Most survey scopes for a utility corridor run about a paragraph.
Something like: provide a topographic survey of the corridor from Station 0+00 to Station 212+00, 50 feet either side of centerline. Deliverable in AutoCAD.
The crew will do exactly that. They will do it well. And the file that comes back may still be missing four things the design team needs, because nobody asked for them.
A topographic survey records existing conditions: ground elevations, surface features, visible utilities, structures, and the survey control tying it all to a known reference. What it records beyond that is a scoping decision, not a technical one. Below are four lines worth adding, what each one prevents, and roughly what they cost you to include.
Line one: state the coordinate system completely
Coordinates shall be referenced to NAD83 Arizona State Plane, [East / Central / West] zone, with vertical referenced to NAVD88. Coordinates shall be reported as [ground / grid]. If ground, the combined scale factor and the point of application shall be stated on the survey.
This is the line that prevents the most expensive failure on a long corridor, and it is the one most often left out.
Arizona State Plane produces grid coordinates. Field staking and most utility standards work in ground coordinates. The two differ by a combined scale factor. On a five acre site the difference is small enough that nobody notices. Across four miles of corridor, stationing and measured distance stop agreeing, and the disagreement surfaces when a crew stakes something and it lands in the wrong place.
Arizona has three State Plane zones. Valley corridors can run close enough to a boundary that picking the wrong one is an easy mistake.
Cost to include: one sentence. Cost to leave out: a resurvey, or worse, a design that gets built off bad geometry.
Line two: name the overhead features
Survey shall include pole locations, pole height and class where visible, all attachment heights identified by owner, guy wires, down guy and anchor locations, and conductor low point elevations at all crossings.
Poles get located on almost every corridor survey. What is on them usually does not.
That gap only becomes visible later, when someone tries to run a clearance check or a pole loading analysis and finds elevations for the pole base and nothing above it. Attachment heights cannot be estimated from a photo. They require a crew with the right equipment standing at the pole, which means a second mobilization to collect something the first trip could have captured in the same visit.
On corridors with existing communication attachments, ask for owner identification too. Knowing a pole carries three attachments is useful. Knowing which carrier owns which one is what lets fiber and telecom design proceed without a round of make-ready guesswork.
Line three: require invert elevations, including dry channels
Survey shall include all drainage features with rim and invert elevations, including culverts, headwalls, inlets, and ephemeral washes, whether or not water is present at the time of survey.
The last clause is the working part of that sentence.
A crew walking an Arizona corridor in May crosses a dry sand channel. It does not read as drainage. It reads as ground. So it gets picked up as topography, with no invert, no flow line, and no note.
It is still drainage. It still controls the profile, it still appears in floodplain review, and the elevation nobody recorded is the one the design needs.
Say it explicitly in the scope. The crew is not going to infer it.
Line four: define the deliverable, not just the format
Deliverable shall include a defined surface (TIN or breakline-defined) in AutoCAD [version] and MicroStation [version] as applicable, with consistent feature coding, plus a survey report stating date of survey, datum, control used, and accuracy achieved. PDF is supplementary only.
Three separate things go wrong here and they all trace to the same line.
A survey delivered as points alone means someone on the design side builds the surface, which is unpaid work and a source of inconsistency. A survey delivered in one platform when the design runs in another loses information in translation, which is why dual-platform AutoCAD and MicroStation capability matters more on utility work than it does elsewhere. And a survey delivered as a PDF cannot be designed from at all. A PDF is a picture of a survey.
The metadata clause is the quiet one. Without a stated datum and control, a file that turns up two years into a program is unverifiable, and nobody can tell whether new survey ties to it.
What these four lines will not do
They will not resolve boundary. Right of way lines, easements, and parcel boundaries are a separate scope requiring a licensed surveyor and usually a title report. Assuming a right of way line from an aerial image is common and it is how projects end up designing into land they do not control.
They will not find buried utilities. A topographic survey records what is visible at the surface. Manholes, valve boxes, risers, pedestals. Anything below grade needs different methods and a different scope, and treating surface evidence as a complete subsurface picture is how strikes happen.
They will not settle whether you need aerial coverage. Aerial LiDAR is efficient across distance and captures overhead features that ground crews reach slowly, which makes it useful for route selection and preliminary profile. Drone photogrammetry builds good surfaces on open terrain and struggles with conductors, guy wires, and anything under canopy. Neither replaces ground control. Most corridors end up using aerial for coverage and ground survey for control and for the detail that carries design risk.
The survey you inherit
Some corridor projects do not scope survey at all. They receive one, from a previous phase or a previous consultant, and design from it.
Two questions in that case. When was it flown or walked, and what has changed since. New driveways, new poles, new attachments, and road work all accumulate. A corridor surveyed three years ago and paused is not the corridor that exists now.
Ask for the survey report before you ask for the file. If it does not state a datum and control, treat everything downstream as unverified.
How ARUSI works with corridor survey
ARUSI is a Service-Disabled Veteran-Owned Small Business (SDVOSB) engineering firm in Phoenix that has designed utility infrastructure across Arizona since 1987.
Our involvement with survey happens at two points. Before it is issued, we specify what the corridor design will require, which is where the four lines above come from. After it comes back, we review it against that specification before design starts rather than after, and build the design surface and drawings in whatever platform the client’s standards call for through our utility engineering coordination work.
The review step is the part worth paying attention to. A gap caught before design begins costs a field visit. The same gap caught during construction costs a change order, and corridors rarely have just one.
Send us your survey scope before you issue it. If something is missing, better to hear it now than after the crew has demobilized.
