1. Louisiana: The History of an American State
Chapter 2
Louisiana’s Geography: Rivers and Regions
Study Presentation
©2005 Clairmont Press

2. Louisiana: The History of an American State
Section 1: Louisiana’s Location
Section 2: Louisiana’s Waterways
Section 3: Louisiana’s Natural Regions
Section 4: Louisiana’s Climate
Section 5: People and the Environment

3. Section 1: Louisiana’s Location
ESSENTIAL QUESTION:
What are the differences between absolute and relative location, and what are Louisiana’s boundaries?

4. Section 1: Louisiana’s Location
What words do I need to know?
absolute location
relative location
latitude
longitude
prime meridian
cartographer

5. Section 1: Louisiana’s Location
Louisiana in the United States
Boundaries

6. Louisiana in the United States
Louisiana: between 28° 55 ́ & 33° north (N) latitude & between 89° & 92° west (W) longitude
North Africa, the Middle East, & the Indian subcontinent (approximate same latitude)
24 states east of Louisiana
25 states westernmost of Louisiana
31st rank order in physical size
Total area (land & water): 49,651 sq. miles
Alaska: capable of holding 12 Louisianas
Louisiana: capable of holding 48 Rhode Islands

7. Boundaries
One between Mississippi and Louisiana near the 31st parallel north (31° N latitude)
Another between Arkansas & Louisiana near the 33rd parallel north (33° N latitude)
Louisiana & Texas separated by 94th meridian west (94° W latitude)
Upper boundary shaped by Mississippi River
Lower boundary formed by Pearl River
Southern boundary marked by the Gulf of Mexico
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8. Section 2: Louisiana’s Waterways
ESSENTIAL QUESTION:
What are Louisiana’s major rivers and lakes?

9. Section 2: Louisiana’s Waterways
What words do I need to know?
navigable
bayou
terrain
brackish
cutoff lakes
raft lakes
marsh lakes

10. Louisiana’s Waterways
Rivers
Lakes
Bayous

11. Rivers Names and meanings designated for the Mississippi River:
Algonquin Indians: Messipe (meaning the “great river”)
Spanish: Rio del Espiritu Santo (the river of the Holy Spirit)
The “Nile of America”
Area Mississippi River covers (1,245,000 square miles)
Red River (2nd largest river drainage area)
Other rivers: the Ouachita, Little, Tensas, Black, Atchafalaya, Pearl, Calcasieu, & Sabine

12. Lakes
Manmade Lakes: Toledo Bend, Lake D’Arbonne, Lake Claiborne, Sibley Lake, & Lake Chicot
Natural Lakes: Lake Pontchartrain (Louisiana’s largest – 625 square miles) & Lake Maurepas (lagoonal lake)
Cutoff Lakes: False River, Lake Bruin, & Larto Lake
Raft Lakes: Caddo Lake & Lake Bistineau
Marsh Lakes: White Lake, Grand Lake, & Calcasieu Lake

13. Bayous Name most connected with Louisiana waterways
Popular slogan “Louisiana, The Bayou State”
Name derived from the Choctaw Indian language, meaning “creek”
Designated as “the sleeping water” by early French culture
Well-known bayous: Bayou Lafourche and Bayou Teche
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14. Section 3: Louisiana’s Natural Regions
ESSENTIAL QUESTION:
What are the five major natural regions of Louisiana?

15. Section 3: Louisiana’s Natural Regions
What words do I need to know?
elevation salt dome
relief geologist
alluvial delta
swamp floodplain
estuary loess
topography 13. uplift
marsh wolds

16. Louisiana’s Five Major Natural Regions
Mississippi Floodplain Region
Terraces Region
Marsh Region
Red River Valley Region
Hills Region

17. Mississippi Floodplain Region
Floodplain – the level along a river that is likely to flood
Mississippi floodplain region – a parallel to Mississippi River in the eastern part of the state
Soil – deposited by the river (alluvial)
Fertile soil – producer of abundant natural vegetation & valuable agricultural crops
Floodplain region – divided into three parts:
The Natural Levee, the Swamp, & the Passes

18. The Natural Levee
Natural riverbanks – built up over time by silt deposits from flooding
Natural Levees –
Lie within 100 feet of the river & cover area of about 5 miles wide
Rise 10 to 15 feet high: do not keep river from flooding
Possessed a canebrake of switch cane in early times
Batture – contains trees that survive flooding

19. The Swamp Lowest part of the river basin
One definition: “a seasonally flooded forest”
Much of New Orleans was built in the drained swamp of the Mississippi floodplain
Cypress & tupelo gum trees abundant in swamp
Spanish moss not harmful to trees - moss nutrients absorbed from the air

20. The Passes
Routes the Mississippi River takes to merge with the Gulf of Mexico
Area called a delta (mouth of river triangle-shaped like the Greek letter delta)
Sometimes called the “birdsfoot delta” (looks like the foot of a monster-sized bird from the air)

21. Terraces Region Contains the old Mississippi floodplains
Changed its course after every ice age
Once natural levees & low swamps
Three divisions in the Terraces Region
The Blufflands
The Prairies
The Flatwoods

22. The Blufflands The old natural levees
Highest part of the Terraces region
Loess (wind-deposited soil) – causing increased heights of old levees
Fine silt eroding easily – Result: vertical slopes on the high bluffs (good example: West Feliciana Parish)
State Flower – the magnolia showcased by beautiful forests (blooms in summer)
Other trees abundant: dogwood, holly, ash, & oak
Ferns, green mosses, & wildflowers on forest floor

23. The Prairies Formed by old river channels
Flat as a giant table top (hard clay just below topsoil – few trees)
Similar to Midwestern United States
2,000,000 acres once grasses & wildflower: some common plants – broom & bluestem sedge, water & switch grass
Resemblance of tall grass to rippling water – hence, occurrence of names like “points,” “islands,” & “coves”

24. The Flatwoods Covered with a forest
Better soil drainage than Prairies, allowing trees to grow
Covered with pine & hardwoods along with wire grass & palmetto
Region called “piney woods” by early settlers

25. Marsh Region Located along Louisiana’s Gulf Coast
More than 2.5 million acres of marsh
People habitation along the chenier ridges
French meaning of Chenier – “places of the oak”
Sandy soil of chenier ridges (composed of shells and sand)
Marsh grass in the fertile muck & peat soil
Abundant rainfall & a long growing season
Plant life & habitat for bird species

26. Salt Domes Found in the salt marsh
Layers of rock that have folded upward
Hold sulphur, petroleum, & salt
Main domes between New Iberia & Morgan City called the Five Islands:
Avery, Weeks, Jefferson, Cote, and Bell Islands
Foods & petroleum products produced

27. Red River Valley Region
Borders the Red River from the northwestern corner to central Louisiana
Resembles small version of Mississippi Floodplain
Single stream with natural levees & low-lying areas (fertile red soil found)
Forests created by trees that survived flooding
Contains some swamp forest

28. Hills Region Covers much of North Louisiana
Highest region with roughest terrain
Major part – Sabine Uplift (also called Dolet Hills)
Included in Hills Region: Nacogdoches Wold & Kisatchie Wold (contains Louisiana’s highest point)
Contains old (not fertile) soil – usually red due to iron content
Much of region planted in tree farms
Pine forest (part of vegetation in Hills)
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29. Section 4: Louisiana’s Climate
ESSENTIAL QUESTION:
What is the difference between weather and climate and its effect on the people and the physical environment?

30. Section 4: Louisiana’s Climate
What words do I need to know?
weather
climate
precipitation
hurricane (& hurricane eye)
tornado
growing season
humid subtropical

31. Section 4: Louisiana’s Climate
Weather & Climate
Weather measures the current conditions of the atmosphere:
temperature, precipitation, & wind
Climate
Climate is the average weather of an area over a long period of time, i.e., years

32. Section 4: Louisiana’s Climate
Affected by the Gulf of Mexico, distance, and position on North American continent
Two climate regions:
North Louisiana and South Louisiana
Louisiana noted as humid subtropical
Result of high pressure systems from Florida (carry large moisture amounts)
Influenced by continental air masses

33. Section 4: Louisiana’s Climate
Temperature
Precipitation
Wind
Climate and Agriculture

34. Temperature North Louisiana – highest temperatures in the state
South Louisiana – benefits from the cooling effects of the Gulf of Mexico
Record state temperatures
Highest: 114° August 10, 1936
Lowest: -16° February 15, 1899
Northwest Louisiana – greatest temperature range

35. Precipitation
Water – liquid or solid – that falls from the atmosphere & reaches the ground
Rain – most frequent precipitation
Occasional summer hail storms
Winter – sleet more common than rare snowfall
Most rainfall – southeast
Least rainfall – northwest
Some areas annual rainfall, 48 inches
1899 – rare snowfall for all of Louisiana

36. Wind
Causes worst weather
Two kinds of windstorms
Hurricanes
Tornadoes

37. Tornadoes Give little warning Can develop in 5–10 minutes
In clouds of a thunderstorm
When cool air meets a layer of warm air
Spotted by radar & computer technology
Usually 50 mph, perhaps 100 yards wide
Winds circling (up to 300 mph) inside funnel cloud
Most damage caused by extreme low pressure (called the eye)

38. Hurricanes Begin over tropical ocean waters 74 mph minimal wind speed
Rotation of hurricane winds around calm center or eye
Energy created from warm, moist air
Attacks coastline with high winds & high water (10-20 feet, possible)
Can cause major flooding
Greatest risk in September, although season from June 1 to November 30

39. Hurricanes
More than 60 hurricanes have hit Louisiana in past 150 years
Recent hurricanes include: Audrey (1957), Betsy (1965), Andrew (1992), Katrina (2005)
2005: Hurricanes Katrina & Rita – flooded New Orleans. More than 1000 died; damage over $25 billion

40. Climate and Agriculture
Effect of climate & weather on natural environment important
Growing season
210 days in north-central Louisiana
290 days near the Passes
Occurrence of severe freeze – once every 7 years at mouth of Mississippi
Important crops: citrus trees, strawberries, sugar cane & cotton
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41. Section 5: People and the Environment
ESSENTIAL QUESTION:
What are the factors that have affected Louisiana’s coastline and the ways in which people have affected the environment?

42. Section 5: People and the Environment
What words do I need to know?
wetlands
subsidence
barrier island
time zones
nutria
Asian carp

43. Descriptions of the Mississippi River
Conflicting relationships indicated between people & the river
Names assigned to Mississippi:
“father of waters”
“great artery of the continent”
“unruly neighbor of the farmers”
“raging killer of small towns”

44. Flood Control
1719 – Flood warnings ignored by French king, first levees soon built
1927 – Great flood driving ½ million people from homes, leading to new system:
U.S. Army Corps of Engineers responsible for controlling flooding
Bonnet Carre Spillway built 1935
Old River Structure completed 1963
Plan to protect people & property disastrous for Louisiana’s wetlands

45. Vanishing Coastline Louisiana in a crisis
State having 30% of U.S. coastline; experiencing 90% land loss
Since 1950 land loss comparable to area size of Delaware
Once dry lands now covered by water

46. Causes Sustenance of marsh dependent on rivers, water runoff, & silt
Causes of coastline’s sinking:
Flood-control efforts reducing the amount of silt
Underground faults resulting in shifting and sinking of land

47. Impact of the Land Loss Louisiana ports vital to U.S. economy
Handles 20% of all U.S. imports
Supplies more than ⅓ of U.S. oil & gas needs
Coastal marshes
Provides 75% of Gulf of Mexico’s seafood industry
Generates annual billion $ income
Impacts habitat of migratory birds & waterfowl
Barrier islands affected by coastal changes
Lessens effectiveness of islands & marshes to protect from hurricane storm surge
Brings about possible losses:
Buildings, railroads, highways
Humans, wildlife, & natural environment
Coastal erosion

48. Response Early damage to the marsh unnoticed
Billions needed to correct problems
1990 Senator John Breaux responsible for U.S. Congressional bill to save wetlands:
CWPPRA (the Coastal Wetlands Planning, Protection & Restoration Act)
Federal funds for wetlands projects
Hopeful to create a new manmade river channel to re-direct Mississippi River
Scientists studying flood control options in light of hurricane Katrina

49. Other Environmental Problems
Efforts to save Louisiana’s coast:
Environmental groups
The Nature Conservancy
Unintended negative impacts:
water hyacinth
nutria
Asian carp
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