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water-stores-1 · content 1 · setup format 1
What supports the explanation?
Impervious surfaces reduce infiltration and tend to increase surface runoff.
USGS Water Science School, Infiltration and the Water Cycle, land cover discussion. Supports the direction of the paving effect; the exact rain-split coefficients remain illustrative.
The USGS’s updated diagram includes human use and multiple stores and fluxes.
USGS Water Data Blog, October 13, 2022 release discussed in A New Take on the Water Cycle. Supports the decision to show a network and land-use control; no artwork is copied.
Six stores with deterministic, bounded transfers. Real global water storage is distributed very differently; store sizes here are chosen for visual comparison.
No weather forecast, precipitation triggering, soil-capacity threshold, atmospheric transport, ice/snow, water quality, withdrawals or spatial flow solver.
The landscape is a projected illustration, not a map or spatial flow solver. Paving changes its appearance and the modeled rain split. Arrows and moving dots show transfer direction, not real particle routes, speeds or water amounts. Read quantities in the budget; groundwater occupies pores in the cut face. Energy affects only the two evaporation terms.
Condensation on a cold cup depends on humidity and surface temperature. A dry result is a useful observation, not evidence that vapor is absent.
Count the stores: Start with 100 arbitrary water units: 50 ocean, 10 vapor, 10 cloud, 15 soil, 10 groundwater, 5 river. These are teaching amounts, not global water percentages or a measured watershed.
Every transfer has two entries: Each transfer subtracts from one store and adds to another. Thus change in total storage is zero in this closed model. Rain partition is 20% + 75% × paved fraction to the river, with the rest to soil. This is an illustrative rule, not an empirical runoff coefficient.
Rates are a model choice: Fixed 0.1-unit time steps update first-order transfers. Evaporation is 0.02 × ocean × energy setting; transpiration 0.005 × soil × energy; condensation 0.08 × vapor; rain 0.12 × cloud; percolation 0.02 × soil; groundwater discharge 0.02 × groundwater; river return 0.12 × river. Time is deliberately not mapped to hours or years.
What has been checked
Analytical reference cases, conservation or transition invariants, finite drawing commands, bounded setup parsing, discovery and route integrity are checked automatically. These checks do not establish anatomical fidelity, learner outcomes or browser/device compatibility. Independent subject review, learner trials, comprehensive accessibility review and browser video encoding checks remain pending.
Each source supports the associated claim. Sources do not certify this implementation or its visuals.
About the cover illustration
The topic card uses an AI-generated editorial illustration. It introduces the subject; it is not a validated anatomical reference or a measured landscape. The experiment’s diagrams, readouts and assumptions explain the model separately.