# TerrainLogic Terrace Verification: Protocol and Findings

**Public engineering record | Preliminary planning**

## Validation question

Does TerrainLogic consistently use field information to propose a preliminary terrace layout, produce internally coherent sizing and earthwork documentation, and clearly identify decisions requiring field survey, outlet design, applicable state FOTG review, and professional approval?

## Product-scope decision

TerrainLogic is a preliminary planning and design-assistance system. It does not produce sealed plans, certify compliance, replace the responsible designer, or assume professional liability. Alignment, spacing, hydrology, outlets, utilities, constructability, permits, and final dimensions require project-specific review.

## Governing references

Verification is grounded in applicable USDA-NRCS conservation-practice standards and engineering references, including CPS 600 Terrace, associated National Engineering Handbook guidance, approved hydrologic methods, and the governing state FOTG.

## Verification protocol

The public protocol separates:

1. dimensional, unit, boundary, geometry, and earthwork checks;
2. independent worked-example comparisons across the supported planning range;
3. terrain-derived alignment proposal review;
4. hydrology and stable-outlet-system review;
5. professional review against applicable criteria; and
6. future field-survey and as-built evidence.

Reference cases cover representative field grades, runoff volumes, preliminary storage and conveyance conditions, level and graded configurations, settlement/freeboard checks, and cut/fill balance. Independent calculations must not call the production calculation helpers.

## Acceptance criteria

- Calculations remain dimensionally consistent and conserve reported geometry and earthwork quantities.
- Independent reference cases agree within declared numerical and reporting tolerances.
- Spacing, capacity, storage, settlement/freeboard, and outlet-related checks return the expected pass/review status at boundaries.
- Survey, profile, report, saved-design, as-built, and inspection workflows remain internally consistent.
- Missing or unverified hydrology, outlet, survey, utility, constructability, or FOTG information is surfaced rather than silently approved.

## Findings

- The combined preliminary-engineering verification matrix contains 50 checks; all 50 pass.
- Independent checks of preliminary spacing, runoff conversion, section geometry, capacity/storage, and cut-to-fill conservation agree within frozen numerical tolerances.
- The largest discrepancy in the representative terrace matrix is 0.11%, attributable to rounded reporting precision in a graded-flow comparison.
- Focused automated engineering, survey, report, saved-design, lifecycle, and inspection tests pass.

## Validated claim at this stage

Within the tested numerical domain, TerrainLogic consistently evaluates its preliminary terrace spacing, runoff conversion, section sizing, capacity/storage, settlement/freeboard, survey/profile, earthwork, report, and lifecycle calculations. This is **software and calculation verification**.

It is not validation of the design storm, proposed alignment, outlet system, state spacing criteria, utility clearance, constructability, or final field design.

## Open validation requirements

Independent professional review, field-survey comparison, hydrologic and stable-outlet verification, jurisdiction-specific criteria, constructed as-built comparison, and multiyear inspection evidence remain open. Until those are completed, all terrace outputs must retain preliminary-planning language.

Exact production equations as assembled, alignment logic, solver details, internal validators, source paths, development tolerances, and correction history are maintained as confidential engineering records.