Developed by T. Endreny at SUNY ESF in the Department of Environmental Resources Engineering
Fluvial Geomorphology
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The process by which a Stream's gradient steepens due to increased Deposition of sediment
Process where transported chiefly by water and is sorted.
Alluvial Fans
A triangular deposit of sediment left by a Stream that has lost velocity upon entering a broad, relatively flat Valley
Transported chiefly by water and is sorted.
This stage is delineated by the Elevation point of incipient flooding, indicated by deposits of sand or silt at the active scour mark, break in Stream bank slope, perennial vegetation limit, rock discoloration, and root hair exposure
Bankfull Depth


. The average depth measured at Bankfull Discharge.
Bankfull Discharge

(Qbkf ):

The dominant channel forming flow with a recurrence interval seldom outside the 1 to 2 year range.
Bankfull Width


. Channel width at Bankfull Discharge.
Stage at Average Low Flow
Baseflow Width
Wetted width at Baseflow. Critical for fisheries passage and other biotic indices.
Channel Length
Curvilinear distance measurement along the center of the channel
Channel Slope
Change in Elevation divided by the length of channel along a channel distance of 20-30 riffle/pool sequences or 2 Meander lengths. Valley Slope/Sinuosity.
Process where transported chiefly by gravity and is unsorted. It may travel within water
Transported chiefly by gravity and is unsorted. It may travel within water
A Streams ability to transport sediment. The diameter of the largest sediment grain transported
An arbitrary Elevation from which all vertical measurements are taken in a design
The process by which a Stream's gradient becomes less steep, due to the Erosion of sediment from the Stream bed. Such Erosion generally follows a sharp reduction in the amount of sediment entering the Stream
An Alluvial fan having its apex at the mouth of a Stream
The terminus of Erosion - the settling of particles
Measure of vertical length relative to a Datum
Entrenchment Ratio


. The channel width at two times the Bankfull Depth divided by the channel width at Bankfull.
The process by which particles of rock and soil are loosened, as by weathering, and then transported elsewhere, as by wind, water, ice, or gravity
Fluvial Geomorphology
Flood-Prone Area
A relatively flat lowland that borders a Stream and is covered by its waters at flood stage of twice the maximum Bankfull Depth.
Flood-Prone Width


. The Stream width at a discharge level defined as twice the maximum Bankfull Depth.
Land that is actively (flooded beyond Bankfull once every 1-2 years), generally broad, gently sloped Valley floor, often bounded by a Terrace (abandoned Floodplain) or encroaching side slope
Geologic Material
Solid inorganic substratum of the earth and all possible derivatives
Natural features of a land surface
Low Flow
Groundwater fed flow
Curves deviating from a linear course. Components of Meander geometry include length, amplitude, belt width.
Meander Width Ratio
Meander Belt Width divided by the Bankfull Width
A channel type unit length with the same channel type existing for a length over twenty Bankfull channel widths (Rosgen). The length of channel uniform with respect to discharge, depth, area, and slope. The length of a channel for which a single gage affords a satisfactory measure of the stage and discharge. The length of a river between two gaging stations. More generally, any length of a river.
Ratio of Channel Length to Valley Length. Ratio of Valley Slope to Channel Slope.
A body of water found on the Earth's surface and confined to a narrow topographic depression, down which it flows and transports rock particles, sediment, and dissolved particles. Rivers, creeks, brooks, and runs are all Streams
An abandoned Floodplain, due to river incision or downcutting, etc
Longitudinal outline/trace/survey of a deepest part of riverbed from source to mouth (upstream/downstream). Line of steepest descent along the Stream.
A depression on the earth surface drained by, and whose form is changed by, water under the attractive force of gravity, between two adjacent uplands
Valley Length
Horizontal distance measured in the Thalweg of two cross sections in a linear depression between two adjacent uplands
Valley Slope
Slope of a Valley for a given Reach where Valley and Reach intersect for some longer distance (several Meanders or step pools)
Wetted Width
The width of the wetted Stream at the time of the survey. Wetted Width is generally less than Bankfull Width. Wetted Width is also referred to as "low flow channel