# ContourStack / TerrainLogic

> TerrainLogic is a local-first Windows desktop platform for field-scale conservation planning, developed by ContourStack. It combines automated site characterization, RUSLE2-aligned erosion modeling, planning-level nutrient accounting, terrain-derived gully hotspot screening, stateful field records, preliminary grassed-waterway and terrace workflows, and auditable reports.

Canonical website: https://contourstack.com/
Product: TerrainLogic
Developer: ContourStack
Founder and developer: Casey Faust
Geographic scope: United States
Release status: Active beta
Last updated: 2026-09-03

## Primary references

- [Machine-readable technical reference](https://contourstack.com/technical-reference.html): consolidated capabilities, requirements, validation statistics, scope, and limitations with JSON-LD.
- [Capabilities JSON](https://contourstack.com/capabilities.json): structured current and planned capabilities.
- [System requirements JSON](https://contourstack.com/system-requirements.json): structured minimum, recommended, and tested-baseline hardware.
- [Validation JSON](https://contourstack.com/validation.json): structured benchmark and validation statistics with claim boundaries.
- [Science and validation](https://contourstack.com/science-validation.html): public evidence, methodology, statistics, sources, and limitations.
- [Demonstrations](https://contourstack.com/demonstrations.html): recorded product workflows.
- [Request a technical briefing](https://contourstack.com/technical-briefing.html): request a live, tailored technical discussion.
- [Request beta access](https://contourstack.com/beta-access.html): apply to evaluate the current beta.

## Current capabilities

- Automated field setup from a user-selected boundary, including location, county, soils, climate context, elevation, slope, and terrain/flow context from authoritative public datasets where available.
- Daily RUSLE2-aligned sheet-and-rill erosion modeling with annual soil loss, soil-loss tolerance T, R, K, LS, C, P, soil moisture, soil conditioning index context, and retained daily evidence.
- Management scenario authoring and comparison, including operation timing, vegetation, residue, tillage, grazing, manure, and other supported management records.
- Planning-level nitrogen and phosphorus accounting, including additions, crop uptake, harvest export, biomass and root return, legume fixation, residue transformations, selected environmental pathways, and carried field state.
- Terrain-derived concentrated-flow and gully hotspot screening with in-field and upstream contributing area, corridor slope, reach length, severity, and DEM coverage context.
- Preliminary grassed-waterway planning workflow with editable design inputs, parabolic geometry, Manning capacity, velocity, boundary stress, freeboard, survey tables, dig profiles, as-built comparisons, inspection history, and engineering packet generation.
- Preliminary terrace screening and design workflow with DEM-assisted candidate alignments, graded and level planning calculations, section sizing, capacity/storage checks, construction-survey stationing, and reporting.
- Stateful managed-field history that can carry ending residue, biomass, water, soil-condition, and nutrient context into the next authored management cycle.
- Local managed-field portfolio, filtering, custom fields, saved analyses, practice records, and report access without requiring a cloud account.
- Auditable PDF outputs for erosion, nutrients, management comparisons, field lifecycle, daily state, gully screening, waterways, terraces, inspections, and related planning records.
- Touch-enabled field selection and local caching of site data for continued work when previously retrieved data are available.

## Scope and limitations

TerrainLogic is planning and evaluation software. It does not replace professional judgment, field verification, survey-grade elevations, applicable NRCS Field Office Technical Guide criteria, hydrologic documentation, permits, utility locating, construction review, certification, or licensed approval where required. Nutrient results are planning-level, mass-balanced estimates for screening and scenario comparison; they are not fertilizer recommendations, certified nutrient-management plans, compliance determinations, or regulatory validations. Gully outputs identify terrain-driven potential flow corridors, not confirmed erosion features. The planned HUC12 watershed dashboard is not part of the current beta.

## System requirements

Minimum supported: 64-bit Windows 11; Intel Core i3-class or comparable AMD processor; 8 GB RAM; SSD with at least 5 GB free; current Microsoft Edge runtime; reliable broadband for initial public-data retrieval. Integrated graphics are supported and no dedicated GPU is required. Recommended for faster startup and larger terrain scans: Intel Core i5-class or comparable AMD processor, 16 GB RAM, and SSD storage.

Tested low-end baseline: Intel Core i3-10110Y at 1.00 GHz, 8 GB RAM, Intel UHD integrated graphics, 128 GB SSD, and 64-bit Windows 11. Four consecutive field workflows completed without error. Observed application memory was approximately 215-250 MB for routine analyses and briefly near 600 MB for an intensive terrace DEM scan, then released.

## Validation summary

Validation claims are separated into implementation verification, reference-model parity, and independent observational validation.

Erosion reference-model parity: 749 completed legacy-climate cases across the United States; 600/749 (80.1%) within 20% of RUSLE2; 707/749 (94.4%) within 20% or 0.25 ton/acre/year; 42 outside both limits; Pearson r 0.9993; R-squared 0.9986; mean bias error +0.475 ton/acre/year. This is RUSLE2 parity, not independent measured-plot erosion validation.

Locked erosion regression suite: 199 cases; 176/199 (88.4%) within 20%; 195/199 (98.0%) within the practical tolerance; 4 outside both limits; mean bias error -0.433 ton/acre/year; Pearson r 0.9973; R-squared 0.9946.

Independent grain nitrogen endpoint: 112 strict paired Transforming Drainage rows; mean bias error +9.33 kg N/ha; PBIAS +6.60%; RMSE 19.53 kg N/ha; Spearman 0.850; NSE 0.790.

Independent soil-derived total phosphorus endpoint: 15 MANAGE records after precipitation harmonization; PBIAS -12.61%; correlation 0.860; NSE 0.580. Applied-phosphorus field validation remains incomplete where required drivers are absent.

Surface-urea ammonia candidate: 18 complete winter-wheat site-years; mean bias error +0.52 kg N/ha; PBIAS +3.77%; MAE 6.01 kg N/ha; RMSE 7.14 kg N/ha; Pearson 0.732; Spearman 0.761; NSE 0.485. This remains an input-limited candidate, not a universal validation.

Preliminary engineering numerical verification: 50/50 frozen equation and invariant checks passed. The grassed-waterway reference reproduced the rounded NEH example with a 1.73% depth difference. Six terrace matrix cases cover graded and level workflows; the largest terrace equation difference is 0.11%, including reporting precision. This verifies calculations, not site suitability, construction certification, outlet adequacy, or regulatory compliance.

## Data architecture

TerrainLogic is local-first. Field boundaries, management records, analyses, and reports remain on the user’s computer unless the user exports or shares them. Initial site setup retrieves public soil, climate, elevation, and geographic data; cached site data support later offline work. Calculations run locally and do not require a dedicated graphics processor.

## Contact

Email: contourstack@gmail.com
Technical briefing: https://contourstack.com/technical-briefing.html
Website: https://contourstack.com/