Drainage basins, outlets and water divides
Surface drainage boundaries depend on the chosen outlet and need not bound groundwater flow.
Key knowledge
A surface-water drainage basin, catchment or watershed is the land area contributing surface drainage to a specified outlet. Neighboring basins are separated by drainage divides, commonly associated with topographic high ground. Changing the outlet changes the basin; smaller basins can nest within larger ones. Infiltration, storage and evaporation mean precipitation does not all immediately become streamflow. Groundwater divides describe subsurface flow systems and need not coincide with surface-water divides.
Conditions and scope
- Here 'watershed' means the contributing basin. State the outlet and whether a boundary describes surface drainage or groundwater.
- Water transfers, engineered drainage, geological pathways and changing hydraulic heads can affect a water budget; a topographic boundary does not prove hydrological closure.
Sources · 3
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
- Watersheds and drainage basinsU.S. Geological Survey, Water Science SchoolReference guide
- Simulation of regional groundwater flow in southeastern Wisconsin (2004), groundwater and surface-water dividesD. T. Feinstein, D. J. Hart, T. T. Eaton, J. T. Krohelski and K. R. Bradbury · Wisconsin Geological and Natural History Survey and USGSReference guide · PDF
- Water catchmentsUniversity of Waikato / Science Learning HubTextbook chapter
Evidence and review
Outlet-dependent and nested surface drainage areas, incomplete precipitation-to-streamflow conversion and distinct groundwater divides.
2026-10-10 · Independent Mathematics and Information editor (AI editorial/source review; not the Chemistry/Biology/Earth author). The specified introductory inventory has no unresolved demonstrated material gap after the changes and body-based reuse. Existing advanced references retain their historical scoped approvals. English-only reference prose and explicit Lithuanian-translation-pending status are preserved.
Foundational review
2026-10-10 · Independent AI editorial inspection of this new compact reference entry, its equations, applicability, sources and knowledge connections.
Sources from other places
Scope or convention differs
Land drainage to an outlet and nested catchment examples.
The regional catchment examples do not imply coincident surface and groundwater divides.
University of Waikato / Science Learning Hub
- Water catchments New ZealandEnglish
Opening definition; Catchments can be small or large; Why catchments matter
- Water catchments
Entry details
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- foundation-earth-watershed-divide
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- foundations-audit.1
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- Foundational core completion