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How land and water are linked (Video)

Video Transcript

[A maple leaf flies across the screen and lands to the left. A photo of wheat plots fades into the background. Small circles appear containing images relevant to agriculture. The Canada wordmark and the departmental signature fade in. The title of the video appears on screen.]

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Text on screen: Watershed Management - How Are Land and Water Linked?

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[A blue background containing many light squares fades in over the whole frame. Text starts to fade in over the blue background. A large, cartoon drop of water appears in the upper left side of the frame next to the first line of text.]

Text on screen: Saline water in oceans: 97.2%

Male narrator: More than 97% of all the world's water is found in the oceans. Since ocean water is saline, that means less than three percent of all water is fresh.

[More lines of text start fading in over the blue background. Beside each new line of text a cartoon drop of water appears. The drops get smaller as they go towards the bottom of the screen.]

Text on screen: Ice caps and glaciers: 2.14%, Groundwater: 0.61%, Surface water: 0.009%, Soil moisture: 0.005%, Atmosphere: 0.001%

Of this amount, almost all is in the form of glaciers and groundwater, which leaves less than one one-hundredth of one percent of the earth's water as fresh surface water.

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[A picture of a lake fades up on screen.]

Twenty percent of this surface water is in a single lake—Lake Baikal in Russia.

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[A different picture of a lake fades up on screen.]

With another 20% in the Great Lakes of North America.

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[The blue background fades back up. A picture of the planet earth fades up over the blue background.]

The remainder forms all the other lakes, rivers, streams and wetlands on earth. The final tiny fraction exists as soil moisture and atmospheric water vapour.

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[A photo of an irrigated field fades up on screen.]

The agricultural sector is by far the biggest user of freshwater.

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[A photo of cattle grazing in a field with pronounced mountains in the background. The photo appears to have been taking somewhere in Asia.]

In Africa and Asia, an estimated 85-90% of all fresh water used is for agriculture.

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[A photo of flooded rice fields fades in.]

According to estimates for the year 2000, agriculture accounted for 67% of the world's total freshwater withdrawal, and 86% of its consumption.

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[A photo of a field being irrigated by a machine.]

We use the water to irrigate crops and although a large percentage of the water returns to the fields...

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[A photo of a field being irrigated by a large sprinkler.]

...often it has been changed and is carrying soil and dissolved compounds.

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[A blue background containing many light squares fades in over the whole frame. Text starts to fade in over the blue background. A three dimensional representation of how land meets water fades in over the blue background.]

Land and water are linked together through the Hydrologic Cycle. Although the atmosphere may not be a great storehouse of water, it is the superhighway used to move water around the globe. Liquid water is changed into water vapour with 90% due to evaporation and 10% due to transpiration.

[A blue arrow fades in. The arrow is indicating the direction of evaporation from the body of water.]

This water vapour rises into the atmosphere on warm air currents.

[A cloud appears to indicate how evaporated water creates clouds.]

Cooler temperatures high in the atmosphere cause vapour to condense into clouds.

[Two new clouds fade in to indicate how clouds shed their moisture over land.]

Strong winds move the clouds around the world until the water falls as precipitation.

[Two additional arrows fade in. The arrows are indicating how moisture travels back to the body of water after being deposited on land.]

Precipitation that falls on land completes the cycle of fresh water and results in either runoff or groundwater.

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[A blue background containing many light squares fades in over the whole frame. Text starts to fade in over the blue background. A photo of a field fades up. There is water runoff on the surface of the field.]

Text on screen: Runoff - Runoff is simply water that is transported over the earth's surface.

Runoff is simply water that is transported over the earth's surface. As it flows, it may move into the ground, evaporate into the air, be stored in lakes and reservoirs, or be extracted for agricultural or other human uses.

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[A blue background containing many light squares fades in over the whole frame. Text starts to fade in over the blue background. A graphic showing how rainwater infiltrates the layers of the ground.]

Text on screen: Infiltration - Infiltration is the penetration of water on the soil, or ground surface, into the ground.

Infiltration is the penetration of water on the soil, or ground surface, into the ground. Once it has infiltrated, water is held as soil moisture or groundwater.

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[A blue background containing many light squares fades in over the whole frame. Text starts to fade in over the blue background. A graphic showing how rainwater moves under the surface of the ground appears. A blue arrow fades in to indicate the direction of flow; left to right.]

Text on screen: Subsurface Flow - Subsurface flow is the flow of water underground, in unsaturated soil and aquifers. Groundwater tends to move slowly, and is replenished slowly, so it can remain in aquifers for up to thousands of years.

Subsurface flow is the flow of water underground, in unsaturated soil and aquifers. Subsurface water may return to the surface by way of a spring, by being pumped to the surface, or eventually seeping into the oceans. Groundwater tends to move slowly, and is replenished slowly, so it can remain in aquifers for up to thousands of years.

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[A blue background containing many light squares fades in over the whole frame. A drawn graphic fades in over the blue background. Blue arrows appears to indicate how contaminants flow downwards into the groundwater.]

Since most water that falls on the land eventually makes its way to either a ground water or a surface water source, anything that happens on the landscape can have a big impact on the quality of the water.

[New blue arrows appear to indicate how contaminants can flow overland and contaminate nearby waterways.]

There may be surface runoff of pesticides, fertilizers and manure, or leaching of nitrogen into groundwater, the fate of which is discharge to surface water bodies.

[The original blue arrows now change direction to indicate how groundwater contamination can also contaminate area waterways.]

That means dissolved contaminants will eventually find their way into lakes, rivers or the ocean.

[The blue arrows fade out. A symbol with the letter "p" appears over the waterway. It sinks into the waterway and slowly fades out. Smaller symbols with the letter "p" fade in and move into the ground from the water source.]

Much of the phosphorus that is moved from agricultural lands is bound to soil particles. Although it may not be a problem in this form, once deposited in fresh water sediments, there may be slow release of phosphorus in a dissolved form that can be readily taken up by aquatic plants. For this reason, the effects of deposition may be felt for many years after the source is removed or controlled.

[The symbols with the letter "p" fade out. Blue arrows fade back in to indicate how air contaminants, such as airborne pesticides and dust from pesticide treated fields, can also contaminate area waterways.]

Also notice that airborne dust with adsorbed phosphorus and organic matter can travel great distances before being deposited by gravity or with precipitation.

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[A blue background containing many light squares fades in over the whole frame. A chart containing information on how long water stays contained in various natural sources fades up.]

Text on screen: Residence Time

Reservoir Average Residence Time
Atmosphere 9 days
Soil Moisture 1-2 months
Snow 2-6 months
Rivers 2-6 months
Lakes 50-100 years
Glaciers 20-100 years
Shallow Groundwater 100-200 years
Oceans 3,200 years
Deep Groundwater 10,000 years

Residence time is the average period water spends in different parts of the hydrologic cycle.

[A red circle appears around "10,000 years".]

Notice that groundwater can spend more than 10,000 years beneath the earth's surface before entering another part of the cycle, which means polluted groundwater may remain contaminated for very long periods.

[The red circle around "10,000 years" fades out. A red circle appears around "1-2 months".]

On the other hand, water stored in the soil remains there only very briefly, because it's spread so thinly across the Earth, and is readily lost by evaporation, transpiration, stream flow, or groundwater recharge.

[The red circle around "1-2 months" fades out. A red circle appears around "9 days".]

After evaporating, water remains in the atmosphere for about 9 days on average, before condensing and falling to the Earth as precipitation.

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[Three circles containing images moving quickly towards the camera. Once full screen they slip off to the upper left and off screen. A grey ribbon moves in behind the circles as they become full screen. The circles line up, zoom out, and center themselves in the middle of the screen. The Agriculture and Agri-Food Canada departmental signature appears below the circles.]

Text on screen: Agriculture and Agri-Food Canada. Agriculture et Agroalimentaire Canada.

[Cross-fade to the Canada with an animated Canadian flag over the last letter in the word.]

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