# Components of the Natural Water Balance

A thematic map of the Atlas of Switzerland, the national atlas published by ETH Zurich. The map is drawn in the browser; this file describes it and lists its variants and links, but not the data values shown on the map.

- Map: https://atlasderschweiz.ch/en/theme/components-of-the-natural-water-balance/
- Short title: Natural Water Balance
- Map id: 1169
- Categories: Nature and Environment › Water › Water balance
- Keywords: Discharge, Evaporation, Precipitation, Runoff coefficient, Storage change, Water, Water balance
- Published: 2026-04-08
- Last revised: 2026-04-08
- Content language: English
- Other languages: [Deutsch](https://atlasderschweiz.ch/de/thema/komponenten-des-natuerlichen-wasserhaushalts.md), [Français](https://atlasderschweiz.ch/fr/theme/elements-du-bilan-hydrologique-naturel.md), [Italiano](https://atlasderschweiz.ch/it/tema/componenti-del-bilancio-idrologico-naturale.md)

## Description

By examining the natural water balance—that is, the balance between precipitation on the one hand and evaporation and runoff on the other—it is possible to characterize watersheds and analyze current and future water availability issues. This map incorporates newly modeled balances for all 4,500+ HADES catchments in hydrological Switzerland for the reference period 1991–2020.

## Sources

- HADES (2026): [HYDROmaps](https://hydromaps.ch/)

## Data sources

- HADES (2026): [HYDROmaps](https://hydromaps.ch/)

## Data owners

- [Hydrological Atlas of Switzerland (HADES)](https://www.hydrologischeratlas.ch/)

## Citation

The terms of use ask to name the Atlas of Switzerland and the data owners, and to keep the source references in exports, screenshots and embeds. Cite the map as:

> Atlas of Switzerland (2026): Components of the Natural Water Balance. ETH Zürich. Map data © HADES. https://atlasderschweiz.ch/en/theme/components-of-the-natural-water-balance/

## Variants

The map has 20 variants. Levels: variant → spatial unit → time. The `u` value of a variant selects it in the links below.

- Precipitation
  - Sub catchment areas
    - 1991-2020: `u=BBoBEAIc` (default)
  - Medium catchments
    - 1991-2020: `u=BBoBEQIc`
  - Hydrological study areas
    - 1991-2020: `u=BBoBEgIc`
  - River basins
    - 1991-2020: `u=BBoBEwIc`
- Actual Evaporation
  - Sub catchment areas
    - 1991-2020: `u=BBoBEAId`
  - Medium catchments
    - 1991-2020: `u=BBoBEQId`
  - Hydrological study areas
    - 1991-2020: `u=BBoBEgId`
  - River basins
    - 1991-2020: `u=BBoBEwId`
- Discharge
  - Sub catchment areas
    - 1991-2020: `u=BBoBEAIe`
  - Medium catchments
    - 1991-2020: `u=BBoBEQIe`
  - Hydrological study areas
    - 1991-2020: `u=BBoBEgIe`
  - River basins
    - 1991-2020: `u=BBoBEwIe`
- Storage change
  - Sub catchment areas
    - 1991-2020: `u=BBoBEAIf`
  - Medium catchments
    - 1991-2020: `u=BBoBEQIf`
  - Hydrological study areas
    - 1991-2020: `u=BBoBEgIf`
  - River basins
    - 1991-2020: `u=BBoBEwIf`
- Runoff coefficient
  - Sub catchment areas
    - 1991-2020: `u=BBoBEAIg`
  - Medium catchments
    - 1991-2020: `u=BBoBEQIg`
  - Hydrological study areas
    - 1991-2020: `u=BBoBEgIg`
  - River basins
    - 1991-2020: `u=BBoBEwIg`

## Links

Replace `{u}` with the `u` value of a variant above, or leave out `u={u}` for the default variant. The map opens at its full extent; a link cannot set the map position.

- Map: https://atlasderschweiz.ch/en/theme/components-of-the-natural-water-balance/?u={u}
- Short link, stays valid when the title changes: https://atlasderschweiz.ch/en/t/1169/?u={u}
- Side by side with another map: https://atlasderschweiz.ch/en/comparison/?lt=1169&lu={u}&rt={id of the other map}&ru={u of the other map, or leave out}

Embed in another website (allowed by the terms of use, as long as the source references stay visible):

```html
<iframe src="https://atlasderschweiz.ch/en/embed/?id=1169&u={u}&dm=e&ig=1" style="border:0;width:100%;height:600px;max-width:100%;" loading="lazy" title="Thematic map 'Natural Water Balance' in the Atlas of Switzerland" allowfullscreen sandbox="allow-scripts allow-same-origin allow-popups" allow="geolocation" referrerpolicy="strict-origin-when-cross-origin"></iframe>
```

In the embed URL, `dm` sets what is shown: `e` the map with its title bar (default), `p` also the values of an object clicked on the map, `m` only the map with a button that opens it in the atlas. `ig=1` (default) lets the map react to scrolling and dragging only after a click into it, `ig=0` right away. The size can be changed in `style`.

## Related maps

- [Catchment areas and watersheds](https://atlasderschweiz.ch/en/theme/catchment-areas-and-watersheds.md) (id 134)
- [Yield of  near-surface groundwater resources](https://atlasderschweiz.ch/en/theme/yield-of-near-surface-groundwater-resources.md) (id 923, former edition, desktop atlas only)
- [Mean water retention capacity of the soil](https://atlasderschweiz.ch/en/theme/mean-water-retention-capacity-of-the-soil.md) (id 254)
- [Mean water permeability of the soil](https://atlasderschweiz.ch/en/theme/mean-water-permeability-of-the-soil.md) (id 253)
- [Mean annual evaporation per balance basin (1973–1992)](https://atlasderschweiz.ch/en/theme/mean-annual-evaporation-per-balance-basin-19731992.md) (id 920)

For the use and citation of maps and data, see the [terms of use](https://atlasderschweiz.ch/en/terms-of-use/).