MARIUS COMPERPUBLIC OBJECTS

ONE CITY, ONE STORM

Rain Has Five Exits

When rain hits a city, the surface beneath it chooses the first route. Follow one drop and watch asphalt, soil, plants, a tank and a pipe divide the same water.

Follow the drop modeled scenario for 100 m²
30 mmone chosen storm
3,000 Lwater that falls
5routes followed
Urban cutaway with five routes for rainwater Rain falls on a roof and street. Five coloured routes show water returning to air, entering soil, reaching a tank, moving through a pipe or leaving toward a river. roof asphalt soil tree tank pipe river

Original illustration. An urban cutaway with simplified proportions, drawn for explanation.

THE FIRST TOUCH

The 3,000 litres do not travel together

Across 100 m², 30 mm of rain equals exactly 3,000 litres. The water reaches the same city, but the first surface it touches changes its speed, filter and next destination.

Calculation: 30 mm × 100 m² = 3,000 L. The volume is exact under this assumption. The split below is modeled.

FOLLOW THE DROP

Put the rain in motion

Choose the rainfall, then send one drop through the city cutaway. In a large storm, soil and storage take less while pipe and river take more.

Urban cutaway with five routes for rainwater Rain falls on a roof and street. Five coloured routes show water returning to air, entering soil, reaching a tank, moving through a pipe or leaving toward a river. roof asphalt soil tree tank pipe river

Routes in the illustration

30 mm
5 mm60 mm

The drop is waiting at the edge of the roof.

Where the water went

3,000 L in total
Air 27%
Soil 27%
Storage 27%
Pipe 27%
River 27%

of volume, in model

Without JavaScript, the cutaway remains a static map of the five routes. The initial values describe the 30 mm scenario.

FIVE ROUTES

The same drop, five first moves

Use these five routes as a working map. One drop can pass through several over time. The model follows the destination that appears first for each portion of water.

01

air

Air

evaporation and transpiration

Some water returns to the atmosphere through evaporation or plants.

02

soil

Soil

infiltration

Water enters the ground. Speed depends on pores, compaction, slope and what is already there.

03

tank

Storage

retention and reuse

A roof, barrel or planted hollow can hold water long enough to release it slowly.

04

pipe

Pipe

fast conveyance

Impervious surfaces send water quickly toward gutters, drains and pipes.

05

river

River

surface runoff

Water that leaves over the surface can carry sediment, nutrients and metals with it.

ASPHALT AND PIPE

Asphalt shortens the trip to the pipe

Street, parking lot and roof do not let water enter soil easily. Rain moves fast, picks up sediment and other substances from the surface, then enters drains or reaches surface water.

Documented fact

The EPA describes runoff from streets, parking lots and roofs as a route that can carry trash, bacteria, nutrients, sediment and metals into water.

What the model shows

In the model, pipe and river grow when the surface becomes compact and rain arrives faster than water can enter the soil.

Source for this distinction ↗

WHAT SLOWS THE WATER

Soil can buy time

Rain gardens, permeable pavement, green roofs and storage tanks put distance between a drop and a pipe. They can store, filter, infiltrate or evapotranspirate water when the site and maintenance allow it.

A rain garden cannot fix every street. The EPA ties the result to site, soil, design and maintenance.

01

rain garden

holds water in a planted hollow and lets it pass through soil

02

permeable pavement

lets water reach gravel and soil layers below

03

green roof

holds some rain and releases it more slowly

04

rain barrel

keeps water for later use or slower release

AFTER THE STORM

Start where the rain lands

Before asking how large the pipe should be, look at which water reaches it and how fast. A storm is not one event. It is a sequence of surfaces and routes.

  1. Which impervious surfaces send water straight into the network?
  2. Where can water be held or infiltrated without moving pollution into groundwater?
  3. After an intervention, what should be measured: volume, speed, water quality, or all three?

When the next storm arrives, look first at the place where water meets the ground.

SOURCES AND MODEL

What is measured and what is built here

The sources below support the hydrologic mechanisms and infrastructure described on the page. The 3,000-litre figure is a direct calculation. The percentages splitting water across five routes are an editorial model, used to make the shift between a small and a large storm visible.

  1. primary sourceU.S. Geological Survey

    Water Cycle

    Explains evaporation, infiltration and runoff as parts of the water cycle.

    Scope: General hydrologic principles; it does not supply the coefficients used in the interactive model.

    Open source
  2. primary sourceU.S. Environmental Protection Agency

    About Green Infrastructure

    Defines infiltration, filtration and evapotranspiration and describes the difference between impervious surfaces and systems that manage water where it falls.

    Scope: Definitions and mechanisms; examples come from EPA guidance, not a local measurement.

    Open source
  3. primary sourceU.S. Environmental Protection Agency

    Sources and Solutions: Stormwater

    Shows how rain from streets, parking lots and roofs picks up pollutants and reaches drains or surface waters.

    Scope: General explanation of urban runoff and green solutions.

    Open source
  4. primary sourceU.S. Environmental Protection Agency

    Types of Green Infrastructure

    Describes rain gardens, permeable pavements, green roofs, planters and rain barrels.

    Scope: Intervention types and possible functions: retention, filtration, infiltration and evapotranspiration.

    Open source
  5. primary sourceU.S. Environmental Protection Agency

    Environmental Benefits of Green Infrastructure

    Connects the volume of water entering pipes with localized flooding risk and water quality.

    Scope: System-level benefits and limits; exact effects depend on site and design.

    Open source
  6. Romanian contextAdministrația Națională Apele Române, ABA Argeș-Vedea

    Wastewater 2020, Bucharest

    Describes wet-weather flow, retention basins and discharge toward the Dâmbovița in documentation for Bucharest’s treatment plant.

    Scope: Local institutional and technical context; this page does not transfer the document’s flows into the 100 m² model.

    Open source
Fixed profiles used as interpolation points
StormTotal volumeModeled split
5 mm500 LAir: 11% · Soil: 43% · Storage: 22% · Pipe: 19% · River: 5%
30 mm3,000 LAir: 7% · Soil: 27% · Storage: 12% · Pipe: 38% · River: 16%
60 mm6,000 LAir: 4% · Soil: 15% · Storage: 6% · Pipe: 43% · River: 32%