Burned Area Emergency Response Tools

BAER Road Treatments

The BAER specialists have been using various road treatments to increase flow and debris flow capacity of road drainage structures due to wildland fires. Depending on regional climate and fire regimes, different road treatments were preferred. Chapter 4 of Napper (2006) describes implementation details of most of these treatments, including primary use, description, purpose, suitable sites, cost, and construction specifications. A discussion of each of the BAER specialist's preferred treatments is discussed below: culvert inlet/outlet modification (culvert modifications), culvert removal, culvert upgrading (culvert modifications), relief culvert, armored ford crossing (low-water stream crossing), channel debris cleaning (catchment-basin cleanout), ditch cleaning/armoring, culvert risers (riser pipes), debris/trash rack, road closure, road decommissioning, rolling dip/water bar, storm patrol (storm inspection and response), hazard/warning sign, and outsloping road. Terms within parentheses were used by Napper (2006).

Culvert Treatments (alphabetically)

Culvert inlet/outlet armoring/modification
The culvert inlet/outlet is often armored to protect the culvert inlet and fillslope. Culverts are modified to increase the flow and debris passage capacity to prevent road damage. Flared/winged metal end sections are often attached for these purposes, especially in California. Only a very small fraction of BAER specialists recommended these treatments. Culvert modification is not commonly recommended by the BAER specialists in the other areas.

Culvert removal
Culvert removal uses each of the Forest's guidelines for culvert hydraulic capacity to determine if a replacement is necessary in the post-fire environment. If vehicle access is not needed, temporary culvert removal is an option until the area stabilizes. Culvert removal is frequently recommended by Regions 3 and 6 BAER Specialists.

Culvert risers (Riser Pipes)
Culvert risers help prevent the culvert from plugging with sediment and floating debris. The risers allow sediment to accumulate while allowing the water to flow through the culvert. This storage of water and sediment also reduces the peak flows. Only Region 5 BAER specialists recommended culvert risers on a small number of occasions.

Culvert upgrading (culvert modifications)
Culvert upgrading incorporates each Forest's guidelines for both hydraulic capacity of the culvert and any requirements for aquatic species passage to determine if a culvert should be replaced with one of a larger size. Given the values at risks the culvert upgrading must be designed and implemented to maintain vehicle access and protect aquatic resources. To determine size of culverts to be upgraded, often culvert design tools are used, such as Circular Culvert Design Spreadsheet (Cahoon, 2005) and flow capacity table (Robison and others, 1999). Culvert upgrading is the second most frequently recommended BAER road treatment. Flow capacity of typical culverts in forestlands is shown in table 23.

Relief culvert
An additional relief culvert is sometimes used to increase the flow capacity of water and debris for an existing culvert. A relief culvert is not frequently recommended by BAER specialists.

Low-Water Stream Crossing

Armored ford crossing
Armored ford crossing prevents stream diversion and keeps water in its natural channel; prevents erosion of the road fill and reduces adverse effects to water quality; and maintains access to areas once storm runoff rates diminish. Permissible velocities to withstand erosion can be found from Watkins and Fiddes (1984) and Novak and others (2001). Only a small fraction of BAER specialists recommended armored ford crossing.

Clean-Ups

Channel debris cleaning (catchment-basin cleanout)
Channel debris cleaning involves removing organic debris and sediment deposits from above the culvert to prevent them from becoming mobilized in debris flows or flood events. Channel debris cleaning is not frequently recommended by BAER specialists.

Ditch cleaning/armoring
Ditches are cleaned to prevent culvert plugging and armored to prevent erosion in the ditch bed. Many BAER specialists considered ditch cleaning/armoring to be an efficient road treatment, consequently, frequently recommended it.

Debris Protection

Debris/trash rack
A debris/trash rack is a barrier across the stream channel that is used to stop debris too large to pass through a culvert. Debris/trash racks are designed for small and medium floating debris. The storage area upstream from the debris/trash rack should be large enough to accumulate the anticipated size and quantity of debris, and be accessible for clean-out equipment. Only Regions 3 and 5 BAER specialists recommended debris/trash racks frequently, whereas other Regions only occasionally recommended them.

Road Closure/Decommissioning

Road closure
A road closure is intended to prevent unacceptable degradation of critical natural or cultural resources or downstream values. Region 3 BEAR specialists considered a road closure as an alternative to other road treatments to protect possible road users in the event of flash flooding. However, road closure is generally not liked by the public. A road closure is seldom recommended.

Road decommissioning
Road decommissioning is intended to restore the natural hillslope and reduce degradation of natural resources and downstream values. It is seldom recommended, however, it is a viable treatment in cases where roads are either not part of the classified road system or have have gone through a process (usually including public involvement) that clears restrictions for decommissioning. Classified roads are not eligible for road decommissioning using BAER fund. There are five levels of treatments for road decommissioning: (1) block entrance, (2) revegetation and waterbarring, (3) remove fill and culverts, (4) establish drainage ways and remove unstable road shoulders, and (5) full obliteration, recontouring, and restoring natural slopes (USDA Forest Service 2003). If road decommissioning is prescribed in BAER, it is usually at the level of full recontouring.

Overflow Structures

Rolling dip/water bar
A rolling dip/water bar is used to drain water effectively from the road surface and reduce the concentration of flow. A rolling dip/water bar also provides a relief valve when a culvert is plugged. Often, a rolling dip/water bar is armored and it is used instead of a culvert upgrade because of its relatively low cost. Rolling dip/water bar is the most frequently recommended road treatment by BAER specialists. However, a rolling dip/water bar may erode away with strong currents in high discharge. The dipped road surface must be able to withstand these flow velocities. Details about how to make effective water bar can be found in Furniss (2002). Permissible velocities 1) to withstand erosion and 2) in vegetated channels can be found in Watkins and Fiddes (1984) and Novak and others (2001). Overflow discharge for rolling dip/water bar can be estimated by a weir formula from Novak and others (2001).

Storm Inspection and Response

Storm patrol
A storm patrol keeps culvert and drainage structures functional by cleaning sediment and debris from the inlet between or during storm events. It is an efficient measure to protect the transport infrastructure after a wildfire and provides needed road access throughout the designated storm season by ensuring road drainage function.

Other Treatments

Hazard/warning sign
Hazard/warning signs inform the public of potential hazards created by the fire, including flooding, falling rock, and debris. Stocking hazard/warning signs for immediate use in advance of the fire season is useful.

Outsloping road
An outsloped road design disperses water along the fillslope and can reduce erosion. Outsloping is often combined with other road treatments such as rolling dip and armored ford crossing. Outsloping is not frequently recommended by BAER specialists.

REFERENCES

Boiten, Wubbo. 2002. Flow measurement structures. Flow Measurement and Instrumentation. 13(5-6): 203-207.

Cahoon, Joel. (2005 August 11-last update). Circular Culvert Design Spreadsheet [Online]. Available: http://www.wti.montana.edu/Documents/Reports/PDF/CMP_Hydraulics.xls [2008 July 8].

Furniss, Michael J. (2002-last update). The six-D system for effective waterbars [Online]. Available: http://www.fs.fed.us/r5/baer/six-d.html [2008 July 13].

Napper, Carolyn. 2006. Burned Area Emergency Response Treatment Catalog. Watershed, Soil, Air Management 0625 1801-SDTDC. San Dimas, CA: U.S. Department of Agriculture, Forest Service, San Dimas Technology & Development Center. 254 p.

Novak, P.; Moffat, A. I. B.; Nalluri, C.; Narayanan, R. 2001. Hydraulic structures (3rd ed.). London, UK: Taylor & Francis Group. 666 p.

Robison, E. George; Mirati, Albert; Allen, Marganne. 1999. Oregon road/stream crossing restoration guide: spring 1999. Salem, OR: Oregon Department of Forestry. 79 p.

U.S. Department of Agriculture, Forest Service. 2003. Forest Service Manual 7712.11, Exhibit 01. Available: www.fs.fed.us/im/directives/dughtml/fsm.html [2007 May 28].

Watkins, L. H.; Fiddes, D. 1984. Highway and urban hydrology in the tropics. London, UK: Pentech Press Limited. 206 p.

USDA Forest Service - RMRS - Moscow Forestry Sciences Laboratory
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