Source: California State Parks Trails Handbook
abutment – The foundation at either end of a bridge, boardwalk, or puncheon that supports the sills, stringers, decking, and railing (superstructure); typically constructed with earth, concrete, wood, plastic wood, or rock.
ADA – Acronym for the Americans with Disabilities Act of 1990, the federal law prohibiting discrimination against people with disabilities.
alignment – The route proposed for or taken by a trail.
amenities – Any structure used to enhance the user’s experience and comfort along a trail or at a trailhead, such as a restroom, picnic table, or drinking fountain.
angle of repose – The maximum angle measured from the horizontal at which rocks, sand, soil, etc. will stay at rest without moving down the slope.
armoring – Reinforcement of a surface, whether trail or creek bed, with a protective layer of rock, aggregate, concrete, or similar material to carry traffic or prevent erosion.
aspect – The compass direction a topographical slope faces. Aspect affects the amount of solar radiation and year-round moisture to which a site is subjected.
backcountry – Remote areas where trails and trail facilities have lower levels of use, lower user expectations, and lower design and construction standards.
backfill – Fill material place behind a supporting engineered structure such as a retaining wall, abutment, or steps to elevate a trail structure or feature.
backslope – Excavation occurring on the uphill side of the trail, sloped back to an angle to where it is stable and will not unravel or slide onto the trail.
berm – Ridge of material formed on the outside edge of the trail that is higher than the center of the trail.
borrow – Soil, gravel, or rock taken from an approved location for use as fill material elsewhere.
brush – Small vegetation less than 20 feet in height such as herbaceous plants and low-growing woody shrubs.
brushing maintenance – Removal of living and dead vegetation in the travelway, completed on a cyclical basis.
canopy – The more or less continuous cover of branches and foliage formed collectively by the crowns of adjacent trees and other woody growth in a forest.
causeway – An elevated section of trail tread that is raised above the ground by the placement and compaction of permeable backfill material contained by rock. Usually constructed through permanently or seasonally wet areas.
CEQA – Acronym for the California Environmental Quality Act, the State law that requires analysis of potential environmental and cultural impacts of any proposed project.
check dam – A barrier of logs, rocks, wood, or other material set perpendicular to a rill or gully to slow the flow of water and allow particulate material to settle, filling in the rill or gully.
climbing turn – A turn in a trail constructed on a less than 30% slope.
clinometer – A hand-held instrument used to measure a change in slope and grade. Readings are in degrees or percent.
compaction – Consolidation obtained through the removal of voids in soil or earthen materials by tamping the materials with hand tools or machinery, accomplished in lifts no greater than three inches.
control point – Existing natural or man-made feature that the trail alignment must go to or avoid.
downed tree – Tree that has fallen across the trail.
drain dip/grade reversal – A gradual dip in the trail bed between natural topographic watercourse features that diverts water off the trail bed.
drain lens – Drainage structure placed under the trail consisting of either porous rock wrapped with geotextile fabric or a graded aggregate that is intended to allow water to seep under the trail while keeping the trail’s surface dry.
drain swale – A small topographic feature naturally formed by an ephemeral drainage that does not have a visible stream channel or bed. The trail should gradually dip in and climb out of the swale.
duff – Layer of decaying organic material deposited on the ground and comprised of leaves, needles, woody debris, and humus.
energy dissipater – A rock tray constructed below the outflow of a drainage feature, such as a culvert or drain dip, that is used to reduce the energy of flowing water onto the slope below.
entrenched trail – A trail with cupping, rutting, or trenching on the trail tread from trampling, standing water, uncontrolled surface run off, and/or accumulation of slough and berm. The resulting tread surface is lower than the inboard and outboard hinges.
erosion control – Techniques used to minimize soil movement caused by water runoff, wind, or user traffic.
fall line – A trail aligned with the natural direction of water flowing down a slope.
fill – Native or imported material used to construct trail structures. Fill can include soil, aggregate, crushed rock, or rock cobble.
flag line – A proposed trail alignment delineated with flagging that has been attached to branches, stakes, or wires
flagging – A roll of thin, colored ribbon or squares of colored plastic fabric attached to wires (“pin flags”) used for marking trail alignments, trail structure locations, or control points.
frontcountry – The area near developed facilities such as campgrounds, visitor centers, or day use areas that have high levels of use, user expectations, and design and construction standards.
grade – The slope of the land expressed as a percentage of rise and fall and measured from level.
grub – To excavate and remove roots and tree stumps within the trail bench.
gully – When concentrated runoff cuts into soil forming a channel greater than one square foot in cross section area.
hazardous tree – An unstable tree, usually greater than five inches in diameter at breast height (dbh), in danger of falling where people congregate, such as a trailside shelter bridge, campsite, or overlook.
headwall – A retaining or support structure installed at the inlet or outlet of a culvert.
impermeable material – Natural or man-made material that does not allow the passage of water.
inboard hinge – Slope transition on the inside, or uphill side, of trail tread where the trail tread and backslope converge
inboard ditch – A drainage ditch cut along the inboard side of the trail to intercept drainage from the slope above or from small springs emanating from the hillslope.
inslope – When the trail bed slopes down toward the inboard hinge or back slope.
key stone – A large stone placed at the bottom or lowest elevation of a rock retaining wall or other rock structure to buttress the rest of the structure.
meander – A series of gentle curves in a stream, road, or trail.
mineral soil – Soil or aggregate that is free of organic substances and contains no particles greater than two inches in diameter.
mitigate – Action taken to avoid, minimize, reduce, eliminate, or rectify adverse impacts related to trail construction, maintenance, or use.
outboard hinge – Slope transition on the outside, or downhill side, of trail tread where trail tread and hillslope converge.
outcrop – A rock formation that protrudes through the surface of the surrounding soil.
outslope – Where trail tread is sloped downward toward the outboard hinge of the trail.
permeability – The property of a material that permits the passage of water.
pinch points – Locations on a trail where features, such as downed and standing trees, rock outcrops, logs, or large rocks, are used in conjunction with curves in the trail to create the appearance that trail has substantially narrowed. Pinch points are used to slow user traffic, thereby reducing user conflicts and improving safety.
piss anting – A technique for rolling a large stone across the ground, typically used by trail workers to move stones that are too large to lift and carry. While in a squatting position, with hands under the edge of the stone and arms and back straight, push with legs while using arms to roll the stone in the desired direction.
puncheon – A type of rustic log or timber boardwalk that is used as a watercourse crossing structure and is built close to the ground (< 24 inches above ground) with an individual span that is usually less than 12 feet. It may be used to cross a small ephemeral drainage or wet, boggy area. It usually consists of mudsills, joists, soil dams, and wood decking, but does not include a railing.
railing – Horizontal and/or diagonal structural members attached to vertical posts for delineating trails, protecting vegetation, and providing safety barriers for hikers.
raveling – Rocks or soil separating from the hillslope and depositing on the trail bed, usually associated with an overly-steep or unstable cutbank.
rebar – A steel-reinforcing rod commonly used in construction projects to strengthen concrete, pin material together, or anchor structures.
reconnaissance – Thorough investigation and evaluation of alternative trail locations prior to selecting the final trail route location.
reconstruction – The work necessary to repair or replace trail structures and features when routine and cyclic maintenance is insufficient to keep the trail safe for users and from impacting resources.
rehabilitation – The work necessary to bring a trail or trail system up to the design standards and construction specifications appropriate for the trail classification and user type.
restoration – The work necessary to return a disturbed landscape to its natural or original condition.
retaining wall – A wooden, rock, log, or concrete wall used to support trail tread or retain slope cuts.
rill – A small erosional feature similar to a gully in morphology but less than one square foot in area. Rills often form on soft bare soil or road surfaces. Compare with gully
rise and run – The angle of inclination of a slope or structure expressed as a ratio of the horizontal length (run) to the vertical ascent (rise).
rolling dip – A trail structure similar to a drain dip or grade reversal but the trail coming into and out of the dip are steeper in grade and shorter in length.
runoff – Water flow on the ground surface usually generated by rain falling on saturated ground or from heavy rain that cannot soak into the ground fast enough.
scarify – To break-up and decompact trail bed material so it can be reshaped or bond to new tread material being applied to the trail bed.
sediment – Soil particles that have been transported away from their natural location by wind or water and re-deposited down slope or downstream.
sediment control – Structures, including silt fences and sediment retention basins, that filter, trap, or contain water-carried sediments and prevent them from being further mobilized.
side slope – The angle of a hill slope measured in degrees or percentage along the fall line
sight distance – Visible, unobstructed, forward and rear view seen by a user from any point on a trail.
sinuosity – The relative amount of curves along a trail alignment.
slide – Section of soil or rock, located above, below, or within the trail, that gives way and moves down a slope.
slough – Material from the backslope (or area of the backslope) deposited on the inboard hinge of the trail bed.
soil – Material of clay, silt, sand, organic material, air, water, and weathered rock mixed in various proportions. Soil consists of horizons or layers that have different amounts of weathering and fertility.
specifications – Standards to which trails and structures are built and maintained according to classification and user type.
steps – A structure that provides a safe, stable, vertical rise in steep or unstable terrain, usually made of wood or rock.
stream crossing – A trail section constructed across a natural stream, such as rock armored, step stone, open culvert, closed culvert, or bridge.
stringer – The primary member of a bridge superstructure that rests on sills and supports the bridge’s decking, posts, and rails. Also known as a girder or beam
switchback – A turn in a trail constructed on a slope greater than 30%.
talus – A collection of broken rock fragments at the base of a crag or mountain cliff that has accumulated through periodic rock falls.
topographic turn – A turn in a trail made by incorporating a topographic feature, such as a knoll or knob of land, to keep the lower section of the trail out of view of the upper section.
topography -The shape and relief of the earth’s surface.
trail bed – The entire width of the trail that is graded and cross sloped to facilitate drainage, and extends from the inboard hinge point at the base of the backslope to the outboard hinge at the outside edge of the trail.
trail corridor – The general location of a potential trail alignment.
trail hardening – The manual, mechanical, or chemical compaction of the trail tread to create a hardened surface that sheets water and resists indentations from traffic.
trail log – A record of each structure, feature, facility, and improvement along or adjacent to a trail.
trailhead – The access point to a trail, often accompanied by public facilities such as a parking area, drinking fountain, restroom, informational signage, and an equestrian or off highway vehicle staging area.
trail tread – The portion of the trail bench intended for user traffic.
travelway or trailway – The outer limits of the trail, extending 2 feet beyond the top of the cutbank and 2 feet beyond the outboard hinge.
trio maintenance – The set of measures used to maintain a trail, including removal of slough and berm, reestablishment of the designed surface drainage, and brushing to original construction standards.
turnpike – A section of trail tread that is raised above the ground by the placement and compaction of permeable backfill material contained by logs or dimensional lumber. Usually constructed through permanently or seasonally wet areas.
viewshed – The landscape that falls within view from a given point.
waterbar – A structure, usually constructed of wood or rocks, built into the trail to collect and divert water to the downhill side of the trail.
watercourse – Any permanent or re-occurring surface flow such as a river, stream, or tributary
watershed – A region or area joined peripherally by a water-parting formation such as a ridge, hill, or mountain range, and draining to a particular watercourse or body of water.