# DepthScout lake maximum-depth snapshot — August 17, 2026

This frozen CSV supports DepthScout Research report 02, “The 33-Foot Lake.” It contains the 37,234 lake records in the public DepthScout catalog on August 17, 2026. Rivers and saltwater segments are outside this analysis.

The report calculates its findings from 37,233 rows. One record failed a physical-plausibility screen because its stored maximum depth exceeded 6,000 feet—higher than the deepest known freshwater lake. The row remains in the download with `included_in_analysis=false` so the exclusion is visible and reproducible.

## Fields

| Field | Description |
|---|---|
| `snapshot_date` | Date on which the catalog was frozen for this analysis. |
| `water_id` | Stable DepthScout identifier. |
| `water_name` | Display name in the catalog. Names are not globally unique. |
| `region` | Display region attached to the lake record. |
| `state` | One or more state, province, territory, or country codes used by DepthScout. Multiple codes are separated by `/`. |
| `maximum_depth_ft` | Catalog maximum depth in feet. This is the deepest recorded point, not mean depth and not the depth across most of the lake. |
| `depth_data_label` | `survey-backed` when the displayed contours derive from measured bathymetry; otherwise `approximated`. This describes contour provenance, not the quality of the maximum-depth value. |
| `source_key` | DepthScout's internal provenance key for the lake record. Source details are shown on the linked lake page. |
| `canonical_url` | Public DepthScout lake page. |
| `included_in_analysis` | Whether the row passed the report's depth-validity screen. |
| `exclusion_reason` | Reason an excluded row was not used in calculations. Blank for included rows. |

## Calculation rules

- Deduplicate the catalog by `water_id`, keeping the last manifest record, consistent with the production loader.
- Keep records whose `waterType` is `lake`.
- Include finite maximum depths greater than zero and no greater than 6,000 feet.
- Calculate percentiles with linear interpolation on the sorted included values.
- Define `at most 25 feet`, `at most 50 feet`, and `over 100 feet` inclusively as written.
- Round displayed percentages to one decimal place. Counts use unrounded rows.

## Limitations

This is a census of one product catalog, not a random or globally representative sample of lakes. Regions with broad public lake inventories contribute more rows than regions with limited coverage. The dataset mixes natural lakes, ponds, reservoirs, and impoundments that DepthScout classifies as `lake`.

Maximum depth is not mean depth, usable habitat, current water depth, or the depth at which fish will be found. Source dates, survey methods, water-level references, and precision vary. A survey-backed label applies to the contour geometry; it does not guarantee that the maximum-depth field was measured recently or at today's water level.

Do not use these records for navigation.

## Reproduction

Run:

```text
node scripts/generate-lake-depth-research.mjs
```

The generator validates the expected catalog size, exclusion count, median, and 50-foot threshold before rewriting the CSV.

## Provenance and reuse

This file is a frozen export of the public DepthScout lake manifest captured on August 17, 2026. Each row retains the catalog's `source_key` and a `canonical_url` for the lake page where DepthScout displays the source label and available source details. The export does not replace the underlying agency record, and it does not imply that every source uses the same survey method, date, datum, or precision.

The analysis and export are based on the [DepthScout data and methodology](https://www.depthscout.com/methodology) and the catalog-coverage context documented in [The Uneven Map Beneath the Water](https://www.depthscout.com/research/public-lake-depth-mapping-2026). Reuse is governed by the [DepthScout Terms](https://www.depthscout.com/terms). Source-agency data may carry additional terms; follow the source shown on the applicable lake page when reusing an underlying record.

Suggested citation:

> DepthScout Research. “DepthScout lake maximum-depth snapshot — August 17, 2026.” DepthScout, 2026. https://www.depthscout.com/research/data/depthscout-lake-maximum-depths-2026-08-17.csv