Frequently asked questions
Answers to the most common questions about water levels, discharge and the data shown on this site.
What does "m a.s.l." mean for a water level?
"m a.s.l." stands for "metres above sea level" and gives the height of the water surface relative to sea level (reference system RPN, Repère Pierre du Niton). Some stations show discharge in cubic metres per second (m³/s) instead.
How often is the data updated?
Depending on the official source, each measuring station delivers a new value every 10 to 60 minutes. The timestamp next to each value shows how current it is.
What's the difference between level and discharge?
Level (in m a.s.l. or cm) measures the height of the water surface at one point. Discharge (in m³/s) measures how much water passes that point per second — relevant for a lake's inflows and outflows, see each lake's water balance page.
Where does the data come from?
Levels and flows come from official hydrological services. Seepegel supplements them with clearly labelled Simstrat lake-temperature models from Alplakes/Eawag. Details are on the sources page.
Why does a lake's level rise or fall?
A lake's level results from the balance of inflow (rain, meltwater, rivers) and outflow (drainage, evaporation, sometimes regulation by weirs). Each lake's water balance page shows this live.
Can I use this data for my own purposes?
Yes, with attribution to "seepegel.ch" and subject to the terms of use of the respective official original source. For press enquiries and CSV/image exports, see the media page.
What does above or below the seasonal median mean?
The current level is compared with the middle historical value for the same calendar day. Where FOEN reference data is available, the period is 1991–2020. This is a statistical comparison, not an official warning level. See our water knowledge guides.
Why do two stations on the same waterbody show different values?
Each station measures a different location. Tributaries, outlets, vertical datum, wind, hydropower and the travel time of a flow wave can all change the reading. Compare the trend of the same station before comparing isolated numbers.
Why is a reading sometimes old or missing?
Sensors, transmission or the original data portal can fail temporarily. Seepegel does not invent a replacement value; it keeps the original timestamp or shows no current value.
Does a high deviation automatically mean flooding?
No. A statistical deviation, a rising trend and an official flood warning are different statements. Official, waterbody-specific thresholds and warnings determine risk.
Are temperature forecasts and weather values measured?
Not always. Seepegel labels measured, modelled and forecast values separately. The operator and data type are displayed with the value.
Where can I find all river stations and variables?
The river overview groups stations by water level, discharge and temperature. Each detail page includes timestamp, unit, trend and official source.
Find more background in our water knowledge guides – with detailed explanations, examples and our methodology.