Erosion and Sediment Pollution Control Program Manual.pdf

Frost Action (Soils) -----The likelihood of upward or lateral expansion of the soil caused by the
formation of segregated ice lenses, or frost heave, and the subsequent collapse of the soil and
loss of strength on thawing, which can damage roads, buildings, and other structures as well as
plant roots.
Frost Heave -----The raising of a surface or object due to the accumulation of ice in the underlying soil.
Frost Line -----The depth to which frost penetrates the soil.
Froude Number -----An expression used to classify channel flow into subcritical, critical, and
supercritical flow. Flow is at critical depth when the Froude number is 1.
V
F = -----------
(g D) 0.5
Where: V = Velocity (fps)
g = gravitational constant
D = hydraulic depth of flow (ft)
A high Froude number (>1) indicates rapid (supercritical) flow, while a low Froude number ( 12” high) filled with riprap used to stabilize stream
banks, hillsides, and other areas subject to flowing water with high velocities.
Gabion Mattress -----A series of gabion baskets tied together by the manufacturer.
Gaging Station -----A selected section of stream channel equipped with a gage, recorder or other
facilities for measuring streamflow.
Gap-graded -----A soil with a discontinuous range of soil particle sizes. For example, having largesized
particles and small-sized particles, but not medium-sized particles.
Gage (Gauge)-----1. A device for measuring precipitation, water level, discharge rate or volume,
pressure, temperature, etc. 2. A measure of the thickness of meta, such as the diameter of wire.
Gallons per Minute (GPM) -----A measure of the rate of discharge typically used for well capacity or for
flow rates less than 1 cfs. 1 cfs = 448.83 gpm.
General Information Form (GIF) -----An additional form (Document No. 8000-PM-IT001) required for
Individual NPDES Permit Applications
General 105 Permit (GP)
GP-1 -----GP for Fish Habitat Enhancement Structures.
GP-2 -----GP for Small Docks and Boat Launching Ramps.
GP-3 -----GP for Bank Rehabilitation, Bank Protection and Gravel Bar Removal.
GP-4 -----GP for Intake and Outfall Structures.
GP-5 -----GP for Utility Line Stream Crossings.
GP-6 -----GP for Agricultural Crossings and Ramps.
GP-7 -----GP for Minor Road Crossings.
GP-8 -----GP for Temporary Road Crossings.
GP-9 -----GP for Agricultural Activities.
GP-10 -----GP for Abandoned Mine Reclamation.
GP-11 -----GP for Maintenance, Testing, Repair, Rehabilitation, or Replacement of Water
Obstructions and Encroachments
GP-15 -----GP for Private Residential Construction in Wetlands.
General NPDES Permit -----The category into which most construction permits fall. It is required for all
earth disturbances greater than or equal to 1 acre in a non-special protection watershed. Earth
disturbances associated with agricultural plowing and tilling and animal heavy use areas, timber
harvesting, and roadway maintenance are exempt.
363-2134-008 / March 31, 2012 / Page 521