kathleen a. garland [email protected] 281-283-3249 eih envirothon teacher workshop february 18, 2012
TRANSCRIPT
What’s a point source?
Industrial or municipal discharge
End-of-pipeThe key concepts for understanding point
source pollution
Channelized flowIt has a distinct sourceYou can identify that sourceYou can control that source
Non-point source pollutionNo specific source location Acid mine drainage
A map of eastern streams impacted by coal mine drainage
Agricultural runoff
During storms
Runoff from livestock
Concentrated animal feeding operations
Urban stormwater runoff
Characteristics of Non-point source
Sheet flow
No identified point where all discharge takes place
Source generally cannot be directly controlled
What’s in the water?Debris
Sediment in stormwater
Chemicals of concern: Metals
COC’s: oils and greases
Thermal pollution
Nutrients
What are nutrients?Things that make plants grow…
NitrogenPhosphorusPotassium
Algae is a plant (sort of, a Protist, actually, but close to a plant…it photosythesizes)
Nutrients make algae grow—or overgrow!
Not all algal blooms are green…
Why is too much algae a bad thing?
EutrophicationNutrients feed algaeAlgae bloom, creating large amounts of biomassAlgae die, sinking to the bottom of the water
bodyAlgae decay, using up the oxygen in the lower
layer of the waterBenthic (bottom-dwelling) organisms cannot
surviveFish eat benthics, so they either move away, or
they die, too
Eutrophication leads to HypoxiaHypoxia: the condition of extremely low
levels of oxygen in the waterIn the Gulf of Mexico, we call the hypoxic
zone—
The Dead Zone
How does the Dead Zone Form?
Hypoxic zone in the GOM
Source area for GOM Hypoxic Zone
Global hypoxic zones
Impacts of hypoxiaFisheries
Affects fish stocksAffects nursery areas for future fish stocks
Water qualityRecreationalFishing and boatingShellfish
Coral reefs
Recent example: TPWDhttp://www.tpwd.state.tx.us/landwater/
water/environconcerns/hab/redtide/status.phtml
Coral reefs in the northern GOM
Corals in FGBNMS
Invasive species
Who regulates non-point source pollution?EPA: Section 319 of the Clean Water Act
http://www.epa.gov/owow_keep/NPS/cwact.htmlFor freshwater systemsRequires states to implement plan
Coastal Zone Act Reauthorization Amendments (CZARA) Section 6217http://www.epa.gov/owow_keep/NPS/czara.htmlSpecifically relates to coastal areas—like us!
Why should we care?Galveston Bay is an estuary—a drowned river
basinThe most productive aquatic habitats on the planet
Wetlands and marshes Seabirds, turtles, shellfish, and ocean fish
Extremely vulnerable to pollution from NPSNeeds freshwater inflows to surviveDownstream from two massive urban areas: DFW
and Houston Industrial pollution Urban runoff Agricultural runoff
If those inflows are nutrient loaded, the Bay suffers
Chesapeake BayA very badly damaged estuary
We don’t want to get that way!What can we do to reduce NPS?
Stay tuned! Dr. John Jacob, of Texas Coastal Watersheds will be speaking at 1:30 on exactly this topic!