How Much Do You Need to Know?
Why better land decisions don't always require more engineering.
Land acquisition and development teams face an interesting challenge during due diligence. They want to understand potential earthwork exposure as early as possible, but they also have to be disciplined about how much money they spend investigating a property they may never own. During an inspection or feasibility period, there may still be entitlement risk, utility questions, environmental concerns and plenty of other reasons a deal may never move forward. Fully engineering every potential acquisition wouldn't make sense.
But neither does waiting until everything is designed to begin understanding the dirt. The question is somewhere in the middle: How much information do you actually need to make a better land decision?
More Information Isn't Always the Answer
We recently worked through an early-stage project with a land team that had a site plan, an existing topographic survey and a geotechnical report, but no developed grading plan. The project was still in its inspection period, and the team wasn't ready to authorize that level of engineering expense. Their concern was straightforward: How close can we get to understanding the earthwork without fully designing the site?
The answer wasn't necessarily more engineering. It was identifying the small amount of additional information that could make the existing information more useful.
With usable topography already available, the missing piece was basic proposed vertical control. Preliminary roadway centerline grades, pond top-of-bank elevations and a few key design elevations can begin establishing the intent of the proposed site. From there, a conceptual grading model can be developed using those controls along with reasonable development standards and clearly documented assumptions.
It isn't a replacement for the engineer's final design, and it isn't supposed to be. It is a way to start answering important earthwork questions before paying to develop information that may not yet be necessary.
Precision and Decision-Making Are Two Different Things
There is an important distinction between the information needed to build a project and the information needed to evaluate a deal. Before construction, final elevations and detailed quantities matter. The contractor needs enough information to price and build the work accurately.
During acquisition, the questions can be different. Does the proposed site generally work with the existing terrain? Are we likely looking at import or export? Are the ponds, roads and pads creating an obvious imbalance? Does the geotechnical information affect how much excavated material we should expect to reuse? Is there one assumption capable of materially moving the budget?
Sometimes knowing the direction and magnitude of a potential issue is more valuable at that stage than knowing the final quantity to the last cubic yard.
What Can Limited Information Actually Tell You?
On this recent project, the proposed vertical information was limited primarily to roadway centerline grades. There was no completed grading design showing exactly how every road, lot, pad and pond would ultimately be built.
Using those preliminary controls along with documented assumptions for roadway slopes, pad elevations, stripping, compaction and pond geometry, we developed an early conceptual grading model.
What it showed was significant.
The current concept was materially import-driven. The model indicated approximately 58,000 cubic yards of usable cut against approximately 245,000 cubic yards of compacted fill demand, resulting in roughly 187,000 cubic yards of potential import before considering whether some of the stripped material could be reused.
At a hypothetical planning figure of $25 per cubic yard, that volume represents approximately $4.7 million of potential earthwork exposure. That's not a construction estimate, but it is enough magnitude to deserve attention during due diligence.
More importantly, the model began showing why. The residential areas were carrying significant fill while much of the available cut was being generated around the stormwater excavation areas. That made several assumptions worth keeping visible: proposed vertical design, pond geometry, compaction, stripping and the suitability of material for reuse.
At this stage, whether the final import quantity ultimately becomes 175,000 yards or 190,000 yards isn't necessarily the most important question. The important information is that the current concept is pointing toward a significant import condition—and understanding which assumptions have the ability to change that position.
That's the difference between precision and useful information.
Spend the Next Dollar Where It Matters
Good due diligence isn't about answering every question as early as possible. It's about knowing which question deserves the next dollar.
On this review, the early model narrowed the discussion to a handful of issues capable of materially changing the earthwork position: pond excavation and groundwater conditions, the suitability of stripped material for reuse, the compaction assumption and how the preliminary vertical design might evolve.
That might mean asking the engineer to look more closely at a roadway elevation or pond configuration. It could require additional geotechnical investigation in a specific area. Or it may simply mean carrying a more appropriate earthwork allowance while the deal continues through underwriting.
The early information isn't replacing the next step. It's helping determine what the next step should be.
There Is a Middle Ground
Land teams don't always need to choose between spending heavily on engineering and carrying the dirt as a complete unknown.
There is a middle ground. A conceptual model won't eliminate every assumption, and quantities will change as engineering progresses. That's okay. The objective during acquisition isn't to build the project. It's to make the best decision possible with the information appropriate for that stage of the deal.
Sometimes a surprisingly small amount of additional information can tell you whether you're generally headed in the right direction—or whether something deserves a much closer look.
A Question Worth Asking
Before spending more to answer everything about your next acquisition, what is the one assumption that could actually change the way you look at the deal?
Knowing that may be more valuable than simply knowing more.
Bill Cheatham
President | Earth Tek
Questions This Issue Explores
How much design information is really needed to evaluate earthwork during due diligence?
Can earthwork be evaluated before a complete civil grading plan is available?
Which earthwork assumptions are important enough to investigate during an inspection or feasibility period?
When does additional engineering provide meaningful decision-making value—and when can it wait?
Can an early conceptual earthwork model identify meaningful exposure before final grading plans are complete?
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