
c. New hydraulic analysis accounting for the effects of the
changes
d, New hydrologic analysis using the new flood discharge values
resulting from the hydrologic analysis
e, Revised delineations of the floodplain boundaries and
floodway
2, Changes Affecting Hydraulic Conditions, The following data must
be submitted:
a, General description of the changes (channelization, new
bridge. culvert. levees, etc,)
b, Construction plans for as.built condition
c, New hydraulic analysis accounting for the effects of the
changes and using the original flood discharge values
d, Revised delineations of the floodplain boundaries and
floodway
3, Changes Affecting Topographic Conditions, The following data.
certified by a registered professional engineer or licensed land
surveyor. must be submitted:
a General description of the changes (grading, filling. etc.)
b, New topographic information, such as spot elevations, grading
plans. or contour maps
c. Revised delineations of the floodplain boundaries and, if
necessary, floodway

F. Revisions Based On The Use Of Better Data
1, Better Hydrologic Data, The following data must be submitted:
a Data that are believed to be better than those used in the
original hydrologic analysis (such as additional years of stream
gage data)
b, Documentation for the source of the data
c, Explanation of why the use of these data improve the results
of the original hydrologic analysis
d, New hydrologic analysis using the better data
e. New hydraulic analysis using the new flood discharge values
resulting from the hydrologic analysis
f. Revised delineations of the floodplain boundaries and
f100dway
2, Better Hydraulic Data, The following data must be submitted:
a Data that are believed to be better than those used in the
original hydraulic analysis (such as supplementary floodplain
and stream channel cross sections)
b, Documentation for the source of the data
c. Explanation of why the use of these data will improve the
results of the original hydraulic analysis
d. New hydraulic analysis using the better data and the original
flood discharge values
e, Revised delineations of the floodplain boundaries and
floodway
3, Better Topographic Data, The following data, certified by a regis'
tered professional engineer or licensed land surveyor, must be
submitted:
a, Data that are believed to be better than those used to plot
the original flood boundaries (detailed topographic maps,
grading plans, spot elevations, etc,)
b, Documentation of the source of the data
c. Revised delineations of the floodplain boundaries

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