Controlling Waterand WetlandsAPES 2009-10

DamsDiversionsChanneling

Flood plains, flood controlAND

Wetlands

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

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.

Dams and Fish

Fish “ladder” on Lehigh River, Allentown

Fish Passage - Lehigh River, Easton, PA

Shad in Pennsylvania

Grand Coulee

Glen Canyon

Lehigh River - Francis E. Walter Dam

Channel that Water

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

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

Values of Wetlands View this EPA slideshow, then list the

numerous values of wetlands

Inland Wetlands

Fig. 7-25 p. 162Fig. 7-25 p. 162

Plants and Animals of a Bog EcosystemPlants and Animals of a Bog Ecosystem

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?

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

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?

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

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

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

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

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

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

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

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

How Could L.A. survive? Key is conservation Recycling of brown water: population has

risen 1 million, no more water used than in 1972!!!

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!!

Dangers of living in floodplain Flooding Lack of Flood Insurance

Army Corps of Engineers- protecting cities

Build dikes – “mounds” along rivers – hold water from flooding Increases downstream flooding

Channels and diversions Dams

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