Forest Road Forest Road Erosion Assessment Information


 Mark Scott 1997

The purpose of this survey form is to identify and document areas that are definite and/or probable sources of sediment delivery to rivers, streams, and tributaries within the forest road network in the Willapa Bay Watershed.  A significant number of drainage problems that contribute sediment to a water body can be identified through visual cues, such as water flow along a road surface, a collapsed culvert, or a landslide.  The goal of this survey is to collect information about identifiable sediment sources and their associated drainage problems.  A parallel goal of this assessment survey is to document the location and general condition of the road network itself, with emphasis on potential future sources of sediment, such as side-cast materials.  These goals will be accomplished through a vehicle survey of forest roads with a portable Personal Computer (PC) and a Trimble Global Positioning system (GPS).  These tools will allow for continual collection of information on both the location and description of potential and definite sources of sediment.  Briefly, continuous line coverage with attribute information regarding the presence and condition of side-cast material and the road ditch system will be collected while specific point data will be collected on the identifiable sediment source areas.  Additionally, all culverts and bridges will be recorded in the point coverage.

Initially, the content and organization of this assessment methodology will be evaluated in the Bear River Watershed, SE Willapa Bay.  After a field trial of the content and format of the survey, revisions will be made and a peer review will be conducted.


Field Name:

Rd_PT_ID        = (N) 5- Unique Id number used to identify file.

SURVEYOR    = (C) 20-Name or initials of all people working on the survey.

ID                     = (C ) 4- Unique identifier for all erosion features.

                           In the field, record which watershed you are in.

DATE               = (C ) 20-Date work performed.

TRS                  = (C ) 6-Location identifier (Township, Range, Section).  Refer to the map.

QUARTER       = (C) 4-Location sub-identifier for the section (ABCD)

ROAD_NAME = (C) 6-Name or number of the road containing the feature. If there is no known name or number for the road, mark the road on your map with a number and record that number in this field.

MILEAGE        = (N) 10-Distance on road from known location (intersection or landmark) to the erosion feature. Whenever possible, measure your mileage from a known intersection.  When this is not possible, identify a clear landmark, record that landmark in the field below, and record your mileage from that landmark.

LANDMARK   = (C) 6-Verbal description or name of the landmark referred to above.

PHOTO_DATE = (C) 6- Date photo was taken

PHOTO_ID =      (C) 6-Photo number (if available).  If you have the camera and take a photograph of the sediment source, record the number of the photo. 

GP_X                = GPS generated latitude or UTM coordinate.

GP_Y                = GPS generated longitude or UTM coordinate.

DIFF _CORR   = Differential correction (YES/NO).  If the coordinates above have been differentially   corrected.  In the field, this response will currently always be NO.

ROVER            = Name of the rover file generated.  This refers to the name of the GPS file generated   during the survey.  

FEATURE        = (C) 20-Road (RD), Slope (SL), Culvert (CL), Bridge (BR), Adjacent(AJ).

DELIVERY      = (C) 20-Possible delivery to stream (YES/NO/UNSURE).  Does the feature you describe in the field above appear to be delivering sediment to the nearest water body?  If you are positive that sediment delivery is occurring from or through the feature, record YES and complete the survey form.  If you are UNSURE, complete the survey form.  If you are positive that NO sediment is being delivered to the nearest waterbody from or through the feature recorded above, DO NOT complete the survey form UNLESS the feature is a culvert or a bridge. 

DISTANCE_T = (N) 10-Distance to nearest anadromous fish-bearing waterbody (in feet) from the      feature recorded above.  Determine this distance visually or estimate from the map. 

PRIMARY_SE = (C) 20-If you determined that sediment was definitely (YES) or possibly (UNSURE) delivering sediment to the nearest waterbody, attempt to determine the PRIMARY SOURCE of the SEDIMENT.  Choose the closest option from the follwong list.  Source of sediment: road (RD), cutslope (CT), fill material (FM), ditch (DT), culvert (CL), landslide (LS), bridge (BR), side cast (SC), rockpit (RP), pothole (PH), washboard (WB), rill (RL).

SEC_SED_SO  = (C ) 20- If you determined that a SECONDARY source of sediment was definitely (YES) or possibly (UNSURE) delivering sediment to the nearest water body, attempt        to determine the actual SOURCE of that SEDIMENT.  Choose the closest option from             the following list.  Source of sediment: Road (RD), Cutslope (CT), Fill material (FM),                            Ditch (DT),    Culvert (CL), Landslide (LS), Bridge (BR), Sidecast (SC), Rockpit (RP), Pothole (PH), Washboard (WB), Rill (RL).



ROAD__SURFA= (C) 20-Should the road be resurfaced? (YES/NO)

ROAD_STATU  = (C) 20- Road status:   Active operations (A), No active operations (Inactive) (I), Decommissioned (D), Unknown (U).

ROAD_MATER = (C) 20-Surface material : Dirt (DR), Rock (RK), Clean rock (CR), Dirt\Rock mix (DM)

ROAD_SHAPE  = (C) 20-Shape of the road surface : Crowned (CR), Uncrowned (UC)

RD_SLOPE_L    = (C ) 20-Relative location of the road to the hill slope : Ridge (R), Valley (V), Mid-slope (M) If you are not on a ridge or valley road, you are mid-slope.



CUTSLOPE     = Is there a cut-slope? (YES\NO)

CS_PER          = Record the percent the road construction cut into the bank.

                           (0-25%, 26-50%, 51-75%, 76-100%)

CUTSLOPE_S = (C ) 20-Cutslope stability : If no visible signs of cracking/crumbling or surface erosion are visible, record as Stable (S).  Visible signs will be recorded as Unstable (U).


SIDECAST     = (C ) 20-If sidecast material is present at the feature location, recored Yes (Y).  If not, No (N).

SIDECAST_S = (C ) 20-Sidecast stability :  If no visible signs of cracking/crumbling or surface erosion are visible, record as Stable (S).  Visible signs

will be recorded as Unstable (U).


DITCH             = (C) 20-Is there a ditch associated with this feature? (YES/NO)

DITCH_BLOC = (C) 20-Ditch blockage : Record if ditch drainage is blocked by Wood (W),  Rock (R),

                           Debris (D), Other (O), or Nothing (N).

DITCH_DRAI  = (C) 20-Ditch drainage : Record where the ditch drains; to the  Forest Floor (F),

                           another Ditch (D), a Tributary (T), Stream (S), or Other (O).


CULVERT_MA= (C) 20-Culvert material : Metal (M), Plastic (P), Wood (W), Concrete (C).

CULVERT_FU = (C) 20-Culvert Function: Cross Drainage (CD) or live Stream Passage (SP).

CULVERT_ CO= (C) 20-Present condition of culvert : Good (G), Rusted (R), Bottom Out (B), Collapsed (C).

CULVERT_ DI = (C) 20-The diameter of the culvert (record in inches).

CULV_FIL_D   = (N) 10-The fill depth from top of road to the top of the culvert (record in feet).

CULV_FIL_L    = (N) 10-Length of the culvert fill material (record in feet).

CULVERT__DR= (N) 10-The drop from the outlet of the culvert to the forest floor or stream (record in feet).

CULV_POOL    = (N) 10-Record the depth of  the pool that has formed below the culvert outlet (in    inches) or, if there is no pool, (NA).

CULVERT_OP  = (C) 10-Record the percentage of the culvert that is open and functioning.

                           (0-25%, 26-50%, 51-75%, 76-100%).

CULV_FISH      =(C) 10-Do anadromous fish use the area around this feature?  Base this judgment on maps, prior knowledge, visible clues, and professional opinion. (YES\NO)

CULV_PAS       =(C) 10-Record the potential for fish passage through this culvert : Passable (P), Impeded (I), Not passable (NP).                          


LS_TYPE          =(C) 10-Record the type of landslide : Debris\earth flow (DF), Rotational block\slump (RS), Rock\debris\earth slide (RS).

LS_REL_POS    =(N) 10-Record the distance, in feet, that the landslide feature is above or below the road

                           (“+” if above the road, “-” if below the road)

LS_ASPECT      =(C) 20-Record the direction the feature faces : N/NW/W/SW/S/SE/E/NE.

LS_AGE             =(N ) 20-(Estimate the time since the event occurred, i.e., the age of the landslide in   years.

LS_TRIGGER    =(C) 20-The cause or a major contributor to the wasting event :

                           Road (R), Harvest (H), Stream (S), Culvert (C), Fault (F), Unknown (U)


BRIDGE_MAT =(C) 20-Record the material of the bridge: Wood (W), Concrete (C), Steel (S).

BRIDGE_ABU  =(C) 20-Record the type of bridge abutment : Piling (P), Gabion (G), Gravel (G), None (N).

BRIDGE_DEC  = (C) 20-Record whether the bridge deck has an Open (O) or Closed (C) surface for drainage.

BRIDGE_APP  =(C ) 20-Record if the bridge approaches are Raised (R), Level (L), or Depressed (D).

Record the following for the Feature identified at beginning of this record.  Record for all features.

ADJACENT     = (C) 20-Adjacent feature located by main feature (Unaided Stream    Crossing\Road\Water-barrier).

FEATURE_LE =(N) 10-The length of feature (record in feet).

FEATURE_W  =(N) 10-The width of feature (record in feet).

FEATURE_DE =(N) 10-The depth of feature (record in feet).

SURFACE_VE =(C) 20-Record the type of surface vegetation associated with the feature:

                           Trees (T), Shrubs (S), Grass (G), None (N).

SLOPE              =(N) 10-Record the slope of the feature in degrees. 

EXISTING_F    =(C) 20-Is there an existing failure associated with this feature : Yes (Y), No (N).

CRACKING      =(C ) 20-Is there cracking associated with this feature : Yes (Y), No (N).

MASS_WASTE =(C) 20-Is this a mass wasting prone area : Yes (Y), No (N), Unsure (U).

WATER_SOUR =(C) 20-( Is there a defined water source to this feature? :

                           Spring (S), Tributary (T), None (N), Unsure (U).

FLOW_TYPE    = (C) 20-If there is flow associated with this feature, what type of flow is there?

                           Sheet (S), Ponded P), Channelized (C), None (N), Other (O).

LANDING         =(C) 20-Is this feature associated with a landing : Yes (Y), No (N).

LAND_STATU  =(C) 20-Record the present status of land use :  Agricultural (AG), Clearcut (CC),

                           Second Growth (SG), Third Growth (TG), Old Growth (OG).

PRESCRIBE      =(C ) 8-Record a possible remedy for the feature.

COMMENTS     =(C ) 10-Record any useful information not already included.

Line Coverage:  Keep track of the six following attributes of the road condition as you drive.  Change each attribute as if varies along the road network.

ROAD_L3_ID    =(N) 5- Unique Id number used to identify file.

ROAD_LINE_   =(C) 20-Feature identifier.

ROAD_SURFA  =(C) 20-Dirt, Gravel, No Gravel, Potholes, Gulley, Rill, Rut, None.

SIDE_CAST_     =(C) 20-Light, Moderate, Heavy, N/A.

COND_OF_SI    =(C) 20-Stable, Unstable, Unsure, N/A.

SIDECAST_V    =(C) 20-Grass, Brush, Trees, None

DITCH_LEFT    =(C) 20-Good, Bad, None.

DITCH_RIGH    =(C) 20-Good, Bad, None.

CUTSLOPE        =(C) 20-Stable, Unstable, None

DELIVERY_P (of sidecast) =(C) 20-Yes, No, Unsure