2D Floodways

Revise the standards and guidance on modeling and mapping the regulatory floodway using a two-dimensional (2D) model. Update standards (Standard Identification Number of SID#) associated with floodway analyses and technical approaches and outputs. Also update multiple technical references, guidance documents, and templates.

Coastal Zone Management Act (CZMA) Compliance

Create SIDs and guidance to clarify how to issue consistency determinations for the CZMA.

Automated Map Production (AMP)

Revise associated SIDs, technical references, guidance documents, and templates to allow flexibility in Flood Insurance Rate Map (FIRM) panel layout as the AMP tool is introduced into the Risk MAP workflow per SID 630.

Changes Since Last FIRM (CSLF)

Revise associated SIDs and the CSLF guidance document to integrate FEMA’s automated CSLF utility.

Key Decision Point (KDP)

Revise the KDP guidance and associated SIDs to allow more ownership by the FEMA Regional Offices.

FEMA IT Security/Privacy

Create SID to increase the Risk MAP program’s safe handling and security of Personally Identifiable Information (PII).

MT-2 Guidance

Create guidance document with more direction and clarity on developing and submitting Letters of Map Revisions and other MT-2 documents.

Standard IDs (SIDs)

Standards Change Description

SIDs 66, 69, 73, 75, 77, 78, 79, 128, 248, 335

Updating to include edits and refinements associated with the 2D Floodway Significant Update.

SIDs 89, 96

Updating to clarify the use of regulatory products and the applicability of this standard.

SID 99

Rescinding standard in association with edits and refinements associated with the 2D Floodway Significant Update.

SIDs 101, 103, 229, 232, 256, 265, 274, 507

Updating to clarify standard, and align to current standard operating procedures.

SID 230

Rescinding standard because this is covered by other standards and guidance.

SID 235

Updating to comply with current style guide specifications.

SIDs 264, 272, 279, 280

Updating to incorporate clarifications or corrections in the wording of the standard.

SID 415

Updated to removed confusing language and emphasize the focus on quality.

SID 417

Align the Standard to current standard operating procedures regarding automated creation of CSLF.

SID 424

Rescinding standard because the tiling structure is no longer applicable.

SID 443

Updating to direct information on NFIP policy and claims information to OpenFEMA.

SID 628

Updating to reflect the automated creation of CSLF through Customer and Data Services (CDS) tools and removes it from the list of products required to align with model information.

SID 630

Updating to establish understanding that AMP output products will look different than current requirements, but that is ok.  Quality control (QC) will still be required for the engineering and flood hazard information. 

SID 640

To keep Risk MAP IT systems secure and appropriately protect the privacy of individuals who are referenced in Risk MAP data, a User Account Management Plan is being established so that all Risk MAP Providers understand the protocols that must be followed and managed.

SID 641

Updating as expired Provisionally Accredited Levee (PALs) are emerging issues and HQs is requiring more oversight on the use of an expired PAL on an updated regulatory product.

SID 642

Updating because seclusion should no longer be used for a Risk MAP study unless a specific case or set of circumstances dictates its use.

SID 643

New standard developed to address CZMA consistency determination requirements.

66

Effective Immediately

Flood Profiles

Each modeled split or diverted flow path must be plotted with individual Flood Profiles.

Each significant split or diverted flow path modeled in 1D and mapped as Zone AE or AH must be plotted with individual Flood Profiles.

69

Effective Immediately

Floodway

Floodway surcharge values must be between zero and 1.0 ft. If the state (or other jurisdiction) has established more stringent regulations, these regulations take precedence over the NFIP regulatory standard. Further reduction of maximum allowable surcharge limits can be used if required or requested and approved by the communities impacted.

Floodway surcharge values must be less than or equal to 1.0 ft.  If the State (or other jurisdiction) has established more stringent regulations, these regulations take precedence over the NFIP regulatory standard.  Further reduction of maximum allowable surcharge limits can be used if required or requested and approved by the communities impacted.

73

Effective immediately

Floodway

An equal conveyance reduction method must be used to establish the minimal regulatory floodway, except where an initial equal conveyance floodway is adjusted in coordination with FEMA and the impacted communities.

A methodology based on equitable consideration of both overbanks must be used to establish the minimal regulatory floodway. Variations to this approach must be made in coordination with FEMA and the impacted communities.

75

Effective immediately

FIS Tables

For each stream with cross sections where a floodway was determined under the scope of work, a Floodway Data Table compliant with the FIS Report Technical Reference must be prepared as part of the hydraulic analysis. The Floodway Data Table must contain an entry for each lettered, mapped cross section that includes the following information:

§ Cross-section identification shown in a georeferenced spatial file;

§ Stream or profile baseline station of the cross section;

§ Width of the floodway at the cross section;

§ Wetted area of the cross section under encroached conditions;

§ Average velocity of the floodwaters at the cross section under encroached conditions;

§ The greater of BFEs from all flooding sources, including from backwater, affecting the cross section (regulatory elevation);

§ The BFE from the existing conditions model (without-floodway elevation);

§ The BFE from the encroached existing conditions model (with-floodway elevation); and

§ Difference between with- and without-floodway elevations (surcharge).

For each stream where a floodway was determined under the scope of work, a Floodway Data Table (FDT) compliant with the FIS Report Technical Reference must be prepared as part of the hydraulic analysis. The FDT must contain an entry for each lettered, mapped cross section or evaluation line and must include the information outlined in the FIS Report Technical Reference.

77

Effective Immediately

Floodway

Unless the coincident peak situation is assumed floodway computations for tributaries must be developed without consideration of backwater from confluences.

Floodway computations for tributaries must be developed without consideration of backwater from confluences unless a coincident frequency analysis or detailed historical observations prove otherwise. If either of these exceptions is used, it must be done in coordination with FEMA.

78

Effective immediately

Flood Profiles

The water-surface profiles of different flood frequencies must not cross one another.

The water-surface profiles of different flood frequencies modeled in 1D must not cross one another, unless technical justification is provided in coordination with FEMA.

79

Effective immediately

Flood Profiles

Water-surface elevations shown on the Flood Profiles shall not rise from an upstream to downstream direction.

Water-surface elevations shown on the Flood Profiles for 1D models shall not rise from an upstream to downstream direction, unless technical justification is provided in coordination with FEMA.

89

Effective Immediately

Coastal - Analysis

For coastal Flood Risk Projects, non-levee coastal structures must be evaluated and the profile adjusted as necessary to reflect expected storm impacts on the structure for the purpose of establishing appropriate risk zone determinations for NFIP maps.

For coastal Flood Risk Projects, non-levee coastal structures must be evaluated and the profile adjusted as necessary to reflect expected storm impacts on the structure for the purpose of establishing appropriate risk zones for regulatory products.

96

Effective immediately

Coastal - Analysis

Coastal analyses shall not account for future impacts due to long term erosion. Episodic, storm-induced erosion must be included in the flood hazard analysis.

Coastal analyses shall not account for future impacts due to long term erosion. Episodic, storm-induced erosion must be included in the flood hazard analysis in establishing appropriate flood hazard zones for regulatory products.

99

Effective immediately

Shallow Flooding

Areas of shallow flooding shall not have modeled/computed floodways due to the inherent uncertainties associated with their flow patterns. However, communities can choose to have administrative floodways for such areas.

Proposed to rescind

101

Effective immediately

Shallow Flooding

Sheet runoff areas shall be delineated as Zone AO with average flooding depths above the ground surface, rounded to the nearest whole foot, indicated on the work map or digital GIS data.

Sheet runoff areas shall be delineated as Zone AO with average flooding depths above the ground surface, rounded to the nearest whole foot.

103

Effective immediately

PMR

For areas where new regulatory maps are being issued, flood hazard information on the effective NFIP map (i.e., FIRM, FBFM, FHBM) that is not being updated through a separate flood hazard analysis or floodplain boundary redelineation shall be “carried over” to the new or updated FIRM.

For areas where new or updated regulatory maps are being developed, effective flood hazard information on NFIP maps (i.e., FIRM, FBFM, FHBM) not being updated through a separate flood hazard analysis or floodplain boundary redelineation shall be maintained, either by digitally transforming information from existing NFIP paper maps and / or transferring existing digital data, on the new or updated FIRM.

128

Effective immediately

2D Models

For floodplains mapped from 2-D models, separate Flood Profiles for significant flow paths must be created.

For floodplains mapped from 2D models, BFE lines on the FIRM must match modeled water surface elevations and must be plotted at intervals sufficient to interpolate accurate BFEs in between BFE lines. If this is not possible, separate Flood Profiles for significant flow paths and/or FIS Report inserts must also be created.

229

Effective immediately

Flood Profiles

Profiles shall be plotted as the projection of the stream invert and the flood surface(s) onto the flow path. The plots should show the locations of and clearly label:

§ Each lettered mapped cross section;

§ Splits and diversions;

§ Confluences with tributaries, splits, and diversions;

§ Each stream crossing with symbology depicting the top of road and low chord elevations of modeled bridges and culverts along with the name of the bridge/culvert (e.g., Pine Street);

§ Extents of modeled hydraulic structures adjacent to the flooding source;

§ Upstream and downstream study limits of the flooding source;

§ Extent of backwater or flooding controlling the receiving stream and depiction of the backwater elevation along the Profile.

Flood Profiles shall be plotted as the projection of the stream invert and the flood surface(s) onto the flow path. The plots should show the locations of and clearly label:

§ Each lettered mapped cross section;

§ Separately modeled splits and diversions;

§ Confluences of modeled tributaries, splits, and diversions;

§ Each stream crossing with symbology depicting the top of road and low chord elevations of modeled bridges and culverts along with the name of the bridge/culvert (e.g., Pine Street);

§ Extents of modeled hydraulic structures adjacent to the flooding source;

§ Upstream and downstream study limits of the flooding source;

§ Extent of backwater or flooding controlling the receiving stream and depiction of the backwater elevation along the Profile.

230

Effective immediately

FIS/FIRM

The FIRM panels must be derived directly from the FIRM database and must be in agreement with the information shown in the FIS Report.

Proposed to rescind

232

Effective immediately

Flood Profiles

Unless it can be demonstrated that the vertical and horizontal scale of the effective Flood Profiles are inadequate, re-analyzed streams must be produced using the same horizontal and vertical scales that were used in the effective Flood Profiles.

Unless it can be demonstrated that the vertical and horizontal scale of the effective Flood Profiles are inadequate, re-analyzed or redelineated streams must be produced using the same horizontal and vertical scales that were used in the effective Flood Profiles.

235

Effective immediately

FIS Report

If an FIS Report is published in 2 or more volumes, no volume shall exceed 100 pages.

If an FIS Report is published in two or more volumes, no volume shall exceed 100 pages.

248

Effective immediately

FIS Tables

All lettered or numbered cross sections must be shown on the Flood Profiles and, if a floodway was computed, must also be shown in the FDT. Unlettered cross sections shown on the FIRM are not to be included on the Floodway Data Table or Flood Profiles.

All lettered or numbered cross sections or evaluation lines must be shown on the Flood Profiles and, if a floodway was computed, must also be shown in the Floodway Data Table. Unlettered cross sections shown on the FIRM are not to be included on the Floodway Data Table or Flood Profiles.

256

Effective immediately

Flood Profiles

Flood Profiles for Zone AE must show data for each of the 5 standard (10-, 4-, 2-, 1-, and 0.2-percent-annual-chance) flood events if they were calculated as part of the Flood Risk Project.

Flood Profiles for Zone AE must show data for each of the six standard (10-, 4-, 2-, 1-, 1-percent-plus-, and 0.2-percent-annual-chance) flood events if they were calculated as part of the Flood Risk Project.

264

Effective immediately

FIS Tables

For cross-sections shown in areas of backwater flooding, elevations in the “Without Floodway” column of the Floodway Data Table shall not include backwater effects. The "Without Floodway" values must include a footnote stating, "Elevation Computed Without Consideration of Backwater Effects From (Source of Flooding)". The words “Backwater Effects” are to be replaced with “Tidal Effects,” “Overflow Effects,” “Ice Jam Effects,” or “Storm Surge Effects,”, as needed, to reference the appropriate flooding situation.

For cross-sections shown in areas of backwater flooding, elevations in the “Without Floodway” column of the Floodway Data Table shall not include backwater effects. The "Without Floodway" values must include a footnote stating, "Elevation Computed Without Consideration of Backwater Effects From (Source of Flooding)." The words “Backwater Effects” are to be replaced with “Tidal Effects,” “Overflow Effects,” “Ice Jam Effects,” or “Storm Surge Effects,” as needed, to reference the appropriate flooding situation.

265

Effective immediately

FIS Tables

When a part of a regulatory floodway lies outside the jurisdiction, both the total floodway width, and the width within the jurisdiction, shall be listed in the FIRM database and Floodway Data Table.

When a part of a regulatory floodway lies outside the jurisdiction, both the total floodway width, and the width within the jurisdiction, shall be listed in the FIRM database and Floodway Data Table unless the stream forms the boundary between two states with differing surcharge requirements.

272

Effective immediately

Flood Profiles

A vertical elevation scale of 1 inch equals 1, 2, 5, 10, or 20 feet is to be used for the Flood Profiles. Elevations shall be shown on the left side of the grid at 1-inch intervals within the profile elevation range.

A vertical elevation scale of 1 inch equals 1, 2, 5, 10, or 20 feet is to be used for the Flood Profiles. Elevations shall be labeled on the left side of the grid at 1-inch intervals within the profile elevation range.

274

Effective immediately

Flood Profiles

The horizontal and vertical scales of the Flood Profiles shall be chosen so that that Flood Profile slopes are reasonable and can be easily interpreted by the user.

The horizontal and vertical scales of the Flood Profiles for newly studied streams  shall be chosen so that that Flood Profile slopes are reasonable and can be easily interpreted by the user.

279

Effective immediately

Flood Profiles

Downstream flood elevations are to begin on the left edge of the Flood Profile.

Downstream flood elevations are to be oriented towards the left edge of the Flood Profile.

280

Effective immediately

Flood Profiles

Stream distances reported in the FDTs, Profiles, and FIRM database must be measured along the profile baseline.

Stream distances reported in the FDTs, Flood Profiles, and FIRM database must be measured along the profile baseline.

335

Effective immediately

Floodway

Regulatory floodways shall be shown on the FIRM panel within the SFHA and, at lettered or numbered cross-section locations, floodway widths must agree with the values shown on the FDT in the FIS Report and the FIRM Database tables, within a maximum tolerance of 5 percent of the map scale or 5 percent of the distance, whichever is greater.

Regulatory floodways shall be shown on the FIRM panel within the SFHA and, at lettered or numbered cross-section and evaluation line locations, floodway widths must agree with the values shown on the FDT in the FIS Report and the FIRM Database tables, within a maximum tolerance of 5 percent of the map scale or 5 percent of the distance, whichever is greater.

415

Effective immediately

Flood Risk Datasets

Water-surface elevation (WSEL) grids produced as part of a Flood Risk Project must be of such a quality that they could be used for regulatory and other official purposes as the digital source from which to retrieve flood elevations. Additionally, for each mapped flood frequency (e.g. 1-percent, 0.2-percent, etc.), there must be agreement in extent and coverage between the WSEL grid and its associated flood hazard area polygon.

Water-surface elevation (WSEL) grids produced as part of a Flood Risk Project must be of such a quality that they can be used for regulatory and other official purposes, and blended into a seamless dataset. For each mapped flood frequency (e.g. 1-percent, 0.2- percent, etc.), there must be agreement in extent and coverage between the WSEL grid and its associated flood hazard area polygon.

417

Effective immediately

Flood Risk Datasets

The minimum datasets associated with the Flood Risk Project are defined as follows:

The minimum datasets associated with the Flood Risk Project are defined as follows:

424

Effective immediately

Flood Risk Database

As an outcome of Discovery, a tiling structure must be defined for products.

Proposed to rescind

443

Effective immediately

Flood Risk Database

In order to maintain privacy, the L_Claims table, if there are less than five claims, five repetitive loss claims, or five severe repetitive loss claims in a community, then the relevant value field shall be set to null.

Do not populate the L_Claims table. Please refer to OpenFEMA for all National Flood Insurance Program policy and claims information.

507

Effective Immediately

FIS/FIRM

The FIRM, FIRM database, NFHL, Flood Profiles and Floodway Data Tables must all be in agreement with each other, including decimal point precision, as it relates to the depiction of flood hazards and hydraulic structures.

The FIRM, FIRM database, NFHL, Flood Profiles and Floodway Data Tables must all be in agreement with each other, including decimal point precision, as it relates to the depiction of flood hazards and hydraulic structures.

628

Effective immediately

Flood Risk Datasets

All Flood Risk Products will be deemed of acceptable quality if they meet the following conditions:

§ All Flood Risk Products pass the MIP Validation step

§ All raster datasets and the Changes Since Last FIRM dataset align with the underlying model information used to develop the associated regulatory products

§ All other database elements align with regulatory products as of the time they are contracted, if they are developed from regulatory products

All Flood Risk Products will be deemed of acceptable quality if they meet the following conditions:

§ All Flood Risk Products pass the MIP Validation step

§ All raster datasets align with the underlying model information used to develop the associated regulatory products

§ All other database elements align with regulatory products as of the time they are contracted, if they are developed from regulatory products

630

Implemented with all new flood risk projects initiated in FY20 and MT-2s received after the automated mapping tool is implemented.

Map Format and Layout

All preliminary and final FIRM panels, including FIRM attachments delivered with MT-2s, must be developed using the FEMA FIRM panel creation tool.

All preliminary and final FIRM panels, including FIRM attachments delivered with MT-2s, must be developed using the FEMA FIRM panel creation tool. The output panel layout and cartographic design from the FEMA FIRM panel creation tool are considered FEMA compliant with no edits, however the output products, including the FIRM database, must be quality controlled by the producer to confirm the engineering and flood hazard data align with the related regulatory products. Quality control must be performed, documented and completed prior to the issuance of preliminary and final regulatory products.

640

Effective immediately

Project Management

New

All organizations and users that access FEMA RAM applications must comply with applicable RAM policies and SOPs.

641

Implemented with all new Flood Risk Projects initiated in FY21

Levee

New

Justification to use an expired PAL agreement date on the FIRM panel must be approved by the FEMA Region and FEMA Headquarters.

642

Implemented with all new Flood Risk Projects initiated in FY21

Levee

New

Justification to use Seclusion mapping on the FIRM panel must be approved by the FEMA Region and FEMA Headquarters.

643

Effective Immediately

CZMA

New

Prior to preliminary issuance of FIRMs affecting tidally influenced floodplains within the coastal zone, as defined by the Coastal Zone Management Act of 1972 (16 U.S.C. § 1451-1464), the FEMA region shall submit to the coastal management program for the state or territory in which the project takes place a federal consistency determination that the project is consistent to the maximum extent practicable with the enforceable policies of the coastal management program.

Areas of Mitigation Interest, General Hydraulics Considerations, MT-1 Technical, Shallow Flooding Analyses and Mapping, MIP Guidance, Physical Map Revision (PMR)

Clarify standards and guidance information, and align them to current standard operating procedures.

Changes Since Last FIRM, Flood Risk Database, Flood Depth and Analysis Grids Guidance, Flood Risk Assessments

Integrate the automated creation of CSLF with current standard operating procedures and updates to terminology.

Combined Coastal and Riverine Floodplains, Contiguous Community Matching, Data Capture - Workflow Details, FIRM Database, FIRM Graphics, Floodway Analysis and Mapping, Levee, LOMR Incorporation, Mapping Base Flood Elevations on Flood Insurance Rate Maps, Profile Baseline, Riverine and Floodplain Boundaries, Flood Insurance Study (FIS) Report, Hydraulics: Two-Dimensional Analysis, Flood Profiles

Edit and refine parts associated with proposed 2D floodway changes, and incorporate changes resulting from the revised flood profile SIDs.

Quality Management of Flood Risk Projects, FIRM Index, ,

Updates to add general reference for AMP.

MT-2

Create a new guidance document with more direction and clarity on developing and submitting LOMRs and other MT-2 documents.

Coastal Zone Management Act (CZMA) Guidance

New guidance to provide guidance on roles, responsibilities, and procedures for project compliance with consistency determinations.

Key Decision Point (KDP)

Allow more ownership by the FEMA Regional Offices.

Accepting Numerical Models for Use in the NFIP

Add new models to the guidance.

Flood Insurance Study (FIS) Report

Updates include changes associated with the 2D floodway update; updates to information regarding Levee Systems; incorporate changes from revising the flood profile SIDs; align with standard operating procedures; and incorporate routine maintenance revisions and corrections.

Flood Insurance Rate Map (FIRM) Panel, Flood Insurance Rate Map (FIRM) Database, Domain Tables

Updates to add reference to Automated Map Production (AMP); and updates to information regarding Levee Systems.