Culvert Inventory and Assessment Protocol

2015 Field Season

Conduct Field Inventory

Inventory andAssessment Process

Coarse Filters

GREEN(Passable)

RED(Impassable)

GREY(Indeterminate)

Prioritize for remediation

Further Analysis

Field Survey – Main Steps

• Navigate to predetermined road crossing using maps and/or GPS

• Perform longitudinal survey

• Complete site sketch

• Take and document photos of site

Field Equipment

$100

$450

$300

$300

$25

$15$30

$70 $200

$200

Safety• All crew members must wear a safety vest and

hardhat when performing surveys.• Slip resistant wading boots are required for all

crew members, regardless of what job you are assigned.

• Know the hazards in and around the stream channel (e.g., slick rocks, broken glass, wasp nests, snakes, etc.)

• Follow all USDA Forest Service rules and guidelines when operating FS vehicles and equipment.

Non-surveyed crossings

Natural Ford

Insufficient Upstream Habitat

No access

Bridge

Does Not Exist

Flow Condition

Isolated pools,

discontinuous flow

Dry, no flowWet, continuous flow

Pipe Shapes

• Circular

• Pipe Arch

• Open Bottom Arch

• Box

• Ford

• Vented Ford

Circular

Diameter

Circular

Pipe Arch

Rise

Pipe Arch

Span

Open Bottom Arch

Rise

Span

Open Bottom Arch

Box

Height

Width

Box

Fords

Vented Fords

• Corrugated Metal• Concrete• Plastic• Smooth Metal• Wood• Unknown

Crossing Material

Continuous Substrate

Continuous

Not continuousNot continuous

Longitudinal Profile Survey

Culvert inlet P2

Culvert outlet P4

Tailwater control P6

Deepest point within 1 foot P5

Outlet drop

Road surface P3

culvertPipe slope & slope x length

Outlet perch

Surveying the Crossing

Establish Benchmark

Surveying the Crossing

P3 Road Surface

Surveying the CrossingP2 inlet, and P4 outlet bottoms

P2 = inlet

P4 = outlet

Surveying the CrossingP5 Max Pool Depth within 1 foot of Outlet

Max Pool Depth w/in 1’

1’ Max Pool

Max Pool Depth w/in 1’ AND Max Pool Depth1’

Surveying the CrossingP5 within 1 foot of P4b when Apron Present

P4b

P5

P4bP5

P4b

P5

Surveying the CrossingP6 Tailwater Control

Tailwater Control

• Place rod at average depth of tailwater control

x

Surveying the CrossingP6 Tailwater Control

Measuring tailwater control depth

Surveying the CrossingWhere is the (P6)Tailwater Control?

Surveying the Crossing(P6) Tailwater Control

Surveying the Crossing

Closing the Survey

The survey must be closed to check for accuracy

BM

P3

1

2

BM Rod Read + 100 = Height of Instrument (HI)

HI - P3 Rod Read = Known Elevation for P3

Move Level

New P3 Rod Read

New P3 Rod Read + Known Elevation for P3= New HI

New BM Rod Read

New HI – New BM Rod Read = New Elevation

100 – New Elevation = Error (Must be within ±0.02)

P6>P2 = fully backwatered

P4-P6 = outlet drop (in)

P4-WSP5= outlet perch (in)

pipe slope (%) x pipe length (ft) = slope x length

Elevations measurements

Culvert inlet P2

Culvert outlet P4

Tailwater control P6

Water surface

Outlet drop

Road surface

culvert

Pipe slope

Outlet perch

Calculations

Incomplete Site Sketch

Complete Site Sketch

Items to include:• Flow direction• North arrow• Channel alignment• Photo location• Road features• Stream features• Level setup location• Road descriptions• Crossing features

Take Photos

Photos of the inlet and outlet

Items to capture in photos:• ID board with proper info• Entire culvert opening• Some adjacent channel• Stadia rod

Good Photos

Good Photos

Bad Photos

Things to avoid in photos:

• Blurriness

• Zoomed in too far

• Zoomed out too far

• Cannot see board

• Rod not included

• Cannot see all the pipes

• Light reflecting off the board

• Incorrectly labeled board

Special Cases

– No crossing in GPS, but you are at a crossing– Multiple pipe crossings– Fords– Vented Fords– Dry Streams– No Outlet Pool– Dry Stream and no outlet pool

Multiple Pipe Crossings

• You will still follow the single pipe crossing Forms, there will just be more than one pipe for that crossing.

• Pipes are counted from left to right when looking downstream.

Fords

• Leave unnecessary fields blank on survey form (e.g. pipe width, pipe height)

• Number of pipes for ford = 1

• Pipe number for ford = 0

Vented Fords

• Survey all the points for the pipes and all the points for the ford

• Number of pipes = pipe count + 1• Ford pipe number = 0

– Photo: number of pipes = 5– Photo: label the pipe numbers

?

14

0

23

Dry Streams

• Dry streams are surveyed in the same manner as continuous flow or discontinuous flow streams.

• Outlet drop (P4 - P6) is used in the calculations, even without water being present.

No Outlet Pool• Sometimes there is no outlet pool

• No outlet pool means no P6

– i.e. there is no tailwater control to make a pool

• Leave P6 blank, but make a comment

• We use P5 + water depth at P5 to calculate outlet perch in these situations

No Outlet Pool + Dry Stream

• Unique situation, but it happens

• Record all available points (excluding P6)

• Record 0 for water depth at P5

• Be sure to record in comments: “Dry and no outlet pool”

Final Thoughts

• Every crossing is unique, that’s why we have cameras and a comments field.

• Pay attention to detail during the entire survey process.

• Don’t cut corners to save time, it’s about quality not quantity.

• You represent CATT & VT, make sure your behavior and professional demeanor are reflective of all of us.

The End

P6>P2 = fully backwatered

P4-P6 = outlet drop (in)

P4-WSP5= outlet perch (in)

pipe slope (%) x pipe length (ft) = slope x length

Elevations measurements

Culvert inlet P2

Culvert outlet P4

Tailwater control P6

Water surface

Outlet drop

Road surface

culvert

Pipe slope

Outlet perch

Calculations

P6>P2 = fully backwatered

P4-P6 = outlet drop (in)

P4-WSP5= outlet perch (in)

pipe slope(%) x pipe length (ft) = slope x length

Elevations measurements

Culvert inlet P2

Culvert outlet P4

Tailwater control P6

Water surface

Outlet drop

Road surface

culvert

Pipe slope

Outlet perch

Calculations

P6>P2 = fully backwatered

P4-P6 = outlet drop (in)

P4-WSP5= outlet perch (in)

pipe slope(%) x pipe length (ft) = slope x length

Elevations measurements

Culvert inlet P2

Culvert outlet P4

Tailwater control P6

Water surface

Outlet drop

Road surface

culvert

Pipe slope

Outlet perch

Calculations

No Outlet Pool

• The absence of an outlet pool results in the “leap” (usually calculated as the distance between the tailwater control (P6) and the culvert outlet (P4)) being calculated by using outlet perch (water depth at P5).