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Last Modified: 2 Aug 2026
Source URL: https://data.source.coop/cholmes/portolan-nl/rijkswaterstaat/rijksviswegen_2024/AGENTS.md
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Fish Migration Routes (2024) — Rijkswaterstaat / Netherlands

What This Dataset Is

The national fish migration route network (rijksviswegen) of the Netherlands — 2,122 LineString features representing waterways that are part of the national fish passage network. This dataset tracks the connectivity status of each route segment over time, from 2009 through projected targets in 2033.

Fish migration is critical in the Netherlands because the extensive system of dams, weirs, and locks can block fish from reaching spawning grounds, feeding areas, or the sea. The Dutch government has committed to making these routes passable, and this dataset records progress toward that goal.

Provider: Rijkswaterstaat (Directorate-General for Public Works and Water Management) License: Public domain (Dutch government open data)

How to Access

The data is a GeoParquet file in EPSG:28992 (Amersfoort / RD New). Use DuckDB with the spatial extension.

Schema — Field Meanings

Field	Type	Meaning
`geometry`	WKB LineString	Route geometry in EPSG:28992.
`NAAM`	string	Waterway name (e.g., "Maas", "IJssel", "Noordzeekanaal").
`CODE`	string	Route segment code.
`BEHEERDER`	string	Manager/operator. Mostly null.
`MIGR_TYPE`	string	Migration type — always `"rijk"` (national).
`Status2009`	string	Connectivity status in 2009.
`Status2015`	string	Connectivity status in 2015.
`Status2019`	string	Connectivity status in 2019.
`Status2021`	string	Connectivity status in 2021.

Status Values

"Verbonden" — Connected (fish can pass)
"Niet verbonden" — Not connected (fish passage blocked)
"Geen onderdeel visroutenetwerk" — Not part of the fish route network

Useful Query Patterns

Track connectivity improvement over time

Count connected vs not connected for current year

Find routes that became connected between 2009 and 2024

Routes by waterway name

Geometry Notes

CRS is EPSG:28992 (Amersfoort / RD New). Coordinates are in metres.
All geometries are LineString.
Reproject to EPSG:4326 for web maps.

Visualization Styles

Two Mapbox GL v8 styles are available for interactive map visualization via the PMTiles file.

Style files are Mapbox GL v8 JSON with relative PMTiles source paths. They can be used with MapLibre GL JS, OpenLayers (via ol-mapbox-style), or any Mapbox GL v8-compatible renderer.

styles/default.json — Teal-colored line network showing all national fish migration routes. Clean single-color rendering of the full network.
styles/by-status.json — Fish passage connectivity analysis. Colors routes by Status2024: green = connected (fish can pass), red = not connected (blocked), gray = not part of the network. Visualizes progress on fish passage restoration — nearly all routes (2,086 of 2,122) are now connected.

Style files are at: https://data.source.coop/cholmes/portolan-nl/rijkswaterstaat/rijksviswegen_2024/styles/

Caveats

BEHEERDER is mostly null — manager information is largely missing.
MIGR_TYPE is always "rijk" — this dataset only covers national-level routes, not regional fish migration paths.
Status years from 2027 onward are projected targets, not observed status.
Column names use uppercase (e.g., NAAM, STATUS2024).
The "Geen onderdeel visroutenetwerk" status means the segment was redefined as outside the network — it does not indicate a physical barrier.

Hand-maintained agent guide (ported from this collection's llms.txt in August 2026). Update it alongside collection.json.