1. Chapter 2 The Flow of Fresh Water
Section1
The Active River

2. Rivers: Agents of Erosion
Six Million Years ago the Grand Canyon was as flat as Pitt County farm land.
The Colorado River has worn down through the river bed a distance of over 1 mile.
Erosion is the process by which soil and sediment are transported from one location to another.

3. The Water Cycle
The water cycle is the continuous movement of Earth’s water from the ocean to the atmosphere to the land and back to the ocean

5. 0.7 is All!!!
Out of all the water on Earth, only 2.75 percent is fresh water, including 2.05 percent frozen in glaciers, 0.68 percent as groundwater and percent of it as surface water in lakes and rivers.

6. River Systems
River System – the network of creeks and streams that join to form rivers
These river systems drain a land area of its run off water
Tributary – a creek or stream that drains into a lake or larger stream
In North Carolina, rivers run down from mountains in the west and drain/run east until emptying into the Atlantic Ocean

7. Watersheds Watershed – the drainage basin of a river system
The area of land that is drained by a river system
Greenville, Tarboro, and Washington are in the Tar River/Pamlico River watershed
Raleigh, Kinston and New Bern are in the Neuse River watershed.
Divide – high ground that divides watersheds; example: Continental Divide

8. North American Divides

9. Stream Erosion
As a stream forms, it erodes soil and rock to make a channel
A stream’s ability to erode is influence by three factors: gradient, discharge, and load.
Gradient is the measure of the change in elevation over a certain distance. A high gradient gives a stream or river more energy to erode rock and soil

10. Gradients Low Gradient Less/Slower Erosion Less Energy High Gradient
More/Faster Erosion
More Energy

11. Stream Erosion (cont.)
Discharge is the amount of water that a stream or river carries in a given amount of time. As discharge increases, erosive energy and speed also increase.
Large storms/Snow melt cause increase
Load is the materials carried by a stream. The size of a stream’s load affects its rate of erosion
Fast moving water can move large particles
Rocks in mountain streams
Sand at the ocean

12. 3 Kinds of River Loads
Bed Load – large materials, such as rocks and boulders, that are bounced along a stream bed
Suspended Load – small rocks and soil carried suspended in the water column; gives river its muddy look
Dissolved Load – material carried in solution; dissolved in the water such as calcium, sodium and oxygen

13. How Rivers Change Over Time
Young Rivers – narrow, straight & deep channel, steep gradient, more erosion; many rapids and waterfalls, few tributaries
Mature Rivers – wide channel, lower gradient, less mass erosion, more tributaries = more water discharge

14. How Rivers Change Over Time
Old Rivers – wide, flat flood plains; many curves or bends in the channel, deposit silt and sand along banks
Rejuvenated Rivers - result of tectonic (earth moving) activity
steep gradient again, forms terraces
Terraces - step like formations; like Grand Canyon

15. Chapter 2 The Flow of Fresh Water
Section 2
Stream and River Deposits

16. Deposition in Water
Deposition – the process of rivers dropping their suspended load of rocks and soil.
Sediment – the rocks, sand, pebbles and silt that is deposited by a river as its waters slow down
Rocks
Pebbles Sand Silt
Fast Water
Slow Water

17. Deposition in water (cont.)
Placer Deposits – where a river slows in a curve it can deposit heavy minerals like
Delta – fan shaped deposit where a river empties into a large body of water like an ocean or large lake
Deposits cause new land to be formed
Eventually very fertile soil
Gold

18. Satellite Photo - Nile River Delta
Land build-up with fertile soil showing green plants

19. Deposition on Land
Alluvial Fan - a fan shaped delta-like deposit formed at the base of a mountain

20. Deposition on Land (cont.)
Floodplain – the Pitt-Greenville airport and the land north of the river is on the floodplain for the Tar River.
That’s why that land flooded so badly during Hurricane Floyd

21. Flood Control Dam – Across a river to stop or divert water flow
Levee – sediment built up along a river channel to keep river in its banks

22. Chapter 2 The Flow of Fresh Water
Section 3
Underground Water

23. Location of Groundwater
Water located within the rocks below the Earth’s surface is called groundwater
Zone of Aeration – spaces between soil & rocks is filled with air
Water Table - Dynamic (changing) boundary between zones
Zone of Saturation – spaces between soil and rocks is filled with water

24. Aquifers
A rock layer that stores and allows the flow of groundwater. Affected by…
1. Porosity - the % of open space between particles
2. Permeability – the amount of H2O that can pass through
Impermeable – cannot penetrate

25. Permeability & Recharge Zones

26. Castle Hayne Aquifer

27. Springs & Wells
Natural Spring – where the water table meets the surface of the Earth
Lake - when the water table is higher than the earth’s surface for a large area

28. Artesian Springs
Artesian formation - permeable rock sandwiched between 2 layers impermeable rock
Middle permeable rock = aquifer
top layer = cap rock
Artesian spring – when cap rock breaks or cracks at Earth’s surface
Geothermal (earth heat) heated water = hot spring
“Old Faithful” Geyser

29. Well Human drilling in Earth’s surface down to water table.
If water is drawn out too much or too quickly = cone of depression

30. Underground Erosion and Deposition
Underground water, especially acidic water, can dissolve underground rock resulting in sinkholes or caves
Limestone rock is easily dissolved because it is relatively soft
In caves, form stalactites and stalag ites
If meet in the middle = dripstone column

31. Sinkholes-Underground Cave Breaks Through

32. Chapter 2 The Flow of Fresh Water
Section 4
Using Water Wisely

33. Water Pollution Point Source Pollution – you can point to the source
Nonpoint Source Pollution –
most by runoff – fertilizers,
waste runoff, cattle farms, etc.

34. Health of a Water System
Dissolved Oxygen – fish kills
Temperature – too hot, low D.O.
Nitrates – Weyerhauser (Neuse)
Phosphates – Texas Gulf Mining (Pamlico)
pH - acidic
Turbidity – sediment, too much algae
Biological Indictors – algae, fish kills

35. Monitoring Water Quality
Ground Truthing – Taking samples on the ground to check with satellite images

36. Monitoring Water Quality

37. Cleaning Polluted Water
Sewage Treatment Plants – clean waste out of water
Primary Treatment
1. Large screen to catch solids, paper, bottle caps, etc. Add chemicals to make it clump together
2. Placed in large tank for smaller sludge can settle out. Oils and scum skimmed off of surface.
Secondary Treatment
1. Aeration Tank where H2O & bacteria are added
2. Settling Tank where particles settle out & Chlorine is added

38. More than ½ of NC depend on water from Aquifers
Where Water Comes From:
More than ½ of NC depend on water from Aquifers
Where the water goes:
The average household uses 100 gallons of fresh water per day

39. (Native-naturally found in that area)
Water in Agriculture:
Most lost through evaporation and runoff
Ground level drip hoses – a lot more efficient
Water in Industry:
19% of world’s water used for industry
Most industrial water is now recycled
Water at Home:
Conservation - Low-flow Shower Heads
Wash only full loads of clothes
Plant Native plants to avoid having to water
(Native-naturally found in that area)