Culvert Inventory and Assessment Protocol 2015 Field Season
Conduct Field Inventory Inventory and Assessment 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 $25 $15 $30 $70 $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 flow Wet, 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 continuous
Longitudinal Profile Survey Culvert inlet P 2 Culvert outlet P 4 Tailwater control P 6 Deepest point within 1 foot P 5 Outlet drop Road surface P 3 culvert Pipe slope & slope x length Outlet perch
Surveying the Crossing Establish Benchmark
Surveying the Crossing P3 Road Surface
Surveying the Crossing P2 inlet, and P4 outlet bottoms P2 = inlet P4 = outlet
Surveying the Crossing P5 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 Depth 1’
Surveying the Crossing P5 within 1 foot of P4b when Apron Present P4b P5 P4b P5 P4b P5
Surveying the Crossing P6 Tailwater Control Tailwater Control
Place rod at average depth of tailwater control x Surveying the Crossing P6 Tailwater Control
Measuring tailwater control depth
Surveying the Crossing Where 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 12 BM Rod Read = 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-WS P5 = outlet perch (in) pipe slope (%) x pipe length (ft) = slope x length Elevations measurements Culvert inlet P 2 Culvert outlet P 4 Tailwater control P 6 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
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 ?
Dry Streams Dry streams are surveyed in the same manner as continuous flow or discontinuous flow streams. Outlet drop (P 4 - P 6 ) is used in the calculations, even without water being present.
No Outlet Pool Sometimes there is no outlet pool No outlet pool means no P 6 –i.e. there is no tailwater control to make a pool Leave P 6 blank, but make a comment We use P 5 + water depth at P 5 to calculate outlet perch in these situations
No Outlet Pool + Dry Stream Unique situation, but it happens Record all available points (excluding P 6 ) Record 0 for water depth at P 5 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-WS P5 = outlet perch (in) pipe slope (%) x pipe length (ft) = slope x length Elevations measurements Culvert inlet P 2 Culvert outlet P 4 Tailwater control P 6 Water surface Outlet drop Road surface culvert Pipe slope Outlet perch Calculations
P6>P2 = fully backwatered P4-P6 = outlet drop (in) P4-WS P5 = outlet perch (in) pipe slope(%) x pipe length (ft) = slope x length Elevations measurements Culvert inlet P 2 Culvert outlet P 4 Tailwater control P 6 Water surface Outlet drop Road surface culvert Pipe slope Outlet perch Calculations
P6>P2 = fully backwatered P4-P6 = outlet drop (in) P4-WS P5 = outlet perch (in) pipe slope(%) x pipe length (ft) = slope x length Elevations measurements Culvert inlet P 2 Culvert outlet P 4 Tailwater control P 6 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 (P 6 ) and the culvert outlet (P 4 )) being calculated by using outlet perch (water depth at P 5 ).