CPESC PART 2 PRACTICE EXAM: SCENARIOS AND SOLUTIONS
COMPLETE 200 QUESTIONS AND DETAILED SOLUTIONS|
LATEST UPDATE THIS YEAR JUST RELEASED
EXAM INTRODUCTION
This practice examination simulates the Certified Professional in Erosion and
Sediment Control (CPESC) Part 2 certification exam. It covers:
- Soil Science and Erosion Processes – RUSLE/MUSLE, soil properties, mechanics
- Sediment Transport and Hydrology – Runoff calculations, peak flow, yield
- Best Management Practices (BMPs) – Selection, design, implementation
- Regulatory Framework – NPDES, CWA, SWPPP, general permits
- Site Assessment and Planning – Evaluation, design, stabilization
- Sediment Basin and Trap Design – Sizing, storage, outlet structures
- Inspection and Maintenance – Monitoring, compliance, recordkeeping
- Specialized Applications – Linear construction, mining, agriculture, forestry
SECTION 1: SOIL SCIENCE AND EROSION PROCESSES (Questions 1–40)
Question 1
You are evaluating a construction site and receive a soils report showing: 48%
Sand, 30% Clay, and 22% Silt. Using the USDA Soil Texture Triangle, what is
the soil type?
A. Clay Loam
B. Loam
C. Sandy Loam
D. Sandy Clay Loam
Answer: B. Loam
Rationale: Plotting 48% sand, 30% clay, and 22% silt on the USDA triangle
places the sample in the loam region. Loam has balanced properties—moderate
infiltration, moderate erodibility, and good workability.
Question 2
1
,Which soil textural class is generally the MOST susceptible to water erosion?
A. Clay
B. Silt loam
C. Gravelly sand
D. Heavy clay
Answer: B. Silt loam
Rationale: Silt and very fine sand particles have low cohesion and are easily
detached by raindrop impact and transported by overland flow. Clay aggregates
are cohesive, and gravel/sand are too heavy to readily suspend.
Question 3
Which soil property most directly influences the erodibility factor (K) in RUSLE?
A. Soil color
B. Soil texture, organic matter, and permeability
C. Soil depth to bedrock
D. Soil temperature
Answer: B. Soil texture, organic matter, and permeability
Rationale: The K factor is a function of primary particle size, organic matter
content, structure, and permeability. Finer silts have higher K values; high
organic matter and good structure lower K.
Question 4
A soil has a high percentage of smectite clays. During a heavy rain event, what
erosion-related phenomenon is most likely to occur?
A. Severe rill erosion due to high infiltration
B. Surface sealing and reduced infiltration, increasing runoff
C. Complete erosion resistance due to clay hardness
D. Accelerated wind erosion
2
,Answer: B. Surface sealing and reduced infiltration, increasing runoff
Rationale: Smectite clays expand when wet, dispersing and sealing the soil
surface. This creates a crust that drastically reduces infiltration, promotes
runoff, and increases erosion potential despite the clay's cohesion.
Question 5
In the RUSLE equation (A = R × K × L × S × C × P), which factor accounts for
slope steepness and length?
A. R factor
B. K factor
C. LS factor
D. C factor
Answer: C. LS factor
Rationale: The LS factor combines slope length (L) and steepness (S). Longer
and steeper slopes increase runoff velocity and erosive energy, directly
increasing soil loss.
Question 6
A construction site has a 200-foot slope at 15% grade. You plan a slope
interruption. What is the primary hydraulic benefit?
A. Increases the R factor
B. Decreases the LS factor by reducing effective slope length
C. Increases soil permeability
D. Reduces the K factor
Answer: B. Decreases the LS factor by reducing effective slope length
Rationale: Slope interruptions (diversions, terraces) break a long slope into
shorter segments. Since the LS factor is length-dependent, reducing effective
length significantly lowers predicted soil loss.
3
, Question 7
What is the primary erosive force during interrill (sheet) erosion?
A. Channelized flow shear stress
B. Raindrop impact and thin sheet flow
C. Groundwater seepage
D. Wind abrasion
Answer: B. Raindrop impact and thin sheet flow
Rationale: Interrill erosion is driven by raindrop detachment and shallow,
diffuse overland flow that transports particles. It occurs before flow
concentrates into rills.
Question 8
A soil has an infiltration rate of 0.5 in/hr. A storm delivers 1.2 in/hr for
2 hours. What is the approximate runoff depth (no depression storage)?
A. 0.7 inches
B. 1.4 inches
C. 1.0 inches
D. 2.4 inches
Answer: B. 1.4 inches
Rationale: Total rainfall = 1.2 × 2 = 2.4 in. Infiltration = 0.5 × 2 = 1.0 in.
Runoff = 2.4 - 1.0 = 1.4 inches.
Question 9
Which best defines "soil erodibility"?
A. The resistance of soil to detachment and transport
B. The rate of rainfall intensity
C. The vegetation cover percentage
D. The slope angle only
4
COMPLETE 200 QUESTIONS AND DETAILED SOLUTIONS|
LATEST UPDATE THIS YEAR JUST RELEASED
EXAM INTRODUCTION
This practice examination simulates the Certified Professional in Erosion and
Sediment Control (CPESC) Part 2 certification exam. It covers:
- Soil Science and Erosion Processes – RUSLE/MUSLE, soil properties, mechanics
- Sediment Transport and Hydrology – Runoff calculations, peak flow, yield
- Best Management Practices (BMPs) – Selection, design, implementation
- Regulatory Framework – NPDES, CWA, SWPPP, general permits
- Site Assessment and Planning – Evaluation, design, stabilization
- Sediment Basin and Trap Design – Sizing, storage, outlet structures
- Inspection and Maintenance – Monitoring, compliance, recordkeeping
- Specialized Applications – Linear construction, mining, agriculture, forestry
SECTION 1: SOIL SCIENCE AND EROSION PROCESSES (Questions 1–40)
Question 1
You are evaluating a construction site and receive a soils report showing: 48%
Sand, 30% Clay, and 22% Silt. Using the USDA Soil Texture Triangle, what is
the soil type?
A. Clay Loam
B. Loam
C. Sandy Loam
D. Sandy Clay Loam
Answer: B. Loam
Rationale: Plotting 48% sand, 30% clay, and 22% silt on the USDA triangle
places the sample in the loam region. Loam has balanced properties—moderate
infiltration, moderate erodibility, and good workability.
Question 2
1
,Which soil textural class is generally the MOST susceptible to water erosion?
A. Clay
B. Silt loam
C. Gravelly sand
D. Heavy clay
Answer: B. Silt loam
Rationale: Silt and very fine sand particles have low cohesion and are easily
detached by raindrop impact and transported by overland flow. Clay aggregates
are cohesive, and gravel/sand are too heavy to readily suspend.
Question 3
Which soil property most directly influences the erodibility factor (K) in RUSLE?
A. Soil color
B. Soil texture, organic matter, and permeability
C. Soil depth to bedrock
D. Soil temperature
Answer: B. Soil texture, organic matter, and permeability
Rationale: The K factor is a function of primary particle size, organic matter
content, structure, and permeability. Finer silts have higher K values; high
organic matter and good structure lower K.
Question 4
A soil has a high percentage of smectite clays. During a heavy rain event, what
erosion-related phenomenon is most likely to occur?
A. Severe rill erosion due to high infiltration
B. Surface sealing and reduced infiltration, increasing runoff
C. Complete erosion resistance due to clay hardness
D. Accelerated wind erosion
2
,Answer: B. Surface sealing and reduced infiltration, increasing runoff
Rationale: Smectite clays expand when wet, dispersing and sealing the soil
surface. This creates a crust that drastically reduces infiltration, promotes
runoff, and increases erosion potential despite the clay's cohesion.
Question 5
In the RUSLE equation (A = R × K × L × S × C × P), which factor accounts for
slope steepness and length?
A. R factor
B. K factor
C. LS factor
D. C factor
Answer: C. LS factor
Rationale: The LS factor combines slope length (L) and steepness (S). Longer
and steeper slopes increase runoff velocity and erosive energy, directly
increasing soil loss.
Question 6
A construction site has a 200-foot slope at 15% grade. You plan a slope
interruption. What is the primary hydraulic benefit?
A. Increases the R factor
B. Decreases the LS factor by reducing effective slope length
C. Increases soil permeability
D. Reduces the K factor
Answer: B. Decreases the LS factor by reducing effective slope length
Rationale: Slope interruptions (diversions, terraces) break a long slope into
shorter segments. Since the LS factor is length-dependent, reducing effective
length significantly lowers predicted soil loss.
3
, Question 7
What is the primary erosive force during interrill (sheet) erosion?
A. Channelized flow shear stress
B. Raindrop impact and thin sheet flow
C. Groundwater seepage
D. Wind abrasion
Answer: B. Raindrop impact and thin sheet flow
Rationale: Interrill erosion is driven by raindrop detachment and shallow,
diffuse overland flow that transports particles. It occurs before flow
concentrates into rills.
Question 8
A soil has an infiltration rate of 0.5 in/hr. A storm delivers 1.2 in/hr for
2 hours. What is the approximate runoff depth (no depression storage)?
A. 0.7 inches
B. 1.4 inches
C. 1.0 inches
D. 2.4 inches
Answer: B. 1.4 inches
Rationale: Total rainfall = 1.2 × 2 = 2.4 in. Infiltration = 0.5 × 2 = 1.0 in.
Runoff = 2.4 - 1.0 = 1.4 inches.
Question 9
Which best defines "soil erodibility"?
A. The resistance of soil to detachment and transport
B. The rate of rainfall intensity
C. The vegetation cover percentage
D. The slope angle only
4
