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A
Abutment: A structure at either
end of a bridge that supports the superstructure (sill,
stringers, trusses, or decks), composed of stone, concrete,
brick or timber. (Pier) Return to top
Access Points: Designated areas
and passageways that allow the public to reach a trail from
adjacent streets or community facilities. Return to top
Accessible: According to ADAAG
(Americans with Disabilities Act Accessibility Guidelines),
the term “accessible” is used to describe a
site, building, facility, or portion thereof that complies
with the ADA (American Disabilities Act) guidelines. According
to UFAS (Uniform Federal Accessibility Standards), the term
“accessible” describes a site, building, facility,
or portion thereof that “complies with these standards
[UFAS] and … can be approached, entered, and used
by physically disabled people.” (Wheelchair Accessible,
Handicap Accessible, Disabled Access) Return to top
Adopt-A-Trail: A program in which
individuals, groups or businesses “adopt” trails,
providing volunteer work parties at periodic intervals to
help maintain those trails. Return to top
Aggregate: Material made up of
crushed stone or gravel used as a base course for riprap,
asphalt, or concrete pavement. Aggregate is also used in
asphalt and concrete mixes. Return to top
Alignment: The configuration of
a trail in a horizontal plane. The bends, curves and tangents
of the path.
Return to top
All Terrain Vehicle (ATV): Any
motorized, off-highway vehicle 50 inches or less in width,
having a dry weight of 600 pounds or less that travels on
three or more low-pressure tires with a seat designed to
be straddled by the operator. Low-pressure tires are 6 inches
or more in width and designed for use on wheel rim diameters
of 12 inches or less. Manufacturers do not provide a steering
wheel, roll bar or seat belt. (Quad, Four-Wheeler)
Return to top
Alternate Line: Intentional design
of trails to provide users with options in alternative routes.
Return to top
Anchor: A large stone that holds
other stones and/or soil in place. Also a tree or rock used
to hold (anchor) one end of a winch or come-along (horizontal
hoist) stationary while it pulls on another object. Also
an object, such as a stone, that defines the sides of the
trail, helping to keep users in the center of the tread.
(Keystone, Gargoyle, Corral Rock, Corralling, Dragon’s
Tooth, Shepherd) Return to top
Angle of Observation: The angle,
both vertical and horizontal, between a viewer’s line
of sight and the landscape being viewed. Return to top
Angle of Repose:
The steepest slope angle (measured from the horizon) at
which material will rest without moving or sliding down
the slope. Loose material would slide across the trail or
roll downhill at any steeper angle. For large blocky rocks,
the angle of repose will be much higher than for sand or
small round rocks. Return to top
Apex: The sharpest part of a turn,
where the transition from entering to exiting takes place.
Return to top
Armoring: Reinforcement of a surface
with rock, brick, stone, concrete, or other wear resistant
“paving” material so as to provide a hardened
tread or prevent erosion on a steep slope or in a drainage.
May be used to prevent soil loss in steep or soft tread
and around roots. The manual, mechanical, or chemical compaction
of the trail tread resulting in a hard and flat surface
that sheets water effectively and resists the indentations
that are created by use. (Hardening, Flag Stoning, Paving,
Stone Pitching, Boulder Causeway) Return to top
Aspect: The particular compass
direction a trail or site faces. Aspect affects the amount
of solar radiation and year-round moisture to which a site
is subjected.
Return to top
Asphalt: Petroleum-based flexible
surface material that provides a smoothly paved surface
suitable for bicycles and in-line skates. It is preferred
in urban areas where trails are often used for commuting
to and from work or school. (Macadam, Asphaltic Concrete)
Return to top
At-Grade Crossing: A trail crossing
a roadway on the same elevation. Ideally, a safe at-grade
crossing has either light automobile traffic or a traffic
signal that can be activated by trail users. Return to top
Attractive Nuisance: Something
on a trail or greenway that attracts users and that is potentially
dangerous to them, such as a mineshaft without a fence around
it. Return to top
B
Backslope: The excavated slope
“in back” or uphill of the trail, rising from
the uphill (inside) edge of the tread, and eventually transitioning
into native hillside by varying degrees, depending on bank
composition and slope stability. (Cutbank, Backcut, Cutslope)
Return to top
Backfill: Material used to refill
a ditch or other excavation, or the process of doing this
action. The stone or soil material used to fill gaps in
trail, step, or wall construction work. (Infill)
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Backramp: An angled diversion dam
or earthen wall leading out of the center of a drainage
dip. Serves as a backup to change direction of water flow
if needed.
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Ballast: Stone, cinders, gravel,
or crushed rock fill material used to elevate a railroad
bed above the surrounding grade. It drains water away from
the ties, spreads the track load over softer subgrade, provides
an even bearing for ties, holds ties in place and checks
the growth of grass and weeds.
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Baluster: One of many vertical
pieces between the top and bottom rails of a guardrail.
Return to top
Bank: The part of the soil next
to a stream, lake, or body of water where the soil elevation
adjacent to the water is higher than the water level. Also
see embankment. (Stream Bank) Return to top
Barricade: A portable or fixed
barrier having object markings, used to close all or a portion
of the trail right-of-way to traffic. Return to top
Barrier: A structure installed
to protect an environmentally sensitive area. A barrier
can be hard (fence); live (planted); a combination of hard
and live; or a terrain feature (berm). A barrier can be
physical (obstructing passage) or psychological (deterring
access). Return to top
Barrier Free Design: A trail design
that promotes the elimination of physical barriers that
reduces access to areas by people with disabilities. (Universal
Design)
Return to top
Base Course: The layer or layers
of specified material of designed thickness placed on a
trailbed to support surfacing or be tamped in. (Foundation)
Return to top
Batter: The angle at which an abutment
or rock/timber wall is inclined against the earth it retains.
The process of sloping the exposed face of a wall back either
at a uniform angle or stepping it back uniformly. (Battering)
Return to
top
Bed: The primary excavated surface
of a trail upon which the tread or finished surface lies.
(Base) Return
to top
Bedrock: Solid rock material underlying
soils and other earthy surface formations. Return to top
Bench: A relatively level section
of a hillside, occurring naturally or by excavation.
Return to top
Bench Cut: A relatively flat, stable
surface (tread) on a hillside made by excavation. When excavated
it is often referred to as full, half or partial bench to
describe the proportions of excavation and fill comprising
the trail bed.
Return to top
Bench Cut, Full: The total width
of the trail tread is excavated out of the slope, and the
trail tread contains no compacted fill material.
Return to top
Bench Cut, Half: Half of the width
of the trail tread is excavated out of the slope and the
downhill (outside) half of the trail tread contains the
excavated and compacted material. (Cut and Fill)
Return to top
Bench Cut, Partial: Part of the
width of the trail tread is excavated out of the slope,
and the rest of the trail tread is made up of fill material.
(Cut and Fill)
Return to top
Berm: A raised shoulder or dike
along the downhill (outside) edge of the tread. Berms prevent
the flow of water across the trail tread, thus causing erosion
along the length of the trail tread. Return to top
Blaze: A trail marker. Blazes can
be carved into a tree with a 2-inch by 6-inch vertical rectangle
painted. Plastic or metal triangles or diamonds (known as
blazes) with the name of the trail or a directional arrow
imprinted can be purchased and nailed to posts to mark a
trail route. Nailing onto or scraping away bark to create
a blaze is no longer recommended.
Return to top
Blowdown: Trees toppled over by
high winds. See windfall. Return to top
Blowout: An area from which soil
material has been removed by wind. Such an area appears
as a nearly barren, shallow depression with a flat or irregular
floor consisting of a resistant layer, an accumulation of
pebbles, or wet soil lying just above a water table.
Return to top
Boardwalk: An elevated, fixed-plank
structure, usually built on pilings in areas of wet soil
or water to provide dry crossings. Return to top
Bollard: A barrier post, usually
30 to 42 inches in height, used to block vehicular traffic
at trail access points. Should be installed in odd numbers
(one or three). Also an electric light post found alongside
trails. Return to top
Borrow: Fill material, usually
mineral soil or gravel, taken from a site other than the
trail tread excavation. Return to top
Borrow Pit: A hole dug out of sight
of a trail corridor to provide fill material for trail tread
construction or trail structures such as turnpikes or rock
walls. (Borrow Site)
Return to top
Boulder: A large substrate particle
that is larger than cobble. Return to top
Bridge: A structure, including
supports, erected over a depression (stream, river, chasm,
canyon or road) and having a tread or deck for carrying
trail traffic. Return to top
Bridleway: Public way designed
and maintained primarily for equestrian use. Other non-motorized
uses may be permitted. (Bridle Path) Return to top
Brush: Vegetation or small flora.
Return to
top
Brushing: The process of clearing
the trail corridor of plants, trees, and branches that could
impede the progress of trail users. Return to top
Brushing-In: To pile logs, branches,
rocks, slash, or duff along the sides of the tread to keep
users from widening the trail; or to fill in a closed trail
with debrisso that it will not be used. (Obliteration)
Return to top
Broadcasting: The process of widely
distributing excavated soil, cut branches, and duff as far
downhill or uphill and away from the new tread as possible.
Widely distributing so as to blend in with the natural soil
contours and vegetation and be as inconspicuous as possible.
Return to top
Buffer: Any type of natural or
constructed barrier (trees, shrubs, wooden fences, etc.)
used between the trail and adjacent lands to minimize physical
or visual impacts. Buffers also provide a transition between
adjacent land uses. (Buffer Zone) Return to top
Bushwhack: Term applied to off-trail
hiking (originally where the going was difficult, where
many bushes had to be whacked). Now it is often used to
mean off-trail travel regardless of whether the going is
difficult or not. Hiking off of established trails can create
unwarranted reroutes or ill considered short cuts.
Return to top
C
Cable Fly Zone: The hazardous area
a cable can potentially move to when it comes under tension,
or is suddenly released from tension. Return to top
Cairn: A constructed pile of rocks
located adjacent to a trail used to mark the route in lieu
of a blaze. Often used in open or treeless areas where the
tread is indistinct or there is no constructed tread. (Duck)
Return to top
Canal: An artificial waterway for
transportation or irrigation. Canal and irrigation ditch
banks are often used as trails. Return to top
Canopy: The leaf cover in a forest
stand, consisting of its upper layers. Return to top
Cantilever: The portion of a beam
or plank extending beyond one or both of its supports.
Return to top
Capacity: The maximum number of
trail users that can pass through a section of trail during
a given time period under existing trail conditions. Also
refers to the amount of use a given resource can sustain
before an irreversible deterioration in the quality of the
resource begins to occur. (Carrying Capacity) Return to top
Capstone: A stone placed in the
top or uppermost layer of a structure such as a rock retaining
wall or cairn. (Caprock) Return to top
Centering: Constructing a trail
in a manner that encourages traffic to use the center portion
of the trail. Return to top
Center Line: The proposed or envisioned
mid-line of the tread. Return to top
Challenge Park: A special-use area
that features a variety of challenging technical trail features,
generally for mountain bicycle or motorized recreation uses.
(Skills Area, Terrain Park) Return to top
Channel: An area that contains
continuously or periodically flowing water that is confined
by banks and a streambed. Also used as a verb “to
channel” water.
Return to top
Channelization: The process of
changing (usually straightening) the natural path of a waterway.
Return to
top
Characteristic: A distinguishing
trait, feature, or quality. Return to top
Check Dam: An earthen, stone, or
log dam used to slow erosion in a washed-out trail or gully.
Recommended primarily for use in trail reclamation or revegetation.
(Sediment Trap, Silt Trap) Return to top
Check Step: A rock or timber step
placed in or across the trail tread and designed to act
as both a low dam (to slow water flowing down a trail) and
as a step for trail users. A retainer bar is usually longer
or larger than a check step. (Retainer Bar) Return to top
Chink: A small fissure or crack;
the space between larger rocks used to armor a trail. Also
used as a verb: to chink. Return to top
Chinking: To fill the crack or
space between larger rocks with smaller rocks and soil to
stabilize the paving. Return to top
Chromated Copper Arsenate (CCA):
A wood preservative for boardwalks, decks, and other common
trail applications where treated lumber is used. CCA treatment
has been banned. Return to top
Circle of Danger: The area surrounding
a trail worker that is unsafe due to tool use. The inner
(or primary) circle of danger is the area the tool can reach
while being used. The outer circle of danger is the area
the tool could reach if the trail worker lost control or
let go of the tool. Return to top
Clear-cut: Removal of all trees
and shrubs, not just mature growth. (Clear-Cutting)
Return to top
Clearing: Removal of windfall trees,
uproots, leaning trees, loose limbs, wood chunks, etc. from
both the vertical and horizontal trail corridor.
Return to top
Clearing Height: The vertical dimension,
which must be cleared of all tree branches and other obstructions
that would otherwise obstruct movement along the trail.
(Vertical Clearance) Return to top
Clearing Limit: The area over and
beside a trail that is cleared of trees, limbs, and other
obstructions.
Return to top
Clearing Width: The outer edges
of clearing areas (cleared of trees, limbs, and other obstructions)
as specified by trail use. Return to top
Climbing Turn: A turn to reverse
direction that doesn’t have a constructed turning
platform or landing. The upper and lower legs of a climbing
turn are generally joined by a short section of trail (the
apex of the turn) that lies directly in the fall line. As
a result, climbing turns located on hillsides with a grade
of more than 7 percent can be erosion prone. In a climbing
turn, water drains off the outside edge on the entire length
of the turn. A thru-cut climbing turn is constructed on
a sidehill of 20% or more when measured between the exterior
boundaries of the turn, and cuts through the sidehill grade
as it changes the direction of the trail 120 to 180 degrees.
(Thru-Cut Climbing Turn)
Clod: A mass of soil produced by
digging, which usually clumps together easily with repeated
wetting and drying. Return to top
Closure: Designating areas or trails
by the appropriate land manager agency where specified trail
uses are permanently or temporarily prohibited. Return to top
Cobble: Loose rock, with rounded
edges, generally 2" inches in diameter used to pave trail
tread. Can be further classified as small or large cobble.
(Cobblestone, Baby Heads)
Collector Ditch: A drainage structure
that runs parallel to the trail and intercepts water flowing
toward a trail and channels it underneath the trail with
a culvert or across the trail. See Parallel Ditching. (Collection
Ditch, Sidehill Ditch) Return to top
Colluvium: Mixed deposits of soil
material and rock fragments near the base of steep slopes.
Deposits accumulate through soil creep, slides, and local
wash. Return
to top
Compaction: The compression of
aggregate, soil, or fill material into a more dense mass
by tamping. The degree of soil consolidation that is obtained
by tamping with hand tools or, or heavy equipment. (Compacted,
Soil Compaction) Return to top
Concrete: A composition of coarse
and fine aggregates, Portland cement, and water, blended
to give a hard, unyielding, nearly white pavement, which
can be finished to any degree of smoothness. Concrete is
most often used in urban areas with anticipated heavy trail
use, or in areas susceptible to flooding. Return to top
Contour Line: A line on a map connecting
points of the land surface having the same elevation. (Contour)
Return to
top
Control Point: Places that influence
where the trail goes. The beginning and end of a trail are
basic control points. Other control points include parking
areas, trailheads, structures, slopes for turns, or switchbacks,
road or water crossings, and other trails. Positive control
points are places where you want users to visit. Negative
control points are places you want users to avoid. (Target)
Return to top
Corduroy: A trail tread made of
logs laid side-by-side transversely. Return to top
Course: A single layer of building
material of a uniform height. The material is placed one
layer (course) at a time on top of another layer (course)
to form a foundation, intermediate layer, or cap layer.
Materials laid in courses include bricks, concrete blocks,
timbers, stone, and logs. (Tier, Foundation) Return to top
Critical edge: The rounded outside
edge of the trail tread where water travels off the tread
and drains onto the native hillslope below. This edge is
critical because it is essential to the proper drainage
of the trail and prevention of erosion to the tread. (Outside
Edge, Lower Edge, Shoulder, Critical Point, Daylight Edge,
Toe) Return to top
Crown: A method of trail construction
where the center portion of the tread is raised to allow
water to disperse to both sides of the trail. (Crowning)
Return to top
Cross-Country: Hiking or riding
across open country rather than on a trail. (Travel)
Return to top
Cross Section: Diagrammatic presentation
of a trail profile that is right angles to the centerline
at a given location. (Typical Cross Section) Return to top
Cross Slope: The slope or gradient
of the undisturbed hillside; the amount or grade of the
pre-existing slope across a trail corridor. (Side Slope,
Side Hill) Return to top
Crosswalk: Any portion of a roadway
distinctly indicated for pedestrian crossing by lines or
other markings on the surface. Return to top
Crusher Fines: Rock fragments ranging
in size from dust to a specified size that have been produced
by mechanical crushing. For example: 1/4- (one quarter minus)
indicates crusher fines whose maximum size is .25 inch.
Crusher fines bind well when compacted and are typically
used as a tread material, especially on accessible trails.
(Inch-to-Dust, Crushed Granite)
Return to top
Culvert: A pipe or box-like construction
of native rock, wood, metal, plastic, or concrete that conveys
water under a trail without constricting the flow.
Return to top
Cupped: A board or plank whose
edges are higher or lower than the center. Cupping is often
found in decks, where the board edges are higher than the
middle. Water, trapped in the cupped area, accelerates rot.
Cupping also refers to a process of erosion that turns the
trail into a gully or the opposite of crowning. Lowering
of the center portion of the tread due to user caused erosion
or stock traffic, loosening soil in the center of the tread
which is then removed by water or kicked off and built up
into a berm. (Cupping) Return to top
Curb: A wood, concrete, or stone
component (2 to 8 inches high) built along the edge of a
trail or street to form part of a gutter. Return to top
Curb Cut: A cut in the curb where
a trail crosses a street. The curb cut should be the same
width as the trail. Return to top
Curvilinear: A free-flowing trail
layout pattern characterized by the general absence of straight
trail segments allowing for ease of trail user movement.
Return to top
Cushion Material: Native or imported
material, generally placed over rocky sections of unsurfaced
trail to provide a usable and maintained travelway.
Return to top
D
Dam: An embankment or dam made
to confine or control water to prevent flooding by the sea,
a river/stream, or lake. The embankment is often used as
a trail. (Dike, Groin, Spur, Jetty, Tramway, Tram, Levee,
Deflector, Boom) Return to top
Daylighting: Clearing a ditch or
drain so that water can run freely, or all the way to “daylight.”
Return to
top
Deadman: A log or logs, heavy timber
or timbers, a large block of concrete, a large rock or boulder,
or a combination of these materials that is partially or
completely buried. Deadmen are used to anchor sections of
armored trail, retaining wall, or the end of a winch or
come-along chain or cable. See anchor, tie stone, and tie
log. (Deadmen, Facer) Return to top
Deberming: Removing the high ridge
of material that has formed along the outer (downhill) edge
of a trail, allowing water to once again flow off the side
– and not down – the trail. Return to top
Decking: The portion of a bridge,
puncheon, or corduroy upon which trail traffic will travel.
(Plank Decking, Flooring) Return to top
Ditch: A long, narrow trench or
furrow dug in the ground or along the edge of a trail to
improve drainage. (Gutter) Return to top
Dirt Bike: Off-Highway Motorcycle.
(OHM) Return
to top
Dodgeway: A v-shaped stile through
fences to allow hikers to pass through. Return to top
Drain, Cobble: A cobbled improvement
to the trail surface that allows drainage (usually from
an intermittent wet seep) across the trail for continued
passage along the trail without damage to the soil.
Return to top
Drain, French: A stone-filled ditch
that can have a porous pipe laid along the base to collect
the water and carry it away from the site. The top must
be kept clear of the surfacing material; allowing water
to run freely into the drain.
Return to top
Drainage: The way in which water
flows downhill and/or off the trail. Return to top
Drainage, Cross: Running water
in wetlands, springs, creeks, drainages, or draws that the
trail must cross. Return to top
Drainage Dip: A reverse or gradual
dip in the grade of the trail, usually 20 to 40 feet long,
followed by a gradual rise of 2 to 3 feet with the rise
at an angle to the outslope to divert water off the trail.
This accomplishes the same effect as a waterbar. An armored
or paved dip is a drainage structure paved with stones to
enable water to run across a trail without erosion. A reinforced
dip is a drainage structure that has a water bar buried
under a layer of compacted soil. These structures may be
added after initial trail construction. (Grade Dip, Grade
Brake, Drain Dip, Reinforced Drainage Dip, Rolling Dip,
Rolling Grade Dip, Spoon Dip, Coweta Dip, Grade Reversal,
Kick Out, Diversion Dip) Return to top
Drainage, Sheet: Condition in which
water flows in smooth sheets rather than rivulets or channels.
Return to
top
Drainage, Surface: Rain or snow
runoff from the surface of the tread. Return to top
Drainage Ditch: Open ditches that
collect water and carry it away from a site or trail. (Ditching)
Return to
top
Drainage Structure: A water diversion
structure constructed across the trail tread to remove water
flowing down the trail tread or to prevent it from entering
the tread.
Return to top
Dress: To chip or shape a rock
finely to fit into a space in a structure. Return to top
Driftpin: A 12- to 30-inch steel
bar or pipe used to keep logs and timbers in place.
Return to top
Dry Cement: A gray powder made
from limestone that is mixed with sand and water to make
mortar, or mixed with sand, small stones or gravel, and
water to make dry cement concrete. Return to top
Dry Stone: Rock or stonework without
mortar or other adhesive. Return to top
Drop-off: Slope that falls away
steeply.
Return to top
Duff: Any combination of loose
vegetation, vegetable matter, roots, and/or organic laden
soil produced by cutting trail. Duff retains moisture and
rots away quickly if not removed from trails. This results
in the formation of depressions and pockets, which retain
water and cause erosion problems. (Organic Matter, Leaf
Litter) Return to top
E
Easement: Grants the right to use
a specific portion of land for a specific purpose or purposes.
Easements may be limited to a specific period of time or
may be granted in perpetuity, or the termination of the
easement may be predicated upon the occurrence of a specific
event. An easement agreement survives transfer of land ownership
and is generally binding upon future owners until it expires
on its own terms.
Return to top
Ecosystem: A system formed by the
interaction of living organisms, including people, with
their environment. An ecosystem can be of any size, such
as a log, pond, field, forest, or the earth’s biosphere.
Return to top
Elevated Tread: Trail tread that
is raised above the level of the surrounding ground by the
placement and compaction of mineral soil or other material.
Elevated tread is similar to a low turnpike and is usually
crowned. (Raised tread)
Return to top
Embankment: An artificial deposit
of material that is raised above the natural surface of
the land and used to contain, divert, or store water, support
roads, railways, trails, or for other similar purposes.
Return to top
Environmental Impact Statement(s) (EIS):
A full disclosure, detailed federal report which, pursuant
to NEPA law and regulation, establishes the need for the
proposed action, identifies alternatives with the potential
to meet the identified need, analyzes the anticipated environmental
consequences of identified alternatives, and discusses how
adverse effects may be mitigated. An EIS is prepared in
two stages: a draft (DEIS) statement which is made available
to the public for review and a final (FEIS) statement which
is revised on the basis of comments made on the draft statement.
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Equestrian: Of horses, horseback
riding, riders, and horsemanship. Return to top
Erosion: The natural process of
wearing down and removing rock and soil by wind, water and
traffic.
Return to top
Exclosure: An area fenced to exclude
grazing animals and/or OHV’s, usually for protection
and study purposes. Return to top
Exposure: The relative hazard encountered
when on trails and takes into consideration obstacles, alignment,
grade, clearing, tread width, tread surface, cross slope,
isolation, and proximity to steep slopes or cliffs.
Return to top
F
Face: The steep exposed side of
a slope or rock. Also used to describe the exposed side
of a rock in rock structures such as steps. (Facer)
Return to top
Fall Line: Steepest line across
a given contour or the direction water flows down a slope
(path of least resistance) under most circumstances.
Return to top
Fall Zone: The area on either side
of or below a technical trail feature that provides a clear
landing for a rider who has failed to negotiate the obstacle.
Return to top
Fault: A fracture in rock along
which movement can be demonstrated. A fracture in the earth’s
crust forming a boundary between rock masses that have shifted.
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top
Fence: A constructed barrier of
wood, masonry, stone, wire, or metal, erected to screen
or separate areas.
Return to top
Fill: Material (usually mineral
soil and rock) excavated from the trail or a borrow site
to fill holes or stabilize rock steps and walls. See Borrow.
Return to top
Filter: Obvious terrain change
to let trail user know that a more difficult section of
trail or technical trail feature is ahead. (Qualifier)
Return to top
Filtration Zone: Material placed
in such a way as to act as a filter or cleaning bed to slow
down the flow of and filter water. Return to top
Flagging: Thin ribbon used for
marking during the location, design, construction, or maintenance
of a trail project. Return to top
Flag Line: A series of pin flags
used to mark the intended route for trail construction.
Usually placed in trees or on the centerline, inside edge,
or critical edge of the proposed trail. Return to top
Flow: (Water Flow or Sheet Flow).
Water moving in a layer (sheet drainage) or stream (channeling).
Return to
top
Flow: The rhythm or “feel”
of a trail. Two basic types include “open and flowing”
and “tight and technical”. Return to top
Flushcut: Branch or sapling cut
flush with the trunk or ground. Return to top
Footing: The part of a structural
foundation that rests on the ground, spreading the weight
of the structure and supporting the structure above. Footings
are usually concrete. At remote sites the footings may also
be mortared stone masonry. Return to top
Footpath: A path over which the
public has a right-of-way on foot only. Wheelchairs are
also permitted, although this may not be practical due to
surface or slope.
Return to top
Fragmentation: Process by which
habitats are increasingly subdivided into smaller units
resulting in their increased insularity as well as losses
of total habitat area. (Fragmented, Habitat Fragmentation)
Return to top
Friction Pile: Post hammered into
muck until friction prevents further penetration; foundation
for puncheon or boardwalk. Return to top
Full Clean: Trail construction
where all spoils must be removed vs. “rake down”
which allows the spoils to be distributed below or to the
side of the trail. Return to top
G
Gabion Baskets: Rectangular containers
(usually made of heavy galvanized wire) that can be wired
together, and then filled with gravel or cobble to make
quick retaining walls for erosion control. Return to top
Gate: Structure that can be swung,
drawn, or lowered to block an entrance or passageway.
Return to top
Geotextile: A semi-impervious,
petrochemical fabric cloth that provides a stable base for
the application of soil or gravel. Most commonly used in
construction of turnpikes. (Geo-Synthetic, Geo-Fabric, Filter
Fabric)
Return to top
Glulaminated: A process used to
fabricate long beams from short lengths of 2x4, 2.6, or
2x10 lumber. The pieces are placed flat on top of each other
with glue spread between them. Lengths are varied so that
transverse joints in each layer are not opposite one another.
Pressure binds the pieces together. The assembly may be
two to four time longer than the longest individual piece
of lumber within it. (Gulams) Return to top
Grade: The vertical distance of
ascent or descent of the trail expressed as a percentage
of the horizontal distance, commonly measured as a ratio
of rise to length or as a percent. For example, a trail
that rises 8 vertical feet in 100 horizontal feet has an
8% grade. This is not the same as measuring in degrees.
See Rise and Run. (Percent Slope, Percent of Grade)
Return to top
Grade, Average Trail or Segment:
The average steepness of a trail over its entire length
or a certain trail segment. (Overall Trail Grade)
Return to top
Grade, Maximum Sustainable: The
steepest acceptable grade permitted on any part or segment
of a trail or over the majority of the trail length. (Sustained
Grade) Return to top
Grade Reversal: A reverse in the
trail grade – usually a short dip followed by a rise
– that forces water off the trail. Grade reversals
are subtle and typically designed into the alignment of
the trail. When designed into the alignment they can prevent
the need for more artificial water diversion structures
such as rolling dips. (Grade Change, Adverse Pitch)
Return to top
Grade-Separated Crossing: Overpasses
or tunnels that allow trail users to cross a railroad right-of-way
or street at a different level than trains or traffic.
Return to top
Gravel: Rock fragments ranging
from 1/5 to 3 inches in diameter. Return to top
Grubbing: Removal of roots, stumps,
rocks, soil, etc., from the trail tread and corridor.
Return to top
Guardrail: A 36- to 42-inch railing
at the edge of a deck, bridge, stairway, or boardwalk to
prevent people from falling. Horizontal or diagonal structural
member which is attached to vertical posts for the purpose
of delineating trails, protecting vegetation, providing
safety barriers for trail users at overlooks, and assisting
users when crossing bridges or using steps. (Handrail, Railing)
Return to top
H
Habitat: A place that supports
a plant or animal population because it supplies that organism’s
basic requirements of food, water, shelter, living space,
and security.
Return to top
Hazard Tree: Tree or limb that
is either dead, or has some structural fault, that is hanging
over, or leaning towards the trail or sites where people
congregate. (Danger Tree, Widow Maker) Return to top
Header: (Stone or Rock). A long,
uniform stone laid with its narrow end towards the face
of a retaining wall or crib used intermittently to structurally
tie in the other rocks laid in the wall. See Tie Stone.
Return to top
Headwall: A support structure at
the entrance to a culvert or other drainage structure.
Return to top
Helical Pier or Pile: Steel post
with auger-shaped bit-end that is screwed into wet soils
either by hand, or with the aid of specialized hydraulic
tools to establish a foundation for puncheon or boardwalk.
Return to top
Hewing: Using an ax or adze to
cut a log so that its cross section is a square or rectangular.
Return to
top
Humus: The well-decomposed, more
or less stable part of the organic matter in mineral soils.
Return to top
Hybrid: A trail design that blends
“open and flowing” and “tight and technical”
features. Return to top
Hybrid Trail Construction: Concept
where an agency uses a combination of trail contracting
and volunteers to construct a trail. Return to top
I
Impermeable Material: A soil or
material whose properties prevent movement of water.
Return to top
Impervious Surface: Hard surfaces
that do not allow absorption of water into the soil and
that increase runoff. Examples of such surfaces include
concrete or asphalt paved trails and parking areas.
Return to top
Inslope: Where the tread is sloped
downward toward the backslope of the trail. An inslope drain
causes water to run along the inside (uphill) edge of the
trail. Return
to top
Inside Turns: On a trail traversing
a hillside, concave, or naturally banked turns in which
the sideslope helps direct trail riders around the turn.
Return to top
Invert: The bottom inside surface
of a pipe, ditch, or culvert over which water flows.
Return to top
J
Joist: Usually a wooden 2x6, 2x8,
2x10, or 2x12, with the 2-inch dimension resting on a sill
or ledger, toe nailed into place, supporting a floor or
deck. Return to top
Joist Hanger: A steel angle or
strap nailed to the side of a ledger and shaped to hold
a joist. After the joist hanger is installed, the joist
is placed within the hanger and the two are nailed together.
Return to top
K
Return
to top
L
Land Management Agency: Any agency
or organization that manages public lands—many managed
as recreation and/or wilderness areas. Examples include
federal agencies such as the US Forest Service, the National
Park Service, and the Bureau of Land Management; state,
county, and local park system agencies; as well as The Nature
Conservancy. Return to top
Landing: The transition area on
a switchback. (Apron, Deck) Return to top
Landslide: Dislodged rock or earth
that has slipped downhill under the influence of gravity
and obstructs passage on a trail. Return to top
Ledger: A horizontal piece of wood
attached to, and supported by, piles or concrete or stone
masonry piers. Ledgers support stringers or tread timbers.
Return to top
Lifts: Layers of loose soil. Used
to specify how much loose soil should be laid down at a
time before it must be compacted or wrapped in geotextile
fabric. Return to top
Load, Dead: The total physical
weight of a bridge or structure, equal to the combined weight
of all structural components. Return to top
Load, Design: The maximum weight
a trail tread or structure can carry at any point along
its length. Service and emergency vehicles need to be considered
when determining the design load of trails and structures.
Return to top
Logged Out Tree: Down tree across
the trail with sections already removed to permit passage.
Return to
top
M
Machine Built: Trail or feature
constructed with the use of an excavator, trail dozer, or
other piece of equipment. Return to top
Maintenance: Repair, improvements
or other work done on or near a trail to improve the safety
and sustainability of the trail, correct any original design
defects or otherwise improve usability of the trail.
Return to top
Maintainer: A volunteer who maintains
a section of trail as part of a trail-maintenance program
of a trail organization. Return to top
Mineral Soil: A soil comprised
of rock fragments, sand and smaller sized particles, and
free of organic matter. Mineral soil is typically buried
under layers of surface organic matter (duff). Mineral soil
is relatively stable and is the preferred material upon
which to build a trail tread. When compacted carefully,
mineral soil also provides good support to rock walls and
other trail structures. Return to top
Minimum Clear Width: The narrowest
point on a trail; created when significant obstacles, such
as utility poles or tree roots, protrude into and reduce
the design width.
Return to top
Minor Field Adjustments: Deviations
of the trail alignment made during the course of normal
construction or maintenance as determined by the supervisor
or crew leader, and not part of an original survey.
Return to top
Mitigate: Actions taken to avoid,
minimize, reduce, eliminate, or rectify the adverse impact
from erosion, management practice or the impacts of trail
users. (Mitigation) Return to top
Monitor(ing): Check systematically
or scrutinize for the purpose of collecting specific data
along a trail in relation to a set of standards to determine
whether progress is being made in achieving management objectives
or goals.
Return to top
Mono-wall: A short wall of one
or two courses of rock, timbers or other material on the
lower edge of the tread used to maintain the tread in place,
usually when full bench construction is not possible.
Return to top
Mortar: A mixture of sand, lime,
Portland cement, and water that is used in masonry construction
to bind bricks, concrete blocks, or stone to form structural
elements such as retaining walls and piers. Mortar may also
be used when constructing rip rap. Return to top
Mountain Bike: Designed for trail
riding and characterized by upright handlebars, heavy-duty
brakes, wide tires, and low gearing. They are used for both
recreational and competitive bicycling. Return to top
Mulch: Organic matter spread on
newly constructed trail work to help stabilize soils and
protect them from erosion. Examples include bark chips or
shredded wood fiber.
Return to top
Multi-Tier Wall: A wall constructed
of several layers of stone, usually drystacked, with one
layer laid on top of the layer below and usually offset
or battered to ensure sustainability of the structure. Multi-tiered
walls are usually used to retain soil and fill material
where cross slope and tread stability may be lost due to
erosion. Return to top
N
Nailer: A strip of wood
attached to a stringer that tread planks are nailed or screwed
to. Return
to top
National Recreation Trail (NRT):
Existing trails that provide a variety of outdoor recreation
uses in or reasonably accessible to urban areas (over 800)
recognized by the federal government (Secretary of Interior
or Secretary of Agriculture, not Congressional action) as
contributing to the National Trails System. Return to top
National Scenic Trail (NST):
Federally designated extended trails (over 100 miles
in length), which provide for the maximum outdoor recreation
potential and for the conservation and enjoyment of the
significant scenic, historic, natural, or cultural qualities
of the areas through which they pass. The Appalachian and
the Pacific Crest Trails were the first to be designated
as National Scenic Trails in 1968.
Return to top
National Trails System: A
network of trails (National Scenic, Historic, or Recreation)
throughout the country authorized by the 1968 National Trails
System Act (16 U.S.C. 1241-51). Return to top
National Trails System Act
(NSTA): Was passed as Public Law 90-543, signed by
President Johnson on October 2, 1968, after several years
of negotiations. It has been amended more than 20 times
since. Return to top
Non-motorized: Trail
recreation by modes such as bicycle, pedestrian, equestrian,
skate, ski, etc. Return to top
Noxious Weeds: Plant
species designated by Federal and State law as generally
possessing one or more of the following characteristics:
aggressive and difficult to manage; parasitic; a carrier
or host of serious insects or disease; or non-native, new,
or not common to the United States.
Return to top
O
Off-Highway Vehicle (OHV): A motorized
vehicle designed for use off paved roads intended for travel
in areas normally considered inaccessible to conventional
highway vehicles. OHV’s do not generally meet federal
equipment and emissions standards, but do have to comply
with special noise standards. (Dirt Bikes, Dune Buggy, ATV,
Four-Wheel Drive Vehicles, 4WD, Mule, UTV) . Return to top
Open and Flowing: A type of trail
design that allows for sweeping turns, higher speeds, and
longer sight lines. Primarily applies to bicycling and motorized
traffic.
Return to top
Organic Soil: Soil that is made
up of leaves, needles, plants, roots, bark, and other organic
material in various stages of decay, and that has a large
water/mass absorption ratio. Generally the first (outermost)
layer of soil. Return to top
Outfall: The drainage channel of
a drainage dip, water bar, reinforced drainage dip, or switchback
drainage trench. Water exits the structure through the outfall.
(Outlet, Outflow Channel, Outwash) Return to top
Outside Turns: Convex or off-camber
turns (usually on trails that traverse hillsides) that are
more difficult to navigate, as centrifugal force pulls trail
riders to the outside of the turn. Turns in which the ground
slopes toward the outside, making it harder to keep (wheeled)
traction as speed increases. (Off-Camber) Return to top
Outslope: The downward grade from
the backslope (inside or uphill edge) of the tread to the
critical edge (outside or downhill) edge of the trail tread.
(Cant, Camber)
Return to top
Overpass: A crossing of two highways
or a highway and a trail or railroad at different levels
where clearance for traffic on the lower level is obtained
by elevating the higher level. Return to top
P
Parallel Ditching: A lateral drainage
ditch constructed adjacent to the trail tread to catch surface
water sheeting from the tread surface and divert it away
from the trail. Generally this drainage system is utilized
in low flat areas or areas where multiple entrenched trails
have developed. See Collector Ditch. Return to top
Passing Space: A section of trail
wide enough to allow two users to pass one another or travel
abreast. (SeeTurnout) Return to top
Passing Space Interval: The distance
between passing spaces. Return to top
Pavement: That part of a trail
having a constructed hard paved surface for the facilitation
of wheeled trail traffic. Return to top
Pile: A timber, pipe, or metal
pole, or cast in place concrete, or metal to serve as a
support for a bridge or boardwalk. The pile is either placed
in a hole dug to the depth required (end bearing pile),
driven with a heavy weight (friction pile), or screwed into
the ground by a machine (helical pile). (Piling) Return to top
Pilot Hole: A small hole drilled
in wood or steel to guide a nail, screw, or drill bit.
Return to top
Pin Flags: Wire wands with square
plastic flags at one end for field layout and marking of
new trail, maintenance work, or relocations of trail sections.
Return to top
Pinning: Driving drift pins through
a log or timber into a log or timber, or into the ground.
Return to top
Pitch: An increase in the prevailing
grade of a trail, used during construction to avoid an obstacle,
to catch up with the intended grade, or to meet a control
point. Return
to top
Pitch, Maximum: The highest percent
of grade on a trail. Return to top
Pitch, Maximum Sustained: The highest
percent of grade on a trail that is sustained for a significant
distance. Return to top
Plan and Profile Sheets: Drawings
(usually prepared for trail construction) used to record
horizontal and vertical geometry of a trail alignment as
well as other required improvements to the trail corridor.
Return to top
Planimetric map: A map that shows
features such as roads, trails, and mountains, but does
not show contour lines of elevation changes. Return to top
Plank Run: Usually wood planks
laid lengthwise on top of bridge decking used as the tread
surface. (Running) Return to top
Plumb: A line or plane perpendicular
to the Earth’s surface. Return to top
Project Construction Notes: Notes
and drawings written by a Technical Advisor, Trail Designer,
or agency personnel for a project and used to inform Crew
Leaders and their crew of specific tasks to be completed
on the project. The notes usually provide technical information
by section. The tasks to be done in the section are noted
specifically by the linear footage or station, measured
from a common starting point for the project. Return to top
Pruning: The removal of normal
vegetation that intrudes into a trail corridor. Return to top
Puncheon: A log or timber structure
built on the ground for the purpose of crossing a boggy
area. Usually consists of sills, stringers, decking, and
often a soil or loose gravel tread laid on top of the decking.
(Bog Bridge) Return to top
Q
Quadrangle: A tract of land represented
by one US Geological Survey map sheet. Return to top
R
Rail Corridor: The path of a railroad
right-of-way, including the tracks and a specified tract
of land on either side of the tracks (generally one hundred
feet wide).
Return to top
Rail-Trail: A multi-purpose, public
path or trail (paved or natural) created along an inactive
railroad corridor. (Rail-to-Trail) Return to top
Railbank(ing): Retaining a rail
corridor for future railroad uses after service has been
discontinued. The National Trails System Act, Sec. 8d, provides
for interim public use of the corridor, allowing the establishment
of recreational trails. Return to top
Rake Down: Trail construction where
all spoils are distributed below or to the side of the trail
vs. “full clean” where all spoils must be removed.
Return to top
Ramp: A sloped transition between
two elevation levels. One of the three main elements of
a drainage dip. It catches water running down the trail
and directs it off. (Apron) Return to top
Read(ing): To study the terrain
and obstacles to determine a course or possible locations
for a trail through the area. Return to top
Rebar: Steel-reinforcing rod that
comes in a variety of diameters, useful in fabricating pins
or other trail anchors. Return to top
Reclamation: The process of restoring
a denuded and/or eroded area to close to its original condition
with soil and vegetation. Clumps of native turf or sod removed
from areas of new trail are often reused for revegetation
and closure of disturbed areas. To restore a site to its
previous state so that it appears untouched by human use.
(Rehabilitation, Rehab, Revegetation, Restoration, Naturalize)
Return to top
Reconnaissance: Scouting out alternative
trail locations prior to the final trail route location
being selected. (Recon) Return to top
Reconstruct: To replace or rebuild
a trail or trail structure (switchback, waterbar, bridge,
etc.) that is no longer safe to use or in poor condition.
Also can include all work to bring an existing trail up
to its classification standard, including necessary relocation
of minor portions of the trail. (Reconstruction, Renovate)
Return to top
Recreational Trails Program (RTP):
Federal program providing funds to the States for motorized
and non-motorized trails and trail related projects, based
on non-highway recreational fuel use. (www.fhwa.dot.gov/environment/rectrails)
Return to top
Register, Trail: Along long-distance
trails or at a trailhead you may find “trail registers”
that allow users the chance to make comments to those behind
them, and read comments from those ahead. Registers can
be an important safety measure for land management agency
staff to pinpoint the location of trail users. Return to top
Registration, Trail: A survey form
filled out and left at a trailhead drop box or office that
allows managers to obtain trail use information. Or a required
permit to use trail. Return to top
Reroute: A new section of trail
that replaces an existing section. Rerouting is often the
best remedy for a poorly designed trail that requires frequent
maintenance.
Return to top
Retaining Wall: A structure used
to prevent soil from slumping, sliding, or falling, usually
made of log or stone. Often used to provide stability and
strength to the edge of a trail. (Crib Wall, Revetment,
Cribbing) Return to top
Right-of-Way: A linear corridor
of land held in fee simple title, or as an easement over
another’s land, for use as a public utility (highway,
road, railroad, trail, utilities, etc.) for a public purpose.
Usually includes a designated amount of land on either side
that serves as a buffer for adjacent land uses. See Easement.
Return to top
Riparian: A habitat that is strongly
influenced by water and that occurs adjacent to streams,
shorelines and wetlands. The land and vegetation immediately
adjacent to a body of water. (Riparian Zone) Return to top
Rip Rap: Rough, large stones or
rocks placed across an outfall or downslope, along the bank
of a watercourse, or other appropriate areas used to dissipate
the energy of flowing water retarding erosion. Also used
to prevent soil from slumping, sliding, or falling.
Return to top
Rise and Run: A measurement of
grades expressed as a proportion of the amount of vertical
rise in a given horizontal run. For example, “1:4”
means that the grade or slope rises one unit for each four
units of horizontal run. Taking this one step further, 1:4
is a 25% grade or slope, where 25% is obtained by dividing
1 by 4 and expressing the result as a percentage. See Grade.
Return to top
Road: A vehicle route that has
been improved and maintained by mechanical means to ensure
relatively regular and continuous use. A way maintained
solely by the passage of vehicles does not constitute a
road. Return to top
Road Base: A mixture of sand, clay,
and gavel commonly used underneath asphalt on paved roads
and trails. For trails, this material can be compacted into
a fairly hard surface, yet it remains soft enough to be
comfortable for trail users. Return to top
Road-crossing: Intersection of
trail and road traffic-maybe the most dangerous parts of
a trail since they are sometimes located on ridge tops,
blind hills, or hairpin turns.
Return to top
Road-to-Trail Conversion: Involves
narrowing an old logging road to provide a meandering trail
with a solid trail tread for users. Return to top
Root: The part of a plant/tree,
usually underground, that anchors the plant/tree. Can be
a hazard to trail users when they protrude through the tread
surface. Return to top
Root Ball: Earth and soil that
is lifted up when a tree and its roots fall over. (Rootwad)
Return to top
Route: A traveled way, a means
of access, a line of travel, an established or selected
course of travel.
Return to top
Rubble: Rough, irregular fragments
of broken rock or concrete. Return to top
Rubble Wall: A roughly built wall
or structure of irregular or greatly differing sizes of
stone usually laid at or nearly at the same angle as the
cross slope; frequently used to discourage shortcutting
corners and to armor native slopes to prevent erosion.
Return to top
Runoff: Water (not absorbed by
the soil) that flows over the land surface and ultimately
reaches streams. Return to top
Running Joint: A vertical joint
or seam, which is continuous through two or more courses
in a wall. Running joints weaken a wall and should be avoided.
Return to top
Runout: A section of trail, usually
at or near the base or bottom of a decent, that provides
adequate length and grade reduction in order for the user
to safely slow, stop or negotiate turns, intersections or
structures. (Outrun)
Return to top
Rut(s): Sunken tracks or grooves
in the tread surface cut in the direction of travel by the
passage of water or trail users. (Entrenchment) Return to top
S
Saddle Notch: A half-circle notch
cut in the bottom of a log to fit over a log in the course
below. Return
to top
Scale: The proportionate size relationship
between an object and the surroundings in which the object
is placed. The relationship of the length between two points
as shown on a map and the distance between the same two
points on the Earth. Return to top
Scour (Scouring): Soil erosion
through the force of moving water. Return to top
Scree: Gravel-size loose rock debris,
especially on a steep slope or at the base of a cliff, formed
as a result of disintegration largely by weathering. (Scree
Slope) Return
to top
Screening: Full or partial concealment
of unsightly views to render them unnoticeable from the
trail, by means of natural objects, plantings, fences, or
other appropriate means. Return to top
Sediment: Soil that has been removed
from its place of origin by erosion and re-deposited in
a different area down-slope or down-stream. Return to top
Sedimentation: Deposition of soil
particles or other material carried in water, usually the
result of a reduction in water velocity below the point
at which the material remains in suspension. Return to top
Sediment Basin: A natural or constructed
bowl or basin to catch or slow water run-off to allow the
sediment to settle out of suspension. (Catch Basin)
Return to top
Seep: A saturated zone at or near
the ground surface where voids in the rock or soil are filled
with water at greater than atmospheric pressure. Seep or
spring sites are typically characterized by riparian vegetation
and soil formed in the presence of water. Water may or may
not be discharging from these sites, depending on the underlying
geology, water source, season, or long term climatic trends.
(Seepage, Spring)
Return to top
Segment: A portion of a trail.
Changes in geographic features, jurisdiction and/or political
boundaries often distinguish segments (passages). (Passage)
Return to top
Setting Bed: A layer of aggregate
(either crushed stone or crushed gravel), mason’s
sand, or mortar placed on solid rock, or a compacted subgrade
of existing ground or fill as a base for a row of stone
or block. Depending on the setting bed, material, and subsurface
conditions, the setting bed may be from 4 to 12 inches deep.
Return to top
Shear: Force parallel to a surface
as opposed to directly on the surface. An example of shear
would be the tractive force that removes particles from
a trail as flow moves over the surface of the slope.
Return to top
Sheetwash: The widespread removal
of surface debris by the steady and continuous flow of water
on low gradient slopes. Generally at slow speeds and over
long periods. Return to top
Shim(s): A short, thin wedge of
wood or metal used to fill a space. Used to bring a ledger,
stringer, or tread to level. Also used as a verb: to shim.
Stone chip or fragment; to break up into chips or fragments
(spall). Shims or spalls are wedged between stones that
have been placed without mortar. (Spall(s), Wedging)
Return to top
Shoulder: The side or edge of a
rock or trail. The paved portion of a highway, which is
contiguous to the travel lanes, allowing motor vehicle use
in emergencies. They can also be specialized use by pedestrians
and bicyclists.
Return to top
Shrink-Swell Potential: The susceptibility
to soil to change in volume due to a loss or gain in moisture
content. A shrink-swell potential is typically associated
with soils that have a high percentage of clay. Return to top
Shrub: A woody plant that usually
remains low and produces shoots or trunks from the base;
it is not usually tree-like or single stemmed. Return to top
Shy Distance: The distance between
the trail edge and any fixed object capable of injuring
someone using the trail. Return to top
Sidehilling: Process of excavating
or cutting a bench across the slope. Return to top
Sidewalk: A paved strip (typically
concrete four feet in width) which runs parallel to vehicular
traffic and is separated from the road surface by at least
a curb and gutter. Sidewalks are common in urban areas and
in some suburban residential areas. Return to top
Sight Distance: The distance a
trail user can clearly and safely observe the trail ahead
or behind. (Sight Line)
Return to top
Sign: A board, post, or placard
that displays written, symbolic, tactile, or pictorial information
about the trail or surrounding area. Signage increases safety
and comfort on trails. There are five basic types of signs:
Cautionary, Directional, Interpretive, Objective, and Regulatory.
(Signage) Return to top
Sill: Stone or timber supports
that keep bridge, boardwalk or puncheon stringers from contacting
the ground. A horizontal log or timber laid in a shallow
trench to support a plank or log. (Sleeper) Return to top
Silting-in: The filling in of a
drainage structure or low segment of the trail tread by
sediment settling out due to improper design or construction
or because of infrequent maintenance. (Sand or Soil Puddle)
Return to top
Silt Fence: Temporary sediment
barrier consisting of filter fabric, sometimes backed with
wire mesh, attached to supporting posts and partially buried.
Return to top
Skirt: To construct a trail around
a mountain, often at an even grade, instead of climbing
over the mountain. Return to top
Slash: The branches, bark, tops,
cull logs, and broken or uprooted trees left on the ground
after a windfall/blowdown or through logging and trail construction.
See Windfall and Blowdown. Return to top
Slope: The natural or man made
pitch of the land, as shown on contour maps. Generally refers
to the hillside (land), not the trail, as trail “slope”
is called the grade.
Return to top
Slope, Cut: The exposed ground
surface resulting from the excavation of material on the
natural terrain. (See backslope.) Return to top
Slope, Fill: The exposed ground
surface resulting from the placement of excavated material
on the natural terrain. Return to top
Slope, Running: The average slope
of a contiguous section that is in the same direction as
the trail; measured by averaging the values of slop measurements
taken periodically at different points along the trail.
Return to top
Slope, Running Cross: The average
cross slope of a contiguous section of a trail; measured
by averaging the values of cross slope measurements taken
periodically at different points along a given section of
trail. Return to top
Slope Stabil | 
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