NPDES FINAL EXAM ACTUAL QUESTIONS AND ANSWERS
GUARANTEE A+
✔✔A diversion or earthen dike shall be used to direct stormwater into the temporary
slope drain. (True/False) - ✔✔True
✔✔The height of the dike at the inlet shall be equal to the ____ plus __ inches. -
✔✔Pipe diameter plus 6"
✔✔The maximum spacing between check dams should be such that the ____ of the
upstream dam is at same elevation as the ___ of the downstream dam. - ✔✔Bottom,
top
✔✔Sediment should be removed from check dams, when it reaches ____ of the original
height or before. - ✔✔half
✔✔A floating turbidity curtain is designed to ____ sediment laden water and allow
enough ____ for sediments to settle out of suspension. - ✔✔contain, time
✔✔A type III floating turbidity curtains may be used in considerable flow conditions,
meaning less than _ feet per second or _ knots. - ✔✔5, 3
✔✔In flowing water turbidity curtains should be placed _____ to the direction of flow, not
____ - ✔✔Parallel to, not perpendicular
✔✔Anchor lines shall be attached to the ____, not to the bottom of the _____. -
✔✔buoys, bottom of the curtain or float
✔✔In tidal and/or wind and wave conditions there should be a ___-foot gap between
bottom of the curtain and the floor of the water body at mean low water. - ✔✔one
✔✔Sediments shall be allowed to settle a minimum of 72 hours prior to removal of the
turbidity curtain (True/False). - ✔✔False
✔✔What are the three purposes of soil roughening? - ✔✔aid in establishment of
vegetative cover; reduce runoff velocity & increase infiltration, and reduce erosion and
provide for sediment trapping.
✔✔The purpose of ____ is to provide a suitable growth medium for final site
stabilization with vegetation. - ✔✔Topsoiling
, ✔✔The subgrade should be prepared by ____ or ____ to insure bonding of the topsoil
with the subsoil. - ✔✔discing or scarifying
✔✔Areas that are at rough grade for 14 days or more should receive ____ seeding
immediately. - ✔✔temporary
✔✔List three soil conditioners: - ✔✔peat, sand, vermiculite, rotted manure, rotted
sawdust, treated sewage sludge (biosolids).
✔✔Name the two soil amendments usually required prior to permanent seeding: -
✔✔fertilizer and lime.
✔✔A stand of vegetation is considered fully established after ___ year. - ✔✔one
✔✔When sodding a slope, strips should be laid (along/ perpendicular to) the contour.
Joints should be (staggered/ in line). Start from the ___ and ____ toward the top. -
✔✔along, staggered, Bottom and work
✔✔List three beneficial functions of mulch: - ✔✔1) Protects soil from raindrop erosion,
2) Moderates soil temperature, 3) Moderates soil moisture, 4) Reduces velocity of
overland flow, 4) Improves soil texture and/or nutrients, 5) Control/reduce weeds.
✔✔Straw mulch should be applied at rate of ____ lbs. per 1000 sq. ft.; _____ bales per
1000 sq. ft.; or _____ tons per acre. - ✔✔70 - 90 lbs, 1.5-2 bales, or 1.5-2
✔✔When installing erosion control nets or blankets, work from the ___ towards the
_____. - ✔✔top, bottom
✔✔Effective tree protection should be installed no closer than _ feet from the trunk or
the _____ of the tree. - ✔✔8, drip line
✔✔A good place for material storage, parking, and portable toilets is inside the tree
protection zone. (True / False). - ✔✔False
✔✔What types of dewatering systems generally produce clear, non-turbid groundwater?
_________ - ✔✔Well-point & Sock/Horizontal pumps
✔✔What kind of water quality does a rim ditch system produce? - ✔✔The poorest water
quality with highest turbidity NTU levels.
✔✔What must a well-point and horizontal pump system have in order to function
properly? - ✔✔Primarily sandy soil.
GUARANTEE A+
✔✔A diversion or earthen dike shall be used to direct stormwater into the temporary
slope drain. (True/False) - ✔✔True
✔✔The height of the dike at the inlet shall be equal to the ____ plus __ inches. -
✔✔Pipe diameter plus 6"
✔✔The maximum spacing between check dams should be such that the ____ of the
upstream dam is at same elevation as the ___ of the downstream dam. - ✔✔Bottom,
top
✔✔Sediment should be removed from check dams, when it reaches ____ of the original
height or before. - ✔✔half
✔✔A floating turbidity curtain is designed to ____ sediment laden water and allow
enough ____ for sediments to settle out of suspension. - ✔✔contain, time
✔✔A type III floating turbidity curtains may be used in considerable flow conditions,
meaning less than _ feet per second or _ knots. - ✔✔5, 3
✔✔In flowing water turbidity curtains should be placed _____ to the direction of flow, not
____ - ✔✔Parallel to, not perpendicular
✔✔Anchor lines shall be attached to the ____, not to the bottom of the _____. -
✔✔buoys, bottom of the curtain or float
✔✔In tidal and/or wind and wave conditions there should be a ___-foot gap between
bottom of the curtain and the floor of the water body at mean low water. - ✔✔one
✔✔Sediments shall be allowed to settle a minimum of 72 hours prior to removal of the
turbidity curtain (True/False). - ✔✔False
✔✔What are the three purposes of soil roughening? - ✔✔aid in establishment of
vegetative cover; reduce runoff velocity & increase infiltration, and reduce erosion and
provide for sediment trapping.
✔✔The purpose of ____ is to provide a suitable growth medium for final site
stabilization with vegetation. - ✔✔Topsoiling
, ✔✔The subgrade should be prepared by ____ or ____ to insure bonding of the topsoil
with the subsoil. - ✔✔discing or scarifying
✔✔Areas that are at rough grade for 14 days or more should receive ____ seeding
immediately. - ✔✔temporary
✔✔List three soil conditioners: - ✔✔peat, sand, vermiculite, rotted manure, rotted
sawdust, treated sewage sludge (biosolids).
✔✔Name the two soil amendments usually required prior to permanent seeding: -
✔✔fertilizer and lime.
✔✔A stand of vegetation is considered fully established after ___ year. - ✔✔one
✔✔When sodding a slope, strips should be laid (along/ perpendicular to) the contour.
Joints should be (staggered/ in line). Start from the ___ and ____ toward the top. -
✔✔along, staggered, Bottom and work
✔✔List three beneficial functions of mulch: - ✔✔1) Protects soil from raindrop erosion,
2) Moderates soil temperature, 3) Moderates soil moisture, 4) Reduces velocity of
overland flow, 4) Improves soil texture and/or nutrients, 5) Control/reduce weeds.
✔✔Straw mulch should be applied at rate of ____ lbs. per 1000 sq. ft.; _____ bales per
1000 sq. ft.; or _____ tons per acre. - ✔✔70 - 90 lbs, 1.5-2 bales, or 1.5-2
✔✔When installing erosion control nets or blankets, work from the ___ towards the
_____. - ✔✔top, bottom
✔✔Effective tree protection should be installed no closer than _ feet from the trunk or
the _____ of the tree. - ✔✔8, drip line
✔✔A good place for material storage, parking, and portable toilets is inside the tree
protection zone. (True / False). - ✔✔False
✔✔What types of dewatering systems generally produce clear, non-turbid groundwater?
_________ - ✔✔Well-point & Sock/Horizontal pumps
✔✔What kind of water quality does a rim ditch system produce? - ✔✔The poorest water
quality with highest turbidity NTU levels.
✔✔What must a well-point and horizontal pump system have in order to function
properly? - ✔✔Primarily sandy soil.
