Water and waste

Urban Geology, Spring 2011

Source: http://ga.water.usgs.gov/edu/earthwherewater.html

Water availability for human use

http://ga.water.usgs.gov/edu/earthwherewater.html

Hydrologic Cycle

Source: http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/hydrosphere/hydrologic_cycle.html

What affects water infiltration?

Source: http://pubs.usgs.gov/fs/OFR93-643/

Questions

• What happens to rain in NYC?

• Which do you think will infiltrate more water into the groundwater?– Slow, gentle rain for a long time

– Quick downpour with lots of water

• What happens when it rains with saturated soil?

Estimated Use of Water in the US in 2000

• 408 billion gallons per day were withdrawn for all uses (fresh and saline)

– 85% freshwater

– 137 Bgal/d: Irrigation

– 43 Bal/d: Public-supply withdrawals:

– 20 Bgal/d: self-supplied industrial withdrawals

• 195 Bgal/d : thermoelectric power

– 1/3 saline

Source: http://pubs.usgs.gov/circ/2004/circ1268/

Every day in the US:

On average, 1000 gal/d per person, about 40 bathtubs

What is a watershed?

http://geoscape.nrcan.gc.ca/h2o/bowen/images/watershed_e.jpg

Surface waters Watersheds (Drainage Basins)

Estuaries

http://www.niot.res.in/m5/mbic/me/zones/images/estuary_clip_image001.jpg

Hudson-Raritan Estuary

http://www.saltwedge.org/assets/images/harbormap.png

Estuaries

• Highly productive

– Many species spend all or part of their live cycle in estuaries including wetlands

• Salinity gradient from fresh to saline

• Fluctuations in salinity through tides and freshwater input

Water Budget

A basic water budget for a small watershed can be expressed as:

P + Qin = ET + ΔS + Qout (A1)where

P is precipitation, Qin is water flow into the

watershed (can be subsurface and surface),

ET is evapotranspiration (the sum of evaporation from soils, surface-water bodies, and plants),

ΔS is change in water storage, and Qout is water flow out of the

watershed.

Annual precipitation in the US

Where are the places likely for a water deficit?

PET: amount of evapotranspiration that would occur if sufficient amount of water is available

Aral Sea: disastrous consequences of water use

Aral Sea

• Water diverted from rivers in 1960’s for agriculture

• Fishing industry collapsed and eventually agriculture

• Local climate has changed

• Beyond restoration

New York City Water Supply

New York City water supply

• Largest unfiltered water supply system in the world– Catskill/Delaware watersheds– Provides 90% of NYC water

• 95% of the water delivered is gravity fed• Every day, about 1.3 billion gallons of water used

by over 8 million people in NYC and 4 other counties

• Watershed protection: NYC Department of Environmental Protection (DEP) and EPA

• 2 watershed systems

– Catskill/Delaware

– Croton

• 3 aqueducts

– Croton

– Catskill

– Delaware

Croton watershed

• Placed in service in 1842

• No significant interruptions in service since then

Catskill/Delaware watersheds

• 1928: Catskill water system finished

• 1937: Delaware water system begun

• 1964: Delaware system finished

• 1997: MOU for an extensive watershed management plan, EPA, NYC DEP, 73 local municipalities, and 8 counties

New York City water supply watersheds

Source: Pires, M., Watershed protection for a world city: the case of New York, Land Use Policy, 21, p. 165

NYC water distribution

• 1917: Water tunnel number 1 completed

• 1935: Water tunnel number 2 completed

• Tunnel Number 3 under construction

– Began in 1970s

– Projected completion: 2020

Tunnel #3 construction

http://www.water-technology.net/projects/new_york/new_york5.html

Tunnel boring machine technology

should allow tunnel workers to

excavate at an average of 50 feet per

day at a diameter of 23 feet.

http://www.popularmechanics.com/science/earth/1484317.html

p

Why is protecting the watershed important?

Why is protecting the watershed important?

• 1989 Surface Water Treatment Rule– Criteria for filtration and disinfection treatment

• Filtration avoidance determination (FAD) EPA allows unfiltered water if supplier demonstrates that

water quality criteria are being met

• 9 other major cities in the US have filtration waiver

• $6 billion to design and construct filtration plant; $300 million annual operation

Clean Water Act, 1972

Surface water quality protection

Amended over the years, 1977, 1981, 1990, 2002

Act established the basic structure for regulating discharges of pollutants into the waters of the United States

Gave EPA the authority to implement pollution control programs

Restore and maintain chemical, physical and biological integrity of nation’s waters

Safe Drinking Water Act (SWDA)

• 1974

• Established national standards for public water supply systems

Why is there a conflict between upstate and NYC residents?

• Regulating development –poor counties in protected areas

• Historical precedents in eminent domain as shown in documentary, Deep Water

What strategies have been implemented in the MOU to avoid installing a water filtration plant for

the Catskill and Delaware watersheds?

Strategies

• Watershed protection and partnership programs

• Land acquisition program

• Water supply rules and regulations

Land water connections

• What happens on land affects the water quality

• Some management strategies include:

– Wastewater treatment

– Best management practices (BMPs)

– Land use and economic development plans

Managing land activities

• Land acquisition: buy land in protected watersheds– Purchase land on a voluntary basis at fair market value

determined by independent appraiser

• Conservation easements– Pay landowners to forgo certain use rights on land

• Setbacks and buffer zones– Place barrier between water (stream, reservoir) and land

practices such as farming

• Land trusts: “nonprofit legal entity established under state law that buys, manages, and occasionally sells or leases interests in undeveloped real estate” (NRC, 2000; 286)– Preserves open spaces

EPA organization

Liquid Wastes

• Result in surface and groundwater contamination

• Non-point

• Point– Sanitary sewers

– Storm sewers

– Often combined sewer overflow (CSO)

– Septic tanks• Nearly 1 in 4 US households

Long history of water pollution in NYC (Chap. 6, City at Water’s Edge)

• Remember our discussion on Gowanus Canal becoming a superfund site?

• 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

NYC water pollution

• 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 governmentagencies to prepare Environmental Assessments (EAs) and Environmental Impact Statements (EISs)

• Clean water act in 1974• Ocean dumping banned in 1988 and 1991

Urban runoff

Sewage treatment

Tertiary Treatment Plants

• 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

Traditional septic systems

NYC: What happens to used water?

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.

Biochemical oxygen demand (BOD)

• 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

p. 256

Eutrophication: estuaries and lakes

http://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Scheme_eutrophication-en.svg/800px-Scheme_eutrophication-en.svg.png

Low oxygen

• Anoxia: near or no oxygen available

• Hypoxia: less than 2 ppm

• Many organisms need above 5 ppm

Harmful algal blooms

http://www.noaa.gov/features/earthob

s_0508/images/deadfish.jpg

http://www.whoi.edu/cms/images/lstokey/2005/1/v43n1-

sengco2en_5571.jpg

World distribution of harmful algal blooms

http://images.google.com/imgres?imgurl=http://oceanworld.tamu.edu/resources/oceanography-

book/Images/toxinmaptrans.gif&imgrefurl=http://oceanworld.tamu.edu/resources/oceanography-

book/harmfulagalblooms.htm&usg=__P6kTjIiOAlKgE2BKcn5tOS1msM4=&h=546&w=414&sz=9&hl=en&start=8&tbnid=YykmHbpIvR1DYM:&tbnh=1

33&tbnw=101&prev=/images%3Fq%3Dharmful%2Balgal%2Bblooms%26gbv%3D2%26hl%3Den

Harmful algal blooms in the US

http://dels.nas.edu/oceans/images/algalbloommap.jpg

Jamaica Bay - eutrophication