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NSPS CST Level II study materials
NSPS CST Level II study resources

NSPS CST Level II practice questions

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Question 1Field track - Level II work elements

During a field inspection, the CST observes that a temporary stockpile has been placed within a drainage swale. Which Level II action best reflects the intent of the approved erosion and sediment control plan?

  1. Document the condition and notify the responsible contractor so the material can be relocated and the swale restored Correct answer.
  2. Approve the condition because the stockpile will eventually be used as fill on site
  3. Wait for the next scheduled inspection cycle before raising the issue with anyone
  4. Photograph the stockpile and take no further action because the plan does not name stockpile locations

Explanation

Level II field work requires recognizing a deviation from the approved plan and initiating corrective communication, not simply recording it. A stockpile blocking a swale changes drainage and increases sediment transport risk, so it must be addressed promptly. Documentation plus notification creates the record needed to verify correction.

Question 2Field track - Level II work elements

Which record is most important for a CST to capture when a sediment basin outlet structure is found partially blocked during a routine field visit?

  1. The estimated total project cost of the basin structure
  2. The weather forecast for the following week
  3. The names of all subcontractors working anywhere on the site that day
  4. The date, time, location, observed condition, and the person notified Correct answer.

Explanation

Inspection records must tie an observation to a specific place and time and show who was informed so follow-up can be tracked. Those elements make the record usable for compliance verification and corrective action. Unrelated site or cost information does not support that purpose.

Question 3Field track - Level II work elements

A silt fence has been installed along a contour but the fabric is torn over a ten-foot section. What is the most appropriate Level II response?

  1. Note the tear only in the final closeout report at project completion
  2. Ignore it because silt fence is a secondary practice behind other controls
  3. Record the tear, notify the installer, and confirm repair or replacement before the next runoff event Correct answer.
  4. Remove the entire fence line so the site looks uniform

Explanation

A torn section defeats the purpose of the fence and allows sediment-laden runoff to pass untreated. The observer should document the deficiency, notify the responsible party, and verify repair in a timely manner. Deferring to closeout leaves the control nonfunctional through potentially many storms.

Question 4Field track - Level II work elements

When a CST performs a field check of a stabilized construction entrance, which condition indicates the practice is functioning as intended?

  1. The pad is entirely covered with tracked mud carried off the roadway
  2. Aggregate has been displaced so bare soil is exposed across most of the pad
  3. Aggregate is clean and the pad length is sufficient to remove mud from tires before vehicles reach the road Correct answer.
  4. Vehicles bypass the pad because a shorter route exists through the lot

Explanation

A construction entrance works by providing a stable, clean aggregate surface long enough to knock mud off tires before vehicles leave the site. Mud buildup, displaced stone, and bypass routes all reduce that effectiveness. Inspectors look for a maintained pad that vehicles actually use.

Question 5Field track - Level II work elements

A CST is asked to verify that a newly installed inlet protection device meets the site plan. Which check is most directly relevant?

  1. Confirm the surrounding pavement has fully cured
  2. Confirm the device is the type specified, is properly seated around the inlet, and does not cause flooding of the roadway Correct answer.
  3. Confirm the inlet grate has been painted a uniform color
  4. Confirm the inlet is the highest point on the site

Explanation

Inlet protection must match the approved design, seal against the structure so sediment cannot bypass it, and still allow water to drain without ponding hazards. Those are the functional checks a Level II observer makes. Cosmetic or unrelated conditions do not verify performance.

Question 6Field track - Level II work elements

What is the primary purpose of a concrete washout area on a construction site?

  1. To contain alkaline washwater and solids so they do not enter stormwater or stabilize in unwanted locations Correct answer.
  2. To provide a mixing pad for fresh concrete deliveries
  3. To serve as a temporary parking area for ready-mix trucks
  4. To store rebar and formwork between pours

Explanation

Concrete washwater is highly alkaline and carries fine solids that can harm receiving waters and clog drainage. A designated washout contains that material for proper disposal. Using it for storage or parking would defeat its containment function.

Question 7Field track - Level II work elements

During a site walk, a CST notices that a stabilized access road has begun to rut and channel stormwater toward a neighboring property. What should the CST do first?

  1. Close the entire project until the road is repaved
  2. Wait until the neighbor files a complaint before acting
  3. Fill the ruts with any available soil from the site
  4. Document the condition and elevation of the problem and notify the responsible party for corrective action Correct answer.

Explanation

The CST's role is to identify and communicate a condition that is causing off-site discharge before it worsens. Documenting location and extent supports a targeted fix. Filling with erodible soil or waiting for a complaint does not correct the drainage problem.

Question 8Field track - Level II work elements

Which statement correctly describes the CST's role during a field inspection relative to the approved stormwater pollution prevention plan?

  1. The CST rewrites the plan on site whenever a control looks inconvenient
  2. The CST approves design changes without notifying the plan preparer
  3. The CST compares observed conditions against the plan and reports deviations to the responsible party Correct answer.
  4. The CST signs off on final stabilization without inspecting the site

Explanation

Field inspection is a comparison activity: what the plan requires versus what is actually installed and maintained. Deviations must be communicated so they can be corrected or formally revised. The inspector does not unilaterally alter the plan or certify conditions not observed.

Question 9Field track - Level II work elements

A CST is reviewing a site where topsoil has been stockpiled beside an active earthwork area. Which practice best protects the stockpile from wind and water erosion?

  1. Place the stockpile directly against a storm drain inlet
  2. Leave the stockpile loose so it drains freely
  3. Water the stockpile daily to keep dust down without any other control
  4. Stabilize the stockpile surface and provide a perimeter control downslope of it Correct answer.

Explanation

Stockpiles are disturbed areas that shed sediment and dust, so they need surface stabilization plus a perimeter control to capture runoff. Leaving material loose or adjacent to inlets increases the chance of sediment leaving the site. Watering alone does not address runoff-borne sediment.

Question 10Field track - Level II work elements

What distinguishes a check dam from a sediment trap in terms of function on a construction site?

  1. A check dam slows flow in a channel and promotes settling, while a sediment trap impounds runoff in a defined basin for settling Correct answer.
  2. A check dam is a permanent structure, while a sediment trap is always temporary
  3. A check dam is used only for concrete washwater, while a sediment trap handles all site runoff
  4. A check dam stores large volumes of runoff, while a sediment trap only slows channel flow

Explanation

Check dams are small grade structures placed across swales or channels to reduce velocity and encourage deposition. Sediment traps are excavated or bermed basins that detain runoff long enough for particles to settle. Confusing the two leads to misapplied controls.

Question 11Field track - Level II work elements

A CST observes that a recently seeded slope has bare patches and rill formation after a storm. Which sequence of actions best reflects Level II field practice?

  1. Record the affected area, identify the cause, and recommend repair such as reseeding, mulching, or additional erosion control Correct answer.
  2. Apply additional seed without addressing the concentrated flow that caused the rills
  3. Note the rills as cosmetic and continue monitoring without changes
  4. Remove all vegetation from the slope to expose uniform soil

Explanation

Rills indicate that the slope is not yet stabilized and that concentrated flow is eroding soil. Effective response documents the failure, identifies the cause, and applies a repair that addresses both surface protection and flow. Repeating the failing treatment without diagnosis invites recurrence.

Question 12Field track - Level II work elements

Which condition most clearly indicates that a sediment basin is not functioning as designed?

  1. The basin perimeter is stabilized with vegetation
  2. The basin shows a normal pool elevation after a storm
  3. The basin has filled with sediment to the point that its storage volume is substantially reduced Correct answer.
  4. The basin has a visible riser and outlet structure

Explanation

A sediment basin depends on adequate storage volume to detain runoff and allow settling. When accumulated sediment reduces that volume, residence time drops and treatment effectiveness falls. The other listed conditions are normal features of a working basin.

Question 13Field track - Level II work elements

A CST is asked to evaluate whether a disturbed area meets the criteria for final stabilization. Which evidence is most relevant?

  1. The area has been graded smooth but remains bare soil
  2. Construction equipment has been removed from the area
  3. Uniform vegetative cover or equivalent permanent stabilization across the disturbed area with no visible erosion Correct answer.
  4. Temporary silt fence remains in place around the area

Explanation

Final stabilization means the disturbed area is protected from erosion on a permanent basis, typically by established vegetation or an equivalent measure. Smooth bare ground and temporary controls do not meet that standard. Removal of equipment alone does not stabilize soil.

Question 14Field track - Level II work elements

During a rain event, a CST sees that a temporary diversion berm is directing runoff into an unstabilized area instead of the intended outlet. What is the most appropriate observation to record?

  1. The berm is functioning correctly because it is moving water away from the work area
  2. The berm should be removed immediately because diversions are not allowed during construction
  3. The diversion alignment is sending flow to an unstabilized area, creating an erosion risk that requires correction Correct answer.
  4. The condition is acceptable until the next scheduled inspection

Explanation

Diversions must route water to a stabilized conveyance or outlet; sending flow onto bare ground creates new erosion. The inspector should record the misdirected flow and the resulting risk so it can be corrected. Accepting the condition because water is moving misses the purpose of the practice.

Question 15Field track - Level II work elements

A CST finds that dust from an unpaved haul road is drifting onto adjacent property. Which combination of measures is most appropriate to recommend?

  1. Remove the road surface entirely and leave exposed subgrade
  2. Apply water or a dust palliative to the road surface and limit vehicle speeds Correct answer.
  3. Increase vehicle speeds so trucks spend less time on the road
  4. Ignore the dust because it is not a stormwater pollutant

Explanation

Dust control on haul roads typically combines surface moisture or a palliative with speed reduction to limit airborne fines. Speeding increases dust generation, and bare subgrade is more erodible. Airborne dust can also settle and become a stormwater pollutant.

Question 16Field track - Level II work elements

Which factor most directly affects the sediment removal performance of a silt fence installation?

  1. The fence is installed in a straight line regardless of contour
  2. The fabric is stretched loosely to allow water to pond against it
  3. The fabric is trenched or otherwise anchored into the ground so flow cannot pass beneath it Correct answer.
  4. The fence posts are painted a high-visibility color

Explanation

Silt fence works by ponding runoff so sediment settles, which requires the fabric to be sealed into the ground along its entire length. Flow that passes under the fabric carries sediment around the control. Post color and loose fabric do not improve performance.

Question 17Field track - Level II work elements

A CST is reviewing a site's inspection log and finds several entries that say only 'inspected, OK' with no location or condition details. Why is this a deficiency?

  1. The entries are too long and should be shortened further
  2. The entries are acceptable because a positive result needs no detail
  3. The entries do not identify what was checked or observed, so they cannot support verification or corrective action Correct answer.
  4. The entries should include only the inspector's signature

Explanation

An inspection record must allow a reader to know what was examined, where, and what condition was found. Vague entries cannot demonstrate compliance or support follow-up when problems arise. Brevity is not a substitute for specificity.

Question 18Field track - Level II work elements

What is the most appropriate way for a CST to handle a minor deficiency that can be corrected immediately during the inspection, such as a displaced inlet filter?

  1. Photograph it and take no action because it is minor
  2. Report it only if it recurs in a later inspection
  3. Leave it for the contractor's next monthly report
  4. Note the deficiency, have it corrected on the spot if authorized, and record the correction Correct answer.

Explanation

Prompt correction of a small deficiency prevents it from becoming a larger compliance problem. Recording both the finding and the correction maintains an accurate trail. Deferring or ignoring minor items allows them to persist and multiply.

Question 19Field track - Level II work elements

A CST observes that a swale lined with riprap has lost stone along one section, exposing bare soil. What is the most likely consequence if the condition is not corrected?

  1. Flow will erode the exposed soil and carry sediment downstream, potentially undermining the lining further Correct answer.
  2. The riprap will migrate back into place during the next storm
  3. The swale will carry less water because the soil absorbs it all
  4. The exposed soil will stabilize itself once vegetation establishes

Explanation

Riprap protects the swale from scour; where it is missing, concentrated flow attacks bare soil. That erosion releases sediment and can progressively undercut adjacent lining. Self-repair is not a realistic expectation for displaced stone.

Question 20Field track - Level II work elements

Which observation would lead a CST to conclude that a construction site's pollution prevention plan needs a formal revision rather than a routine maintenance fix?

  1. An inlet filter has accumulated sediment and needs cleaning
  2. A washout has reached its planned capacity and needs pumping out
  3. Site grading has changed so that runoff now drains to an area where no control was planned Correct answer.
  4. A silt fence post has loosened and needs re-driving

Explanation

A plan revision is warranted when site conditions or drainage patterns no longer match the approved design. Routine maintenance items like loose posts, dirty filters, and full washouts are addressed without revising the plan. The key distinction is a change in the underlying conditions the plan assumed.

Question 21Field track - Level II work elements

A CST is evaluating a proposed location for a portable toilet and handwash station on a construction site. Which siting consideration is most relevant to stormwater protection?

  1. Place the units in the lowest point of the site to keep them out of the way
  2. Place the units on bare soil so liquids can soak in
  3. Place the units directly over a storm drain so runoff carries waste away quickly
  4. Place the units away from drainage paths and inlets so spills or washwater cannot enter the storm system Correct answer.

Explanation

Sanitary facilities are a potential source of pollutants, so they must be sited away from conveyances and inlets and on stable ground. Locating them in drainage paths or over inlets risks direct discharge. Bare soil does not provide containment for spills.

Question 22Field track - Level II work elements

A CST notices that a subcontractor is pumping turbid groundwater from an excavation directly onto a vegetated buffer. Which response best reflects Level II responsibilities?

  1. Allow the discharge because vegetated buffers filter all sediment
  2. Record the discharge and take no action until the excavation is complete
  3. Stop or redirect the discharge and require treatment or a suitable dewatering control before discharge continues Correct answer.
  4. Recommend increasing the pumping rate to finish dewatering faster

Explanation

Dewatering discharge is a regulated point of concern and must be managed so turbid water does not leave the site untreated. A vegetated buffer alone is not a designed treatment control for high-volume turbid discharge. The inspector should intervene and require an appropriate control.

Question 23Field track - Level II work elements

A CST is comparing two sediment control options for a small disturbed area draining to a sensitive receiving water. Which reasoning is most sound?

  1. Select the option that requires the least maintenance, even if undersized
  2. Select the least expensive option regardless of drainage area
  3. Select the practice that matches the drainage area, expected flows, and required treatment level, and verify it is maintained Correct answer.
  4. Select whichever practice was used on a previous unrelated project

Explanation

Control selection should be based on site-specific hydrology, the sensitivity of the receiving water, and the treatment the practice can provide. Cost or convenience alone can lead to undersized or ineffective controls. Prior use elsewhere does not establish suitability for this site.

Question 24Field track - Level II work elements

During a post-storm inspection, a CST finds that a sediment trap has breached and sediment has reached a roadway. Which immediate priority best reflects Level II field judgment?

  1. Secure the area, stop further release if possible, and notify the responsible parties so cleanup and repair can begin Correct answer.
  2. Complete the routine inspection checklist first and report the breach afterward
  3. Document the breach only in the project closeout file
  4. Wait for the next rain event to see whether the breach worsens

Explanation

An active release is an urgent condition that calls for containment, notification, and repair before routine tasks. Delaying response allows more sediment to migrate off site and may increase cleanup obligations. Closeout documentation is far too late for an active discharge.

Question 25Field track - Level II work elements

A CST is reviewing whether a proposed change from a sediment basin to a series of smaller controls is acceptable for a site with high runoff potential. Which analysis is most defensible?

  1. Accept the change because the contractor prefers the smaller controls
  2. Reject the change because any deviation from the original plan is prohibited
  3. Compare the expected treatment performance, storage, and maintenance burden of the alternatives against the site's runoff characteristics before recommending a change Correct answer.
  4. Accept the change because smaller controls are always easier to install

Explanation

Substituting controls requires an evaluation of whether the alternatives provide equivalent protection given the site's runoff and sensitivity. Neither blanket acceptance nor blanket rejection reflects sound field analysis. Contractor preference is not a technical justification.

Question 26Field track - Level II work elements

In the context of construction site stormwater compliance, what does the term 'CST' most commonly designate when it appears in a field inspection program?

  1. Contractor Site Trainee
  2. Certified Stormwater Technician Correct answer.
  3. Construction Safety Trainer
  4. Concrete Slump Tester

Explanation

Within stormwater inspection programs, CST stands for Certified Stormwater Technician, a credentialed field practitioner who performs inspections and documentation. The other expansions belong to unrelated construction roles and do not carry stormwater inspection authority.

Question 27Field track - Level II work elements

A CST is assigned to inspect a site's erosion and sediment controls. Which document should the CST consult first to determine the required inspection frequency and the specific BMPs approved for the site?

  1. The local building permit fee schedule
  2. The general contractor's project schedule
  3. The site-specific Stormwater Pollution Prevention Plan (SWPPP) Correct answer.
  4. The manufacturer's installation guide for silt fence

Explanation

The SWPPP is the site-specific plan that identifies approved BMPs, inspection intervals, and recordkeeping requirements for that project. Inspection frequency and BMP selection are governed by the plan and its permit conditions, not by schedules or product literature.

Question 28Field track - Level II work elements

During a field inspection, a CST observes that the site's concrete washout pit is nearly full and washwater is pooling on the ground beside it. Which action is most appropriate for the CST to take first?

  1. Dilute the pooled washwater with clean water so it infiltrates faster
  2. Document the condition and notify the responsible contractor so the pit can be cleaned out or replaced before further washing occurs Correct answer.
  3. Wait until the next scheduled weekly inspection to record the condition
  4. Cover the pooled washwater with soil and continue inspections elsewhere

Explanation

A nearly full washout with escaping washwater is an active deficiency that can discharge high-pH water, so the CST should document it and promptly notify the responsible party for correction. Delaying action or attempting to mask the problem allows unauthorized discharge to continue.

Question 29Field track - Level II work elements

A CST is inspecting a silt fence installed along the downslope perimeter of a disturbed area. Which installation condition should the CST flag as a deficiency?

  1. Fabric buried in a compacted trench along the entire fence line
  2. Fence installed across a concentrated flow channel Correct answer.
  3. Fence placed on the contour with the fabric on the upslope side
  4. Posts spaced according to the manufacturer's recommendation

Explanation

Silt fence is a perimeter sediment barrier designed for sheet flow and should not be placed across concentrated flow channels, where it will be undercut or overtopped. Proper trenching, contour placement, and correct post spacing are all acceptable installation practices.

Question 30Field track - Level II work elements

A CST is reviewing the site's inspection records and finds that a required post-storm inspection was not performed after a qualifying rain event. What is the most appropriate way for the CST to handle this finding?

  1. Omit the missing inspection from the report to avoid confusion
  2. Record the missed inspection as a deficiency and note the date and rainfall event that triggered the requirement Correct answer.
  3. Note in the log that post-storm inspections are optional for this site
  4. Backdate an inspection entry to the day after the storm so the record appears complete

Explanation

Missed inspections are compliance deficiencies and must be documented accurately with the triggering event identified so corrective action and follow-up can occur. Falsifying, omitting, or misstating the requirement undermines the integrity of the inspection record.

Question 31Field track - Level II work elements

A CST observes that a stabilized construction entrance has lost most of its aggregate and is tracking mud onto a public road. Which corrective measure is most directly aimed at the source of the problem?

  1. Increasing the frequency of street sweeping on the public road
  2. Replenishing the aggregate and restoring the entrance to the designed depth and length Correct answer.
  3. Posting a sign asking drivers to reduce speed
  4. Applying water to the public road to suppress dust

Explanation

A stabilized construction entrance relies on a properly maintained aggregate pad to remove mud from tires before vehicles leave the site. Restoring the aggregate addresses the source of the tracking, whereas sweeping, signage, and watering treat symptoms without fixing the entrance.

Question 32Field track - Level II work elements

When a CST evaluates whether a temporary sediment basin is sized appropriately for its contributing drainage area, which design parameter is most directly relevant?

  1. The type of vegetation planted on the basin's embankment
  2. The number of trees retained around the basin
  3. The color of the basin's riser structure
  4. The basin's storage volume relative to the disturbed acreage draining to it Correct answer.

Explanation

Temporary sediment basin sizing is based primarily on the contributing drainage area and the required storage volume per disturbed acre. Color, tree retention, and embankment vegetation do not determine whether the basin provides adequate sediment storage.

Question 33Field track - Level II work elements

A CST is checking a site where an earthwork contractor has left a large area of exposed soil without temporary stabilization at the end of the work week. Which principle should guide the CST's recommendation?

  1. Exposed soil should be stabilized as soon as practicable and within any timeframe specified in the permit or SWPPP Correct answer.
  2. Stabilization is unnecessary if rain is not forecast for the next month
  3. Only areas visible from public roads require stabilization
  4. Stabilization can be deferred until the entire project is complete

Explanation

Erosion control requirements call for stabilizing exposed soil promptly and within the timeframe set by the permit or SWPPP, because delaying stabilization increases sediment loss during any storm. Deferral to project completion, visibility-based criteria, and short-term weather forecasts are not valid substitutes.

Question 34Field track - Level II work elements

A CST is inspecting a riprap-lined channel and observes that flow is bypassing the riprap and scouring the adjacent bare soil. Which interpretation is most consistent with this observation?

  1. The scour indicates that the channel slope is too flat
  2. The riprap is functioning as designed and the scour is unrelated
  3. The riprap should be removed to allow natural vegetation to establish
  4. The channel lining is not providing continuous protection, allowing concentrated flow to attack unprotected soil Correct answer.

Explanation

When flow escapes a riprap lining and scours adjacent soil, the lining is discontinuous or improperly keyed, so concentrated flow reaches unprotected material. This is a lining deficiency that requires repair or extension, not removal of the protection.

Question 35Field track - Level II work elements

A CST is reviewing a SWPPP that calls for a sediment trap at a location where the contributing drainage area is much larger than the trap was designed for. What is the most appropriate concern for the CST to raise?

  1. The trap will remove too much sediment and starve downstream waters
  2. The trap may be undersized for the contributing area and could fail to provide adequate sediment removal Correct answer.
  3. The trap should be replaced with a silt fence to reduce maintenance
  4. The trap's location guarantees compliance regardless of size

Explanation

Sediment traps are sized for a specific contributing drainage area, and a trap receiving substantially more drainage than designed can be overwhelmed and pass sediment downstream. The CST should flag the sizing mismatch so the design can be evaluated and corrected.

Question 36Field track - Level II work elements

During an inspection, a CST finds that a fuel trailer is parked on bare ground without secondary containment and a small drip stain is visible beneath it. Which action best reflects the CST's field role?

  1. Wait for the fuel vendor to perform the next scheduled delivery before taking any action
  2. Ignore the drip because it is too small to matter
  3. Document the condition and recommend immediate placement of secondary containment and cleanup of the stained soil Correct answer.
  4. Wash the stained soil into a nearby swale to disperse it

Explanation

Fuel storage without secondary containment is a pollution prevention deficiency, and even small drips can accumulate or migrate. The CST should document the condition and recommend immediate containment and cleanup rather than ignoring, dispersing, or deferring the problem.

Question 37Field track - Level II work elements

A CST is evaluating a proposed location for a portable toilet on a construction site. Which siting consideration is most important for protecting stormwater?

  1. Placing the unit directly adjacent to a curb inlet for convenient servicing
  2. Placing the unit in a drainage swale to keep the surrounding area dry
  3. Placing the unit where spills or leaks cannot drain to a stormwater conveyance or waterbody Correct answer.
  4. Placing the unit on the highest point of the site for visibility

Explanation

Portable toilets should be sited so that any spill or leak cannot enter stormwater conveyances or surface waters, which typically means away from inlets, swales, and waterbodies. Visibility, servicing convenience, and keeping the pad dry do not override the need to prevent pollution.

Question 38Field track - Level II work elements

A CST observes that dewatering discharge from an excavation is being pumped directly onto a vegetated buffer without any treatment. Which response is most consistent with the CST's responsibilities?

  1. Recommend discharging to a storm drain to avoid saturating the buffer
  2. Allow the discharge because vegetated buffers treat all pollutants
  3. Document the discharge and recommend that the water be treated or filtered before release and that the discharge point be relocated or protected Correct answer.
  4. Recommend increasing the pumping rate to shorten the discharge duration

Explanation

Dewatering discharge can carry sediment and other pollutants, and discharging it without treatment onto a buffer can cause erosion and violate permit conditions. The CST should document the condition and recommend treatment or relocation to a protected discharge point.

Question 39Field track - Level II work elements

A CST is inspecting a stockpile of excavated soil that will remain in place over the winter. Which practice is most appropriate for reducing sediment loss from the stockpile?

  1. Leaving the stockpile bare so wind can disperse the soil
  2. Covering the stockpile and installing a perimeter sediment control downslope Correct answer.
  3. Placing the stockpile directly in a drainage channel to consolidate material
  4. Watering the stockpile daily to keep the surface wet

Explanation

Covering a stockpile protects it from rainfall and wind, and perimeter sediment control captures any material that does leave the pile. Leaving it bare, placing it in a channel, or relying on watering does not provide reliable long-term protection.

Question 40Field track - Level II work elements

A CST is reviewing a site's SWPPP and notices that the plan identifies a sediment basin as the primary control, but the field inspection shows a silt fence and no basin. What is the most appropriate conclusion?

  1. The silt fence is an acceptable substitute because it is also a sediment control
  2. The plan should be revised in the field without documentation
  3. The site is not implementing the approved plan and the discrepancy should be documented and reported Correct answer.
  4. The discrepancy is acceptable if the basin is not visible from the site entrance

Explanation

A significant difference between the approved SWPPP and field conditions means the plan is not being implemented as written, and the CST should document and report the discrepancy. Substituting controls without plan revision or documenting the change is not acceptable.

Question 41Field track - Level II work elements

During a rain event, a CST observes that runoff from a disturbed slope is flowing around the end of a silt fence rather than through the fabric. What is the most likely cause?

  1. The silt fence fabric has too many openings to slow flow
  2. The silt fence posts are spaced too closely together
  3. The silt fence does not extend far enough to intercept the full width of flow Correct answer.
  4. The silt fence was installed on the contour

Explanation

Flow that goes around the end of a silt fence indicates the fence does not span the full width of the contributing flow path, leaving a bypass. Fabric openings, close post spacing, and contour installation do not explain flow escaping at the end.

Question 42Field track - Level II work elements

A CST is asked to verify that a disturbed area has achieved final stabilization before the site's stormwater permit is terminated. Which evidence is most appropriate for the CST to rely on?

  1. A single application of seed and fertilizer earlier in the season
  2. The absence of visible rills on the day of the inspection
  3. Uniform vegetative cover established across the disturbed area at the density specified in the permit or SWPPP Correct answer.
  4. A statement from the earthwork contractor that the area is stable

Explanation

Final stabilization generally requires uniform vegetative cover at a specified density, or an equivalent permanent measure, across the disturbed area. A single seeding application, a one-day absence of rills, or a contractor's statement does not demonstrate that the criterion is met.

Question 43Field track - Level II work elements

A CST is inspecting a check dam made of rock across a small swale and observes that the center of the dam is lower than its edges. What is the most appropriate interpretation?

  1. The dam is not properly shaped and flow may concentrate at the low point, reducing its effectiveness Correct answer.
  2. The low center indicates the dam is too tall and should be removed
  3. The shape of the dam has no effect on its performance
  4. The low center is correct because it encourages even spreading of flow

Explanation

Check dams should be shaped so that the center is higher or level, not lower, to prevent flow from concentrating and eroding the structure or bypassing it. A low center concentrates flow and undermines the dam's sediment-capture function.

Question 44Field track - Level II work elements

A CST is reviewing a site's inspection report and notices that several entries lack the date, time, and location of the observed deficiency. Why is this a significant problem?

  1. Inspection reports are only required at project closeout
  2. Dates and locations are only needed for major violations
  3. Incomplete records cannot demonstrate compliance or support timely corrective action Correct answer.
  4. The report should only contain entries for deficiencies that were corrected

Explanation

Inspection records must identify when and where deficiencies were observed so that corrective actions can be tracked and compliance can be demonstrated. Missing date, time, and location information undermines both functions.

Question 45Field track - Level II work elements

A CST observes that a temporary diversion berm is directing runoff into an unstabilized area instead of the intended sediment control. Which corrective action is most appropriate?

  1. Leave the berm as is and rely on the sediment control downslope
  2. Add more unstabilized soil to the area to absorb the runoff
  3. Realign or repair the berm so runoff is directed to the intended control Correct answer.
  4. Remove the berm entirely to eliminate the diversion

Explanation

A diversion berm should route runoff to the designed sediment control, and when it directs flow to an unstabilized area it must be realigned or repaired. Removing the berm or adding soil does not correct the misdirection and can worsen erosion.

Question 46Field track - Level II work elements

A CST is evaluating a site's spill response readiness. Which item is most essential to have available on site for responding to a small fuel or oil spill?

  1. A water truck for diluting spills
  2. A pressure washer for rinsing surfaces
  3. A supply of clean fill soil for covering spills
  4. Spill kit containing absorbent materials and containment tools Correct answer.

Explanation

A spill kit with absorbents and containment tools allows prompt containment and cleanup of small fuel or oil releases before they reach stormwater. Pressure washing, soil covering, and dilution do not properly contain or remove the spilled material.

Question 47Field track - Level II work elements

A CST is inspecting a site where the SWPPP requires weekly inspections, but the log shows inspections were performed only twice in the past month. Which conclusion is most appropriate?

  1. The log should be revised to show weekly inspections
  2. The frequency requirement can be waived if no rain occurred
  3. The inspection frequency does not meet the plan requirement and the deficiency should be documented Correct answer.
  4. Two inspections per month are sufficient because the site is small

Explanation

When the SWPPP specifies weekly inspections, performing only two in a month does not meet the requirement, and the CST should document the deficiency. Small site size or dry weather does not automatically waive the requirement, and revising the log would falsify records.

Question 48Field track - Level II work elements

A CST observes that a sediment basin's riser is clogged with debris and the basin is nearly full of water. Which risk is most directly associated with this condition?

  1. Reduced sediment settling and potential overtopping or failure of the basin Correct answer.
  2. Increased dissolved oxygen in the discharge
  3. Decreased need for basin maintenance
  4. Improved sediment capture because water is held longer

Explanation

A clogged riser prevents controlled release, reducing settling time and raising the water level, which can lead to overtopping or structural failure. The condition increases maintenance needs and does not improve water quality.

Question 49Field track - Level II work elements

A CST is reviewing a site's erosion control plan and notes that a proposed slope stabilization measure relies entirely on a single application of hydromulch with no contingency. What is the most appropriate concern?

  1. A single application may not provide durable cover, and a contingency for reapplication or alternative stabilization should be included Correct answer.
  2. Hydromulch should never be used on slopes
  3. A contingency is unnecessary because hydromulch always establishes permanent cover
  4. The concern is irrelevant because slope stabilization is optional

Explanation

Hydromulch can be an effective slope cover, but relying on a single application without contingency risks failure if the cover does not establish or is damaged. A contingency for reapplication or an alternative measure is prudent, and slope stabilization is not optional.

Question 50Field track - Level II work elements

A CST is inspecting a site where a subcontractor has installed a silt fence without burying the fabric in the ground. The subcontractor argues that the fence will still catch sediment. How should the CST respond?

  1. The fence is acceptable if additional posts are added
  2. The fence is acceptable because silt fence is only a secondary control
  3. The fence is acceptable because the fabric will eventually settle into the soil
  4. The fence is deficient because flow will pass beneath the fabric, and it must be reinstalled with a properly trenched and compacted anchor Correct answer.

Explanation

Silt fence fabric must be buried in a trenched and compacted anchor to prevent flow from passing beneath it, which would bypass the sediment barrier entirely. Additional posts do not correct the missing anchor, and the fence's role does not excuse improper installation.