Figure 3 Concept map describing the among plate magma, and...

Figure 3.

Concept map

describing the

relationships

among plate

boundaries,

magma, and

volcanoes.

1

The Good Earth/Chapter 6: Volcanoes and Other Mountains

ESC1000 • Earth Science • Summer 2016

2

Streams and Floods

(Chapter 11)

Groundwater and Wetlands

(Chapter 12)

What are unique features of some bodies of water in Florida?

- Kissimmee River, Lake Okeechobee, the Everglades

Which areas of Florida are prone to flooding, and why?

What are the major types of groundwater systems and

aquifers here? Which factors influence them?

How have the Everglades changed over time?

What is unique about this ecosystem?

Why are there so many invasive species in South Florida?

(questions to be continued, for Florida’s ocean, atmosphere,

weather, and climate)

Unit 3 of ESC1000 (also known as the next two weeks)Learning Goals: Florida Ecosystems

3

Florida’s Rivers and Wetlands:Focus on the Everglades

The Good Earth/Chapter 11: Streams and Floods

Wildlife:

https://www.youtube.com/watch?v=xfYAj1k9uZM

4


Chapter 11: Streams and Floods

Copyright © McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

1.

2.

3.

4.

5.

6.

7.

Humans and Rivers

The Hydrologic Cycle

Drainage Networks and Patterns

Factors Affecting Stream Flow

The Work of Streams

Floods

Flood Control

5

We will cover the basics of all these topics.

Focus on how these concepts apply to

Florida bodies of water.



6



The vast majority of Earth’s water is in the oceans (97%) with only about

3% on land.7



Most of the water on land is stored in ice or groundwater.8



9



Land receives more moisture by precipitation than it supplies by evaporation.

The balance comes from evaporation from the oceans. This excess water is

returned to oceans via surface streams. 10



What controls the amount

of water in a stream

channel?

The size of the area it

drains

The average precipitation

over the area

The Nile and the Mississippi have

the largest drainage basins, each

covering over 1 million sq mi.

Drainage basin = the area drained by a stream and its

smaller streams (tributaries). Above, the Mississippi

drainage basin is composed of several smaller drainage

basins (colored areas). It takes up half the land area of the

U.S.11



Why do stream patterns

look like the branches

of a tree?

Streams will follow the

path of least resistance,

forming valleys where

rock is most readily

eroded or following the

steepest slope.

Dendritic drainage

patterns are

characteristic of areas

where the geology is

relatively uniform.

The tips of the v’s

where streams come

together point down

stream.

12



Trellis patterns – streams

intersect at right angle

forming rectangular

drainage patterns.

Found in areas of

alternating layers of weak

and resistant rocks.

Main streams flow parallel

to ridges, cutting across at

water gaps.

Smaller streams flow

down slope perpendicular

to the course of the main

stream.13



Rectangular patterns – occur in

regions where the streams are

controlled by joints, fractures in

the underlying bedrock. Streams

exploit these fractures and flow in

them.

Radial patterns – typically found

on the flanks of volcanoes, where

streams flow downhill from the

summit.

14

Factors Affecting Stream Flow


Gradient = the slope of a stream. It is the change in elevation

of the stream over a horizontal distance.

15

The Work of Streams


Erosion produces stream load,

which is the combination of

bed load, suspended load, and

dissolved load.

How is stream color affected by load?

Suspended load increases when discharge increases

(higher velocity = more energy to move particles).

http://highered.mheducation.com/sites/007

3524107/student_view0/chapter11/modes_

of_sediment_transport.html

Animated

Version:

16

http://highered.mheducation.com/sites/0073524107/student_view0/chapter11/modes_of_sediment_transport.html

The Work of Streams


As a stream

slows down it

drops some of

its load. Heavier

particles drop

out first.

When a stream

has a heavy

load, sediment is

often deposited

in the stream

channel itself to

form bars or

islands.

These deposits

split the channel

into smaller

channels

forming a

braided channel.

A braided

channel,

Alaska

The Yellow River,

China, carries the

highest sediment

load relative to its

discharge of any

river in the world!

17

The Work of Streams


Meanders = broad curves in a stream. Velocity of the stream varies as it

moves through these large bends.

As a meander

becomes larger

the channel

migrates across

the flood plain in

the direction of

erosion.

18

The Restored, MeanderingKissimmee River

http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::640::480::/sites

/dl/free/0073524107/30425/10_22_10_23.swf::River Meander Development

River Meander Development:

19

http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::640::480::/sites/dl/free/0073524107/30425/10_22_10_23.swf::River Meander Development


Floods

Influenced by:

- Magnitude, timing, and type

of precipitation

- Human modifications of the

physical landscape

- Capability of the ground to

absorb water

- Evaporation rates

- Physical characteristics of

the stream system

Floods usually occur when the amount of

water on the land surface exceeds the

volume of water that can be transported in

stream channels and absorbed into the

surrounding soil.

20


Floods

This was spatially the largest flood in U.S. history!

It covered 44,000 square km or 17,000 square miles.21


Floods

How do humans influence flooding?

- Paving covers or alters natural surfaces that otherwise

might absorb water.

- Storm sewers that divert water from surfaces dump it into

natural streams causing them to flood.

- Housing developments or agricultural fields replace

natural wetlands, which act as water storage reservoirs.

- Constructed dams collapse.

22


Flood Control

• Cities located on flood plains suffer the most economic losses

• Floodwaters can carry contaminated water (sewage, agricultural chemicals)

• Roads get submerged and have to be closed and repaired after the flood

• Farmland submerged – production falls

• Floods can deposit thick layers of sediment where it should not be

• Can halt barge traffic for months

• People die and are uprooted and evacuated

23

Types of Flood Control


• Levees and Floodwalls

• Dams

• Floodway

24



Wildlife:


Kissimmee River Restoration:

https://www.youtube.com/watch?v=nN95KTVeUDA

25

- How has the shape of the Kissimmee River changed over time?

- How does its shape impact other wetlands and water bodies in

South Florida?

- What is the history of flooding around the Kissimmee River?

- What type of flood control (if any) has been used around the

Kissimmee River and other water bodies or wetlands in South

Florida?



Chapter 12: Groundwater and Wetlands

Copyright © McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

1.

2.

3.

4.

Meet Your Drinking Water

Holes in Earth Materials

Groundwater Systems

A Case Study: The High Plains

Aquifer

Groundwater Quality

Introduction to Wetlands

5.

6.

26

Again, we’ll cover the basics of these topics.

Focus on applying the concepts to Florida

bodies of water – especially the Everglades.

The Good Earth/Chapter 12: Groundwater and Wetlands


Which is

better to

drink?

Whether it is

from a bottle

or the tap,

our drinking

water

comes from

the same

place and

undergoes

similar

processing

and

monitoring

to make it

safe. 27



• The consumption of bottled water in the U.S. is

growing fast, faster than any other beverage.

• Tap water is just as good, and costs 1,000 times less

than bottled water.

• About ¼ of all bottled water is simply bottled tap water.

• Purified water = tap water that has undergone

additional treatment prior to bottling

Where does our drinking water come from?

Streams and lakes (on the Earth’s surface)

Groundwater (water in rocks or unconsolidated materials

below the Earth’s surface)

28



Most of the water on land is stored in ice or groundwater.29



• On average, the length of time that a given volume of water remains in

streams is about 14 days.

• Only a small amount of precipitation on land sinks into the ground, as

infiltration rates are slow compared to runoff rates.

• Many rivers have their sources in springs that bring groundwater to the

surface (e.g. the Nile).

• Many rivers have sources in glacial melt water (e.g. Ganges).

30



• Water supplies are most likely to be contaminated by human actions

• e.g. chemical leaks from storage tanks

• 53,000 community water systems in the U.S.

• Few become polluted, but this pollution can cause health risks

• Cleanups can be tricky, especially for underground sources

31

Holes in Earth MaterialsThere’s more water underground than in lakes and streams on

Earth’s surface (about 70% more!)


Most groundwater is in billions of tiny spaces between mineral

grains or in narrow cracks.

The amount of groundwater at any location depends on the

porosity and permeability of materials beneath the surface.

Porosity = the proportion

of a material that is made

up of spaces.

(e.g. if ½ the total volume

of a rock is pore space,

the porosity is 50%)

Depends on size and

arrangement of the grains

(better sorted – higher

porosity). 32



As material grains compacted or cemented, porosity decreases.

33



Permeability = the capacity of

water to flow through earth

materials.

Water can flow readily through

materials with well connected

pore space or many fractures.

Connections between pore

spaces are wider in coarse-

grained material (gravels) than

fine-grained material (sand).

High permeability does not always

go hand in hand with high

porosity.Q: Why do you think

groundwater flows more

slowly than water on the

Earth’s surface?A: More opportunities for friction to slow it

down as it pushes through spaces between

millions of tiny grains. 34

Groundwater Systems


Groundwater is stored

in bodies of rock

and/or sediment called

aquifers, which are

composed of sufficient

saturated permeable

material to yield

significant quantities of

water.

35

Aquifers can form in a variety of geologic settings

Aquifers can be

composed of

sands, gravels,

sandstone with

good porosity

and permeability,

and fractured

rocks.


Florida:

Sand and gravel aquifers

Carbonate aquifers36

Groundwater Systems

The Good Earth/Chapter 12: Groundwater Wetlands

Aquifer Quality

-High porosity and permeability

-Most productive aquifers are found in unconsolidated earth materials (80% of all

groundwater withdrawn in U.S. comes from sand and gravel aquifers)

-Aquitards – low-permeability materials such as clay, shale, or unfractured igneous

or metamorphic rock, that act as a barrier to water flow

Open water Aquifer. 37

Groundwater Systems

In general, the water table follows the shape of the

land surface


The top of the saturated zone is the water table, and it is highest under

hills and lowest in valleys. Water flows down the slope of the water table.

When the water table intersects the land surface a stream, lake, or spring

will occur. 38

Groundwater Systems


Confined (Artesian) Aquifer – enclosed above

and below by impermeable materials. Water

can only enter the well through the exposed

rock layer (recharge zone).39

Groundwater Systems


How does groundwater interact with oceans?

In coastal regions, fresh water is found floating above a denser layer of

saltwater. Saltwater infiltrates the ground just like fresh water. Where the

freshwater layer meets the coast it flows into the ocean.

In coastal cities, freshwater can be extracted from the freshwater layer, but

if it is extracted faster than it is replenished, saltwater can flow into wells.

40

Groundwater Quality


Potential sources of groundwater pollution in the U.S.

41



To be a wetland an area must be:

• saturated with water and

• have poorly drained soils and

• specific types of plants.

Two types: coastal and freshwater

42



Wetlands must meet the following criteria:

Hydrologic conditions – water present on land surface, or soils in

root zone must be saturated during growing season or longer.

Hydrophytic vegetation – specific plants that are water-tolerant

and grow under wet conditions (e.g. cattails, wild rice, willows,

sawgrass) must be present

Hydric soils – poorly drained soils that exhibit anaerobic conditions

during growing season

43



In lower 48, largest wetland areas are in Texas, Florida, Minnesota.

~10% or less of original wetlands remain in California, Ohio, and Iowa.

Losses are due to draining to support agriculture, or draining and infilling

for urbanization and development.

Why should we care?

Wetlands perform many positive functions in the

environment such as improving water quality in rivers by

filtering out sediments and contaminants, providing breeding

grounds for fish and shellfish which supports commercial

fishing, providing ecological habitats for migrating birds,

modifying the effects of flooding by slowing runoff, and

providing recreation for humans.

44



The Florida Everglades (the “river of grass”) experienced a loss of wetlands due to

population growth and urbanization.

Development in the early 1900’s had four goals – “dike it, dam it, divert it, drain it.”

Lost 50% of original wetlands destroying fish and wildlife habitats.

Wetlands were replaced by agricultural sugarcane, and expansion of coastal cities

further stressed the ecosystem.

Attempts to partially restore the wetlands are ongoing.

45

Earth Science in the News

46



Wildlife:


Kissimmee River Restoration:


TEDxUF Everglades Conservation

https://www.ted.com/talks/mac_stone_stunning_photo

s_of_the_endangered_everglades?language=en

47



https://www.ted.com/talks/mac_stone_stunning_photos_of_the_endangered_everglades?language=en

Date post:	15-Apr-2020
Category:	Documents
Upload:	others
View:	4 times
Download:	0 times

Figure 3 Concept map describing the among plate magma, and...

Documents