A checklist confirms that an item is present. It rarely confirms that two items agree with each other. Most of the expensive grading and drainage errors live in that gap: everything is on the sheet, and the sheet still doesn't work. Here are seven that get through.
1. A flat spot or reverse grade hiding between spot elevations
Each spot elevation looks reasonable. Read together, they create a low point with nowhere to go. Water ponds, the site fails its intent, and the checklist item "spot elevations provided" is satisfied the whole time. Catching it means following flow across the surface, not ticking off labels.
2. Inlet rim elevations that don't match the surrounding grade
The inlet is on the plan, the label is there, and the rim sits higher than the gutter or pavement it's meant to collect from. Or the reverse: the rim is set so low it creates a depression. The structure exists; it just doesn't receive the water.
3. Pipe inverts that disagree between plan and profile
Plan view shows one invert, the profile shows another, and the structure table shows a third after a late revision. Each sheet was correct when it was drawn. Cross-sheet mismatches like this are the most common product of iterative design.
4. Cover, clearance, or slope problems that only show up in profile
A run can look fine in plan and still fall short on cover under a road, cross another utility with too little clearance, or drop below the minimum slope once you read the profile. Requirements vary by jurisdiction, which is exactly why they need checking against the local standard, not memory.
5. Accessible routes that fail on slope, not on presence
The ramp is drawn, the detail is called out, the note is there. The running slope or cross slope implied by the grading doesn't meet the requirement. A checklist confirms the route exists. Only the numbers confirm it works.
6. Grading that doesn't tie into existing conditions
Proposed contours meet existing contours at an elevation that doesn't match, or a tie-in creates an unintended step or a slope steeper than it should be. It reads fine on the proposed sheet and fails where new meets old.
7. Drainage calcs and detention outlet data that don't match the plan
The report assumes one outlet elevation, pipe size, or drainage area. The plan shows another. Both documents pass their own review, and the discrepancy only appears when someone reads them side by side.
The pattern
Every one of these is a consistency failure between sheets, between plan and profile, or between drawings and calculations, rather than a missing item. That is why a person with a checklist can miss them, and why reviewers running short on time miss them first. It's also where a systematic cross-sheet check earns its keep.
CivilPlanAI reviews grading and drainage against the drawing linework itself and checks coordination across sheets. Each finding is pinned to a sheet and location with a confidence level and, where it applies, a code reference. You approve, edit, or reject every one.
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