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Controlling Water and Wetlands APES 2009-10

Learn about the impact of dams, diversions, and channeling on flood control and wetland ecosystems. Discover how beavers change ecosystems and the advantages and negatives of their presence. Explore the importance of wetlands and the various values they provide. Understand the consequences of water diversions and the destruction of wetland habitats.

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Controlling Water and Wetlands APES 2009-10

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  1. Controlling Waterand WetlandsAPES 2009-10 Dams Diversions Channeling Flood plains, flood control AND Wetlands

  2. Natures Dam Builders • How do beavers change an ecosystem? • What are advantages? • Flood control • increase groundwater infiltration • new habitats for many animals • Negatives • Flood highways, usable land • block storm sewers

  3. Beavers in PA • Castor canadensis - North America's largest rodent • 40-60 pounds and grow up to 40 inches • By end nineteenth century, uncontrolled trapping eliminated beavers in Pennsylvania - extirpated • Beaver is back • 1917 - Game Commission released a pair of Wisconsin beavers Cameron County valley. • Over the next decade, the pair and its offspring reproduced and prospered.

  4. Dams and Fish Fish “ladder” on Lehigh River, Allentown

  5. Fish Passage - Lehigh River, Easton, PA

  6. Shad in Pennsylvania

  7. Grand Coulee

  8. Glen Canyon

  9. Lehigh River - Francis E. Walter Dam

  10. Channel that Water

  11. Channeled Streams • Advantages • Reduce flooding – protect floodplains • transportation • Disadvantages • Loss of riparian buffers • Temperature thus lower DO in summer • Food for macros • Loss of filtering • Stream bank erosion • Loss of microhabitats – fish, macros • Habitat Restoration (see page 316) Undo the Damage • Deflectors • Restore riparian buffers

  12. Are Wetlands Always WET?? • Defining a wetland: • Wetlands are unique. They are one of the few habitats that are protected and regulated by state and federal agencies. The following definition of wetlands is used for regulatory and permitting purposes: "Those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal conditions do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas." Source: psu.edu

  13. Values of Wetlands • View this EPA slideshow, then list the numerous values of wetlands

  14. Inland Wetlands Fig. 7-25 p. 162

  15. Plants and Animals of a Bog Ecosystem

  16. Protection of Wetlands • Section 404 of Clean Water Act • EPA • To fill in wetland – must obtain permit from the Corps of Engineers • This has at least DECREASED the loss of wetlands • If MUST destroy a wetland – make a “new” wetland • Mitigation • What are the negatives and positives of this?

  17. The Everglades and the Kissimmee River (READ 318) • Central Florida • Complete channeling of the river – • 100 miles • Eliminate wetlands and riparian buffers • Result: loss of fish, waterfowl (lost 90%), birds (eagles lost 70%) • “Save Our Everglades” – change canal back to rive • 5 years, $276 million for partial restoration

  18. Dam The Delaware • The Tocks Island Dam- a controversy (read 342) • Why did Army Corp plan the dam? • Why did citizens anf environmental groups form “Save the Delaware”? • What Happened?

  19. Dams for Hydroelectric Power (345-346) • Advantages of other types of generating plants • Salmon or electricity • Millions to about 5000 spawning on the Snake River – all endangered • Fish vs. aluminum manufacturers

  20. Water Diversions – Mono Lake (319-324) • Unique ecosystem • hot mineral springs • extremely high salt and alkalinity • up to 1000 time ocean • huge numbers brine shrimp and alkali flies • major migratory food stop for huge numbers birds

  21. The Destruction of Mono Lake • Level decreased 43 feet by between 1941 and1991 (322 to 324) • Tufa towers - up to 30 feet high, formed underwater • Why – extension of LA aqueduct to the Mono Lake Basin • L.A. and Mono Lake • The Mono Lake Story

  22. The Loss of Mono Lake • Four creeks were diverted into the aqueduct, drying up the streams below the diversion dams. Riparian vegetation died, fisheries were destroyed, and occasional floods tore through the desiccated floodplains plugging up side channels and turning the main channels into wide, straight washes. Deprived of most of its inflow, Mono Lake dropped 45 vertical feet, lost half its volume, and doubled in salinity by 1982. The result was a fragmented and poorly functioning ecosystem. • http://www.monolake.org/mlc/restoration

  23. Healing some of the damage • As a result of litigation pursued by the Mono Lake Committee, National Audubon Society, California Trout and others, first the courts and subsequently the State Water Resources Control Board ordered restoration of the area's damaged resources. The L.A. Department of Water and Power is responsible for implementing the Water Board-approved restoration plan. • Today, Mono Basin restoration is aimed at restoring natural processes and ecological function. Raising the level of the lake will lower its salinity, reduce dust storms and reconnect the lake to springs and deltas. • http://www.monolake.org/mlc/restoration

  24. But not all….. • Because water will continue to be diverted to L.A., the Mono Basin resources will not be completely restored. The lake will still be 25 feet lower than its prediversion level, the streams will carry less annual flow than they once did. • http://www.monolake.org/mlc/restoration

  25. The Survival of L.A. • Los Angeles - only 15 inches of rain • Water diverted from Mono Lake to L.A. • Although several hundred miles away, water rights given by federal government to L.A. • Salinity doubled - birds would loose food supply

  26. The Survival of Mono Lake • California Supreme Court - 1983 LA DWP public trust values: …”the purity of the air, the scenic views of the lake and its shore, the use of the lake for nesting and feeding birds…” must be protected • 1994: State Water Resources Control Board • over next 20 years lake must rise to at least 25 feet below pre-diversion level

  27. How Could L.A. survive? • Key is conservation • Recycling of brown water: population has risen 1 million, no more water used than in 1972!!!

  28. Flood Plains - • Low, flat land along river or stream • periodically flooded • Feds - 50, 100 or 500 year floodplain • Why live in floodplains? • Of PA 2800 communities, 2468 at least partially in a floodplain!!

  29. Dangers of living in floodplain • Flooding • Lack of Flood Insurance

  30. Army Corps of Engineers- protecting cities • Build dikes – “mounds” along rivers – hold water from flooding • Increases downstream flooding • Channels and diversions • Dams

  31. Options to Dikes, Dams,and Diversions • Oppose development in 50 to 100 year floodplain • Use for parks, etc. • Encourage wetlands – soak up and retain water for downstream

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