Urban Geology Spring 2011

Transcription

1 Urban Geology Spring 2011

2 Gowanus Canal Historical use New York City Water pollution Sewage treatment plants Eutrophication Combined sewage outflows (CSO) Remediation Sustainability

3 Gowanus Canal today

4 Sunset at Gowanus Bay in the Bay New York (1851) by Henry Gritten

5 1609: Henry Hudson discovered this area Gowanus Creek originally a navigable tidal inlet with marshes and meadows Abundant fish and wildlife, particularly clams and oysters 1600 s 1800 s: Mills built and people began to settle the area Population grew, need for larger navigational creek and docking area Around 1867, creek dredged to create larger canal and surrounding marshes drained Became hub for Brooklyn s commercial shipping activity Factories, warehouses, tanneries, coal stores, and manufactured gas refineries Raw sewage drained into canal

6 1900: very polluted and smelled awful Mid 1900 s: economy changing and area declined 1975: NYC established Gowanus Industrial Renewal Plan for area Throughout 1900 s, attempts to flush and lessen pollution, particularly the smell 2009: EPA declared canal superfund site. Sediments laden with heavy metals, PCBs, coal tar, other

7 1929 study revealed that 10 million people dumping over 1 billion gallons of raw sewage daily between 1914 and 1926 Industries: petroleum, chemical plants, kerosene, other Oil spills Ocean dumping

8 Sewerage commission started in 1903 Treatment plants greatly helped to restore life in river and estuary by 1970s Industrial big problem: PCBs, nuclear power plant, landfills, other chemicals 1969: National Environmental Policy Act (NEPA) set up procedural requirements for all federal government agencies to prepare Environmental Assessments (EAs) and Environmental Impact Statements (EISs) Clean water act in 1974 Ocean dumping banned in 1988 and 1991

9 1.4 billion gallons of wastewater discharged by eight million residents and workers in New York City each day over 6,000 miles of sewer pipes; 135,000 sewer catch basins; over 494 permitted outfalls for the discharge of combined sewer overflows (CSOs) and stormwater; 93 wastewater pumping stations that transport it to 14 wastewater treatment plants located throughout the five boroughs.

10

11 secondary effluent to flow into large ponds where algae grows and uses up the ammonia and nitrates in the water. slow process requires very large holding ponds. algal growth is harvested and used as a nitrogen-rich organic fertilizer

12

13 p. 256 Nutrients in sewage and runoff: Nitrogen and phosphorus Microorganisms decompose the organic matter Generates high BOD Removes dissolved oxygen in water BOD measures how fast microorganisms remove oxygen

14

15 Anoxia: near or no oxygen available Hypoxia: less than 2 ppm Many organisms need above 5 ppm

16 _0508/images/deadfish.jpg sengco2en_5571.jpg

17 Gowanus Canal Historical use New York City Water pollution Sewage treatment plants Eutrophication Combined sewage outflows (CSO) Remediation Sustainability

18 Source:

19

20

21 are real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant. (EPA,

22 n.com/gbd_site/clean_up.ht ml

23 Combined Sewer System. During dry weather (and small storms), all flows are handled by the publicly owned treatment works (POTW). During large storms, the relief structure allows some of the combined stormwater and sewage to be discharged untreated to an adjacent water body. Source:

24 Source: PlaNYC 2030, 2007

25 Communities may implement low impact development techniques to reduce flows of stormwater into the collection system. This includes: constructing new and renovated streets, parking lots and sidewalks with permeable paving and pervious concrete installing green roofs on buildings installing bioretention systems, also called rain gardens, in landscaped areas Rainwater harvesting equipment collects runoff from building roofs during wet weather for irrigating landscapes and gardens during dry weather Graywater collection and use on site reduces sewage discharges at all times

26 Gowanus Canal Historical use New York City Water pollution Sewage treatment plants Eutrophication Combined sewage outflows (CSO) Remediation Sustainability

27

28 The ability to meet humanity s current needs without compromising the ability of future generations to meet their needs.

29 Densely populated, with needs Water supply quality and quantity Waste removal Energy Food Building materials Transportation Cultural and aesthetic considerations

30

31 Air quality Ozone and soot Asthma rates Water quality Streams and surrounding waters Brownfields Urban heat island Rising sea level Intensifying storms

32 Clean air and water Cycles and reservoirs Hazard protection Erosion control

33 Restore to what? Manhattan to 1609? Which ecosystem services? Create framework hydrology, soil and rock and vegetation (Big three)

34