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Section 4 Identification of Problems and Opportunities

EAA Storage Reservoirs Revised Draft PIR and EIS February 2006

4-4

distribution of flow to the STA’s. Nutrient removal by biological and physical

means could occur within the storage reservoirs through uptake by plants and

microorganisms, as well as by physically slowing water and causing sediments

laden with nutrients and agricultural chemicals to settle out of the water

column. During certain hydrologic conditions, operation of a storage reservoir

may require additional water quality treatment capacity to meet desired water

quality goals in the WCAs. An evaluation of the need for supplemental STA

treatment capacity will be completed during the project detailed design phase.

4.1.3 Environmental Resources

4.1.3.1 Everglades and WCAs

The predrainage landscapes of the EAA and WCAs consisted of complex mosaics

of habitat types interspersed variously on the flat peat bed that had accumulated

over the past 5,000 years. These habitat types and the associated peat

developed in response to the expansive sheet flows of water from Lake

Okeechobee, the seasonality of rain, and fire. The remnants of this vast complex

of vegetative and aquatic communities can be found in the tree islands, sawgrass

strands, wet prairies, and aquatic sloughs in the ENP.

Construction and operation of the C&SF Project and its subsequent modification

of the natural system have contributed to the reduction in spatial extent and

resiliency of the Everglades. Current operations of the C&SF Project involve

water supply and flood releases to manage stage levels in Lake Okeechobee, the

WCAs, and the East Everglades. System changes have resulted in peak flows

that are higher, following major rain events, and flow rates that decline more

abruptly following the end of the wet season. Flows to the Everglades from Lake

Okeechobee have shifted from primarily wet season flows in response to rainfall

to controlled dry season deliveries in response to urban and agricultural water

demands. Channelization and impoundment have disrupted the annual pattern

of rising and falling water depths in the remaining wetlands of South Florida.

The network of C&SF Project canals has accelerated the spread of polluted

water, sediments, and exotic species. These cause reduced system-wide levels of

primary and secondary production and changes in the proportions of community

types within the remaining Everglades system. The result is reduced water

storage capacity in the remaining natural system and an unnatural mosaic of

impounded, fragmented, over-inundated, and over-drained marshes.

Specific water management issues and problems differ within each WCA.

Generally, the extreme wet-dry cycle and increased nutrient levels within WCAs

have resulted in the loss of tree island communities and conversion of once wet

prairies into aquatic sloughs.

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Wenger 72944 Spezifikationen Seite 146