Erosion and Sediment Pollution Control Program Manual.pdf

Backflow -----The backing up of water through a conduit or channel in the direction opposite to normal
flow.
Backhoe -----Heavy equipment used in construction, which has a bucket suspended on a movable
boom.
Backshore -----The zone of a shore or beach including the berms that lie between the foreshore and
the dunes or bluffs. The backshore is acted upon by waves only during severe storm events,
especially when combined with exceptionally high water.
Backslope -----The downstream slope of an embankment.
Backwater -----The area upstream of a water obstruction that would be flooded because of the
obstruction.
Backwater Area -----1. The low-lying lands adjacent to a stream that become flooded during periods of
high water.
Baffle -----A wall installed across the bottom of a Sediment Basin or Trap for the purpose of increasing
the length of the flow path of water through the impoundment from the point where it enters the
impoundment to the principal spillway. (See Standard Construction Detail #7-14
Ballast -----1. Stone or gravel that provides drainage and stability as a base for concrete. 2. In
railroads, gravel-sized material, normally an aggregate, on which the railroad ties are placed.
Bank -----The part of the soil adjacent to a stream, lake, or body of water, having an elevation higher
than the normal water level.
Bank Migration -----Lateral or horizontal migration of the banks of a stream channel.
Bank Rehabilitation and Bank Protection -----To restore and/or protect the bank of a stream, lake,
pond, or reservoir against erosion, scour, or sloughing by using any of the following: slope
protection, dumped rock protection, cribbing, walls, channel deflectors, vegetative stabilization
techniques.
Bank Slip -----Downward movement of the bank of a stream or body of water caused by erosion and/or
stress.
Bankfull Discharge (Bankfull Flow) -----The stream flow that transports the majority of a stream’s
sediment load over time and thereby forms the channel; the discharge that fills a stable alluvial
channel to the elevation of the active floodplain; bankfull discharge is the basis for measuring
width/depth ratio and entrenchment ratio.
Bar -----A sand or gravel deposit in a streambed that is often exposed only during low water periods.
Barrel -----The outlet pipe running through the embankment of a Sediment Basin or Trap. (See
Standard Construction Detail #8-2)
Barren Land Use -----Beaches; sandy areas other than beaches; bare exposed rock, such as bedrock,
talus or fill; surface mines; quarries; and transitional zones, such as areas previously bare but
becoming vegetated.
Base Course -----The bottom portion of a pavement where the top and bottom portions are not the
same composition.
Base Flow -----The normal flow in a channel or swale not in response to a recent storm. This flow is
supported by groundwater seepage into the channel.
Base Flow Recession -----The declining rate of discharge of a stream fed only by base flow for an
extended period of time. Typically, a base flow recession will be exponential.
Basin -----An impoundment area constructed to contain and slow runoff to permit the settling and
collection of sediment transported by runoff.
BAT -----Best available technology.
Batch Plant -----Production plant for large quantities of concrete.
Bearing Capacity -----The maximum load that a material (e.g. soil) can support before failing.
Bed -----The bottom of a stream or channel.
Bed Load -----Sediment (up to rock) that is transported in a stream by rolling, sliding, or skipping along
or very close to the channel bottom.
Bed Slope -----The gradient of a channel. It is determined by dividing the difference in elevation —
upper end to lower end of reach — by the channel length.
Bedform -----A relief feature on the bed of a stream, such as dunes, plane bed or antidunes. Also
called bed configuration.
363-2134-008 / March 31, 2012 / Page 502