3.5 Site Research, Site Surveys, and Multi-Site Evaluation

3.5 Site Research, Site Surveys, and Multi-Site Evaluation

The DCDC blueprint asks the consultant to conduct site research or a survey to confirm topography, adjacent areas, and the comparison of multiple sites, and then to evaluate how well potential sites meet the criteria. The earlier sections of this chapter explain what makes a site good or bad (hazards, proximity, utilities, zoning). This section explains how the consultant gathers that evidence and turns it into a defensible comparison.

ANSI/BICSI 002-2024 sets the baseline: the suitability of a site shall be determined by a site survey and evaluation and by a risk analysis. An existing survey may be reused only if it is less than six months old, because land use, utility capacity, and neighboring development change quickly.

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Stage 1: Desktop Research and Screening

Desktop research eliminates weak sites before anyone travels. Typical sources include:

• GIS and internet mapping: aerial and street imagery, parcel boundaries, ownership, land use, and elevation contours. Survey tools such as handheld GPS and mapping software let the team record exact coordinates for every observation later.
• Natural hazard data: flood maps (in the United States, FEMA's National Flood Hazard Layer), the ASCE Hazard Tool for site-specific wind, seismic, snow, and ice loads under ASCE 7, historical weather, wildfire history, and lightning flash density maps.
• Proximity hazards: distances to airports and flight paths, railroads, highways, pipelines, chemical plants, and other hazards, screened against the BICSI 002 Table 5-1 distances (for example, 8 km from airports, 1.6 km from railroads, 80 km from nuclear plants).
• Utilities and telecommunications: transmission and distribution maps, substation locations, utility service territories, water and sewer mains, gas pipelines, and fiber route maps from access providers.
• Regulatory data: zoning maps, comprehensive plans, environmental databases, and airspace restrictions. In the United States, a structure or construction crane near an airport or taller than 200 ft above ground may require FAA notice under 14 CFR Part 77.

Stage 2: The Field Survey

A field survey confirms what the maps suggest and finds what they miss. The survey team typically:

1. Walks the site and records GPS-tagged photographs of boundaries, slopes, drainage, existing structures, and overhead lines.
2. Confirms topography: BICSI 002 recommends avoiding slopes steeper than 15% and sites above 3,050 m (10,000 ft) elevation; standing water and erosion show drainage problems.
3. Inventories adjacent areas: what is on every side of the parcel and what could be built there under current zoning. A quiet field today can be a truck terminal or quarry later.
4. Checks access: BICSI 002 recommends at least two access roads, each with at least 4.3 m (14 ft) of vertical clearance, and routes that stay above flood levels.
5. Locates utility points of connection: the nearest substation and feeders, water and sewer connections, and the poles or manholes where access providers would enter.
6. Notes nuisance sources: radio transmitters, rail lines, and heavy industry. BICSI 002 recommends measuring vibration and electromagnetic interference near railroads over several days, not in a single visit.
7. Meets local stakeholders: planning staff, utility account managers, and economic development officials, who can confirm capacity, schedules, and incentives.

Stage 3: Due Diligence Studies

For the short-listed sites, specialists prepare formal studies, usually while the client holds the land under an option or a contract with a due diligence period:

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Multi-Site Evaluation: Knockouts, Weights, and Scores

Comparing sites is where many consultants lose credibility. A sound method has four parts.

1. Define criteria from the client's requirements. Use the needs assessment (capacity, availability class, growth, schedule, budget) and BICSI's site factors. Each criterion needs a written scoring rubric, such as "5 = two independent substations with capacity available within 18 months."

2. Apply knockout criteria first. Some conditions are pass/fail: inadequate power by the required date, an unmitigable flood risk, or zoning that cannot be changed. A site that fails a knockout is removed, no matter how well it scores elsewhere.

3. Weight and score the remaining criteria. Weights reflect client priorities and must total 100%. The weighted score is:

$\text{Site Score} = \sum_{i=1}^{n} (w_i \times s_i)$

where $w_i$ is the weight of criterion $i$ and $s_i$ is the site's score on that criterion.

4. Test sensitivity. Shift the weights within a reasonable range and confirm whether the ranking changes.

Worked Example

Three sites survive the knockout screen. Scores use a 1-to-5 scale:

Site A scores $5(0.30) + 3(0.20) + 4(0.20) + 3(0.15) + 4(0.15) = 3.95$.

Now test sensitivity. If the client decides telecommunications diversity matters more and shifts the weights to 20% power and 30% telecommunications, Site A falls to 3.75 and Site B rises to 4.05. The ranking flips. The report must show this, and the consultant should confirm the weights with the client before recommending a site. A recommendation that depends on one disputed weight is a decision for the client, not a fact for the consultant to assert.

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Common Exam Traps & DCDC Pitfalls

• Relying on an old survey: BICSI 002 accepts an existing site survey only if it is less than six months old.
• Averaging away a fatal flaw: A site in a flood hazard area should fail a knockout screen, not lose a few weighted points.
• Scoring before agreeing weights: Weights set after scores are known invite bias. Agree the criteria, rubrics, and weights with the client first.
• Skipping the field visit: Maps rarely show a new neighbor under construction, a shared fiber bridge crossing, or poor drainage.
• Confusing survey types: A topographic survey shows grades; an ALTA/NSPS survey shows boundaries and easements; a geotechnical investigation shows soil and groundwater conditions.