Emily Mitchell Ayers, Ph.D.

1. Ecological SystemsMaintaining and Enhancing Natural Features and Minimizing Adverse Impacts of Infrastructure ProjectsModule 3Impacts of Infrastructure

2. Emily Mitchell Ayers, Ph.D. The Low Impact Development Center, Inc. emayers@lowimpactdevelopment.org

3. Learning Outcomes • Learn how infrastructure projects can cause habitat loss • Learn how pollution can harm ecosystems • Learn how discharges to ecosystems can disrupt ecological stability

4. Outline • Causes of ecosystem degradation • Impacts of infrastructure projects • Major impacts in the United States • Major impacts globally

5. Ecosystem Degradation • Ecosystems are comprised of complex linkages between species and their environment • Damage can cause cascading impacts throughout the ecosystem • Ecological damage can be caused by local or non-local activities

6. Types of Ecosystem Degradation • Direct loss of habitat due to development • Damage resulting from human use and/or discharges • Decline in one or more species • Degradation or collapse of food webs • Loss of ecosystem function

7. Causes of Ecological Damage • Direct habitat loss • Habitat fragmentation • Damage to physical environment • Chemical toxicity • Hunting and harvesting • Introduction of exotic species

8. Examples • Eutrophication • Loss of top predators • Loss of the base of the food chain • Stream degradation • Xenobiotic contamination

9. Eutrophication Overuse of fertilizers in landscaping and agriculture Inadequate sewage treatment Discharge of nitrogen and phosphorus Overgrowth of algae Death of algae Overgrowth of bacteria Oxygen depletion Fish kills

10. Eutrophication

11. Eutrophication EPA

12. Loss of top predators X Hunting Habitat fragmentation Loss of wolves X Deer become overpopulated Plants are overgrazed XXX Deer population crashes

13. Loss of the base of the food chain Fossil fuel consumption Deforestation Global climate change Loss of Antarctic sea ice Expansion of krill fisheries Decline in krill population Decline in penguin populations

14. Stream degradation Roads Buildings and parking lots Lawns Agricultural fields Fertilizer Increased stormwater runoff Pesticides Increased temperature Habitat destruction Heavy metals Eutrophication Loss of invertebrates Loss of fish

15. Xenobiotic contamination (PCBs) PCBs in transformers and capacitors Spillage and leaks Migration into groundwater Leaching into waterbodies Buildup in sediments Bioaccumulation in invertebrates Bioaccumulation in fish Bioaccumulation in humans Cancers, damage to skin, stomach, liver, kidneys, thyroid

16. Types of Pollutants • Directly harmful • Heavy Metals • Xenobiotic compounds (man-made) • Indirectly harmful • Nutrients • CO2 • Organic matter

17. Directly harmful pollutants • Cause illness or mortality through ingestion • Are not “naturally” present, or naturally occur in minute quantities (with exceptions)

18. Indirectly harmful pollutants • Are not directly toxic • Normal flows are necessary for ecosystem function • Elevated flows cause ecosystem imbalance and cascading negative effects

19. Course Outline • Causes of ecosystem degradation • Impacts of infrastructure projects • Major impacts in the United States • Major impacts globally

20. Infrastructure-specific impacts • Roads • Sprawl • Stormwater Runoff • Wastewater treatment • Mining • Dams • Navigation projects • Power generation • Agriculture

21. Local impacts of roads • Habitat fragmentation • Road kills • Impedes migration and dispersal DOT, FHWA

22. Impacts of sprawl • Habitat loss and fragmentation • Introduction of invasive species • Increased driving leads to increased CO2 • Increased stormwater runoff, including lawn chemicals (fertilizers and pesticides) NASA

23. Impacts of stormwater runoff • Hydromodification • Loss of habitat features (in-stream shelter, deep pools, base flow) • Elevated water temperature • Eutrophication USGS

24. Impacts of wastewater treatment discharges • Eutrophication • Elevated temperatures • Xenobiotics USGS

25. Impacts of mining and extraction • Habitat loss • Contamination due to leaching from spoils • Groundwater contamination EPA

26. Impacts of dams • Habitat loss • Altered hydrology • Reduced sediment flows downstream • Habitat fragmentation USACE

27. Impacts of navigation projects • Loss of river and estuary bottom habitat • Estuary sediment starvation • Wetland subsidence USGS

28. Impacts of power generation • Local: • Elevated water temperature • Habitat fragmentation due to transmission corridors • Contamination due to accidental chemical release • Non-local: • Air pollution • Climate change • Impacts of extraction USGS

29. Course Outline • Causes of ecosystem degradation • Impacts of infrastructure projects • Major impacts in the United States • Major impacts globally

30. Impacts in the United States • Habitat loss and fragmentation • Depletion of fresh water resources • Eutrophication • Coastal Louisiana wetland loss • Hydromodification

31. Habitat loss • 60% of the US (outside Alaska) has lost its natural vegetation • 53% of wetlands in the lower 48 states have been lost • Habitat destruction is the leading threat to US species • Flyways used by migrating waterfowl are threatened • Sprawl is a major cause of destruction TJ Watt

32. Habitat fragmentation • Sprawl and unplanned growth contribute to habitat fragmentation • Fragmentation isolates populations, limiting migration, dispersal, and genetic exchange • Fragmentation eliminates habitat for animals with large home ranges USGS

33. Depletion of water resources • Freshwater availability is becoming a serious issue, especially in western states • Rapid population growth puts pressure on water supplies • Climate change reduces mountain snowpack, reducing stream flows • Changes in surface waters and shallow groundwater disrupt ecological function NOAA

34. Eutrophication • Caused by excess nutrient discharges (nitrogen and phosphorus) • Major cause of coastal hypoxia • Mississippi Gulf • Chesapeake Bay NASA

35. Coastal Louisiana Wetland Loss • Subsidence resulting from natural sediment compaction is no longer balanced by inflowing sediment from upstream • Subsidence combines with sea level rise to create water depths too deep to support marsh grass • Marsh grass dies off, resulting in erosion and permanent marsh loss State of Louisiana

36. Hydromodification • Development increases watershed imperviousness, which causes increased storm flows • High peak flows erode stream banks, altering stream morphology and destroying habitat Ken Andrews

37. Course Outline • Causes of ecosystem degradation • Impacts of infrastructure projects • Major impacts in the United States • Major impacts globally

38. Global Impacts • Depletion of fresh water resources • Climate change • Excessive nutrient loading • Loss of biodiversity • Habitat loss

39. Loss of fresh water • Overuse for irrigation • Discharge to oceans USGS/ Woods Hole Oceanographic Institute

40. Climate Change • Caused by increasing atmospheric CO2 and CH4 • Power generation using coal, oil, and gas • Reliance on gasoline-powered vehicles • Deforestation • Methane emissions from landfills NASA

41. Excessive nutrient loading • Primarily the result of increasing use of fertilizers in agriculture and landscaping

42. Loss of Biodiversity • Rate of extinctions in the last century is 50-500 times greater than the background rate • Primarily caused by habitat loss

43. Habitat Loss • Deforestation for agriculture • Desertification, loss of polar habitat, coral bleaching resulting from climate change Millennium Ecosystem Assessment

44. Discussion Questions • What ecological impacts might you expect from the construction of a new office park on the outskirts of town?

45. Discussion Questions • As an engineer, what role can you play in minimizing the non-localized impacts of infrastructure projects?

46. Review • Infrastructure can cause direct loss of ecosystems through habitat loss, or indirect damage to ecosystem function • Damage can cause cascading impacts throughout an ecosystem • Infrastructure impacts can be local or non-local • Individual infrastructure decisions have cumulative impacts of global significance

47. Recommended Reading • Endangered Ecosystems of the United States: A Preliminary Assessment of Loss and Degradation http://biology.usgs.gov/pubs/ecosys.htm • Ewing, R., J. Kostyack, D. Chen, B. Stein, and M. Ernst. Endangered by Sprawl: How Runaway Development Threatens America’s Wildlife. National Wildlife Federation, Smart Growth America, and NatureServe. Washington, D.C., January 2005. http://www.nwf.org/~/media/PDFs/Wildlife/EndangeredbySprawl.ashx • Water Availability for the Western United States--Key Scientific Challenges http://pubs.usgs.gov/circ/2005/circ1261/

48. Recommended Reading • Precious Heritage: The Status of Biodiversity in the United StatesEdited by Bruce A. Stein, Lynn S. Kutner, and Jonathan S. AdamsOxford University Press. Published March 2000.  • USGS. Sea-level rise, subsidence, and wetland loss [video presentation]. http://gallery.usgs.gov/videos/347#.T8fpp9VYt_c • USGS, 2002. Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in U.S. Streams. USGS Fact Sheet FS-027-02. http://toxics.usgs.gov/pubs/FS-027-02/