NPDES Class questions and answers with
solutions 2025
Erosion - ANSWER is the process by which the land surface is worn away by the action of wind,
water, and gravity.
Sedimentation - ANSWER is the settling out of soil particles transported by water and wind.
Soil erosion can be classified as 2 types. What are they? - ANSWER Wind and Water.
What are the two sources of Soil erosion. - ANSWER Natural and Manmade
Water erosion can be classified as two type of erosions. What are they? - ANSWER Overland and
Stream/Channel erosion.
Four process of overland erosion are? - ANSWER Splash, sheet, rill, and gully erosion.
Four principle factors influencing soil erosion are? - ANSWER Soil characteristics, vegetative
cover, topography, and climate.
List three physical effect of erosion and sedimentation: - ANSWER Increased flooding reduced
hydraulic capacity in rivers, and streams; increased maintenance of stormwater systems.;
increased water treatments cost; and decreased recreational value.
List three biological effect of erosion and sedimentation: - ANSWER Reduced light for aquatic
plants; clogs fish gills; impairs spawning; disrupts food chain; blankets bottom, suppresses
aquatic life; and disrupts ecosystem.
, Planning the development to fit the terrain using the particular: - ANSWER Topography; soils;
drainage patterns; natural vegetation of the site; and minimize the extent of the area exposed at
one time and the duration of exposure.
Perimeter Control Practices - ANSWER What you apply to protect the disturbed area from off-
site runoff and to protect off-site areas from sediment damage.
Erosion Control Practices - ANSWER What you apply to prevent excessive on-site damage.
Keep runoff velocities _____ and _______ runoff on the site - ANSWER Low and retain
When do you stabilize disturbed areas after final grading to prevent raindrop impacts from
causing erosion. - ANSWER Immediately
Implement a thorough _____ and _____(inspection) program as required in the Construction
Generic Permit (CGP). - ANSWER maintenance and follow up
Soil particles smaller than 0.002 mm are classified as ____ and along with ____ are the two soil
types that cause the most erosion/turbidity problems in Florida and the World. - ANSWER clay
and muck
Soils in the Type A hydrologic group have ____ infiltration rates and ____ runoff potential even
when thoroughly wetted. - ANSWER high and low
Soils in the Type D hydrologic group have very ____ infiltration rates and ____ runoff potential
when thoroughly wetted. - ANSWER low and high
What is the rainfall erosion index? - ANSWER The rainfall erosion index is the only factor in the
Universal Soil Loss Equation which is beyond the developer's control.
solutions 2025
Erosion - ANSWER is the process by which the land surface is worn away by the action of wind,
water, and gravity.
Sedimentation - ANSWER is the settling out of soil particles transported by water and wind.
Soil erosion can be classified as 2 types. What are they? - ANSWER Wind and Water.
What are the two sources of Soil erosion. - ANSWER Natural and Manmade
Water erosion can be classified as two type of erosions. What are they? - ANSWER Overland and
Stream/Channel erosion.
Four process of overland erosion are? - ANSWER Splash, sheet, rill, and gully erosion.
Four principle factors influencing soil erosion are? - ANSWER Soil characteristics, vegetative
cover, topography, and climate.
List three physical effect of erosion and sedimentation: - ANSWER Increased flooding reduced
hydraulic capacity in rivers, and streams; increased maintenance of stormwater systems.;
increased water treatments cost; and decreased recreational value.
List three biological effect of erosion and sedimentation: - ANSWER Reduced light for aquatic
plants; clogs fish gills; impairs spawning; disrupts food chain; blankets bottom, suppresses
aquatic life; and disrupts ecosystem.
, Planning the development to fit the terrain using the particular: - ANSWER Topography; soils;
drainage patterns; natural vegetation of the site; and minimize the extent of the area exposed at
one time and the duration of exposure.
Perimeter Control Practices - ANSWER What you apply to protect the disturbed area from off-
site runoff and to protect off-site areas from sediment damage.
Erosion Control Practices - ANSWER What you apply to prevent excessive on-site damage.
Keep runoff velocities _____ and _______ runoff on the site - ANSWER Low and retain
When do you stabilize disturbed areas after final grading to prevent raindrop impacts from
causing erosion. - ANSWER Immediately
Implement a thorough _____ and _____(inspection) program as required in the Construction
Generic Permit (CGP). - ANSWER maintenance and follow up
Soil particles smaller than 0.002 mm are classified as ____ and along with ____ are the two soil
types that cause the most erosion/turbidity problems in Florida and the World. - ANSWER clay
and muck
Soils in the Type A hydrologic group have ____ infiltration rates and ____ runoff potential even
when thoroughly wetted. - ANSWER high and low
Soils in the Type D hydrologic group have very ____ infiltration rates and ____ runoff potential
when thoroughly wetted. - ANSWER low and high
What is the rainfall erosion index? - ANSWER The rainfall erosion index is the only factor in the
Universal Soil Loss Equation which is beyond the developer's control.
