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Free CESSWI Practice Questions

10 free, exam-style Certified Erosion (CESSWI) practice questions with answers and explanations. No signup required. Work through them below, then take the full free CESSWI practice test to study every exam domain.

These 10 free CESSWI questions are organized by exam domain, so you can see how each part of the Certified Erosion blueprint is tested. Reveal the answer and explanation under each question.

Domain 3: Site Climatic Conditions and Rainfall Amounts 0% of exam

Question 1

A 20-acre construction site has a runoff coefficient (C) of 0.70 for current disturbed conditions. The design storm produces a rainfall intensity (i) of 3.5 inches per hour for a duration equal to the site's time of concentration. Using the Rational Method, what is the estimated peak discharge from this site?

  1. 14.0 cfs
  2. 24.5 cfs
  3. 49.0 cfs
  4. 70.0 cfs
Show answer & explanation

Correct answer: C - 49.0 cfs

Domain 4: Hydrology and Drainage Principles (1-2%)

Question 2

Final grading is complete on a construction site and 75% vegetative cover has been established across all disturbed areas. All temporary BMPs have been removed and post-construction stormwater controls are installed and functioning. Based on the federal CGP standard for final stabilization, can a Notice of Termination (NOT) be filed?

  1. Yes - 75% cover exceeds the 70% threshold and all other stated criteria appear to be met
  2. No - the CGP requires 90% vegetative cover before a NOT may be filed
  3. No - a NOT may only be filed after the first full growing season following final grading
  4. Yes - but only after the permitting authority conducts its own final site inspection
Show answer & explanation

Correct answer: A - Yes - 75% cover exceeds the 70% threshold and all other stated criteria appear to be met

Domain 5: General Permits (4-6%)

Question 3

A CESSWI conducting a routine inspection determines that the sediment basin serving a 14-acre drainage area is undersized - the design volume appears to be approximately half of what the permit requires. What is the MOST appropriate course of action?

  1. Calculate the correct volume, direct the contractor to expand the basin, and document the correction
  2. Require the contractor to install additional silt fence around the basin perimeter as a compensating measure
  3. Document the deficiency and immediately issue a stop-work order for the entire site
  4. Document the finding in the inspection report and refer it to the CPESC or design engineer for redesign
Show answer & explanation

Correct answer: D - Document the finding in the inspection report and refer it to the CPESC or design engineer for redesign

Domain 6: Inspection Fundamentals and Duties (12-15%)

Question 4

During an inspection, a CESSWI observes that a concrete washout containment area is approximately 70% full. The contractor states they will address it before the project ends. Which statement MOST accurately describes the required maintenance threshold AND the primary environmental concern associated with concrete washwater?

  1. Maintenance is required at 75% capacity; the primary concern is high turbidity from suspended concrete particles
  2. Maintenance is required at 75% capacity; the primary concern is highly alkaline pH (11-13) harmful to aquatic life
  3. Maintenance is required at 50% capacity; the primary concern is high turbidity from suspended concrete particles
  4. Maintenance is required at 50% capacity; the primary concern is highly alkaline pH (11-13) harmful to aquatic life
Show answer & explanation

Correct answer: B - Maintenance is required at 75% capacity; the primary concern is highly alkaline pH (11-13) harmful to aquatic life

Domain 8: Stormwater Monitoring and Sampling (1-3%)

Question 5

An inspector writes the following entry in a field inspection report: 'The silt fence along the northern property boundary appears to have been installed carelessly and is in very poor condition.' Which statement BEST describes this documentation?

  1. It is acceptable because it clearly communicates the severity of the issue to the contractor
  2. It is acceptable if the inspector includes supporting photographs with the report
  3. It is unacceptable because inspection reports should not reference specific BMP locations
  4. It is unacceptable because it contains subjective language and opinion rather than observable facts
Show answer & explanation

Correct answer: D - It is unacceptable because it contains subjective language and opinion rather than observable facts

Question 6

While preparing for an inspection, a CESSWI notices an unlabeled 55-gallon drum stored near an active storm drain inlet. Before handling or moving closer to investigate, the inspector wants to identify potential chemical hazards and required PPE. Which section of the Safety Data Sheet (SDS) provides this information?

  1. Section 2 - Hazard(s) Identification
  2. Section 4 - First-Aid Measures
  3. Section 6 - Accidental Release Measures
  4. Section 8 - Exposure Controls and Personal Protection
Show answer & explanation

Correct answer: D - Section 8 - Exposure Controls and Personal Protection

Domain 9: Documentation, Communication, and Safety (22-27%)

Question 7

During an inspection, a CESSWI identifies that a new stormwater outfall has been constructed on the west side of the site that is not shown on the current SWPPP. The inspector documents the finding. Who is responsible for amending the SWPPP to reflect this change?

  1. The CESSWI, as the qualified inspector who identified the deficiency
  2. Either the CESSWI or the site superintendent, whichever is available on-site
  3. The operator or the SWPPP's qualified preparer
  4. The local permitting authority, upon receiving the inspection report
Show answer & explanation

Correct answer: C - The operator or the SWPPP's qualified preparer

Domain 10: Plan and Site Management (9-11%)

Question 8

During a routine site inspection, a CESSWI observes that accumulated sediment on the upslope side of a silt fence has reached approximately 10 inches in height. The silt fence fabric extends 24 inches above the ground surface. Which action is MOST appropriate?

  1. Note the observation but take no immediate action, as the fence is not yet overtopped
  2. Require sediment removal or installation of a second fence line upslope
  3. Require removal of the existing fence and replacement with a sediment basin
  4. Notify the permitting authority of a permit violation before contacting the contractor
Show answer & explanation

Correct answer: B - Require sediment removal or installation of a second fence line upslope

Question 9

A CESSWI is inspecting a series of rock check dams installed in a vegetated swale with a 4% grade. The most recently installed upstream check dam has its toe (base) positioned 2 feet higher in elevation than the crest (top) of the next check dam downstream. Which condition does this describe?

  1. Correct installation - the upstream toe should always be higher than the downstream crest
  2. A spacing deficiency - the dams are too far apart, leaving unprotected channel between them
  3. A spacing deficiency - the dams are too close together, creating a risk of upstream flooding
  4. Correct installation only if the check dams are constructed of riprap rather than other materials
Show answer & explanation

Correct answer: B - A spacing deficiency - the dams are too far apart, leaving unprotected channel between them

Question 10

A contractor installs a silt fence across the low point of a natural drainage swale that conveys concentrated runoff from a 3-acre upslope area during storm events. When the inspector arrives, the fence appears intact and unovertopped. What should the inspector document?

  1. The silt fence is functioning as intended; no action is required at this time
  2. The silt fence drainage area exceeds per-100-foot limits and a second parallel fence line is needed
  3. The silt fence should be relocated - fabric barriers are not designed for concentrated flow and failure is likely
  4. The installation is compliant because the fence is intact and the drainage area is under 5 acres
Show answer & explanation

Correct answer: C - The silt fence should be relocated - fabric barriers are not designed for concentrated flow and failure is likely

The rest of the CESSWI blueprint

The CESSWI exam also covers these domains. Drill them in the full free practice test:

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