A short, concentrated runoff pulse can raise peak discharge even without a proportionate change in total runoff volume. Soil already wet from earlier rain can also reduce infiltration. This activity isolates surface cover rather than simulating all these processes. Inspect both the water accounting and the timing of the response.
Water and oceans · Discover & try
Why can the same rain make a sharper river peak?
Reading level 4 of 5 · FluentChange
Word help
Catchment
The land area draining to a shared outlet.
Hydrograph
A graph of flow or water level over time.
Infiltration
Water entering the ground from the surface.
Watch · Try · Explain
See how it works
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Hypothetical, volume-accounted rainfall–runoff curves; not observed river data or a flood forecast.
What to look for
- Compare hydrograph peak with curve area.
- Keep rainfall fixed while changing paved cover.
- Check that runoff plus other water equals rainfall.
Explain what you noticed
Two new catchments send the same total runoff volume to a stream. One delivers it in a much shorter time. Which response is more likely?
Keep this idea: Runoff amount and travel time both shape a river’s response to rain.
Follow the sources
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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