The watershed approach is a coordinated framework for environmental management that focuses public and private sector efforts on selected priority problems within hydrologically defined geographic areas, taking into consideration both ground and surface water flow.
What is a watershed?
A watershed is a geographic area in which all water running off the land drains to a specific creek, river or stream. Each region draining into a river system, creek or body of water has a watershed defined by topographic and hydrologic features that separate it from the adjoining watershed.
What's the difference between a watershed and a basin?
Basin - A basin is a large-scale watershed, such as the Kentucky, Salt, Licking and Green rivers. These are also referred to by a U.S. Geological Survey coding scheme called Hydrologic Unit Codes (HUCs). Each of these basins has a six-digit code called HUC6 watersheds. HUC6 watersheds cover an average of 2,525 square miles. Watersheds with more digits are smaller.
Subbasin - Subbasins are smaller scale basins, such as the North Fork Kentucky River, South Fork Licking River, Tygarts Creek, Lower Cumberland or Lower Tennessee. These watersheds have eight-digit codes and may be called HUC8 watersheds. They average 748 square miles.
Watershed - Technically speaking, this refers to all sizes of watersheds as defined above. However, it is common to use this term to refer to watersheds of a size smaller than a basin or subbasin. These watersheds have 10- or 11-digit codes and may be called HUC10 or HUC11 watersheds. HUC11 watersheds average 64 square miles.
Subwatershed - Subwatersheds are smaller watersheds, on the scale of a community. These watersheds have 12- or 14-digit codes and may be called HUC12 or HUC14 watersheds. HUC14 watersheds average 4.4 square miles.
For administrative purposes, Kentucky has grouped the 12 basins into seven management units, each with a dedicated basin coordinator and river basin team, as follows:
Kentucky River Basin
Licking River Basin and minor Ohio River tributaries
Salt River Basin and minor Ohio River tributaries
Green/Tradewater and Ohio tributaries
Upper Cumberland River Basin
Four Rivers (Cumberland, Tennessee, Ohio and Mississippi)
Big/Little Sandy and Tygarts River basins
These management units are each assigned to a five-year basin management cycle, as illustrated by the color-coded map. For example, all basin management units in the green-colored area follow a schedule of activities that includes scoping and data gathering, assessment, prioritization and targeting, plan development and implementation -- then the cycle begins again. Basin management units in the blue-colored area begin the same cycle of activities in the next year, and so on. The Licking and Salt river basins and minor Ohio River tributaries are grouped as are the Upper Cumberland and Four Rivers basins.
