What is a Watershed?

What is a watershed?  A watershed (or drainage basin) is an area of land that drains all of its waters through a network of streams and rivers into larger bodies of water. Everybody lives in a watershed because every part of the earth catches some form of water.

In watersheds, the land from which water drains is as important as the water itself. Topography includes … Mountains, valleys, and plains Bodies of water Sometimes, also includes features on the land (natural and human-made) What are Earth’s land forms called? Topography

The topography of the land around you … is shaped by the flow of surface water, and … determines the direction and speed surface water will flow.

 Watersheds are separated by ridges of high ground called divides. What separates one watershed from another watershed?  Divides are part of Earth’s topography.  Every watershed is bounded by divides.  Different streams or rivers empty each watershed.

Montana British Columbia, Canada Washington Oregon Utah Wyoming Nevada Idaho Alberta, Canada Pend Oreille Lake Flathead Lake Clark Fork River Columbia River Pacific Ocean The Columbia River Basin (watershed)  The Clark Fork River joins the Columbia River in Washington. Pend Oreille River Butte

Montana Watersheds Where is the Continental Divide on this map?

Watershed Trivia: What river in Montana carries the most water as it leaves the state’s boundary? The Mighty Clark Fork River The Clark Fork carries nearly twice as much water as it leaves Montana’s border than the Missouri or Yellowstone Rivers.

The west side of Montana has more steep topography than the east side of Montana (flat plains). Montana Watersheds

Montana Map Least Average Annual Precipitation (inches) Most Continental Divide

Why is it important to know about watersheds?  We know this because of how much life we see around water. WATER IS CRITICAL FOR LIFE

Where is the water in this picture?

Humans and other life on land need freshwater. So how much freshwater is on Earth? Most of Earth is covered with water, BUT most of that water is salty (oceans & seas), and much of the rest is ice and snow. Less than 0.6% of Earth’s water is fresh, and available for human use.  Streams, rivers, lakes, and groundwater are all sources of freshwater. OCEANS ICE Freshwater

Every drop of water that touches the surface of the ground does one of three things …

1.It evaporates. Evaporation puts water back into the atmosphere to again become rain or snow. Every drop of water that touches the surface of the ground does one of three things … (cont’d) 2.It soaks into the ground. Once it soaks into the ground, it becomes groundwater, also known as an aquifer. 3.It runs downhill along the ground. This is surface water, which makes its way into streams, rivers, ponds, lakes, and eventually, into the ocean.

Water is not the only thing that gets carried to the sea by streams and rivers.

Materials (sediments & debris) from the land are moved into the ocean in three ways. 1.Bed load  large particles, such as soil, sand, pebbles, or cobbles, that bounce, roll or slide along the stream bed. 2.Suspended load  fine particles that are light enough to float along in the water; can make water murky or turbid. 3.Dissolved load  dissolved material that also moves by floating in the water. When material is dissolved in water, it becomes invisible to the naked eye.

Bon River Delta, Vietnam Safid River Delta, Iran Copper River Delta, Alaska Streams and rivers carry visible and dissolved material into the sea where it is concentrated. Nile River Delta, Egypt Mississippi River Delta, Mississippi

We ALL live downstream from someone.

How do we know if water is healthy?

Healthy stream conditions in Montana …  Stream water that is …  Cold: <15  C (<58  F)  Clear: Low turbidity (not cloudy)  Clean: No contamination  Complex: Deep pools, rapids, healthy riparian vegetation  Connected: Free-flowing streams without dams The 5 C’s  High biodiversity of organisms in and near the stream’s water.

Watershed Science is … The study of all the chemical, physical and ecological processes within watersheds.

Sciences of Watershed Science Economics Social Studies History Geography Geology Biology Chemistry Physics Engineering Legal Studies Art Journalism Mathematics Also Involved in Watershed Science Literature

We all live in a watershed.

Watershed An area of land that drains all its water into a network of streams and rivers that drain the area is called a …

Our watershed is called … Our Clark Fork River drains into … the upper Clark Fork watershed. the Columbia River Basin (watershed).

Topography is … water flow direction and speed water flows Earth’s land forms and is shaped by … and determines …

Watersheds are separated by … Divides

Water is … Critical to life.

Watershed Science involves … Many sciences and other subjects and Is Fun!

QUESTIONS?