Watersheds and Wetlands
-
Upload
duncanpatti -
Category
Technology
-
view
5.721 -
download
0
Transcript of Watersheds and Wetlands
Watersheds and Wetlands
Chapter 1
Big Blue Marble¾ of the Earth’s surface covered in water
Water is the most common substance on earth and the MOST IMPORTANT
Where is the water?If the world’s total water supply were in a 200 L drum. . .
• Ocean Water: 97.2%• Glaciers and ice caps: 2.11%
• Groundwater: 0.62%
• Lakes: 0.009%
• Atmospheric moisture: 0.001%
• Rivers: 0.0001%
Fresh Water:
Water can exist as:Solid = Ice
Liquid = Water
Gas = Steam
Changes of State
S
G
L
Depos
ition
Condensation
Solidification
Vaporization
Subli
mation
Melting
Several of these processes are part of the:
WATERCYCLE
Also known as the Hydrologic Cycle
• Evaporation: Change of statefrom liquid to gas over a periodof time at various temperatures• Transpiration: Plants releasewater vapor from their leaves • Precipitation: liquid or solid
water that falls from atmosphere to Earth
• In PA… ½ of our annual 42” rainfall is returned to atmosphere via evaporation and transpiration
• Runoff: Precipitation that runs off the ground back into streams, rivers or oceans• Groundwater: Precipitation thatseeps into the ground and isstored beneath the Earth’ssurface• 22% of Earth’s freshwater is groundwater• In PA.. 1 billion gallons of groundwater is used EACH DAY in households, industries, agriculture and mining
Groundwater Contamination
Groundwater Contamination• Contaminants from natural
sources• As water travels over soil and rocks
it dissolves certain minerals and carries them away
• “Hard water” is water that has highconcentrations of Calcium• High concentrations of iron makewater “brown” and metallic tasting • High concentrations of hydrogen sulfide
gives water “rotten egg” odor and taste
Groundwater Contamination• Contaminants from human activities
• As population gets more dense and we “take over” more and more space wecontaminate the water supply
• Poorly installed and maintained septics• Pesticides and fertilizers used on farms
and lawns• Landfills, chemical spills, leaking storage
tanks, salts used on icy roads
Stream Characteristics
Water Flow OrderPrecipitation falls
Water travels along “rills” which are grooves eroded in
the ground by water over time
Rills merge and empty into creeks and streams
Water Flow Order
Creeks and streams feed into rivers
Rivers flow into oceans
The place where a stream or river begins is called
it’s source
The place where a stream or river ends by
flowing into another body of water is called it’s
mouth
Laminar flow: occurs when water moves in straight paths that are parallel to the stream’s channel or bed. Very
little mixingTurbulent flow: occurs when water moves in
tiny circular paths as it flows downstream. Much
more mixing
A stream’s velocity, or the distance
water flows during some period of
time, determines the type of flow
LOW VELOCITY (move slowly)
streams have mostly Laminar flow
HIGH VELOCITY (move quickly)
streams have mostly Turbulent flow
Sediment LoadDissolved Load Suspended
LoadBed Load
Sediment that is “dissolved” in solution
Sediment that is “suspended” in solution
Sediment that is carried along the
bottom of the channelEarth materials that dissolve in the water as it runs over rocks
and soil
Materials such as silt and clay that is carried by water but does not
dissolve in it
Larger materials such as sand, gravel,
pebbles and boulders
Comes from ground water that returns to the Earth’s surface
Constitutes the majority of the river or streams
load comes from banks as water erodes
Sand and gravel “skip” along bed
pebbles and boulders roll and slide along
bed
Sediment LoadSediment: particles that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid.
Sediment is carried in streams and rivers in three ways
Watershed
Also known as a drainage basin
Region OF LAND that contributes water to a stream, lake or other body of water
Watersheds are surrounded by divides
Divide: any ridge between two streams along which precipitation
runs off.The Continental Divide-splits North
America and some of Central America in two watersheds
Watersheds can also be very small
Five of the Major Watersheds in PAPA State water plan: 104
watershedsWe will be focusing on 5 that are considered to be Major Watersheds
Great Lakes Basin (Erie and Genesee)Ohio River BasinSusquehanna/Chesapeake BasinPotomac BasinDelaware Basin
Great Lakes BasinOnly about 1% of this basin
actually lies in PA
Divided into two sub-basins; Erie Basin and Genesee Basin
Rivers and streams in both basins drain to the North into the Great
Lakes
Ohio River BasinPA’s second largest watershed
Ohio River is largest in this watershed
Susquehanna/Chesapeake BasinPA’s largest watershedCovers 46% of the state
Largest river: Susquehanna
Potomac BasinPotomac River does not flow
through PA PA’s Shenandoah River is the
Potomac River’s largest tributary
Delaware Basin 3rd largest watershed in PA
Delaware river and it’s tributaries supply most of New York City’s
freshwater needs
Stream Biology
Ecosystem: all the plants, animals and micro organisms in an area that function together with the non-living factors of that environment
Streams and Rivers are aquatic ecosystems
AlgaePlant like organisms (Protists)Producers: Make their own food
(also known as autotrophs)Use energy from sun and dissolved
nutrients to make foodBase of most aquatic food chains
Animal Like ProtistsSimple organisms that have same
characteristics as animalsEat bacteria, sediments that contain
bacteria and algaeSaprotrophs: feed on decayed
organic materialRaptors: protists that eat other protists
CiliatesParamecia
Amoeba
InvertebratesOrganisms that do not have a back
boneInsects: Flies and beetles found in
nearly every stream or riverLarval stage lives in waterAdults: Most live on land surrounding stream; some live on water surface(water striders)
Invertebrates
Shredders: Eat tissue of other organisms; organic matter; wood(bite and chew)
Predators: ingest prey whole or piercetissues and suck out fluids
FliesSome shreddersSome predators
BeetlesSome saprotrophsSome predators
Freshwater mollusks and some aquatic worms Spend entire lives in waterMost feed on algae and plants(Primary consumers, herbivores
eat producers)Some eat other animals
(Secondary consumers, carnivores)Some eat both plants and animals
(Secondary consumers, omnivores)
Vertebrates
Organisms that have a back boneAmphibians; such as salamanders,
frogs, turtles, newtsFish; such as pike, trout, pickerel,
bullheads, bluegill, bass, sunfishcatfish, perch and suckers
Amphibians
Depend on water at various stages of their life cyclesMost adults live on landMost adults are predators
FishSome are primary consumers of algae
•Grazers•Strainers•Suckers
Some are predatorsSome are detritivores: feed by
shredding sediments or filter food directly from sediments
Class Activity:Identifying Macro
Invertebrates!!http://people.virginia.edu/~sos-iwla/Stream-Study/Key/MacroKeyIntro.HTML
Notes on Factors that Affect Freshwater Ecosystems
WetlandsWetland: an area that contains unique types of soil, is home to plants adapted to the wet environment, and contains water all year or certain times during the year
Types of wetlandsSoil Plants Organisms
Bogvery acidic
Little oxygen
Scrub-shrub wetland
Decomposed plant material called peat or muck
Predominantly mosses; shrubs;
evergreens; water lilies; cranberries;
blueberriesTrees less than 20
feet tall
Few fishFrogs TurtlesInsects
Certain birds
SwampForested wetlands
Drains slowlySome; nutrient rich
but not all
Classified by trees:Conifers; cedars,
pines, sprucesHardwoods; maples
willows, aspens, birches, elms, oaksTrees can be more
than 20 feet tall
White tail deerraccoonsheronsegrets
woodpeckersSnakes, frogs
turtles
Types of wetlandsSoil Plants Organisms
MarshForms at mouth of river or areas of
poor drainageEmergent wetlands
Nutrient rich GrassesSedges
BulrushesCattails
Plants rooted in soil but emerge above
water
BeaversFrogsTurtles
Raccoons Muskrats
OpossumsBirds, insects
Wetlands at work Habitat: home to many species
many threatened or endangeredFood Factories: plants in wetlands serve base of wetland food websSpawning Grounds and Nurseries:Many organisms reproduce hereCycling Nutrients: plants use carbon
dioxide, produce oxygen, cyclenitrogen and phosphorus
Wetlands at work Buffer Zones: act as “natural sponges”, absorb excess runoff and release it back to environment slowly; Wetlands in coastal areas absorb energy of waves and stormsprotecting mainlandPollution Control: Reduce sediment by slowing water movement; many wetland plants store carbon insteadof polluting air with carbon dioxide
Factors That Affect Wetlands and WatershedsHuman Activities:
•Agriculture•Urbanization and construction•Mining•Industry•Waste Disposal
Agriculture:•Harvesting•Irrigation ditches•Animal wastes•Overgrazing (erosion of soil) which
increases sediment that runs off •Chemicals used in pesticides and
fertilizers
Urbanization and Construction•Covering soil with concrete increases
runoff that carries pollutants•Construction of roads and bridges overwetlands; increases runoff and restricts movements of organisms•Paints, cleaners, salt, herbicides used
along roads damage wetlands by increasing turbidity, lowering pH, and decreasing dissolved oxygen
•Canals, ditches, levees divert water from it’s natural flow
Mining:•Mining of substances directly from
wetlands such as phosphorus andpeat
•Mining of rocks and minerals: acid drainage; heavy metals; sedimentIndustry:•Construction; reduces wetland acreage•Pollutants•Water intake, draining of wetlands•Water release, thermal pollution which
can lead to algal blooms
Waste Disposal:•Landfills: solid waste; toxic leakage•Sludge and Wastewater Treatment;
•Introduce of biological pathogensto wetlands
•Rich in nitrogen and phosphoruswhich cause Algal blooms
Factors That Affect Wetlands and WatershedsNatural Events:
•Floods•Erosion and Deposition•Drought•Volcanic Eruptions•Fires•Wind•Global Climate Change
Floods:•Positive impact:
•Move nutrients and organic materials downstream
•Deposit silt into river banks•Change shape and size of river channel;
form new channels•Negative impact:
•Destroy riverbanks•Carry organisms away from natural habitat•Landslides; increases sediment
Erosion and Deposition•Erosion, sediment movement, and deposition all happen as water flows over land•Changes in precipitation causes more erosion which can change size and shape of stream or river channel•Channel changes affects velocity, discharge
and stream biology
Drought•Drought: period in which the amount of precipitation that falls in and area is lower than normal•Reduce the volume of the water
•Lower volume affects clarity, salinity, temperature, pH and amount of sediment•Some bodies of water disappear; causing loss of breeding and feeding grounds
Volcanic Eruptions
•Massive mudslides that cutoff streams and rivers•Vegetation loss changes stream biology•Ash changes pH of water and increases turbidity•Temperature changes and ash kill organisms
Fires•Damage or destroy vegetation; causing increase in runoff and erosion•Loss of habitat•Increase temperature of water•Can be BENEFICIAL; pine tree reproduction
Wind•Carry and drop sediment•Affects evaporation of water
Global Climate Changes•Natural large scale changes in climate occur about every 10,000 years•Cooler climate; freshwater locked in ice and glaciers•Warmer climate; melt off increases sea level; causes flooding; causes salt water to move into fresh water wetlands
•Changes the salinity of wetlands•Salt-tolerant species replace freshwater organisms•Vegetation covered and dies changing wetlands into open water