Environmental Geography

Transcription

1 Environmental Geography Lecture 13 Water Pollution Lecture 13: Water Pollution I. Water Pollution A. Groundwater B. Surface Water C. Regulation II. Water Use in California 1

2 I. Water Pollution Types of Water Pollution: Oxygen demanding wastes Plant nutrients Sediments Disease-causing organisms Toxic minerals and inorganic compounds Synthetic organic compounds Radioactive wastes Thermal discharges I. Water Pollution Water Pollution Sources: Point source pollution Non-point source pollution Pollution concentration Pollution load 2

3 I. Water Pollution Water Pollution Sources: I. Water Pollution 3

4 I. Water Pollution I. Water Pollution Groundwater 4

5 I. Water Pollution Groundwater I. Water Pollution Groundwater 5

6 I. Water Pollution Groundwater Sources of groundwater pollution: Hazardous waste (industry, agriculture, transportation, urban centers, military installations) Solid waste (septic systems, industry, agriculture, mining) Other: Lawns Urban storm water Household materials Pipes and tanks I. Water Pollution Surface Water 6

7 I. Water Pollution Surface Water Some water pollution facts (U.S.A.): 40% of America's rivers are too polluted for fishing, swimming, or aquatic life. 46% of America s lakes are too polluted for fishing, swimming, or aquatic life. The Mississippi River which drains nearly 40% of the continental United States, including its central farm lands carries an estimated 1.5 million metric tons of nitrogen pollution into the Gulf of Mexico each year. The resulting hypoxic coastal dead zone in the Gulf each summer is about the size of Massachusetts. 1.2 trillion gallons of untreated sewage, storm water, and industrial waste are discharged into US waters annually. In any given year, about 25% of beaches in the US are under advisories or are closed at least one time because of water pollution. I. Water Pollution Surface Water 7

8 I. Water Pollution Regulation The Refuse Act of the federal Rivers and Harbors Act of 1899 Clean Water Act (1977), Water Quality Act (1987) California Water Code and Other Regional Laws Other: Department of Defense Department of the Interior, U.S. Fish and Wildlife Service (FWS) National Oceanic and Atmospheric Administration (NOAA) Department of Agriculture, Natural Resources Conservation Service (NRCS) (formerly the Soil Conservation Service) State and local regulations (TMDL) II. Water Use In California Historical Water Supplies Surface water, irrigation ditches Groundwater reserves Los Angeles River, 1890 (USC Digital Archives) Los Angeles River, Griffith Park, 1900 (USC Digital Archives) 8

9 II. Water Use In California Water Supply Today Imported Water: Los Angeles Aqueducts Colorado River Aqueduct California Aqueduct (San Francisco Bay/Sacramento-San Joaquin Delta) Local Sources (groundwater basins) Limited amounts of treated wastewater and locally captured surface runoff in some areas II. Water Use In California Metropolitan Water District Public agency formed in 1928 by a vote of electorates from 13 Southern California cities. 26 member cities and water districts that provide water to 18 million people Goal is to provide adequate and reliable supplies of drinking water to it s service area. 9

10 II. Water Use In California Los Angeles Aqueducts Built in miles from the Mono Basin through Owens Valley to Los Angeles Water is conveyed by gravity alone There are seven reservoirs in the system with a combined storage capacity of 300,560 AF. II. Water Use In California Colorado River Aqueduct Began in 1933, operational in 1941 Covers 242 miles from Lake Havasu to Lake Mathews Can deliver up to 1.3 million acre feet per year There are 9 reservoirs with a storage capacity of 1, 092, 000 AF. 775 miles of pipeline 10

11 II. Water Use In California California Aqueduct Completed in the 1970 s to bring water to the San Fernando Valley Begins at Lake Oroville ends in Los Angeles County Includes 21 lakes and reservoirs, 661 miles of pipeline Average total energy generated annually 7.6 billion Kilowatt hours Photo by William Selby (c) 2004 Andrew Alden II. Water Use In California The creation of dams and alteration of natural hydrology has had a tremendous environmental impact. Alteration of natural hydrological processes (ex. Groundwater recharge, stream flow, etc.) Alteration of vegetation along riverbed Increased use of irrigation in places where there was previously no need The depletion of riverbed gravels reduces habitat for many fish that spawn in the gravelly river bottom, and for invertebrates such as insects, mollusks and crustaceans Decline in fish abundance and diversity Increase in invasive species Decline in habitat available for migratory bird species 11

12 II. Water Use In California City of Los Angeles LADWP sells approx 660,000 acre/feet of fresh water each year. One Acre/foot is about 326,000 gallons (215,160,000,000 gallons) On average, the city has imported about 65% of it s water from the Los Angeles Aqueduct, 15% from local groundwater reserves, and 20% from MWD. Keep in mind every city has slightly different demands and dependencies. Figures from the Los Angeles Department of Water and Power (2005) 12