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Life · Guided lesson

Compare runoff and infiltration from a supplied budget

About 10 minutes · 3 reading + 7 practice and checks
Time includes reading, practice, and questions. Extra videos or further study are optional.
See this course’s project requirements

A fictional watershed diagram tracking runoff, infiltration, groundwater and pollution paths, with a supported upstream/downstream prevention choice.

Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.

What to include

  • Draw outlet-specific and nested drainage boundaries.
  • Label water stores, phase changes and land/plant routes.
  • Balance supplied rain budgets and compare fractions.
  • Read groundwater/stream exchange cross-sections.
  • Trace a possible pollution route without inventing treatment.
  • Explain a responsible paper prevention choice and include all changed cases.

Review and revise

Use these criteria to check your work and choose what to improve.

  • Method: applies the course-specific rules to the supplied cases with visible intermediate work.
  • Accuracy: results agree with the stated facts, units, boundaries and independent checks.
  • Reasoning: explains why the result follows and identifies a limitation or unresolved question.
  • Transfer: completes changed cases and revises the final project when a relevant assumption changes.
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Before you begin

The idea in everyday life

Original matched rain exercise:100 volume units input to each site. Site V: runoff 30, infiltration 60, evaporation/storage 10. Site P: runoff 70, infiltration 20, evaporation/storage 10. Same stated storm interval; other site differences are not fully measured.

The idea

A water budget accounts for an input over a stated place and interval. Surface cover, soil, slope and rainfall conditions can affect runoff and infiltration; a budget does not isolate one cause unless the comparison supplies suitable conditions. All fractions here are fictional model outcomes, not universal pavement or soil coefficients.

Follow along

Compare runoff and infiltration from a supplied budget — worked practice

A water budget accounts for an input over a stated place and interval. Surface cover, soil, slope and rainfall conditions can affect runoff and infiltration; a budget does not isolate one cause unless the comparison supplies suitable conditions. All fractions here are fictional model outcomes, not universal pavement or soil coefficients.

Original matched rain exercise:100 volume units input to each site. Site V: runoff 30, infiltration 60, evaporation/storage 10. Site P: runoff 70, infiltration 20, evaporation/storage 10. Same stated storm interval; other site differences are not fully measured.

  1. 1. 1. Balance

    Add each site’s listed routes.

    You should see: V30+60+10=100; P70+20+10=100.

  2. 2. 2. Fraction

    Calculate runoff fractions.

    You should see: V0.30; P0.70.

  3. 3. 3. Compare

    Calculate the supplied runoff difference.

    You should see: P sends 40 more units to surface runoff.

  4. 4. 4. Limit

    Explain what the data do not isolate.

    You should see: The budgets compare routes; unmeasured site conditions prevent attributing all difference to one factor.

Now change one thing

A changed 100-unit input gives runoff 45, infiltration 45, other 10. Enter runoff fraction as a decimal.

Your work

What to finish

Two water budgets with fractions, differences and assumptions.

Common mistake

Watch for this

The numbers are supplied teaching budgets, and real runoff depends on multiple conditions. A universal causal coefficient would overstate them.

How can I tell I understand it?

Recalculate a changed route fraction without dropping the other budget stores.

Try 3 questions

Quick knowledge check

Answer all 3 questions. Get at least 2 right and the lesson completes automatically.

Not yet passed

You’ll get an explanation for each answer. Signed in? Your results save to your account.

1What is Site V’s infiltration fraction?
2What is P minus V runoff in the record?
3Why not call the difference a universal pavement coefficient?
0 of 3 answeredApply the lesson to a short question, then review the explanation.
3
Finish this lesson

Pass the check. We’ll save the progress.

Answer all 3 questions above and get at least 2 right. You can review the explanations and try again.

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Sources and further reading

Explore the references behind this lesson.

USGS: infiltration and route conditions
Source & access notes · checked 2026-10-01

Web open/search showed the official page, its topic heading and relevant concept description. This is a content/source check, not a provider endorsement.

Access: Official page retrieved with the web reader on 2026-10-01; interactive tools and videos were not certified by retrieval.

Reuse: Original fictional teaching cases, calculations, questions and examples; link and short factual paraphrase only. No copied source exercises or illustrations.

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