Bacias hidrográficas: Vinte e duas casas para a mesma chuva

Cerejo, Lucas Nakamura

doi:10.5281/zenodo.23539331

No. 036 Hydrography Water in São Paulo 1/3

River basins

Twenty-two homes for the same rain

Record, downloads and citation

Map of São Paulo state divided into its 22 UGRHIs, numbered in white seals and coloured by population density in 2022, on a viridis ramp from yellow (under 43 people per km², in the south and west) to dark purple (over 190, in Alto Tietê, Piracicaba/Capivari/Jundiaí and Baixada Santista). A blue line with diamonds marks the Tietê-Paraná waterway and its eight locks. An arrowed callout points to Alto Tietê: 46.1% of the people on 2.4% of the land. In the panel, an index lists the 22 basins by number. — Fig. 036 São Paulo state (SP) EPSG:4674 Source: SEADE, IBGE, MapBiomas

To look after its water, São Paulo does not use the map of municipalities but the map of basins: 22 Water Resources Management Units, the UGRHIs. Coloured by the 2022 Census population, they show a state that is unequal under the same rain. The municipalities of Alto Tietê, around the capital, hold 20.5 million people, 46.1% of the state’s population, on 2.4% of its land: 3,456 people per km². In Pontal do Paranapanema there are 20.8. Along the Tietê and the Paraná runs the waterway too, with its eight locks drawn on the map. First plate of the collection “Water in São Paulo”.

Technical record · downloads · citation

At a glance

Layers

ugrhi polygon 22 UGRHIs: area, municipalities, 2022 population and density
municipios polygon 645 municipalities, with the assigned UGRHI, the share of territory in it and the 2022 population
hidrovia line Tietê-Paraná waterway
eclusas point 8 locks on the waterway
limite_estadual polygon State boundary

Metadata

Sources: SEADE — GeoSEADE: Water Resources Management Units (UGRHIs), as defined by the State Water Resources Council
IBGE — 2022 Population Census: aggregates by municipality (2022)
MapBiomas — infrastructure database: waterways and locks
IBGE — Municipal Mesh 2025 (2025)
Extent: São Paulo state (SP)
CRS / Projection: SIRGAS 2000 (EPSG:4674)
EPSG:4674
Software: Python · GeoPandas · GDAL · QGIS · Node.js · d3-geo
Method: Each municipality assigned to the UGRHI covering most of its territory; 2022 Census population summed by UGRHI and divided by basin area, in six quantile classes.
Version: v1.0.0
Licence: CC BY 4.0
DOI: 10.5281/zenodo.23539331

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The map without a frame, with legend, scale, reference system and credit written on it: ready for papers, lectures and slides. In two versions: with the basemap (neighbours and sea) or only the mapped area, on white.

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How to cite

Cerejo, L. N. (2026). Bacias hidrográficas: vinte e duas casas para a mesma chuva [River basins: Twenty-two homes for the same rain] (Version 1.0.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.23539331

@dataset{cerejo2026_bacias_hidrograficas_sp,
  author    = {Cerejo, Lucas Nakamura},
  title     = {Bacias hidrográficas: Vinte e duas casas para a mesma chuva},
  year      = {2026},
  publisher = {Zenodo},
  version   = {1.0.0},
  doi       = {10.5281/zenodo.23539331},
  url       = {https://doi.org/10.5281/zenodo.23539331},
  language  = {portuguese},
  note      = {English title: River basins: Twenty-two homes for the same rain. Licence CC BY 4.0}
}

How to read this plate area, projection, scale, legend and source · 1 terms

1 Area: São Paulo state (SP) The area the plate covers. Outside it, neighbours and sea are drawn in grey, just for orientation.
2 Coordinates and projection: SIRGAS 2000 (EPSG:4674) The layers are in SIRGAS 2000; the drawing’s projection is written in the colophon at the foot of the panel.
3 Scale: Graphic scale bar in the panel The scale bar is true on the central meridian; away from it, measured distances vary a little.
4 Legend and layers: 5 layers in the GeoPackage · polygon, line, point Read the legend before the map: it tells you whether a colour is a rate or a class, and whether a circle is a total.
5 Sources: SEADE; IBGE (2022); MapBiomas; IBGE (2025) Every figure comes from a public source, with its year. The data sheet gives each one’s address.

Terms on this plate

2022 Census: IBGE’s door-to-door count. Results by census tract give residents, age, household-head income, water, sewerage and rubbish.

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Layers, table and figures, under CC BY 4.0. Cite with the DOI.

Full record and citation

Method notes · No. 036

River basins — São Paulo’s 22 UGRHIs and the people in each one

Português · English

Plate No. 036, the first of three in the collection Water in São Paulo: the basins the state uses to manage its water. The next plates follow the drainage network and the protected areas.

What the files contain

Layer (GPKG)	Geometry	Contents
`ugrhi`	polygon	22 UGRHIs: `codigo`, `nome`, `area_km2`, `municipios`, `populacao_2022`, `densidade_hab_km2`, `pct_populacao`, `pct_area`
`municipios`	polygon	645 municipalities: `ugrhi_codigo`, `ugrhi_nome`, `fracao_na_ugrhi` (share of the municipality inside the assigned UGRHI), `populacao_2022`
`hidrovia`	line	Tietê-Paraná waterway
`eclusas`	point	Barra Bonita, Bariri, Ibitinga, Promissão, Nova Avanhandava, Três Irmãos, Jupiá and Porto Primavera
`limite_estadual`	polygon	outline of the state

The GPKG is zipped and attached to the agua-sp-2026 release. The ugrhi layer carries two QGIS styles: densidade (the default, as on the plate) and contorno, with outlines, number and name only, to lay over other maps.

The CSV holds the table of the 22 UGRHIs, in UTF-8, without geometry.

Method

Polygons of the 22 UGRHIs from GeoSEADE (as defined by the State Water Resources Council). Names follow the official spelling; the original table is in capitals.
Area of each UGRHI in km², computed in the Albers equal-area conic projection IBGE uses for Brazil.
Each municipality in the 2025 Municipal Mesh is assigned to the UGRHI covering most of its territory, by overlaying the geometries.
Resident population from the 2022 Census (IBGE aggregates by municipality), summed by UGRHI; density = population ÷ UGRHI area.
Classes: six quantiles of the 22 densities, limits rounded to two significant figures; the last one is the maximum.
Waterway and locks from the MapBiomas infrastructure database, clipped to São Paulo (including the stretches of the Paraná river on the border).

Limitations

179 municipalities have less than 90% of their territory in the UGRHI they were given: their whole population counts for a single basin. The official State Water Resources Council division, which assigns each municipality by its seat, may differ in a few cases.
Density uses the basin’s total area, reservoirs, floodplains and protected areas included.
The GeoSEADE UGRHI outlines and the 2025 Municipal Mesh boundary do not match exactly along the coast and the borders; the sum of UGRHI areas differs slightly from the state’s area.

View this map’s folder on GitHub