# Presentation: 506953

## Watersheds

- Prepared 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 ridges
- These ridges mark the edge of the basin
- This 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-watersheds

- Watersheds are nearly always part of a larger watershed
- Watersheds 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-watersheds

- Watersheds are a lot like nested toys...
- One fits inside another that is bigger
- That one fits inside one even bigger
- And that one fits inside one that is still bigger yet
- And on and on and on....

## The Neel Creek Watershed

- Now, 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 Creek

- King’s Hill

*Creek*

*Neel*

## The Belt Creek Watershed

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

- King’s Hill

*Neel Creek*

*Belt*

*Creek*

## The Missouri River Watershed

- From Belt Creek, ALL the water, whether it is from rain or snow, flows into the Missouri River

*Missouri*

- King’s Hill

*Neel*
*Creek*

*River*

- Great Falls

## The Missouri River Watershed

- From 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

- King’s
- Hill

*Missouri River*

*Mississippi River*

## The Mississippi River Watershed

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

## 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

- 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

## 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!

## Montana’s Triple Divide

- Montana is the only state with a *triple* watershed divide
- In Glacier National Park
- Instead of the watershed divide sending the water in two directions, the water is sent in *three* directions

## Montana’s Triple Divide

- The rain and snow that falls in this area goes to...
- The Columbia River
- Hudson’s Bay
- The Missouri River

- To the Columbia River

- To Hudson’s Bay

- To the
- Missouri River

## Can you find some watersheds and sub-watersheds?