Storm water Management Inspector Exam
with Questions and Correct Answers 2025
What are the types of disconnection allowed for rooftop disconnection? -
CORRECT ANSWER-1) simple disconnection - rooftops and/or on-lot residential
impervious surfaces are directed to pervious areas
2) disconnection leading to an alternative runoff reduction practice adjacent to
the roof (ex: soil compost amended filter path)
Why have a rooftop disconnection to an alternative practice? - CORRECT
ANSWER--lot size too small
-filter width is too narrow
-need more water quality credit
Functions provided by simple rooftop disconnection - CORRECT ANSWER--
annual runoff volume reduction
-total phosphorus mass load removal
-total nitrogen mass load removal
Alternative rooftop disconnection types - CORRECT ANSWER--soil compost-
amended filter path
-dry-well or french drain
-rain-garden//front yard bioretention
-rainwater harvesting//cistern
-stormwater planter
How does sheet flow to a vegetated filter strip or conserved open space work? -
CORRECT ANSWER-Filter strips are vegetated areas that treat sheet flow
delivered from adjacent impervious and managed turd areas by slowing runoff
velocities and allowing sediment and attached pollutants to settle and/or be
filtered by the vegetation
Gravel diaphragm - CORRECT ANSWER--pretreatment device
,-maintains sheet flow
-not necessary if contributing drainage area is solely turf
-trench is 2 ft. wide and 1 ft. deep
-runs on same contour at top of filter strip
-drop at least 3 inches
-fabric between gravel and soil
Engineered level spreader - CORRECT ANSWER--forebay: max. 3ft. deep,
transition to 1 ft. at level spreader lip
-level spreader lip - concrete, wood, or prefabricated metal, with a well anchored
footer, or other accepted rigid, non-erodible material
-location: 3-6 inches above downstream natural grade to avoid turf buildup
-3ft. of VDOT #3 stone, underlain by filter fabric just below spreader
-vegetated receiving area must be stabilized
Construction sequence for conserved open space - CORRECT ANSWER-- no
clearing, grading, heavy equipment
-protect area during construction
-prevent sediment discharge
-mark limits of disturbance
-drainage area stabilized
-grade with tracked vehicles
-install gravel diaphragm and/or level spreader
-mark filter boundaries
-keep vehicles out
-stockpile topsoil for later use
-divert construction runoff
-install gravel diaphragm and/or level spreader
-grade with tracked vehicles
-open to runoff once stabilized
Maintenance of Vegetated Filter Strips - CORRECT ANSWER-minimal; spring
cleanup, regular mowing, check dam repairs, and other methods of maintaining
hydraulic efficiency
Grass channel design criteria - CORRECT ANSWER--the bottom width of the
channel should be between 4-8 feet wide
-the channel side-slopes should be 3H:1V or flatter
-the maximum total contributing drainage area to any individual grass channel is
5 acres
-the longitudinal slope of the channel is <4%
-max flow velocity of channel must be <1ft/sec during a 1 inch storm event
-the dimensions of the channel should ensure that flow velocity is non-erosive
during the 2-yr and 10-yr design storm events and the 10-yr design flow is
contained within the channel
, Grass channel pretreatment - CORRECT ANSWER--check dams
-tree check dams
-grass filter strip
-gravel or stone diaphragm
-gravel or stone flow spreaders
Check dams - CORRECT ANSWER--Purpose: break-up slopes and increase time
water stays in channel
max desired height 12-18 in
-averaging ponding depth: 12 in
-armoring may be needed downstream
-anchored into side slopes and bottom
-center weir to pass 10-year storm
-weep hole or similar drainage for dewatering, composed of
wood/concrete/stone/other non-erodible material
Grass Channel construction sequence - CORRECT ANSWER--protect area during
construction
-stabilize drainage area
-grade to final dimensions
-install check dams, pre-treatment
-soil compost amendments
-prepare planting holes
Soil Testing before Soil Compost Amendments - CORRECT ANSWER-1st test:
-conducted every 5000 sq. ft. to determine soil properties
2nd test:
-taken at least 1 week after compost has been incorporated to determine if further
amendments are needed
-test during final construction inspection to ensure tilling or subsoiling has
achieved design depth
Construction Sequence for Soil Compost Amendment - CORRECT ANSWER--
Step 1: deep till 2-3 ft. to create rips perpendicular to the direction of flow
-Step 2: deep till again to a depth of 12-18 inches after final building lots have
been graded
-Step 3: conditions must be dry before incorporating compost
-Step 4: Incorporate compost mix using roto-tiller
-Step 5: Level site, seed, or sod to establish vigorous grass cover// lime or
irrigation as needed
-Step 6: Areas exceeding 2500 sq. ft. should employ simple erosion control
measures, such as silt fence, to reduce the potential for erosion and trap
sediment
Vegetated rooftops (aka ecoroofs, living roofs, or green roofs) - CORRECT
ANSWER-alternative roof surfaces that typically consist of waterproofing and
with Questions and Correct Answers 2025
What are the types of disconnection allowed for rooftop disconnection? -
CORRECT ANSWER-1) simple disconnection - rooftops and/or on-lot residential
impervious surfaces are directed to pervious areas
2) disconnection leading to an alternative runoff reduction practice adjacent to
the roof (ex: soil compost amended filter path)
Why have a rooftop disconnection to an alternative practice? - CORRECT
ANSWER--lot size too small
-filter width is too narrow
-need more water quality credit
Functions provided by simple rooftop disconnection - CORRECT ANSWER--
annual runoff volume reduction
-total phosphorus mass load removal
-total nitrogen mass load removal
Alternative rooftop disconnection types - CORRECT ANSWER--soil compost-
amended filter path
-dry-well or french drain
-rain-garden//front yard bioretention
-rainwater harvesting//cistern
-stormwater planter
How does sheet flow to a vegetated filter strip or conserved open space work? -
CORRECT ANSWER-Filter strips are vegetated areas that treat sheet flow
delivered from adjacent impervious and managed turd areas by slowing runoff
velocities and allowing sediment and attached pollutants to settle and/or be
filtered by the vegetation
Gravel diaphragm - CORRECT ANSWER--pretreatment device
,-maintains sheet flow
-not necessary if contributing drainage area is solely turf
-trench is 2 ft. wide and 1 ft. deep
-runs on same contour at top of filter strip
-drop at least 3 inches
-fabric between gravel and soil
Engineered level spreader - CORRECT ANSWER--forebay: max. 3ft. deep,
transition to 1 ft. at level spreader lip
-level spreader lip - concrete, wood, or prefabricated metal, with a well anchored
footer, or other accepted rigid, non-erodible material
-location: 3-6 inches above downstream natural grade to avoid turf buildup
-3ft. of VDOT #3 stone, underlain by filter fabric just below spreader
-vegetated receiving area must be stabilized
Construction sequence for conserved open space - CORRECT ANSWER-- no
clearing, grading, heavy equipment
-protect area during construction
-prevent sediment discharge
-mark limits of disturbance
-drainage area stabilized
-grade with tracked vehicles
-install gravel diaphragm and/or level spreader
-mark filter boundaries
-keep vehicles out
-stockpile topsoil for later use
-divert construction runoff
-install gravel diaphragm and/or level spreader
-grade with tracked vehicles
-open to runoff once stabilized
Maintenance of Vegetated Filter Strips - CORRECT ANSWER-minimal; spring
cleanup, regular mowing, check dam repairs, and other methods of maintaining
hydraulic efficiency
Grass channel design criteria - CORRECT ANSWER--the bottom width of the
channel should be between 4-8 feet wide
-the channel side-slopes should be 3H:1V or flatter
-the maximum total contributing drainage area to any individual grass channel is
5 acres
-the longitudinal slope of the channel is <4%
-max flow velocity of channel must be <1ft/sec during a 1 inch storm event
-the dimensions of the channel should ensure that flow velocity is non-erosive
during the 2-yr and 10-yr design storm events and the 10-yr design flow is
contained within the channel
, Grass channel pretreatment - CORRECT ANSWER--check dams
-tree check dams
-grass filter strip
-gravel or stone diaphragm
-gravel or stone flow spreaders
Check dams - CORRECT ANSWER--Purpose: break-up slopes and increase time
water stays in channel
max desired height 12-18 in
-averaging ponding depth: 12 in
-armoring may be needed downstream
-anchored into side slopes and bottom
-center weir to pass 10-year storm
-weep hole or similar drainage for dewatering, composed of
wood/concrete/stone/other non-erodible material
Grass Channel construction sequence - CORRECT ANSWER--protect area during
construction
-stabilize drainage area
-grade to final dimensions
-install check dams, pre-treatment
-soil compost amendments
-prepare planting holes
Soil Testing before Soil Compost Amendments - CORRECT ANSWER-1st test:
-conducted every 5000 sq. ft. to determine soil properties
2nd test:
-taken at least 1 week after compost has been incorporated to determine if further
amendments are needed
-test during final construction inspection to ensure tilling or subsoiling has
achieved design depth
Construction Sequence for Soil Compost Amendment - CORRECT ANSWER--
Step 1: deep till 2-3 ft. to create rips perpendicular to the direction of flow
-Step 2: deep till again to a depth of 12-18 inches after final building lots have
been graded
-Step 3: conditions must be dry before incorporating compost
-Step 4: Incorporate compost mix using roto-tiller
-Step 5: Level site, seed, or sod to establish vigorous grass cover// lime or
irrigation as needed
-Step 6: Areas exceeding 2500 sq. ft. should employ simple erosion control
measures, such as silt fence, to reduce the potential for erosion and trap
sediment
Vegetated rooftops (aka ecoroofs, living roofs, or green roofs) - CORRECT
ANSWER-alternative roof surfaces that typically consist of waterproofing and
