Watersheds ESI ESI

A map of streams in an area Can you determine the watershed for this stream?

N Major stream in watershed Drainage divide high spot or ridge B What is general streamflow direction? Any water flowing north? Cross-section

B A Cross-section Drainage Divide Runoff to the west Runoff to the east Looking north up ridge B A Cross-section

Major streams in watershed headwaters Watershed boundary headwaters Tributary to major stream mouth main channel mouth

Stream Gradient Water flows downhill ! headwaters Drop in elevation -Idiot’s Guide to Stream Hydrology Drop in elevation mouth Distance traveled Stream Gradient = Drop in elevation, feet Distance traveled, miles (average) Typical stream gradient in Prince George’s County – xxx ft/mi

N Area of collection of precipitation

Steps in the hydrologic cycle precipitation runoff and stream – surface flow evaporation transpiration infiltration groundwater (subsurface) flow evapotranpiration

runoff precipitation transpiration evaporation infiltration groundwater

N Watershed subwatershed Even smaller subwatershed

Nested watersheds airshed watershed Watershed is like a funnel Container such as Chesapeake Bay

Watershed and Airshed of Chesapeake Bay

http://www.dnr.state.md.us/streams/acid/page4.html

Maryland’s Watersheds To the Delaware Bay watershed To the Mississippi River Watershed East coast continent divide 95% of Maryland drains water into the Chesapeake Bay To the Atlantic Ocean directly http://mddnr.chesapeakebay.net/wsprofiles/surf/prof/prof.html

Prince George’s County Potomac River Watershed Patuxent River Watershed Drainage Divide in Prince George’s County