086-0-27B Riverine Structures Form

DEPARTMENT OF HOMELAND SECURITY
FEDERAL EMERGENCY MANAGEMENT AGENCY

O.M.B. NO. 1660-0016
Expires February 28, 2014

RIVERINE STRUCTURES FORM

PAPERWORK BURDEN DISCLOSURE NOTICE

Public reporting burden for this form is estimated to average 7 hour per response. The burden estimate includes the time for reviewing instructions,
searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You are not
required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send
comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management,
Department of Homeland Security, Federal Emergency Management Agency, 1800 South Bell Street, Arlington, VA 20598-3005 Paperwork
Reduction Project (1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please
do not send your completed survey to the above address.
PRIVACY ACT STATEMENT
AUTHORITY: The National Flood Insurance Act of 1968, Public Law 90-448, as amended by the Flood Disaster Protection Act of 1973, Public Law
93-234.
PRINCIPAL PURPOSE(S): This information is being collected for the purpose of determining an applicant's eligibility to request changes to National
Flood Insurance Program (NFIP) Flood Insurance Rate Maps (FIRM).
ROUTINE USE(S): The information on this form may be disclosed as generally permitted under 5 U.S.C § 552a(b) of the Privacy Act of 1974, as
amended. This includes using this information as necessary and authorized by the routine uses published in DHS/FEMA/NFIP/LOMA-1 National
Flood Insurance Program (NFIP); Letter of Map Amendment (LOMA) February 15, 2006, 71 FR 7990.
DISCLOSURE: The disclosure of information on this form is voluntary; however, failure to provide the information requested may delay or prevent
FEMA from processing a determination regarding a requested change to a (NFIP) Flood Insurance Rate Maps (FIRM).
Flooding Source:
Note: Fill out one form for each flooding source studied.
A. GENERAL
Complete the appropriate section(s) for each Structure listed below:
Channelization...............complete Section B
Bridge/Culvert...............complete Section C
Dam...............................complete Section D
Levee/Floodwall............complete Section E
Sediment Transport.......complete Section F (if required)
Description of Structure
1. Name of Structure:
Type (check one):

Channelization

Bridge/Culvert

Levee/Floodwall

Dam

Bridge/Culvert

Levee/Floodwall

Dam

Location of Structure:
Downstream Limit/Cross Section:
Upstream Limit/Cross Section:
2. Name of Structure:
Type (check one):

Channelization

Location of Structure:
Downstream Limit/Cross Section:
Upstream Limit/Cross Section:
3. Name of Structure:
Type (check one):

Channelization

Bridge/Culvert

Levee/Floodwall

Dam

Location of Structure:
Downstream Limit/Cross Section:
Upstream Limit/Cross Section:
NOTE: FOR MORE STRUCTURES, ATTACH ADDITIONAL PAGES AS NEEDED.
FEMA Form 086-0-27B, (2/2011)

MT-2 Form 3 Page 1 of 9

B. CHANNELIZATION
Flooding Source:
Name of Structure:
1. Hydraulic Considerations
The channel was designed to carry

(cfs) and/or the

-year flood.

The design elevation in the channel is based on (check one):
Subcritical flow

Critical flow

Super critical flow

Energy grade line

If there is the potential for a hydraulic jump at the following locations, check all that apply and attach an explanation of how the hydraulic
jump is controlled without affecting the stability of the channel.
Inlet to channel

Outlet of channel

At Drop Structures

At Transitions

Other locations (specify):
2. Channel Design Plans
Attach the plans of the channelization certified by a registered professional engineer, as described in the instructions.
3. Accessory Structures
The Channelization includes (check one):
Levees [Attach Section E) Levee/Floodwall)]
Transitions in cross sectional geometry
Weir

Super elevated sections

Drop structures

Debris basin/design basin [Attach Section D (Dam/Basin)]

Energy dissipater

Other (describe):

4. Sediment Transport Considerations
Are the hydraulics of the channel affected by sediment transport?

Yes

No

If Yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why sediment transport was not considered.
C. BRIDGE/CULVERT
Flooding Source:
Name of Structure:
1. This revision reflects (check one):
New bridge/culvert not modeled in the FIS
Modified bridge/culvert previously modeled in the FIS
New analysis of bridge/culvert previously modeled in the FIS
2. Hydraulic model used to analyze the structure (e.g., HEC-2 with special bridge routine, WSPRO, HY8):
If different hydraulic analysis for the flooding source, justify why the hydraulic analysis used for the flooding source could not analyze
the structures. Attach justification.
3. Attach plans of the structures certified by a registered professional engineer. The plan detail and information should include the following
(check the information that has been provided):
Dimensions (height, width, span, radius, length)

Distance Between Cross Sections

Shape (culverts only)

Erosion Protection
Low Chord Elevations - Upstream and Downstream

Material

Top of Road Elevations - Upstream and Downstream

Beveling or Rounding

Structure Invert Elevations - Upstream and Downstream

Wing Wall Angle

Stream Invert Elevation - Upstream and Downstream

Skew Angle

Cross-Section Locations

4. Sediment Transport Considerations
Was sediment transport considered?

Yes

No

If Yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why sediment transport was not considered.
FEMA Form 086-0-27B, (2/2011)

MT-2 Form 3 Page 2 of 9

D. DAM/BASIN
Flooding Source:
Name of Structure:
1. This request is for (check one):

Existing dam/basin

2. The dam/basin was designed by (check one):

New dam

Federal agency

Modification of existing dam/basin
Local government agency

Private organization

State agency

Name of the agency or organization:
3. The dam/basin was permitted as ( check one):

State Dam

Federal Dam

Provide the permit or identification number (ID) for the dam and the appropriate permitting agency or organization
Permit or ID number
Local Government Dam

Permit Agency or Organization:
Private Dam

Provide related drawings, specifications and supporting design information.
4. Does the project involve revised hydrology?

Yes

No

If Yes, complete the Riverine Hydrology & Hydraulics Form (Form 2)
Was the dam/basin designed using critical duration storm? (Must account for the maximum volume of runoff?)
Yes, provide supporting documents with your completed Form 2.
No, provide written explanation and justification for not using the critical duration storm.
5. Does the submittal include debris/sediment yield analysis?

Yes

No

If Yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why debris/sediment analysis was not considered?
6. Does the Base Flood Elevation behind the dam or downstream of the dam change?

Yes

No

If Yes, complete the Riverine Hydrology & Hydraulics Form (Form 2) and complete the table below.
Stillwater Elevation Behind the Dam
FIS

FEQUENCY (% annual chance)

REVISED

10-year (10%)
50-year (2%)
100-year (1%)
500-year (0.2%)
Normal Pool Elevation
7. Please attach a copy of the formal Operation and Maintenance Plan.
E. LEVEE/FLOODWALL
1. System Elements
a. This Levee/Floodwall analysis is based on (check one):

upgrading of an
existing levee/
floodwall system

a newly
constructed levee/
floodwall system

reanalysis of an
existing levee/
floodwall system

b. Levee elements and locations are (check one):
earthen embankment, dike, berm, etc.

Station

to

structural floodwall

Station

to

other (describe):

Station

to

c. Structural Type (check one):

monolithic cast-in place reinforced concrete

reinforced concrete masonry block

sheet piling

other (describe):
d. Has this levee/floodwall system been certified by a Federal agency to provide protection from the base flood?

Yes

No

If Yes, by which agency?
e. Attach certified drawings containing the following information (indicate drawing sheet numbers):
1. Plan of the levee embarkment and floodwall structures

Sheet Numbers

2. A profile of the levee/floodwall system showing the Base Flood Elevation (BFE), levee
and/or wall crest and foundation, and closure locations for the total levee system.

Sheet Numbers

3. A profile of the BFE, closure opening outlet and inlet invert elevations, type and size
of opening, and kind of closure.

Sheet Numbers

FEMA Form 086-0-27B, (2/2011)

MT-2 Form 3 Page 3 of 9

E. LEVEE/FLOODWALL (continued)
1. System Elements (continued)
e. Attach certified drawings containing the following information (indicate drawing sheet numbers):
4. A layout detail for the embarkment protection measures.

Sheet Numbers

5. Location, layout, and size and shape of the levee embarkment features, foundation treatment,
floodwall structure, closure structures, and pump stations.

Sheet Numbers

2. Freeboard
a. The minimum freeboard provided the BFE is:
Riverine
3.0 feet or more at the downstream end and throughout

Yes

No

3.5 feet or more at the upstream end

Yes

No

4.0 feet within 100 feet upstream of all structures and/or constrictions

Yes

No

1.0 foot above the height of the one percent wave associated with the 1%-annualchance stillwater surge elevation or maximum runup (whichever is greater)

Yes

No

2.0 feet above the 1%-annual-chance stillwater surge elevation

Yes

No

Coastal

Please note, occasionally exceptions are made to the minimum freeboard requirement. If an exception is requested, attach documentation
addressing paragraph 65.10(b)(1)(ii) of the NFIP regulations
If No is answered to any of the above, please attach an explanation..
b. Is there an indication from historical records that ice-jamming can affect the BFE?

No

Yes

3. Closures
a. Opening through the levee system (check one):

Channel Station

Left or Right Bank

exists

Opening Type

does not exist

Highest Elevation for
Opening Invert

Type of Closure Devise

(Extend table on an added sheet as needed and reference)
Note: Geotechnical and geologic data
In addition to the required detailed analysis reports, data obtained during field and laboratory investigations and used in the design analysis
for the following system features should be submitted in a tabulated summary form. (Reference U.S. Army Corps of Engineers (USACE)
EM-1110-2-1906 Form 2086.)

4. Embarkment Protection
a. The maximum levee slope land side is:
b. The maximum levee slope flood side is:
c. The range of velocities along the levee during the base flood is:

FEMA Form 086-0-27B, (12/2007)

(min.) to

(max.)

MT-2 Form 3 Page 4 of 9

E. LEVEE/FLOODWALL (continued)
4. Embankment Protection (continued)
d. Embankment material is protected by (describe what kind):
e. Riprap Design Parameters (check one):
Attach references
Reach
Sta

to

Sta

to

Sta

to

Sta

to

Sta

to

Sta

to

Velocity

Slideslope

Tractive stress

Flow
Depth

Velocity

Curve or
Straight

Stone Riprap
D
D
Thickness
100
50

Depth of Toedown

(Extend table on an added sheet as needed and reference each entry)
f. Is a bedding/filter analysis and design attached?

No

Yes

g. Describe the analysis used for other kinds of protection used (include copies of the design analysis):

Attach engineering analysis to support construction plans.
5. Embankment and foundation Stability
a. Identify locations and describe the basis for selection of critical location for analysis:

Overall height:

Sta.:

ft.

, height

Limiting foundation soil strength
Strength 0 =

degrees, c =

Slope: SS =

(h) to

psf

(v)

(Repeat as needed on an added sheet for additional locations)
b. Specify the embankment stability analysis methodology used (e.g., circular arc, sliding block, infinite slope, etc.):

c. Summary of stability analysis results:
Case

Loading Conditions

Critical Safety Factor

Critical Min.

I

End of construction

1.3

II

Sudden drawdown

1.0

III

Critical flood stage

1.4

IV

Steady seepage at flood stage

1.4

VI

Earthquake (Case I)

1.0

(Reference: USACE EM-1110-2-1913 Table 6-1)

FEMA Form 086-0-27B, (2/2011)

MT-2 Form 3 Page 5 of 9

E. LEVEE/FLOODWALL (continued)
5. Embankment and Foundation Stability (continued)
No

Yes

d. Was a seepage analysis for the embarkment performed?
If Yes, describe methodology used:
e. Was a seepage analysis for the foundation performed?

Yes

No

f. Were uplift pressures at the embankment landside toe checked?

Yes

No

g. Were seepage exit gradients checked for piping potential?

Yes

No
hours.

h. The duration of the base flood hydrography against the embarkment is
Attach engineering analysis to support construction plans.
6. Floodwall and Foundation Stability
UBC (1988)

a. Describe analysis submittal based on Code (check one):
b. Stability analysis submitted provides for:

Overturning

c. Loading included in the analysis where:

lateral earth @ PA=

Surcharge-Slope @

,

Other (specify):

Sliding

surface

If not, explain:
psf; Pp = psf

psf

psf

Wind @ Pw =

%g

Earthquake @ Peq =

Seepage (Uplift):
1%-annual-chance significant wave height

ft.

1%-annual-chance significant wave period

sec.

d. Summary of Stability Analysis Results: Factors of Safety.
Itemize for each range in site lay out dimension and loading condition limitation for each respective reach.
Criteria (Min)

Loading Condition

Overturn

Sliding

Dead & Wind

1.5

1.5

Dead & Soil

1.5

1.5

Dead, Soil, Flood, &
Impact

1.5

1.5

Dead, Soil, & Seismic

1.3

1.3

Sta

To

Sta

To

Overturn

Sliding

Overturn

Sliding

(Ref: FEMA 114 Sept. 1986; USACE EM 1110-2-25020
Note: Extend table on an added sheet as needed and reference)
e. Foundation bearing strength for each soil type:
Bearing Pressure

Sustained Load (psf)

Short Term Load (psf)

Computed design maximum
Maximum allowable
f. Foundation scour protection

is,

is not provided. If provided, attach explanation and supporting documentation.

Attach engineering analysis to support construction plans.
7. Settlement
a. Has anticipated potential settlement been determined and incorporated into the specific construction elevations to maintain the established
freeboard margin?
Yes
No
b. The computed range of settlement is
FEMA Form 086-0-27B, (2/2011)

ft. to

ft.
MT-2 Form 3 Page 6 of 9

E. LEVEE/FLOODWALL (continued)
7. Settlement (continued)
Foundation consolidation

c. Settlement of the levee crest is determined to be primarily from:

Embankment compression

Other (describe):
d. Differential settlement of floodwalls

has

has not been accommodated in the structural design and construction.

Attach engineering analysis to support construction plans.
8. Interior Drainage
a. Specify size of each interior watershed:
Draining to pressure conduit:

acres

Draining to ponding area:

acres

b. Relationships Established
Ponding elevation vs. storage

Yes

No

Ponding elevation vs. gravity flow

Yes

No

Differential head vs. gravity flow

Yes

No

Yes

No

c. The river flow duration curve is enclosed:

d. Specify the discharge capacity of the head pressure conduit:

cfs

e. Which flooding conditions were analyzed?
* Gravity flow (Interior Watershed)

Yes

No

* Common storm (River Watershed)

Yes

No

* Historical ponding probability

Yes

No

* Coastal wave overtopping

Yes

No

If No for any of the above, attach explanation.
f. Interior drainage has been analyzed based on joint probability of interior and exterior flooding and the capacities of pumping and outlet
facilities to provide the established level of flood protection.
No If No, attach explanation
Yes
g. The rate of seepage through the levee system for the base flood is

cfs

h. The length of levee system used to drive this seepage rate in item g:

ft.

i. Will pumping plants be used for interior drainage?

Yes

If Yes, include the number of pumping plants:

No
For each pumping plant, list:
Plant #1

Plant #2

The number of pumps
The ponding storage capacity
The maximum pumping rate
The maximum pumping head
The pumping starting elevation
The pumping stopping elevation
Is the discharge facility protected?
Is there a flood warning plan?
How much time is available between warning
and flooding?
Will the operation be automatic?
FEMA Form 086-0-27B, (2/2011)

Yes

No
MT-2 Form 3 Page 7 of 9

E. LEVEE/FLOODWALL (continued)
8. Interior Drainage (continued)
If the pumps are electric, are there backup power sources?

Yes

No

(Reference: USACE EM-1110-2-3101, 3102, 3103, and 3105)
Include a copy of supporting documentation of data and analysis. Provide a map showing the flooded and maximum ponding elevations for all
interior watersheds that result in flooding.

9. Other Design Criteria
a. The following items have been addressed as stated:
is

Liquidfication
Hydrocompaction

is not a problem
is

is not a problem

Heave differential movement due to soils of high shrink/swell

is

is not a problem

b. For each of these problems, state the basic facts and corrective action taken:

Attach supporting documentation.
c. If the levee/floodwall is new or enlarged, will the structure adversely impact flood levels and/or flow velocities flood side of the structure?
Yes

No

Attach supporting documentation.

d. Sediment Transport Considerations?
Was sediment transport considered?

Yes

No

If Yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why sediment transport was not considered.

10. Operational Plan and Criteria
a. Are the planned/installed works in full compliance with Part 65.10 of the NFIP regulations?

Yes

No

b. Does the operation plan incorporate all the provisions for closure devices as required in Paragraph 65.10(c)(1) of the NFIP regulations?
Yes

No

c. Does the operation plan incorporate all the provisions for interior drainage as required in Paragraph 65.10(c)(2) of the NFIP regulations?
Yes

No If the answer is No to any to the above, please attach supporting documentation.

11. Maintenance Plan
a. Are the planned/installed works in full compliance with Part 65.10 of the NFIP regulations?
Yes

No If No please attach supporting documentation.

12. Operations and Maintenance Plan
Please attach a copy of the formal Operations and Maintenance Plan for the levee/floodwall.

FEMA Form 086-0-27B, (2/2011)

MT-2 Form 3 Page 8 of 9

F. SEDIMENT TRANSPORT
Flooding Source:
Name of Structure:
If there is any indication from historical records that sediment transport (including scour and deposition) can affect the Base Flood Elevation (BFE);
and/or based on the stream morphology, vegetative cover, development of the watershed and bank conditions, there is a potential for debris and
sediment transport including scour and deposition) to affect the BFEs, then provide the following information along with the supporting
documentation:

Sediment load associated with the base flood discharge: Volume

acre-feet

Debris load associated with the base flood discharge: Volume

acre-feet

Sediment transport rate

(percent concentration by volume)

Method used to estimate sediment transport:
Most sediment transport formulas are intended for a range of hydraulic conditions and sediment sizes; attach a detailed explanation for using the
selected method.
Method used to estimate scour and/or deposition:
Method used to revise hydraulic or hydrologic analysis (model) to account for sediment transport:
Please note that bulke flows are used to evaluate the performance of a structure during the base flood; however, FEMA does not map BFEs based
on bulked flows.
If a sediment analysis has not been performed, an explanation as to why sediment transport (including scour and deposition) will not affect the
BFEs or structures must be provided.

FEMA Form 086-0-27B, (2/2011)

MT-2 Form 3 Page 9 of 9