(light adventurous music) I think the water here at Great Falls Park is majestic.

It's hard to believe it's just water moving through a never-ending system.

Today, we're gonna learn the process of how water moves within this system.

(light adventurous music) We're achieving a serious state of flow on this episode of "Spotlight Earth."

(light adventurous music) Looking at this waterfall reminds me of how water moves through our entire Earth, within something called the water cycle.

My co-host Jarrell is back in the studio, shining a rainbow-inducing light on the water cycle.

Jarrell, take it away while I enjoy the view.

Thanks, Hales.

That looks amazing.

Jealous of the experience you're having today.

I may be stuck in the studio, but I've got a lotta cool resources here that will help us understand the water cycle.

(soft contemporary music) Water is all around us, in different states.

In fact, Earth is the only place we found in the cosmos where water exists in liquid, frozen, and gas phases.

And it changes between phases, starting with evaporation.

This is when water, as a liquid, gets heated up and changes to a gas.

This water vapor moves up in the atmosphere, and as it does so, it cools, causing it to condense.

It condenses on what is called a condensation nuclei, which is what scientists call a grain of sand, dust, or particulate in the air.

When it changes from a vapor to a liquid, it is called condensation, which is the next step in the water cycle.

Condensation happens when clouds form as a result of accumulation of condensed water.

It gets too heavy for the air to hold it, and then comes back down to Earth as precipitation.

You know, rain, snow, sleet.

It's pretty much any form of water from the sky.

Once the precipitation hits the ground, it can run off, staying on the surface and eventually moving into bodies of water, or infiltrate, which means it moves into the ground.

We'll get into groundwater and surface water in a bit.

The water cycle is continuous, that means it happens over and over again continuously, which is why it's a cycle.

We also have respiration, vapor coming from animals breathing, and transpiration, vapor coming from plants.

Sublimation is the process of solid water like snow or ice, becoming vapor directly without a liquid phase in between.

These are part of the water cycle as well.

So just to recap, it goes evaporation, condensation, precipitation, and then runoff or infiltration.

Let's head back to Great Falls National Park and Hales, to look at how water is either surface or groundwater.

Thanks, Jarrell, great explanation of the water cycle.

You mentioned runoff and infiltration.

Let's dive deeper into those topics.

(water rushing) If you look around me, you'll see all this water moving on the surface of the Earth.

This water is called surface water.

It's the water we can see.

The Potomac River is a perfect example.

We see this water every day in ponds, lakes, streams and rivers, and at the beach and oceans.

Surface water is on the surface of the Earth.

(waves breaking) Groundwater is in the ground under the Earth's surface.

If we put water on a spot of dirt, we will see the water infiltrate or move into the ground.

Moving through permeable rock layers and into aquifers.

Infiltration is really important.

It's how we raise the water table to meet the needs of usage.

The water is cleaned by the rocks in the ground, and in most cases, can be safely tapped and used for drinking water and agriculture.

Ultimately, water is always trying to get to the lowest elevation point possible.

Normally, that's sea level.

More from Great Falls still ahead, but for now, let's head back to the studio.

Hey, Jarrell you still there?

Hey, Hales.

Yep, still here in the studio.

I wanna tell you about how we use our water in our environment.

There are three main types of water use, residential, agricultural, and industrial.

Residential is the use of water in your home, like watering plants, doing your dishes, washing clothes, and brushing your teeth.

It's the simple task you do every day, all day long.

Agriculture is for farming and livestock, things that are happening on the farm, like watering plants and hydration for animals.

Industrial, according to the United States Geological Survey is water used for fabricating, processing, washing, diluting, cooling or transporting a product.

Water is also used by smelting facilities, petroleum refineries and industries producing chemical products, food and paper products.

Did you know that the most common use of water is in your household?

That means what you do every day really matters.

We know that water moves through a cycle, so we aren't getting rid of any, but it's not always going back where we need it.

The amount of fresh water is the same now as it was 10,000 years ago at the end of the last Ice Age.

But our population has exploded from 1 million people on the planet then to 8 billion people now, and all 8 billion of us, plus all the other living organisms and ecosystems need fresh water too.

If the water table drops too low, there won't be enough water for all the things we need it for.

Water is a precious resource that needs to be protected from overuse and pollution.

So as you can see, we use water in a lot of different ways in our lives, maybe even in ways we might not have known.

Let's wrap up this episode by checking in with Hales who was joined by a very special guest who can tell us more about how water moves and how we use it.

That's right, Jarrell.

Today, I am joined by Susan Finta.

She is a park ranger at Great Falls Park.

Susan, thanks for joining us.

Obviously, the water is a huge feature here at Great Falls Park.

How does the Potomac play into your mission here?

The Potomac River is a state border between Virginia and Maryland.

Starts at Fairfax Stone, West Virginia, and it flows over 380 miles and ends at the Chesapeake Bay.

And where we're standing is about two thirds of the way from start to end.

So where's the water in the park come from?

What's the source?

So starting at Fairfax Stone, West Virginia, a little stream bubbles up out of the ground and along the route of over 200 miles, it's picking up drainage from the mountains, from rain, from snow melt, and all of that water crashes over the waterfalls here at Great Falls on its way down to the Chesapeake Bay and to the Atlantic Ocean.

Very cool.

So does the water here impact the rest of Virginia in any way?

Absolutely.

There are millions of people who depend on this river for fresh drinking water.

Above us here at Great Falls, there's an Aqueduct Dam that was built back in the 1850s by the U.S.

Corps of Engineers, and it draws water out of the Potomac and that feeds the nation's capital fresh water, as well as Arlington County, parts of Maryland.

Fairfax County also draws water out and Loudoun has water above the river, above the Great Falls as well that's being brought in for drinking water.

When you have pollution that is up river, the river is gonna carry that pollution all the way down its course.

And if you have something that's degradating the environment, that will have a terrible impact all along its course.

These are things that are all interwoven and connected, and if we lose our rainwater, if we lose our snowfall, we're gonna lose our fresh Potomac River water as well.

Water is life and the Potomac is an incredible life source for millions of people.

Susan, this place is amazing.

Thank you so much for having us.

Oh, you're very welcome.

Thank you for coming.

(light adventurous music) As we've learned today, water is everywhere and infiltrating every part of our lives.

We need water to make our ecosystems function and our communities thrive, which is why the water cycle is so important to us and our world.

Thanks for watching, and we'll see you next time on "Spotlight Earth."

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