3.1 Scoping Site Analysis & Synthesizing Opportunities and Constraints
Key Takeaways
- Analysis scope is driven by the decisions the analysis must support, the regulatory triggers present on the site, and the consequence of being wrong, not by a standard checklist applied uniformly.
- A screening-level analysis is appropriate where the answer is likely to be clear; an investigation-level analysis is required where a regulatory threshold, a life-safety consequence, or a large cost swing depends on the result.
- Absolute constraints eliminate land from development entirely, while conditional constraints only increase cost or require mitigation; conflating the two produces either an unbuildable plan or an illegal one.
- Opportunities and constraints mapping is a synthesis product, not an inventory product, and every polygon on it must trace to a specific analysis layer.
- Analysis that does not change a design decision is wasted scope, so each proposed analysis should be justified by naming the decision it informs.
1. The Blueprint Task Nobody Plans For
Determine Appropriate Types of Analyses is an explicit task inside the Physical Analysis content area, which carries 39% of the Inventory, Analysis and Project Management section — the single heaviest content area in that exam section. It is tested because scoping errors are expensive in both directions: an under-scoped analysis produces a design that fails at permitting, and an over-scoped analysis burns fee on studies that never change a decision.
The governing question is always the same: what decision does this analysis inform, and what happens if the answer is wrong?
2. Three Drivers of Analysis Scope
Driver 1: The decision to be supported
Each analysis exists to answer a design question. If no design question depends on it, it should not be in the scope.
| Design question | Analysis required |
|---|---|
| Can a building or structure be placed here? | Geotechnical investigation, slope stability, floodplain |
| Where does water go, and how much? | Hydrologic analysis, watershed delineation, existing drainage |
| Can these trees be saved? | Vegetation inventory and tree condition assessment |
| Is this land developable at all? | Wetland delineation, floodway, protected species, contamination |
| Will people be able to get here? | Circulation and access analysis, transit and network connectivity |
| What will it look like from off site? | Visual resource and viewshed analysis |
| Can the utilities serve it? | Utility capacity and availability analysis |
Driver 2: Regulatory triggers present on the site
Certain site conditions convert an optional analysis into a mandatory one:
- Any mapped wetland, stream, or open water → wetland delineation and probable CWA Section 404 review
- Any FEMA Special Flood Hazard Area → floodplain and floodway analysis
- Any federal funding, permit, or land → NEPA review and Section 106 consultation
- Listed or candidate species habitat → ESA consultation
- One acre or more of land disturbance → NPDES Construction General Permit and SWPPP
- Prior industrial or commercial use → Phase I Environmental Site Assessment, and a Phase II if recognized environmental conditions are identified
Driver 3: Consequence of error
Analysis depth scales with risk. The profession distinguishes two levels:
- Screening level. Published, remotely sensed, or desktop data used to determine whether a condition is likely present. Examples: NRCS Web Soil Survey, National Wetlands Inventory, FEMA FIRM panel, published bearing capacity tables. Fast, cheap, and legally non-binding.
- Investigation level. Site-specific, field-verified, professionally certified data. Examples: geotechnical boring log, jurisdictional wetland delineation, ALTA survey, Phase II soil sampling. Slow, expensive, and legally relied upon.
Exam rule: a screening product may be used to plan, but never to permit or to certify. An NWI polygon supports a preliminary layout; only a field delineation with a USACE jurisdictional determination supports a permit application.
3. Sequencing the Analyses
Analyses are not independent. Several must precede others because their outputs are inputs:
- Boundary and topographic survey — everything else registers to it
- Regulatory screening (flood, wetland, species, contamination) — defines what land is even in play
- Physical analyses (soils, slope, hydrology, vegetation, microclimate) — characterize the land that remains
- Systems analyses (utilities, circulation, visual) — characterize connections to context
- Synthesis — opportunities and constraints, then suitability
Running a costly geotechnical program before the wetland delineation is a classic sequencing error: borings placed inside a delineated wetland are wasted, and the drilling access itself may be an unpermitted disturbance.
4. Synthesizing Opportunities and Constraints
The synthesis product is not a stack of inventory maps. It is a single interpretive framework in which every polygon traces back to a specific analysis layer.
Constraint classification is the critical distinction:
| Class | Definition | Examples | Effect on plan |
|---|---|---|---|
| Absolute constraint | Development is prohibited or physically impossible | Regulatory floodway, jurisdictional wetland without a permit, recorded conservation easement, protected species habitat, slopes above the regulated threshold | Land is removed from the development envelope |
| Conditional constraint | Development is possible with added cost, mitigation, or engineering | Expansive clay subgrade, 15–25% slope, high water table, poor soil bearing, utility easement | Land remains in the envelope with a cost or design condition attached |
| Opportunity | A condition that increases value if the design responds to it | Mature canopy, southern exposure, long view corridor, existing stone wall, transit stop at the frontage, existing stormwater outfall | Design should be organized to capture it |
Treating a conditional constraint as absolute needlessly shrinks the buildable area and can make a viable project look infeasible. Treating an absolute constraint as conditional produces a plan that cannot be permitted.
Opportunities are analytically harder than constraints and are routinely under-developed. A constraint announces itself; an opportunity has to be recognized. The discipline is to walk each inventory layer a second time asking not "what does this prevent" but "what does this make possible here that would not be possible elsewhere."
5. Exam Traps & Pitfalls
- Applying a uniform analysis checklist. Scope must be justified by the decisions and triggers actually present.
- Using screening data to permit. NWI, Web Soil Survey, and FIRM panels plan; field delineations, borings, and surveys permit.
- Conflating absolute and conditional constraints. Steep slope is usually conditional; regulatory floodway is absolute.
- Producing an inventory stack and calling it a synthesis. Every synthesis polygon must be traceable to an analysis.
- Sequencing expensive field work ahead of regulatory screening. Delineate before you drill.
A landscape architect is scoping site analysis for a 40-acre mixed-use project. The site contains a mapped National Wetlands Inventory (NWI) polygon along a drainageway. The client asks whether the NWI mapping is sufficient to establish the development envelope for the entitlement application. What is the correct response?
In classifying site analysis findings, which condition is correctly identified as an ABSOLUTE constraint rather than a conditional constraint?
A landscape architect is preparing an analysis scope for a 22-acre former rail yard being converted to a public park. Which sequencing decision reflects correct professional practice?
When determining which site analyses to include in a proposed scope of services, what is the governing professional test for including any individual analysis?