How misapplication of the hydrologic unit framework diminishes the meaning of watersheds

Environmental Management
By: , and 



Hydrologic units provide a convenient but problematic nationwide set of geographic polygons based on subjectively determined subdivisions of land surface areas at several hierarchical levels. The problem is that it is impossible to map watersheds, basins, or catchments of relatively equal size and cover the whole country. The hydrologic unit framework is in fact composed mostly of watersheds and pieces of watersheds. The pieces include units that drain to segments of streams, remnant areas, noncontributing areas, and coastal or frontal units that can include multiple watersheds draining to an ocean or large lake. Hence, half or more of the hydrologic units are not watersheds as the name of the framework “Watershed Boundary Dataset” implies. Nonetheless, hydrologic units and watersheds are commonly treated as synonymous, and this misapplication and misunderstanding can have some serious scientific and management consequences. We discuss some of the strengths and limitations of watersheds and hydrologic units as spatial frameworks. Using examples from the Northwest and Southeast United States, we explain how the misapplication of the hydrologic unit framework has altered the meaning of watersheds and can impair understanding associations between spatial geographic characteristics and surface water conditions.

Publication type Article
Publication Subtype Journal Article
Title How misapplication of the hydrologic unit framework diminishes the meaning of watersheds
Series title Environmental Management
DOI 10.1007/s00267-017-0854-z
Volume 60
Issue 1
Year Published 2017
Language English
Publisher Springer
Contributing office(s) Earth Resources Observation and Science (EROS) Center
Description 11 p.
First page 1
Last page 11
Google Analytics Metrics Metrics page
Additional publication details