HUCs

HUCs, or Hydrologic Unit Codes, are a system of numerical identifiers used to categorize and organize watersheds and drainage basins in the United States. Developed by the United States Geological Survey (USGS), these codes help in the management, analysis, and representation of hydrological data across various scales.

The HUC system assigns a unique code to each watershed, reflecting its hierarchical position within the larger hydrologic framework. These codes are structured in a multi-level hierarchy, with smaller units nested within larger ones. The levels range from two-digit codes representing major drainage basins, to more detailed six-, eight-, or twelve-digit codes for sub-watersheds and smaller hydrologic units. For example, a two-digit HUC might denote a major river basin, while a twelve-digit HUC identifies a specific, localized watershed.

HUCs are widely used in environmental monitoring, water resource management, and policy planning. They facilitate data aggregation and analysis by providing a standardized way to reference specific hydrologic regions. Agencies such as the USGS, Environmental Protection Agency (EPA), and state water authorities utilize HUCs for mapping, data collection, and decision-making purposes.

Overall, the HUC system plays a critical role in hydrological understanding and resource management in the United States, enabling scientists, policymakers, and resource managers to coordinate efforts across different regions and scales efficiently.