WatershedsWatershedsPrepared by the National Weather Service

Great Falls Weather Forecast Office

What is a watershed?A watershed is an area

of land where all the water, on the surface and underground, flows to the lowest point

At the lowest point it joins another stream, lake or river

A watershed is also know as a stream basin, river basin or drainage basin

What is a watershed?The runoff in a

watershed generally begins at the land ridgesThese ridges mark the

edge of the basinThis is the ‘drainage

divide’

What is a watershed?The drainage

divide sends the rain and snowmelt to one side of the divide or the other

What is a watershed?No matter where you

live or play, you’re in a watershed!

What is a watershed?Again... all the

water that falls over a watershed, whether it is rain or snow, drains to a single point at the outlet of that basin

Watersheds and sub-watershedsWatersheds are nearly

always part of a larger watershedWatersheds are

subdivided into smaller pieces known as sub-basins or sub-watersheds

These flow together to form larger sub-basins and river basins. 

Watersheds and sub-watershedsWatersheds are a

lot like nested toys...One fits inside

another that is biggerThat one fits inside

one even biggerAnd that one fits

inside one that is still bigger yet

And on and on and on....

The Neel Creek WatershedNow, let's use the

King’s Hill watershed as an example...

ALL the water, whether it is from rain or snow that falls on this side of King’s Hill eventually finds its way into Neel CreekKing’s Hill

Cre

ek

Neel

The Belt Creek WatershedFrom Neel Creek,

ALL the water, whether it is from rain or snow, flows into Belt Creek

King’s Hill

Neel Creek

BeltCreek

The Missouri River WatershedFrom Belt Creek,

ALL the water, whether it is from rain or snow, flows into the Missouri River

Belt Cre

ek

Missouri

King’s Hill

NeelCreek

RiverGreat Falls

The Missouri River WatershedFrom the

Missouri River, ALL the water, whether it is from rain or snow, flows across eastern Montana, North Dakota, South Dakota, along the border of Nebraska and Iowa, along the border of Kansas and Missouri, across Missouri and into the Mississippi River

Belt

Cre

ek

King’sHill

Missouri River

Mississippi River

Gulf of Mexico

Atlantic Ocean

Pacific Ocean

River BasinRiver BasinRiver BasinRiver Basin

River BasinRiver Basin

River BasinRiver BasinRiver BasinRiver Basin

River BasinRiver Basin

The Mississippi River WatershedFrom the

Mississippi River, the water continues to flow south and eventually empties into the Gulf of Mexico

Gulf of Mexico

Atlantic Ocean

Pacific Ocean

River BasinRiver BasinRiver BasinRiver Basin

River BasinRiver Basin

River BasinRiver BasinRiver BasinRiver Basin

River BasinRiver Basin

King’s Hill

Cre

ek

Neel

Belt Cre

ek

Missouri

King’s Hill

NeelCreek

RiverGreat Falls

So this means that...

Neel Creek is a part (or sub-basin) of Belt Creek watershed

Belt Creek is a part of the Missouri River watershed

The Missouri River is a part of the Mississippi River watershed

And the Mississippi River is a part of the Gulf of Mexico watershed

The Mississippi River Watershed

King’s Hill

Neel Creek

BeltCreek

The Missouri River Watershed... and everything

that happens in the Neel Creek watershed has an impact on Belt Creek, the Missouri River, the Mississippi River and the Gulf of Mexico!

Gulf of Mexico

Atlantic Ocean

Pacific Ocean

River BasinRiver BasinRiver BasinRiver Basin

River BasinRiver Basin

River BasinRiver BasinRiver BasinRiver Basin

River BasinRiver Basin

Montana’s Triple DivideMontana is the

only state with a triple watershed divideIn Glacier

National ParkInstead of the

watershed divide sending the water in two directions, the water is sent in three directions

Montana’s Triple DivideThe rain and

snow that falls in this area goes to...The Columbia

RiverHudson’s BayThe Missouri

RiverTo the Columbia River

To Hudson’s Bay

To theMissouri River

Can you find some watersheds and sub-watersheds?