LRA 218 Final Exam – Landscape Architecture
Construction & Materials Actual Exam | Graded A+ |
Correct & Verified with Detailed Rationales Pass
Guaranteed
Section 1: Site Grading & Drainage (Stormwater Management, BMPs)
Q1: What is the correct formula for calculating percent slope in landscape grading?
A. Run divided by rise, multiplied by 100
B. Rise divided by run, multiplied by 100
C. Rise plus run, divided by 100
D. Rise multiplied by run, divided by 100
Correct Answer: B
Rationale: The best answer is B. Rise divided by run multiplied by 100 is the standard
formula every LA student needs to have memorized—if you have 5 feet of rise over 100
feet of run, you've got a 5% slope, plain and simple.
Q2: A designer is reviewing a pedestrian walkway that rises 4 feet over a 60-foot length.
Which statement is correct regarding ADA compliance?
A. The 6.7% slope meets accessible route requirements but requires handrails
B. The 6.7% slope exceeds the 1:20 maximum for accessible routes and must be
designed as a ramp
C. The 6.7% slope is within the 1:12 ramp maximum and needs no landings
D. The 6.7% slope requires a cross slope of at least 2% for drainage
Correct Answer: B
Rationale: The best answer is B. Four feet of rise over 60 feet gives you 6.7% slope,
which blows past the 1:20 maximum (5%) for accessible routes—so you'd need to treat
it as a ramp, which means handrails, landings, and all the other requirements that come
with it.
,Q3: A plaza slopes from a high point at elevation 102.50 to a low point at elevation
100.10 over a horizontal distance of 120 feet. The designer specifies a 2% cross slope
for drainage. A wheelchair ramp is proposed adjacent to the plaza with a 24-inch total
rise. Which statement is correct?
A. The plaza slope is 2.0% and the ramp exceeds ADA maximum slope
B. The plaza slope is 2.0% and the ramp meets ADA requirements with a 1:12 slope
C. The plaza slope is 2.5% and the ramp requires landings every 30 feet
D. The plaza slope is 2.0% and the ramp at 1:10 slope is acceptable for landscape
applications
Correct Answer: B
Rationale: The best answer is B. The plaza drops 2.4 feet over 120 feet, giving you
exactly 2% slope—perfect for drainage and well within ADA surface slope limits. For the
ramp, 24 inches over 24 feet gives you 1:12, which is the maximum allowed slope and
meets all ADA requirements when proper landings are included.
Q4: What is the minimum recommended cross slope for paved surfaces to ensure
adequate drainage?
A. 0.5%
B. 1.0%
C. 1.5%
D. 2.0%
Correct Answer: D
Rationale: The best answer is D. You need at least 2% cross slope on hardscape to
move water off the surface—anything less and you'll end up with puddling, which leads
to staining, ice hazards, and premature material failure.
Q5: A rain garden is designed to capture a 1-inch rainfall event from a 3,000 square foot
roof. The garden has 12 inches of engineered soil media with a void ratio of 0.30 and a
maximum ponding depth of 6 inches. What approximate surface area is required?
A. 180 sq ft
B. 240 sq ft
C. 300 sq ft
D. 400 sq ft
Correct Answer: C
Rationale: The best answer is C. You're looking at about 250 cubic feet of runoff from
that roof, and with 12 inches of media at 0.30 void ratio plus 6 inches of surface
, ponding, each square foot gives you roughly 0.8 cubic feet of storage—so you need right
around 300 square feet of surface area, which is a pretty standard 10% rule-of-thumb
ratio for rain gardens.
Q6: A site plan shows a 50 ft × 40 ft area where existing ground is at 96.0 feet.
Proposed grading raises this area to 98.5 feet. What is the approximate fill volume in
cubic yards?
A. 120 cu yd
B. 150 cu yd
C. 185 cu yd
D. 220 cu yd
Correct Answer: C
Rationale: The best answer is C. Fifty by forty gives you 2,000 square feet, and with a
2.5-foot lift, that's 5,000 cubic feet—divide by 27 and you get about 185 cubic yards of
fill. Don't forget to account for compaction; your borrow pit volume will be higher
depending on your shrink-swell factor.
Q7: A 5-acre residential subdivision generates significant stormwater runoff. The local
ordinance requires peak flow control. Which BMP combination best addresses both
water quality and quantity while minimizing maintenance?
A. Dry detention basin with concrete outlet structure only
B. Wet retention pond with permanent pool and extended detention
C. Bioswale leading to an underground detention chamber
D. Permeable pavement throughout with no additional storage
Correct Answer: B
Rationale: The best answer is B. A wet retention pond gives you that permanent pool for
water quality treatment through settling and biological processes, plus the extended
detention storage above the permanent pool to shave off peak flows—it's the gold
standard for subdivisions when you have the space and can handle the slightly higher
maintenance of a wet pond.
Q8: A landscape architect is designing a vegetated swale to convey runoff from a 2-acre
parking lot. The swale is 200 feet long with a 2% longitudinal slope. Which design
element is most critical to prevent erosion and enhance infiltration?
A. Check dams spaced at 25- to 30-foot intervals
Construction & Materials Actual Exam | Graded A+ |
Correct & Verified with Detailed Rationales Pass
Guaranteed
Section 1: Site Grading & Drainage (Stormwater Management, BMPs)
Q1: What is the correct formula for calculating percent slope in landscape grading?
A. Run divided by rise, multiplied by 100
B. Rise divided by run, multiplied by 100
C. Rise plus run, divided by 100
D. Rise multiplied by run, divided by 100
Correct Answer: B
Rationale: The best answer is B. Rise divided by run multiplied by 100 is the standard
formula every LA student needs to have memorized—if you have 5 feet of rise over 100
feet of run, you've got a 5% slope, plain and simple.
Q2: A designer is reviewing a pedestrian walkway that rises 4 feet over a 60-foot length.
Which statement is correct regarding ADA compliance?
A. The 6.7% slope meets accessible route requirements but requires handrails
B. The 6.7% slope exceeds the 1:20 maximum for accessible routes and must be
designed as a ramp
C. The 6.7% slope is within the 1:12 ramp maximum and needs no landings
D. The 6.7% slope requires a cross slope of at least 2% for drainage
Correct Answer: B
Rationale: The best answer is B. Four feet of rise over 60 feet gives you 6.7% slope,
which blows past the 1:20 maximum (5%) for accessible routes—so you'd need to treat
it as a ramp, which means handrails, landings, and all the other requirements that come
with it.
,Q3: A plaza slopes from a high point at elevation 102.50 to a low point at elevation
100.10 over a horizontal distance of 120 feet. The designer specifies a 2% cross slope
for drainage. A wheelchair ramp is proposed adjacent to the plaza with a 24-inch total
rise. Which statement is correct?
A. The plaza slope is 2.0% and the ramp exceeds ADA maximum slope
B. The plaza slope is 2.0% and the ramp meets ADA requirements with a 1:12 slope
C. The plaza slope is 2.5% and the ramp requires landings every 30 feet
D. The plaza slope is 2.0% and the ramp at 1:10 slope is acceptable for landscape
applications
Correct Answer: B
Rationale: The best answer is B. The plaza drops 2.4 feet over 120 feet, giving you
exactly 2% slope—perfect for drainage and well within ADA surface slope limits. For the
ramp, 24 inches over 24 feet gives you 1:12, which is the maximum allowed slope and
meets all ADA requirements when proper landings are included.
Q4: What is the minimum recommended cross slope for paved surfaces to ensure
adequate drainage?
A. 0.5%
B. 1.0%
C. 1.5%
D. 2.0%
Correct Answer: D
Rationale: The best answer is D. You need at least 2% cross slope on hardscape to
move water off the surface—anything less and you'll end up with puddling, which leads
to staining, ice hazards, and premature material failure.
Q5: A rain garden is designed to capture a 1-inch rainfall event from a 3,000 square foot
roof. The garden has 12 inches of engineered soil media with a void ratio of 0.30 and a
maximum ponding depth of 6 inches. What approximate surface area is required?
A. 180 sq ft
B. 240 sq ft
C. 300 sq ft
D. 400 sq ft
Correct Answer: C
Rationale: The best answer is C. You're looking at about 250 cubic feet of runoff from
that roof, and with 12 inches of media at 0.30 void ratio plus 6 inches of surface
, ponding, each square foot gives you roughly 0.8 cubic feet of storage—so you need right
around 300 square feet of surface area, which is a pretty standard 10% rule-of-thumb
ratio for rain gardens.
Q6: A site plan shows a 50 ft × 40 ft area where existing ground is at 96.0 feet.
Proposed grading raises this area to 98.5 feet. What is the approximate fill volume in
cubic yards?
A. 120 cu yd
B. 150 cu yd
C. 185 cu yd
D. 220 cu yd
Correct Answer: C
Rationale: The best answer is C. Fifty by forty gives you 2,000 square feet, and with a
2.5-foot lift, that's 5,000 cubic feet—divide by 27 and you get about 185 cubic yards of
fill. Don't forget to account for compaction; your borrow pit volume will be higher
depending on your shrink-swell factor.
Q7: A 5-acre residential subdivision generates significant stormwater runoff. The local
ordinance requires peak flow control. Which BMP combination best addresses both
water quality and quantity while minimizing maintenance?
A. Dry detention basin with concrete outlet structure only
B. Wet retention pond with permanent pool and extended detention
C. Bioswale leading to an underground detention chamber
D. Permeable pavement throughout with no additional storage
Correct Answer: B
Rationale: The best answer is B. A wet retention pond gives you that permanent pool for
water quality treatment through settling and biological processes, plus the extended
detention storage above the permanent pool to shave off peak flows—it's the gold
standard for subdivisions when you have the space and can handle the slightly higher
maintenance of a wet pond.
Q8: A landscape architect is designing a vegetated swale to convey runoff from a 2-acre
parking lot. The swale is 200 feet long with a 2% longitudinal slope. Which design
element is most critical to prevent erosion and enhance infiltration?
A. Check dams spaced at 25- to 30-foot intervals
