Iowa Landscape Architect Examination
Advanced 100-Question Practice Exam
2026 | Questions & Answers with
Detailed Rationales | Complete Exam
Prep & Study Guide
1. A landscape architect is developing a site plan for a commercial
development where storm water must be managed primarily through
green infrastructure. Which approach most directly reduces peak runoff
while improving water quality?
A. Increase the amount of impervious pavement
B. Use larger conventional detention basins only
C. Combine bio-retention, permeable pavement, vegetated swales, and reduced
impervious coverage
D. Route all runoff directly to the municipal storm sewer
Answer: C. Combine bio-retention, permeable pavement, vegetated swales, and
reduced impervious coverage
,Rationale: A distributed green-infrastructure strategy reduces runoff volume
and peak flow while providing filtration, infiltration, and evapotranspiration.
2. During grading design, an existing building entrance is at elevation 812.40 ft
and the proposed accessible route must maintain a maximum running slope
of 5%. What is the maximum allowable elevation change over a 120-ft
horizontal run?
A. 3.0 ft
B. 4.8 ft
C. 6.0 ft
D. 12.0 ft
Answer: C. 6.0 ft
Rationale: A 5% slope equals 0.05 ft/ft. Therefore, 120 × 0.05 = 6.0 ft of
maximum elevation change.
3. A site has highly compacted clay soil with poor infiltration. Which design
strategy is generally most appropriate before establishing a large planting
area?
A. Increase irrigation frequency indefinitely
B. Add a thin layer of sand only
C. Improve soil structure through appropriate amendment, de-compaction, and
organic-matter incorporation
D. Eliminate all vegetation from the site
Answer: C. Improve soil structure through appropriate amendment, de-
compaction, and organic-matter incorporation
Rationale: Compaction limits pore space, root growth, aeration, and infiltration.
Proper soil rehabilitation addresses the physical limitation rather than merely
compensating with irrigation.
4. A landscape architect is selecting plant material for a low-maintenance
streetscape exposed to road salt. Which characteristic is most important?
,A. Shade tolerance only
B. High fertilizer requirements
C. Tolerance to deicing salts and urban soil conditions
D. Large evergreen foliage
Answer: C. Tolerance to deicing salts and urban soil conditions
Rationale: Salt exposure can cause both soil salinity problems and direct foliar
injury. Salt-tolerant species are therefore critical in roadway landscapes.
5. Which grading pattern is most effective for directing surface runoff away
from a building foundation?
A. A reverse slope toward the foundation
B. A level grade immediately adjacent to the wall
C. Positive drainage away from the building with controlled collection points
D. A depression centered against the foundation
Answer: C. Positive drainage away from the building with controlled collection
points
Rationale: Proper positive drainage reduces the risk of ponding, foundation
infiltration, erosion, and moisture-related building problems.
6. A landscape architect needs to determine whether an existing mature tree
can remain during construction. Which factor is most critical?
A. Only the visible trunk diameter
B. Only the tree's species name
C. The extent of the root protection area and expected construction impacts
D. The color of the tree's foliage
Answer: C. The extent of the root protection area and expected construction
impacts
Rationale: Significant roots often extend beyond the visible canopy and can be
severely damaged by grading, trenching, soil compaction, and changes in
drainage.
, 7. Which stormwater facility is specifically designed to temporarily store
runoff and release it at a controlled rate?
A. Riprap apron
B. Infiltration trench
C. Detention basin
D. Vegetated roof
Answer: C. Detention basin
Rationale: A detention facility temporarily stores stormwater and releases it
gradually, reducing downstream peak discharge.
8. A designer is calculating the hydraulic capacity of a vegetated swale. Which
variable has a direct effect on flow velocity and conveyance?
A. Plant color
B. Property ownership
C. Slope, roughness, and hydraulic geometry
D. Building occupancy classification
Answer: C. Slope, roughness, and hydraulic geometry
Rationale: Hydraulic calculations depend on parameters such as channel
geometry, slope, hydraulic radius, and roughness characteristics.
9. Which document typically communicates the exact location, species, size,
quantity, and installation requirements of proposed plant material?
A. Demolition plan
B. Utility plan
C. Planting plan
D. Boundary survey
Answer: C. Planting plan
Rationale: Planting plans identify proposed vegetation and coordinate plant
locations, quantities, sizes, and related installation information.
Advanced 100-Question Practice Exam
2026 | Questions & Answers with
Detailed Rationales | Complete Exam
Prep & Study Guide
1. A landscape architect is developing a site plan for a commercial
development where storm water must be managed primarily through
green infrastructure. Which approach most directly reduces peak runoff
while improving water quality?
A. Increase the amount of impervious pavement
B. Use larger conventional detention basins only
C. Combine bio-retention, permeable pavement, vegetated swales, and reduced
impervious coverage
D. Route all runoff directly to the municipal storm sewer
Answer: C. Combine bio-retention, permeable pavement, vegetated swales, and
reduced impervious coverage
,Rationale: A distributed green-infrastructure strategy reduces runoff volume
and peak flow while providing filtration, infiltration, and evapotranspiration.
2. During grading design, an existing building entrance is at elevation 812.40 ft
and the proposed accessible route must maintain a maximum running slope
of 5%. What is the maximum allowable elevation change over a 120-ft
horizontal run?
A. 3.0 ft
B. 4.8 ft
C. 6.0 ft
D. 12.0 ft
Answer: C. 6.0 ft
Rationale: A 5% slope equals 0.05 ft/ft. Therefore, 120 × 0.05 = 6.0 ft of
maximum elevation change.
3. A site has highly compacted clay soil with poor infiltration. Which design
strategy is generally most appropriate before establishing a large planting
area?
A. Increase irrigation frequency indefinitely
B. Add a thin layer of sand only
C. Improve soil structure through appropriate amendment, de-compaction, and
organic-matter incorporation
D. Eliminate all vegetation from the site
Answer: C. Improve soil structure through appropriate amendment, de-
compaction, and organic-matter incorporation
Rationale: Compaction limits pore space, root growth, aeration, and infiltration.
Proper soil rehabilitation addresses the physical limitation rather than merely
compensating with irrigation.
4. A landscape architect is selecting plant material for a low-maintenance
streetscape exposed to road salt. Which characteristic is most important?
,A. Shade tolerance only
B. High fertilizer requirements
C. Tolerance to deicing salts and urban soil conditions
D. Large evergreen foliage
Answer: C. Tolerance to deicing salts and urban soil conditions
Rationale: Salt exposure can cause both soil salinity problems and direct foliar
injury. Salt-tolerant species are therefore critical in roadway landscapes.
5. Which grading pattern is most effective for directing surface runoff away
from a building foundation?
A. A reverse slope toward the foundation
B. A level grade immediately adjacent to the wall
C. Positive drainage away from the building with controlled collection points
D. A depression centered against the foundation
Answer: C. Positive drainage away from the building with controlled collection
points
Rationale: Proper positive drainage reduces the risk of ponding, foundation
infiltration, erosion, and moisture-related building problems.
6. A landscape architect needs to determine whether an existing mature tree
can remain during construction. Which factor is most critical?
A. Only the visible trunk diameter
B. Only the tree's species name
C. The extent of the root protection area and expected construction impacts
D. The color of the tree's foliage
Answer: C. The extent of the root protection area and expected construction
impacts
Rationale: Significant roots often extend beyond the visible canopy and can be
severely damaged by grading, trenching, soil compaction, and changes in
drainage.
, 7. Which stormwater facility is specifically designed to temporarily store
runoff and release it at a controlled rate?
A. Riprap apron
B. Infiltration trench
C. Detention basin
D. Vegetated roof
Answer: C. Detention basin
Rationale: A detention facility temporarily stores stormwater and releases it
gradually, reducing downstream peak discharge.
8. A designer is calculating the hydraulic capacity of a vegetated swale. Which
variable has a direct effect on flow velocity and conveyance?
A. Plant color
B. Property ownership
C. Slope, roughness, and hydraulic geometry
D. Building occupancy classification
Answer: C. Slope, roughness, and hydraulic geometry
Rationale: Hydraulic calculations depend on parameters such as channel
geometry, slope, hydraulic radius, and roughness characteristics.
9. Which document typically communicates the exact location, species, size,
quantity, and installation requirements of proposed plant material?
A. Demolition plan
B. Utility plan
C. Planting plan
D. Boundary survey
Answer: C. Planting plan
Rationale: Planting plans identify proposed vegetation and coordinate plant
locations, quantities, sizes, and related installation information.
