Levee Analysis and Mapping Procedure (LAMP) for ... - RiskMAP6

Levee Analysis and Mapping 

Procedure (LAMP) 

for Non-accredited Levees 

Brazoria LAMP Pilot Project Webinar 

FEMA Region 6 

August 21, 2013

Webinar Topics 

• Overview of Levee Analysis and Mapping Process 

(LAMP) for Non-accredited Levees Approach 

• Local Levee Partnership Teams (LLPT) 

• Anticipated Issues Specific To Brazoria County 

• Comments and Concerns on Approach 

• Schedule 

• Meet and Greet 

2

The LAMP Process 

Phase 1 

Phase 2 

Phase 3 

3

Overview of LAMP Approach 

There are five procedures detailed in 

the LAMP Final Approach Document. 

• Natural Valley 

• Sound Reach 

• Freeboard Deficient 

• Overtopping 

• Structural-Based Inundation 

A system can be broken up into 

multiple reaches in order to analyze 

the flood risk in its vicinity. 

1 System 

↓ 

Multiple 

Reaches 

4

Natural Valley Procedure 

• Basic analysis to be applied to all levee systems, and/or 

individual reaches (procedure possible with minimal data) 

• This procedure refers to the river channel and floodplain of 

a river system, or coastal area, prior to the addition of 

flood control structures (e.g. levees) 

• No additional 

data needs or 

requirements 

for preparation 

of analysis 

5

Sound Reach Procedure 

For a levee reach designed, constructed, and maintained to 

withstand and reduce the flood hazard posed by the base 

(one-percent-annual-chance) flood. 

• No levee reach-specific modeling 

necessary 

• Zone D landward of the reach 

• Interior drainage may map some 

flood hazard on the landward side 

• Specified reach meets all 65.10 

requirements and each is 

documented 

6

Freeboard Deficient Procedure 

For levee reaches that cannot meet the freeboard regulatory 

requirements in 44 CFR 65.10 (freeboard helps to account for 

uncertainty in design and the base flood). 

• Natural Valley 

Approach is used to 

map landward risk 

• Zone D landward of 

the reach 

• Levee crest must be 

higher than the 

calculated BFE for this 

method to be suitable 

7

Overtopping Procedure 

• Appropriate for levee reaches that are known to overtop 

during the one-percent-annual chance flood. 

• The BFE is calculated to exceed the height of the levee 

crest at a minimum of one location along the levee’s reach 

length). 

• Structure should be 

designed for overtopping 

• Structural requirements 

are met and 

documented 

• Levee modeled as a 

lateral weir 

8

Structural-Based Inundation 

Procedure 

For a levee reach where evaluation reports and/or historic 

performance indicate structural issues. 

• Levee reports and 

historical 

information will 

inform the modeling 

effort for this 

scenario. 

• Need to identify 

the locations of 

structural issues & 

determine failure 

scenarios 

9

Definition of Reach 

Barely overtops & is armored: 

community chooses to do extra 

evaluation for overtopping 

These areas are overtopped 

Recent structural analysis completed 

Operated and Maintained 

Good Survey Information 

Overtops but not armored 

Has required freeboard 

Don’t know anything about 

Not maintained 

No owner 

No structural analysis 

10

Data Available Determines 

Which LAMP Procedure Is Used 

Reach overtops, armoring present, 

community provides additional 

information for evaluation of levee 

reach 


Reach overtops, no armoring 

present, vegetation and sand 

boils present 

Structural-Based Inundation Procedure 

Meets all requirements 

outlined in 44CFR65.10, 

community provided 

documentation noting all 

requisites are met 

Sound Reach Procedure 

Not maintained, No owner, 

No data provided or 

available 


11

Mapping the Results 

If ONLY Natural Valley Procedure is Used 

• In the case that the Natural Valley Analysis is selected and 

utilized for the ENTIRE levee system. 

• Then only Natural Valley analysis/mapping effort will be 

performed 

• The resultant floodplain will be 

depicted as a Special Flood 

Hazard Area 

(SFHA) 

(Zone A, Zone AE, 

Zone AO, Zone AH) 

Special Flood 

Hazard Area (SFHA) 

ONLY 

Natural Valley 


Used 

12


Composite Map - Layer One (Natural Valley) 

• If other analysis procedures are used, the Natural Valley 

Analysis will be depicted as Zone D. 

• Other analysis will be layered on top of these results to build 

the composite floodplain 

Zone D: 


13


Composite Map - Layer Two (Interior Drainage) 

• If system includes drainage features, pump stations or other 

drainage facilities, these areas will be analyzed and their 1% 

annual chance flood zone will be determined and added to 

the mapping (Zone A, Zone AE, Zone AO, Zone AH) 

14


Composite Map - Layer Three (Landward Hazard) 

• System was modeled with Overtopping and Structural Based 

Inundation Procedures 

• These areas are mapped and added to the composite mapping 

as Special Flood Hazard Areas (Zone A/AE, Zone AO/AH) 


Structural-Based 

Inundation 


15


Composite Map - Layer Four (Flooding Source) 

• Finally, the flooding source analysis results will be added to the 

composite map to finalize the composite mapping. 

• The analysis for the open coast or the riverine flood source will 

be based on the calculated Base Flood Elevations (BFEs) for 

the riverward (seaward) side of the levee system. 

16


OR a Composite Map will be prepared 

If a series of procedures are 

used to determine the flood 

risk for a single levee 

system… 

- each reach analysis will be 

performed 

- Each reach mapping effort will be 

prepared 

- And then a composite map will be 

created from the compilation of 

the resultant analysis of each 

procedure. 

17

Documentation of Levee 

Condition 

• Appropriate analysis requires documentation of levee 

condition 

•Structural stability of levee 

•Elevation of levee 

•Armoring 

• FEMA has been instructed that it may not invest in: 

•Data required for levee accreditation 

•Data required for a determination of a levee system’s 

structural condition 

• Responsibility of levee owner 

18

The LAMP Process 

• Previous overviews available at www.riskmap6.com. 

• http://www.riskmap6.com/documents/Meeting_340/FINAL_LAMPInitiationWebinar-2013- 

08-09.pptx 

• Key elements of Phase 2 process going forward: 

• Formation of LLPTs 

• Assessment of levees and appropriate analysis 

• Perform approximate-level hydrologic and 

hydraulic (H&H) analyses, review of results 

• Prepare Levee Analysis 

and Mapping Plan 

19

Local Levee Partnership Team 

(LLPT) 

• FEMA (and USACE where appropriate) will attend 

• Items for Local Communities to Consider: 

• Member with community decision making authority (or one who 

advises decision) is requested 

• Representation from geography and political jurisdictions within 

the system, make sure the levee owner is included 

• Community may want a technical participant to provide input 

(Engineering Department/Consultant) 

• Floodplain Management Staff 

• Others? (What other factors are important in your area) 

20


(LLPT) 

• Meeting-Specific Objectives: 

• Important information and data related to how the levee 

will be analyzed and mapped is obtained and considered. 

• LLPT members have an opportunity to explain the unique 

conditions related to their levee that will impact the 

analysis and mapping. 

• LLPT members comment on methods for levee reaches, 

analyses, and mapping within the allowable guidelines. 

• A reasonable schedule is developed for obtaining input or 

additional data. 

21


(LLPT) 

• Level of effort will vary during this phase based on the 

complexity of the levee system in question. 

• Intention of this phase is to: 

• Coordination with stakeholders external to FEMA 

• Collect existing local data & system knowledge 

• Determine additional data communities plan to submit 

• Perform approximate-level hydrologic and 

hydraulic (H&H) analyses, review of results 

• Prepare Levee Analysis 

and Mapping Plan 

22

Brazoria LLPTs 

• Two LLPTs in Brazoria County 

• Angleton Drainage District 

• Velasco Drainage District 

23

Getting to the LLPT Meeting(s): 

• Initial Pilot Meet and Greet 

•Week of September 17 

•Identified and potential LLPT members 

• Formation of LLPT 

•FEMA coordinating with USACE (where appropriate) 

•Communities should prepare a local participant list 

• Operational Guidance Release (slated for Mid September) 

• Face to Face LLPT (Technical Dive 1) 

24

Things You Can Do Now 

• Local communities should identify which systems 

will need to be reviewed for the application of LAMP 

approach 

• Local communities should begin identifying 

available data and submitting it to their FEMA POC 

• Local communities should begin collection of all 

available data that could inform the determination 

of which procedures may be applicable for your 

levee system 

25

For the Latest Information: 

• Visit FEMA’s LAMP webpage to access available 

information for the Levee Analysis and Mapping 

Procedure: 

http://www.fema.gov/ 

final-levee-analysis-and-mapping-approach 

• Operational Guidance will be released and made 

available through this web page. 

26

Levee Analysis and Mapping Procedure (LAMP) for ... - RiskMAP6

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