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Flood Standards Development Input to Draft Meteorological/Hydrological Flood Draft Standards Dated 11-17-14

December 5, 2014

AIR Input to Draft Flood Standards

Table of Contents Introduction ................................................................................................................................................... 7 1

Standard MHF-1 Flood Event Data Sources.............................................................................................. 8 2

MHF-1 Standards .................................................................................................................................... 8 2.1

2.1.1 Standard MHF-1.B ......................................................................................................................... 8

2.1.2 Standard MHF-1.C, first suggestion ............................................................................................ 8

2.1.3 Standard MHF-1.D......................................................................................................................... 8

MHF-1 Purpose Statement ..................................................................................................................... 9 2.2

2.2.1 MHF-1 Purpose, First Paragraph ................................................................................................. 9

MHF-1 Disclosures ................................................................................................................................ 10 2.3

2.3.1 MHF-1 Disclosure 1, 2 and 4....................................................................................................... 10

2.3.2 MHF-1 Disclosure 5 ..................................................................................................................... 10

MHF-1 Audit Items ............................................................................................................................... 11 2.4

2.4.1 MHF-1 Audit Item 1 .................................................................................................................... 11

2.4.2 MHF-1 Audit Item 5 .................................................................................................................... 12

2.4.3 MHF-1 Audit Item 6 .................................................................................................................... 12

2.4.4 (Moved/New) MHF-1 Audit Items ............................................................................................ 12

Standard MHF- 2 Flood Parameters and Characteristics ...................................................................... 14 3

MHF-2 Standards .................................................................................................................................. 14 3.1

3.1.1 Standard MHF-2.B ....................................................................................................................... 14

3.1.2 Standard MHF-2.C ....................................................................................................................... 15

MHF-2 Purpose Statement ................................................................................................................... 15 3.2

3.2.1 MHF-2 Purpose, First Paragraph ............................................................................................... 15

3.2.2 MHF-2 Purpose, Third and Fourth Paragraphs ....................................................................... 16

MHF-2 Disclosures ................................................................................................................................ 16 3.3

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3.3.1 MHF-2 Disclosure 2 ..................................................................................................................... 16

3.3.2 MHF-2 Disclosures 8, 9 and 10 ................................................................................................... 17

3.3.3 MHF-2 Disclosures 13, 14 and 15 ............................................................................................... 17

3.3.4 MHF-2 Disclosure 17 ................................................................................................................... 18

3.3.5 MHF-2 Disclosure 19 ................................................................................................................... 18

3.3.6 MHF-2 Disclosure 20 ................................................................................................................... 19

3.3.7 MHF-2 Disclosure 21 ................................................................................................................... 19

3.3.8 (new) MHF-2 Disclosures moved from MHF-5 Disclosures 4 & 5 ........................................ 19

MHF-2 Audit Items ............................................................................................................................... 20 3.4

3.4.1 MHF-2 Disclosures 8, 9 and 10 to become new MHF-2 Audit Items .................................... 20

3.4.2 MHF-2 Disclosure 19 to become (new) Audit Item ................................................................. 21



3.4.5 (new) MHF-2 Audit Items moved from MHF-5 Audit Items 2 & 3 ...................................... 22

Standard MHF-3 Flood Probabilities........................................................................................................ 22 4

MHF-3 Standards .................................................................................................................................. 22 4.1

4.1.1 Standard MHF-3.B ....................................................................................................................... 23

4.1.2 Standard MHF-3.C ....................................................................................................................... 23


MHF-3 Disclosures ................................................................................................................................ 23 4.3

4.3.1 MHF-2 Disclosure 20 ................................................................................................................... 23

MHF-3 Audit Items ............................................................................................................................... 24 4.4

4.4.1 MHF-3 Audit Item 2 .................................................................................................................... 24

4.4.2 (new) MHF-3 Audit Item (moved from MHF-1 Audit Item 5) .............................................. 24

4.4.3 (new) MHF-3 Audit Item (moved from MHF-1 Audit Item 6) .............................................. 24

Standard MHF-4 Flood Profile Structure ................................................................................................. 26 5

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MHF-4 Standards .................................................................................................................................. 26 5.1

5.1.1 Standard MHF-4 title ................................................................................................................... 26

5.1.2 Standard MHF-4.A ...................................................................................................................... 26

5.1.3 Standard MHF-4.D....................................................................................................................... 26

5.1.4 Standard MHF-4.E ....................................................................................................................... 27


MHF-4 Disclosures ................................................................................................................................ 27 5.3

5.3.1 MHF-4 Disclosure 1 ..................................................................................................................... 27

5.3.2 MHF-4 Disclosure 2 ..................................................................................................................... 28

MHF-4 Audit Items ............................................................................................................................... 29 5.4

5.4.1 MHF-4 Audit Item 4 .................................................................................................................... 29

Standard MHF-5 Modeling of Natural and Man-Made Flood Mitigation and Prevention Measures6

30

MHF-5 Standards .................................................................................................................................. 30 6.1

6.1.1 Standard MHF-5 title ................................................................................................................... 30

6.1.2 Standard MHF-5.A ...................................................................................................................... 30

6.1.3 Standard MHF-5.B and C moved to Standard MHF-2 ........................................................... 31

6.1.4 Standard MHF-5.D....................................................................................................................... 31

6.1.5 (new) Standard MHF-5 brought in from Standard MHF-6 (modeling failure of flood

mitigation and prevention measures) ...................................................................................................... 32


6.2.1 MHF-5 Purpose ............................................................................................................................ 33

MHF-5 Disclosures ................................................................................................................................ 33 6.3

6.3.1 MHF-5 Disclosure 1 ..................................................................................................................... 33

6.3.2 MHF-5 Disclosure 2 ..................................................................................................................... 33

6.3.3 MHF-5 Disclosure 3 ..................................................................................................................... 34

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6.3.4 MHF-5 Disclosures 4 & 5 ............................................................................................................ 34

6.3.5 MHF-5 Disclosure 6 ..................................................................................................................... 35

6.3.6 (new) MHF-5 Disclosures (brought up from Standard MHF-6 Disclosures 1-4) ................ 35

MHF-5 Audit Items ............................................................................................................................... 36 6.4

6.4.1 MHF-5 Audit Item 1 .................................................................................................................... 36

6.4.2 MHF-5 Audit Items 2 & 3 (moved to MHF-2) .......................................................................... 36

6.4.3 MHF-5 Audit Item 4 .................................................................................................................... 37

6.4.4 (new) MHF-5 Audit Items (brought up from MHF-6) ............................................................ 37

Standard MHF-6 Modeling for the Failure of Flood Mitigation or Prevention Measures ................ 39 7

MHF-6 Standards, Purpose, Disclosures and Audit Items .............................................................. 39 7.1

7.1.1 Standard MHF-6 ........................................................................................................................... 39

Standard MHF-7 Logical Relationships of Flood Characteristics ......................................................... 40 8

MHF-7 Standards .................................................................................................................................. 40 8.1

8.1.1 Standard MFH-7.A ...................................................................................................................... 40

8.1.2 Standard MFH-7.B ....................................................................................................................... 40

8.1.3 Standard MFH-7.C & D ............................................................................................................... 40

8.1.4 Standard MFH-7.F ....................................................................................................................... 41

8.1.5 Standard MFH-7.H ...................................................................................................................... 41

8.1.6 Standard MFH-7.I ........................................................................................................................ 41

8.1.7 (new) Standard MFH-7 ............................................................................................................... 42

8.1.8 All MHF-7 Standards – ordering of ........................................................................................... 42


MHF-7 Disclosures ................................................................................................................................ 43 8.3

MHF-7 Audit Items ............................................................................................................................... 43 8.4

Form MHF-1 Annual Flood Occurrence Rates by County .................................................................... 44 9

Items in Form MHF-1 ........................................................................................................................... 44 9.1

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9.1.1 Form MHF-1 Item A .................................................................................................................... 44

9.1.2 Form MHF-1 Item C .................................................................................................................... 45

9.1.3 Form MHF-1 Item D .................................................................................................................... 45

Form MHF-2 Maps of Flood Profiles by Return Period ................................................................... 46 10

Items in Form MHF-2 ....................................................................................................................... 46 10.1

10.1.1 Form MHF-2 Item x ..................................................................................................................... 46

10.1.2 Form MHF-2 Item x ..................................................................................................................... 46

10.1.3 Form MHF-2 Items C., D. and E. ................................................................................................ 47

10.1.4 Form MHF-2 Item x ..................................................................................................................... 48

Attachment with Track Changes ........................................................................................................ 49 11

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Introduction 1AIR appreciates the opportunity to provide input into the development of the Florida Commission on Hurricane Loss Projection Methodology (FCHLPM or Commission). This document contains AIR’s input into the draft Meteorological/Hydrological Standards published on November 17, 2014.

At the outset of the development of flood standards, we are in a different position than we were in 1995 at the outset of the development of wind standards primarily because most modelers already had existing wind models in 1995. In 2014, while some modelers have flood models, no modeler has a comprehensive flood model (as the Commission currently defines it in working usage). In 1995, the wind standard development could reference the existing modeling methodologies, and over time both the methodologies and the standards evolved together.

The November 17, 2014 draft of the Meteorological/Hydrological standards makes many presumptions about specific details that are assumed to be present in a given flood model. Since the mandate of the Commission is to evaluate the acceptability of a broad range of possible models rather than to dictate how such models must be developed, the standards as written are overly prescriptive on the whole. Rather, it would be more beneficial to word the standards in language that is as generic as possible and require the modeler to fully disclose and justify the flood parameters and characteristics that are specific to their model. To this end, we have tried to identify elements of each standard that fall into this category, which we refer to as “PRESCRIPTIVE”.

AIR believes the modeling firms should develop flood models based on their own scientific expertise and the historical and claims data available. It is true that there are existing flood models in the market that capture certain features of the flood peril, but these models are not necessarily insurance flood loss projection models. Insurance loss projection modelers are always constrained by the amount and detail of insurance claims data available to support different facets of modeling. If the data is not available to properly account for a certain aspect of flood modeling, then requiring it in the standards will only encourage poor modeling practice, which goes against the mission and mandate of the Commission. To this end, we have tried to identify elements of each standard that fall into this category, which we refer to as “POTENTIALLY NO FLOOD DATA”.

Mention has been made that we have over three years until the first submissions are due, so the modelers should be able to create or update their existing models to fit the standards developed. Three years may not necessarily be enough time with flood models. In any case we are confident the Commission would agree that models built hastily or without supporting data

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in order to meet a set of standards that overreach the current state of the insurance flood modeling science is not in anyone’s best interest.

The remainder of this document presents AIR’s suggestions for edits to the draft Meteorological/Hydrological Standards using the required format.

Standard MHF-1 Flood Event Data Sources 2AIR has identified several items in this Standard that we suggest be edited. The Problem Statement and Explanation sections below discuss suggested edits to the various sections (Standards, Purpose, Disclosures, Audit).

MHF-1 Standards 2.1

AIR’s suggested edits to the MHF-1 Standards are described, explained and justified below.

2.1.1 Standard MHF-1.B • Problem Statement: In standard MHF-1.B, the word “all” in the first line of the sentence

is not necessary and may be overreaching. Requiring the model to incorporate relevant data sources should be sufficient.

• Explanation: This is a general edit. Requiring the model to incorporate relevant data sources is sufficient. There is no similar use of the word “all” in the hurricane standards.

• Amendatory Language:

2.1.2 Standard MHF-1.C, first suggestion • Problem Statement: In standard MHF-1.C, the phrase “based upon”is not consistent

with similar phraseology used in the hurricane standards, so we suggest making them consistent by using “consistent with”.

• Explanation: This is an editorial change and should not change the overall meaning. This change will be consistent with similar wording in the hurricane standards.

• Ammendatory Language:

2.1.3 Standard MHF-1.D • Problem Statement:

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o In standard MHF-1.D, the first line, the word “all” is not necessary and may be overreaching.

o Also, the terms “flood plain flooding” and “non-flood plain flooding” are not standard terminology. We suggest instead the terms “fluvial flooding” and “pluvial flooding” which are more common in different parts of the world. This comment applies generally to the rest of the standards but has not always been pointed out.

• Explanation: o Removing the word “all” is a general edit; requiring the model to encompass

relevant flood event data sources is sufficient. There is no similar use of the word “all” in the hurricane standards.

o Changing the terms is a technical edit. The more common terms are fluvial and pluvial; they are also more concise and have standard definitions.


.

MHF-1 Purpose Statement 2.2

AIR’s suggested edits to the MHF-1 Disclosures are described, explained and justified below.

2.2.1 MHF-1 Purpose, First Paragraph • Problem Statement: The first paragraph of the Purpose Statement is problematic

because it could be interpreted as dictating more frequent model updates than is feasible. Some types of flood data get updated every year or more frequently. Incorporating new data after flood events into a model update requires more than a year.

• Explanation: Removing this first paragraph is a general edit. We agree that models should be kept up to date, but it may be too early in the flood modeling lifecycle to dictate what the update frequency should be. At minimum for now we recommend the Commission should not require less than a 5 year update frequency.

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MHF-1 Disclosures 2.3

AIR’s suggested edits to the MHF-1 Purpose Statement are described, explained and justified below.

2.3.1 MHF-1 Disclosure 1, 2 and 4 • Problem Statement: The term “Flood Event Data Sources” (a parallel to the Base

Hurricane Storm Set), if used, should be defined in a very general way, so as to not dictate particular data sources. Given that, it may not be necessary or ideal to use a defined term, when something like “relevant data sources” will suffice.

• Explanation: Removing the defined term “Flood Event Data Sources” is an editorial change. It is appealing to use a defined term because it simplifies references to it, but in this case there is probably no easy way to define the Flood Event Data Sources. The Commission should not look to the modelers to assist with such a definition now because not every modeler has created flood models yet. It migh be best to wait until the 2019 ROA revision or later to create a defined term if necessary.


2.3.2 MHF-1 Disclosure 5 • Problem Statement: There are several problems with this disclosure.

o First, the flood occurrence rates may differ for the different types of flooding.

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o Second, the concept of an occurrence rate for a county does not make sense. The data used for understanding flooding are from gauging stations. It makes more sense to calculate flood occurrence rates in terms of specific gauging stations, or perhaps in terms of a collection of gauging stations, though aggregating across gauging stations may not produce a very meaningful result..

o Finally, the request to show “data for the most recent 5, 25, 50, and 100 years” does not make sense from the perspective of occurrence rates. We believe the Commission might instead be referring to various probabilities of exceedance corresponding to specific return periods.

• Explanation: These suggested edits are technical in nature. o The first edit suggested edit is general. We suggest adding in “storm surge,

fluvial and fluvial flooding” to allow for the reporting of these rates separately if necessary.

o Second suggested edit is technical in nature. We suggest changing the wording to allow the modeler to report the occurrence rates for identified locations (i.e. where there are gauging stations) in a region or for the region as a whole.

o Finally the third suggested edit is technical in nature. The wording “Provide annual historical and modeled flood occurrence rates for the most current 5, 25, 50, and 100 years” is not precise or clear. We suggest clearer wording to be “Provide annual flood occurrence rates. . . which include data for various probabilities of exceedance (corresponding to 5, 25, 50, and 100 year return periods).”


Note: these same edits have been suggested in Form MHF-1.

MHF-1 Audit Items 2.4

AIR’s suggested edits to the MHF-1 Audit Items are described, explained and justified below.

2.4.1 MHF-1 Audit Item 1 • Problem Statement: See section 2.3.1 for the problem statement relating to “Flood

Event Data Sources”. • Explanation: See section 2.3.2 for the explanation relating to “Flood Event Data

Sources”.

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2.4.2 MHF-1 Audit Item 5 • Problem Statement: This audit item deals with modeled flood probabilities; Standard

MHF-1 is about flood event data sources so it doesn’t seem to be in the right place. • Explanation: This is an editorial change. We suggest moving this audit item, dealing

with modeled flood probabilities, to MHF-3 which addresses flood probabilities. • Amendatory Language: Move MHF-1, Audit Item 5 to MHF-3.

2.4.3 MHF-1 Audit Item 6 • Problem Statement: This audit item deals with modeled flood probabilities; Standard

MHF-1 is about flood event data sources. Second issue is there is a typo; “Maximum Envelope of Winds” should be “Maximum Envelope of Water”.

• Explanation: This is an editorial change. We suggest moving this audit item, dealing with modeled flood probabilities, to MHF-3 which addresses flood probabilities. Secondly, correct the typo.

• Amendatory Language: Amendatory Language: Move MHF-1, Audit Item 6 to MHF-3, Audit Item 2 (move others down). Secondly,

2.4.4 (Moved/New) MHF-1 Audit Items • Problem Statement:

o First, there are two disclosures in MFH-2 (Disclosures 11 and 12) that we think belong in MFH-1 and should be audit items rather than disclosures because the information requested is trade secret.

o Secondly, there is an issue with Disclosure 11: it is currently written to be storm surge specific when it should be general to flood.

• Explanation: o The first suggested change is general. Standard MFH-2 deals with flood

parameters and characteristics; Disclosures 11 and 12 have to do with utilizing the historical information in developing the flood frequencies so we think they belong in MFH-1. These disclosures request trade secret information about how the models are built and therefore should be viewd with the Pro Team.

o The second suggested change is general. We suggest changing the wording to make the item more general to all types of flooding rather than focused exclusively on surge.


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o First, Move MFH-2, Disclosures 11 and 12 to be MFH-1, Audit Items o Second: Suggest these edits.

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Standard MHF- 2 Flood Parameters and 3Characteristics

AIR has identified several items in this Standard that we suggest be edited. The Problem Statement and Explanation sections below discuss suggested edits to the various sections (Standards, Purpose, Disclosures, Audit).

MHF-2 Standards 3.1


3.1.1 Standard MHF-2.B • Problem Statement: We think Standard B is PRESCRIPTIVE, and there may be

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is general in nature. We recommend replacing

Standard B with simpler language. The modelers will use their own scientific judgment in selecting the appropriate parameters, and the Commission’s meteorological, hydrological and other experts will evaluate the methods. The simpler language of the suggested edit will allow the Commission to do this. Additionally, the standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.

• Amendatory Language: Strike current B

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Replace with new B

3.1.2 Standard MHF-2.C • Problem Statement: We think Standard C is PRESCRIPTIVE and there may be

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is general in nature. We recommend replacing

Standard C with simpler language of “Flood characteristics produced by the model will be scientifically defensible”. Same reason as given in 3.1.1. above.

• Ammendatory Language:



3.2.1 MHF-2 Purpose, First Paragraph • Problem Statement: The wording of the second sentence is slightly akward and not

consistent with other similar statements in the ROA. • Explanation: The suggested change is editorial in nature. We recommend changing the

phrase, “shall include only floods that have realistic flood characteristics” with “shall be scientifically defensible” because it is more consistent with the language in the rest of the ROA and still achieves the same purpose.

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3.2.2 MHF-2 Purpose, Third and Fourth Paragraphs • Problem Statement: The third paragraph is designed to introduce the concept of what

flood characteristics are (just as the second paragraph introduced the flood parameters). Though it is just a purpose paragraph, since modeling methods may differ, we believe it is best not to be too specific in the examples provided.

• Explanation: These suggested changes are editorial. We suggest removing all but one of the examples provided in order to avoid being too prescriptive. Since the purpose statement is to provide context for the overall standard, it can do this without being overly specific with examples.




3.3.1 MHF-2 Disclosure 2 • Problem Statement: This disclosure accompanies Standard MHF-2.B, which lists many

model parameters. AIR has suggested a major simplification of Standard B, so we also suggest removing this disclosure. By including an extensive list of parameters whose non-inclusion in the model must be defended is PRESCRIPTIVE. Disclosure 1 asks for a list and justification of the various parameters used, so it should be sufficient.

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• Explanation: This suggested change is general. The modelers will use their own scientific judgment in selecting the appropriate parameters, and the Commission’s meteorological, hydrological and other experts will evaluate the methods. The current Disclosure 1 requires enough detail for the Commission to do so.


3.3.2 MHF-2 Disclosures 8, 9 and 10 • Problem Statement: Disclosures 8, 9 and 10 ask for disclosure of trade secret material. • Explanation: The suggested edit is general. We consider the disclosure of details of how

the various flood intensity parameters are calculated to be trade secret and therefore suggest these two items be moved to audit

• Amendatory Language: We suggest moving the following disclosures to audit.

NOTE: We also have suggested edits to these disclosures; they are addressed in section 3.4 below.

3.3.3 MHF-2 Disclosures 13, 14 and 15 • Problem Statement: These three disclosures ask for disclosure of flood frequency

distributions, which is proprietary information. Flood models are in the early stages of development so modelers will not be able to reveal their flood frequency assumptions without revealing trade secrets.

• Explanation: This suggested edit is general in nature. Due to the trade secret nature of the request to reveal flood frequency by segment, we suggest this part of the disclosures be moved to audit items.

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3.3.4 MHF-2 Disclosure 17 • Problem Statement: This disclosure is currently PRESCRIPTIVE. • Explanation: This suggested edit is technical in nature. We suggest making the

disclosure more general to allow modelers to use their own scientific judgment and knowledge of the available data to determine what and how they account for antecedent conditions.


3.3.5 MHF-2 Disclosure 19 • Problem Statement: This disclosurerequests information that is trade secret. • Explanation: This suggested edit is general in nature. We suggest moving this disclosure

to audit items because the information requested would reveal details about modeling methodology.

• Amendatory Language: We suggest moving this disclosure to audit items.

• NOTE: We also have suggested edits to this disclosure; they are addressed in section 3.4

below.

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3.3.6 MHF-2 Disclosure 20 • Problem Statement: This disclosurerequests information that is trade secret. • Explanation: This suggested edit is general in nature. We suggest moving this disclosure




below.

3.3.7 MHF-2 Disclosure 21 • Problem Statement: This disclosure requests information that is trade secret. • Explanation: This suggested edit is general in nature. We suggest moving this disclosure




below.

3.3.8 (new) MHF-2 Disclosures moved from MHF-5 Disclosures 4 & 5 • Problem Statement:

o MHF-5 Disclosures 4 and 5 belong in Standard MHF-2 (Flood Parameters and Characteristics) rather than Standard MHF-5 (Modeling of Flood Mitigation and Prevention Measures) because these two disclosures deal with a flood model parameter handling soil infiltration and saturation. We believe the Commission may have included them in Standard MHF-5 because soil infiltration and saturation can be thought of as natural (as opposed to manmade) mitigation phenomena by reducing the flood severity. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.

o The other issue we have with these two disclosures is that they are PRESCRIPTIVE and may involve POTENTIALLY NO FLOOD DATA.

• Explanation: o This suggested edit is general in nature. Suggest moving MHF-5 Disclosures 4 &

5 up into Standard MHF-2. Natural mitigation phenomena such as these, if

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explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.

o The second suggested change is also general in nature. We recommend editing these disclosures to add “As applicable” to the start, which is less prescriptive language. The modelers will use their own scientific judgment in selecting the appropriate parameters, and the Commission’s meteorological, hydrological and other experts will evaluate the methods. The simpler language of the suggested edit will allow the Commission to do this. Additionally, the standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available. Over time, the Commission will be able to refine the language in the ROA as the modeling methods are established and understood.




3.4.1 MHF-2 Disclosures 8, 9 and 10 to become new MHF-2 Audit Items • Problem Statement:

o Disclosures 8, 9 and 10 ask for disclosure of trade secret material. o Secondly, Disclosures 8, 9 and 10 are PRESCRIPTIVE and may involve

POTENTIALLY NO FLOOD DATA. There also may be different parameters than the ones listed.

• Explanation: o The first suggested edit is general. We consider the disclosure of details of how

the various flood intensity parameters are calculated to be trade secret and therefore suggest these two items be moved to audit.

o The second suggested change is technical. We suggest changing the phrase, “describe how the flood height and the force of the water” to “describe how the relevant intensity parameters” to make it more general.

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•

3.4.2 MHF-2 Disclosure 19 to become (new) Audit Item • Problem Statement: This (proposed) audit item is specific to storm surge but not other

types of flooding events. Also, the information requested in this disclosure is trade secret.

• Explanation: This suggested edit is general in nature. We suggest making the disclosure general to all types of flood events, allowing the response to be tailored to how each modeler has approached the event initialization in its model.


3.4.3 MHF-2 Disclosure 20 to become (new) Audit Item • Problem Statement: This disclosure is specific to storm surge but not other types of

flooding events. Secondly, the information requested is trade secret • Explanation: This suggested edit is general in nature. We suggest making the disclosure

general to all types of flood events, allowing the response to be tailored to how each modeler handles the flood event modeling.


3.4.4 MHF-2 Disclosure 21 to become (new) Audit Item • Problem Statement: This disclosure is specific to storm surge but not other types of

flooding events. Secondly, the information requested is trade secret. • Explanation: This suggested edit is general in nature. We suggest making the disclosure

general to all types of flood events, allowing the response to be tailored to how each modeler handles the flood event modeling. It should be noted that this is a model-to-

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model comparison so there may be issues with the NOAA model. The Commission could also provide the 5 locations and maximum values and ask the modelers to compare with their model results. [leave the storm surge in the edits below]


3.4.5 (new) MHF-2 Audit Items moved from MHF-5 Audit Items 2 & 3 • Problem Statement: MHF-5 Audit Items 2 & 3 belong in Standard MHF-2 (Flood

Parameters and Characteristics) rather than Standard MHF-5 (Modeling of Flood Mitigation and Prevention Measures) because these two audit items deal with a flood model parameter handling soil infiltration and saturation. We believe the Commission may have included them in Standard MHF-5 because soil infiltration and saturation can be thought of as natural (as opposed to manmade) mitigation phenomena by reducing the flood severity. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.

• Explanation: This suggested edit is general in nature. Suggest moving MHF-5 Audit Items 2 & 3 up into Standard MHF-2. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.


Standard MHF-3 Flood Probabilities 4AIR has identified several items in this Standard that we suggest be edited. The Problem Statement and Explanation sections below discuss suggested edits to the various sections (Standards, Purpose, Disclosures, Audit).

MHF-3 Standards 4.1


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4.1.1 Standard MHF-3.B • Problem Statement: The wording of the standard is tied to the definition of a set of

flood event data sources and return periods. We think this wording is to specific and could be generalized without losing their import.

• Explanation: This suggested edit is general. We suggest replacing “shall reflect the Flood Event Data Sources used for a specific set of return periods (and corresponding probabilities)” with “shall be scientifically defensible”. This edit is also consistent with similar wording in the ROA.


4.1.2 Standard MHF-3.C • Problem Statement: We think Standards MHF-3.C is PRESCRIPTIVE and may involve

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is general in nature. We recommend changing the

language to be more general to allow a broad range of possible modeling methods. • Amendatory Language:


AIR has no suggested edits to the purpose statement at this time.



4.3.1 MHF-2 Disclosure 20 • Problem Statement: This disclosurerequires a brief rationale for the probability

distributions used for all flood parameters and characteristics. Disclosing all probability distributions may be revealing trade secret information.

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• Explanation: This suggested edit is general in nature. We suggest making the language more general to allow the modeler to disclose the most relevant probability distributions.

Amendatory Language:



4.4.1 MHF-3 Audit Item 2 • Problem Statement: The audit item does not address the different types of flood

events. • Explanation: This suggested edit is general in nature. We suggest adding in the three

broad categories of flood events. • Amendatory Language:

4.4.2 (new) MHF-3 Audit Item (moved from MHF-1 Audit Item 5) • Problem Statement: This audit item deals with modeled flood probabilities; Standard

MHF-1 is about flood event data sources. • Explanation: This is an editorial change. We suggest moving this audit item, dealing

with modeled flood probabilities, to MHF-3 which addresses flood probabilities. • Amendatory Language: Move MHF-1, Audit Item 5 to MHF-3.

4.4.3 (new) MHF-3 Audit Item (moved from MHF-1 Audit Item 6) • Problem Statement: This audit item deals with modeled flood probabilities; Standard

MHF-1 is about flood event data sources. Second issue is there is a typo; “Maximum Envelope of Winds” should be “Maximum Envelope of Water”.

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• Explanation: This is an editorial change. We suggest moving this audit item, dealing with modeled flood probabilities, to MHF-3 which addresses flood probabilities. Secondly, correct the typo.

• Amendatory Language: Amendatory Language: Move MHF-1, Audit Item 6 to MHF-3, Audit Item 2 (move others down). Secondly,

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Standard MHF-4 Flood Profile Structure 5AIR has identified several items in this Standard that we suggest be edited. The Problem Statement and Explanation sections below discuss suggested edits to the various sections (Standards, Purpose, Disclosures, Audit).

MHF-4 Standards 5.1


5.1.1 Standard MHF-4 title • Problem Statement: The term “flood profile” is not the common term used for referring

to flood events. • Explanation: The suggested edit is general. We suggest using “flood footprint” instead

of “flood profile” because it is the more common term and the concept of a flood profile is included in the concept of the footprint.


5.1.2 Standard MHF-4.A • Problem Statement: The standard currently states that the historical flood footprints

should be adjusted to reflect mitigation and prevention measures taken since the flood occurrence. We don’t agree that the historical event should be adjusted: it is what it is. You will also have the situation where adjustments will not be consistent across modelers.

• Explanation: This suggested edit is technical in nature. We suggest striking the “adjusted for flood mitigation and prevention measures”. Where mitigation and prevention measures have been taken they will be reflected in the model results. The modeler then will explain how the model is different from the historical and why.


5.1.3 Standard MHF-4.D • Problem Statement: We think Standard D is PRESCRIPTIVE by listing parameters and

characteristics modelers should use in developing their models even before all the modelers have developed them. Also, they may involve POTENTIALLY NO FLOOD DATA.

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• Explanation: The suggested change is general in nature. We recommend updating Standard D with simpler language. The modelers will use their own scientific judgment in selecting the appropriate parameters, and the Commission’s meteorological, hydrological and other experts will evaluate the methods. The simpler language of the suggested edit will allow the Commission to do this. Additionally, the standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available. Over time, the Commission will be able to refine the language in the ROA as the modeling methods are established and understood.


5.1.4 Standard MHF-4.E • Problem Statement: We think Standard E is PRESCRIPTIVE by listing parameters and

characteristics modelers should use in developing their models even before all the modelers have developed them. Also they may involve POTENTIALLY NO FLOOD DATA.

• Explanation: The suggested change is general in nature. We recommend updating Standard E with simpler language to allow the modelers to use their own scientific judgment in selecting the appropriate parameters.



AIR has no suggested edits to the MHF-4 Purpose Statement at this time.



5.3.1 MHF-4 Disclosure 1 • Problem Statement: We support the concept of providing visual descriptions to

illustrate stochastic flood footprints for the various types of flood events. The way the

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disclosure is currently written, particularly the second paragraph is PRESCRIPTIVE and may involve POTENTIALLY NO FLOOD DATA.

• Explanation: The suggested change is general in nature. We recommend replacing Disclosure 1 with simpler language. The modelers will use their own scientific judgment in selecting the appropriate modeling methods, and the Commission’s meteorological, hydrological and other experts will evaluate the methods. The simpler language of the suggested edit will still allow the Commission to do this. Additionally, the standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available. Over time, the Commission will be able to refine the language in the ROA as the modeling methods are established and understood.


5.3.2 MHF-4 Disclosure 2 • Problem Statement: We think Disclosure 2 is PRESCRIPTIVE and may involve

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is general. We recommend broadening the wording

of the disclosure to mirror the suggested broader language of the Standard MH4-D. • Amendatory Language:

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5.4.1 MHF-4 Audit Item 4 • Problem Statement: We think Audit Item 4 is PRESCRIPTIVE and may involve

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is general. We recommend adding the words, “If

applicable” to the start of the sentence to allow flexibility in the model development process.


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Standard MHF-5 Modeling of Natural and Man-Made 6Flood Mitigation and Prevention Measures


MHF-5 Standards 6.1


6.1.1 Standard MHF-5 title • Problem Statement: The wording of the standard title is prescribing both natural and

manmade flood mitigation prevention measures be explicitly modeled even before all the modelers have developed their models. The Commission’s role is to evaluate models submitted, and this language seems to go beyond that role. Also, requiring modelers to explicitly include all of these features without first knowing whether the data exists to do so in a credible, robust way goes against the spirit of the Commission’s mission.

• Explanation: The suggested change is general. Removing “Natural and Man-Made” from the title will allow the modelers to reflect the the appropriate mitigation measures based on their judgment and the available data.


6.1.2 Standard MHF-5.A • Problem Statement: The wording of the standard PRESCRIPTIVE and may involve

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is general. We recommend simplifying the language

of the standard to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.

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6.1.3 Standard MHF-5.B and C moved to Standard MHF-2 • Problem Statement: The concepts dealt with in Standards MHF-5.B and C belong in and

are currently covered in Standard MHF-2 (Flood Parameters and Characteristics) rather than Standard MHF-5 (Modeling of Flood Mitigation and Prevention Measures). We believe the Commission may have included Standards MHF-5.B and C because soil infiltration and saturation can be thought of as natural (as opposed to manmade) mitigation phenomena by reducing the flood severity. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.

• Explanation: This suggested edit is general in nature. We suggest deleting Standards MHF-5.B and C because they are already covered Standard MHF-2. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.


6.1.4 Standard MHF-5.D • Problem Statement: The wording of this standard implies it is the job of the modeler to

assess all current flood mitigation and prevention measures in the state of Florida. Such a review is typically done by the USACE or FEMA, not the modelers. The modelers will utilize the latest vintage datasets available during the time of a model update.

• Explanation: The suggested edit is general in nature. We suggest removing the implication that the modelers should regularly survey all mitigation and prevention measures, which we do not have the expertise or manpower to do. The revised wording

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requires the modeler to review and use available data sets, which is our responsibility. The last edit, removing “in their appropriate databases used in the model” is because this is redundant.


6.1.5 (new) Standard MHF-5 brought in from Standard MHF-6 (modeling failure of flood mitigation and prevention measures)

• Problem Statement: o Standards addressing the modeling of flood mitigation and prevention measures

can also address the failure of same. We do not believe there is a need to have a separate set of standards.

o The second problem we see with Standard MHF-6 (proposing to be brought over as new Standard MHF-5) is that it is PRESCRIPTIVE and may involve POTENTIALLY NO FLOOD DATA.

• Explanation: o The suggested edit is general in nature. We suggest moving Standard MHF-6

into Standard MHF-5 because there is no need to have separate standards for modeling the failure of the flood mitigation and prevention measures.

o The second suggested edit is general in nature. We recommend simplifying the language of the standard by removing “natural and manmade” to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.




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6.2.1 MHF-5 Purpose • Problem Statement: Accompanying our suggestion to bring Standard MHF-6 into MHF-

5, the Purpose Statement should also be updated. • Explanation: Accompanying our suggestion to bring Standard MHF-6 into MHF-5, the

Purpose Statement should also be updated. • Amendatory Language:



6.3.1 MHF-5 Disclosure 1 • Problem Statement:

o The wording of the disclosure is PRESCRIPTIVE and may involve POTENTIALLY NO FLOOD DATA.

• Explanation: o The suggested change is general. We recommend adding the words, “If

applicable” to the start of the sentence to allow flexibility in the model development process.

o The second suggested edit is general in nature. We recommend simplifying the language of the disclosure by removing “natural and man made” to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.


6.3.2 MHF-5 Disclosure 2 • Problem Statement: The wording of the disclosure is PRESCRIPTIVE and may involve

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is general. We recommend simplifying the language

of the disclosure by removing “natural and man made” to allow for the broad range of

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possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.


6.3.3 MHF-5 Disclosure 3 • Problem Statement: The wording of the disclosure is PRESCRIPTIVE and involving

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is general. We recommend adding the words, “If

applicable” to the start of the sentence to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.


6.3.4 MHF-5 Disclosures 4 & 5 • Problem Statement: MHF-5 Disclosures 4 and 5 belong in Standard MHF-2 (Flood

Parameters and Characteristics) rather than Standard MHF-5 (Modeling of Flood Mitigation and Prevention Measures) because these two disclosures deal with a flood model parameter handling soil infiltration and saturation. We believe the Commission may have included them in Standard MHF-5 because soil infiltration and saturation can be thought of as natural (as opposed to manmade) mitigation phenomena by reducing the flood severity. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.

• Explanation: This suggested edit is general in nature. Suggest moving MHF-5 Disclosures 4 & 5 up into Standard MHF-2. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.

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6.3.5 MHF-5 Disclosure 6 • Problem Statement: The wording of this disclosure implies it is the job of the modeler

to assess all current flood mitigation and prevention measures in the state of Florida. Such a review is typically done by the USACE or FEMA, not the modelers. The modelers will utilize the latest vintage datasets available during the time of a model update.

• Explanation: This proposed edit is general in nature. Our suggestion is to remove the implication that the modelers should regularly survey all mitigation and prevention measures, which we do not have the expertise or manpower to do.


6.3.6 (new) MHF-5 Disclosures (brought up from Standard MHF-6 Disclosures 1-4) • Problem Statement:

o First, Standards addressing the modeling of flood mitigation and prevention measures can also address the failure of same. We do not believe there is a need to have a separate set of standards.

o The second problem we see with these disclosures is that they are PRESCRIPTIVE and involve POTENTIALLY NO FLOOD DATA.

• Explanation: o The first suggested edit is general in nature. We suggest moving MHF-6

Disclosures 1-4 into Standard MHF-5 because there is no need to have separate standards for modeling the failure of the flood mitigation and prevention measures.

o The second suggested edit is also general in nature. We recommend adding “If applicable” to the beginning of each disclosure to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that

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may be necessary to be supported by the data available.Amendatory Language:



6.4.1 MHF-5 Audit Item 1 • Problem Statement: The problem we see with this audit item is that it is PRESCRIPTIVE

and involves POTENTIALLY NO FLOOD DATA. • Explanation: The suggested edit is general in nature. We recommend simplifying the

language of the audit item by removing “natural and man made” to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.


6.4.2 MHF-5 Audit Items 2 & 3 (moved to MHF-2) • Problem Statement: MHF-5 Audit Items 2 and 3 belong in Standard MHF-2 (Flood

Parameters and Characteristics) rather than Standard MHF-5 (Modeling of Flood Mitigation and Prevention Measures) because these two disclosures deal with a flood model parameter handling soil infiltration and saturation. We believe the Commission may have included them in Standard MHF-5 because soil infiltration and saturation can be thought of as natural (as opposed to manmade) mitigation phenomena by reducing

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the flood severity. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.

• Explanation: This suggested edit is general in nature. Suggest moving MHF-5 Audit Items 2 and 3 up into Standard MHF-2. Natural mitigation phenomena such as these, if explicitly modeled, will likely be a parameter in the model and therefore belong in Standard MHF-2.


6.4.3 MHF-5 Audit Item 4 • Problem Statement: The wording of this audit item implies it is the job of the modeler

to assess all current flood mitigation and prevention measures in the state of Florida. Such a review is typically done by the USACE or FEMA, not the modelers. The modelers will utilize the latest vintage datasets available during the time of a model update.

• Explanation: This proposed edit is general in nature. Our suggestion is to remove the implication that the modelers should regularly survey all mitigation and prevention measures, which we do not have the expertise or manpower to do.


6.4.4 (new) MHF-5 Audit Items (brought up from MHF-6) • Problem Statement:

o First, Standards addressing the modeling of flood mitigation and prevention measures can also address the failure of same. We do not believe there is a need to have a separate set of standards.

o The second problem we see with these audit items is that they are PRESCRIPTIVE and involve POTENTIALLY NO FLOOD DATA.

• Explanation: o The first suggested edit is general in nature. We suggest moving MHF-6 Audit

Items 1-4 into Standard MHF-5 because there is no need to have separate

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standards for modeling the failure of the flood mitigation and prevention measures.

o The second suggested edit is also general in nature. We recommend adding “If applicable” to the beginning of each audit item to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.


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Standard MHF-6 Modeling for the Failure of Flood 7Mitigation or Prevention Measures


MHF-6 Standards, Purpose, Disclosures and Audit Items 7.1


7.1.1 Standard MHF-6 • Problem Statement: Standards addressing the modeling of flood mitigation and

prevention measures can also address the failure of same. We do not believe there is a need to have a separate set of standards. The division of standards should correspond to major divisions or components in the model, and mitigation measures and their failure belong in one component.

• Explanation: The suggested edit is general in nature. We suggest moving Standard MHF-6 into Standard MHF-5 because there is no need to have separate standards for modeling the failure of the flood mitigation and prevention measures.

• Amendatory Language: Move MHF-6 to MHF-5

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Standard MHF-7 Logical Relationships of Flood 8Characteristics


MHF-7 Standards 8.1


8.1.1 Standard MFH-7.A • Problem Statement: The standard should be specific to coastal flooding since it talks

about the windfield over water. • Explanation: This suggested change is general. We suggest adding “coastal” before the

word flood profile. • Amendatory Language:

8.1.2 Standard MFH-7.B • Problem Statement: The wording of the standard is PRESCRIPTIVE and may inolve

POTENTIALLY NO FLOOD DATA. • Explanation: The suggested change is technical. We suggesting testing the logical

relationship of the water level to surface roughness instead of the rate of water flow because it is more general.


8.1.3 Standard MFH-7.C & D • Problem Statement: These two standards are PRESCRIPTIVE and involve POTENITALLY

NO FLOOD DATA. • Explanation: The suggested edit is general in nature. We recommend deleting

Standards MFH-7.C & D to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available.

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8.1.4 Standard MFH-7.F • Problem Statement: This standard is PRESCRIPTIVE and may involve POTENTIALLY NO

FLOOD DATA. • Explanation: The suggested edit is general in nature. We recommend deleting Standard

MFH-7.F to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available. Another alternative is to add the phrase, “If applicable” to the beginning of the standard.


8.1.5 Standard MFH-7.H • Problem Statement: This standard is PRESCRIPTIVE and may involve POTENTIALLY NO

FLOOD DATA. • Explanation: The suggested edit is general in nature. We recommend deleting Standard

MFH-7.H to allow for the broad range of possible models. The standards should foster and encourage the use of various loss projections methodologies, including simpler but more robust methods that may be necessary to be supported by the data available. Another alternative is to add the phrase, “If applicable” to the beginning of the standard.


8.1.6 Standard MFH-7.I • Problem Statement:

o The language is not as precise as one could wish. • Explanation:

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o The suggested edit is editorial in nature to make the language more precise. We suggest changing “the steeper the” to “with increase in steepness in”; and changing “greater the” to “increase in”.


8.1.7 (new) Standard MFH-7 • Problem Statement: AIR has recommended deletion of several MFH-7 standards to

avoid over-prescribing how the modelers build the flood models. We also thought of one additional logical relationship to flood characteristic that was not in the list.

• Explanation: This suggested edit is technical in nature. We suggest adding an addional logical relationship to flood characteristic, “The fluvial flood footprint shall increase with increasing discharge in the river.”


8.1.8 All MHF-7 Standards – ordering of • Problem Statement: Right now the order of the proposed MHF-7 standards is

somewhat random in terms of the type of flooding they address. • Explanation: This suggestion is to reorder the standards to group by general, coastal and

fluvial.

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• Amendatory Language: The table below shows the ordering we recommend.


AIR has no suggested edits to the MHF-7 Purpose Statement at this time.


AIR has no suggested edits to the MHF-7 Disclosures at this time.


AIR has no suggested edits to the MHF-7 Audit Items at this time.

B. The water level shall increase with increasing surface roughness, all other factors held constant.

General

E. The interaction of coastal flooding associated with storm surge and inland flooding shall increase the flood profile area, all other factors held constant.

General

F. The rate of water flow shall increase with increase in steepness in topography and increase in surface slope, all other factors held constant.

General

A. The larger the area of the over water windfield, the greater the coastal flood profile area, all other factors held constant.

Coastal

D. The coastal flooding associated with storm surge shall increase with a shallow and gently sloping shoreline, all other factors held constant.

Coastal

G. The height of storm surge shall increase with increasing windspeeds, all other factors held constant.

Coastal

(new) C. The fluvial flood footprint shall increase with increasing discharge in the river.

Fluvial

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Form MHF-1 Annual Flood Occurrence Rates by 9County

AIR has identified several items in this Form that we suggest be edited.

Items in Form MHF-1 9.1

AIR’s suggested edits to Form MHF-1 are described, explained and justified below.

9.1.1 Form MHF-1 Item A • Problem Statement:

o The wording, “for the most current 5, 25, 50, and 100 years” is not precise or clear. We believe the Commission might instead be referring to various probabilities of exceedance corresponding to specific return periods

o Secondly, for flooding, the concept of an occurrence rate for a county does not make sense. The data used for understanding flooding are from gauging stations. It makes more sense to calculate flood occurrence rates in terms of specific gauging stations, or perhaps in terms of a collection of gauging stations, though aggregating across gauging stations may not produce a very meaningful result.

o Thirdly, the flood occurrence rates may differ for the different types of flooding. • Explanation:

o The first suggested edit is technical in nature. The wording “Provide annual historical and modeled flood occurrence rates for the most current 5, 25, 50, and 100 years” is not precise or clear. We suggest clearer wording to be “Provide annual flood occurrence rates. . . which include data for various probabilities of exceedance (corresponding to 5, 25, 50, and 100 year return periods).”

o The second suggested edit is technical in nature. We suggest changing the wording to allow the modeler to report the occurrence rates for identified locations (i.e. where there are gauging stations) in a region or for the region as a whole.

o The third suggested edit is general. We suggest adding in “storm surge, fluvial and fluvial flooding” to allow for the reporting of these rates separately if necessary.

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9.1.2 Form MHF-1 Item C • Problem Statement: For flooding, the concept of an occurrence rate for a county does

not make sense. The data used for understanding flooding are from gauging stations. It makes more sense to calculate flood occurrence rates in terms of specific gauging stations, or perhaps in terms of a collection of gauging stations, though aggregating across gauging stations may not produce a very meaningful result.

• Explanation: This edit is tehnical. We suggest removing the words “by Florida County” to allow the modeler to provide the bar graphs at the appropriate detail depending on how Form MFH-1 is completed.


9.1.3 Form MHF-1 Item D • Problem Statement: For flooding, the concept of an occurrence rate for a county does

not make sense. The data used for understanding flooding are from gauging stations. It makes more sense to calculate flood occurrence rates in terms of specific gauging stations, or perhaps in terms of a collection of gauging stations, though aggregating across gauging stations may not produce a very meaningful result.

• Explanation: This edit is tehnical. We suggest removing the words “by County” to allow the modeler to provide the bar graphs at the appropriate detail depending on how Form MFH-1 is completed.


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Form MHF-2 Maps of Flood Profiles by Return Period 10AIR has identified several items in this Form that we suggest be edited.

Items in Form MHF-2 10.1

AIR’s suggested edits to Form MHF-2 are described, explained and justified below.

10.1.1 Form MHF-2 Item x • Problem Statement: Historical events do not come with a return period categorization.

You can understand return periods for historical events by viewing them relative to a modeled exceedance probability curve. Perhaps this is what the current wording is getting at, but it is confusing.

• Explanation: This suggested edit is technical in nature. We suggest identifying two of each kind of flood event (surge, fluvial and pluvial) that have recently occurred in Florida and showing a mapping those events.


10.1.2 Form MHF-2 Item x • Problem Statement: The wording is not very clear, and the best way to show flood

profiles may not always be in map format. • Explanation:

o This suggested edit is editorial. We suggest changing the words “color contour maps” to exhibits to allow for displaying the flood profiles in various ways. Also, adding the words, “selected historical” before flood events eliminates the need to have bullets 1., 2. and 3. Finally, we suggest replacing the text “associated with each 10, 25, 50, 75, 100, 250, 500, and greater than 500 year return periods for” with the wording, “illustrating modeled return periods for different river or coastal segments”.

o Suggested edits to the second paragraph of B are editorial in nature. By simply stating that the measures of maximum flood levels should be “relative to the local datum”, it allows the modeler to utilize the datum that makes most sense for each type of flood. Also, adding in wording to specify that the “six historical events” selected in A should be used.

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10.1.3 Form MHF-2 Items C., D. and E. • Problem Statement: The wording in items C. D. and E. is not very clear. We believe the

Commission may be thinking of a model validation exhibit similar to what is required in Standard M-4, disclosure 9 where modeled wind speeds are shown by ZIP, and the observed wind speeds are plotted on top with similar color scheme. The three items are designed to give instructions for each type of flood event, when the wording could be more general and simpler.

• Explanation: This suggested edit is general in nature. We have used language similar to Standard M-4, disclosure 9 to convey the concept very simply: “Demonstrate the consistency of the spatial distribution of model-generated flood profiles with observed flood profiles for storm surge, fluvial and pluvial floods affecting Florida.” Since this wording is general to the different types of floods, we strike items D and E.

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10.1.4 Form MHF-2 Item x • Problem Statement: The wording is not as precise as it could be. • Explanation: This suggested edit is editorial in nature. We suggest adding the word

“profiles” after “historical flood” to be consistent with same after “modeled flood”. • Amendatory Language:

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Attachment with Track Changes 11The attached document called Meteorological Hydrological Flood Standards 11-17-

14_AIR_AllTrackChanges.docx contains all of AIR’s suggested edits in track-changes format. If there is

any disagreement between the appendix and the content in the report, the report edits take

precedence.

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flood standards development - internet > homedec 05, 2014 · • problem statement: the first...

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