Landscape Characterization / Impervious Surfaces / What are watersheds?
What are watersheds?
page index 1 |
2 | 3
| 4
Sub-watersheds and Watershed Order
A large watershed like the Chesapeake Bay Watershed is composed
of numerous sub-watersheds that are drained by tributary streams and rivers.
The Bay's sub-watersheds are shown on the following map. The largest is the
watershed of the Susquehanna River which drains parts of New York, Pennsylvania,
and Maryland before entering the bay at Havre de Grace, Maryland. These sub-watersheds,
in turn, are composed of the yet smaller watersheds of streams draining into
their main channels.
The Sub-Watersheds of the Chesapeake Bay. Source:
www.chesapeakebay.net
Watersheds, like streams, are ranked according to order. A first-order
watershed is drained by a first-order stream, whereas the main channel of a
second-order watershed is a second-order stream, and so on for each higher-ordered
watershed. A large watershed, therefore, is a nested hierarchy of numerous lower-ordered
basins or sub-watersheds.
Nested Watersheds: Source Marsh 1998, 170.
page index 
1 | 2
| 3 | 4
| 
