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3. Projects To Improve the Quantity, Quality, Timing, and Distribution of Water
This chapter addresses DOI interests in individual water projects and the corresponding needs for scientific and technical information to help ensure that the projects achieve their intended purposes consistent with the legal mandates assigned to DOI agencies.
Overview of Water Management Activities and Authorities
Projects to increase environmental water supplies and restore more natural surface and groundwater flows are the core of the South Florida restoration initiative. The changes in the regional hydrology created by the C&SF Project have resulted in a sharp decline in the natural abundance and diversity of organisms in the Greater Everglades. Without corrective actions to restore the predrainage hydrology, natural ecosystem functions cannot be recovered.
Because half of the historical original Everglades has been drained and developed, it will be impossible to restore the entire ecosystem to predrainage conditions. However, managers and scientists believe that for the remaining Everglades it will be possible to achieve a healthy and functioning ecosystem that once again exhibits the essential characteristics of the predrainage system. These characteristics include more natural hydropatterns, including wet and dry season cycles, natural recession rates, natural surface water depths and patterns, and in coastal areas, natural salinity and mixing patterns. These characteristics are a precursor to achieving anticipated ecological benefits, which include improving native flora and fauna, restoring the presence of key species in historic habitats, and promoting natural patterns of plant communities ranging from aquatic communities to uplands.
The water engineering projects required for this initiative are coordinated primarily by the USACE and the SFWMD through the CERP and other project authorities. The water project managers are ultimately responsible for ensuring that the projects under their jurisdiction are producing the desired ecological improvements in the Greater Everglades. As a partner with specific authorities for the protection of fish, wildlife, and parks, DOI works cooperatively with the USACE, the SFWMD, and the Florida DEP to ensure that the improvements planned to restore a more natural hydrology to South Florida adequately consider the intended, anticipated, and actual responses within the ecological communities based on the best possible scientific information and analysis.
Restoring more natural surface and groundwater flows must address four interrelated factors: the quantity, quality, timing, and distribution of water. More water is not always better. Alternating periods of flooding and drying were vital to the historical functioning of the Everglades ecosystem. In general, the CERP and other water management projects include five kinds of engineering components for capturing and redirecting water to simulate a more natural system:
Together these components are planned to recapture much of the 1.7 billion gallons per day of water currently being discharged via canals into Biscayne and Florida Bays, the Straits of Florida, and the Gulf of Mexico. This water will be used to restore natural system functioning and to supplement urban and agricultural water supplies.
A major focus of DOI participation in the water engineering projects is on ensuring that the timing and distribution of water flows to wetlands, especially in the national parks and federal wildlife refuges, mimic natural flow patterns and preserve natural wetland functioning. Natural flows are driven by the seasonal rainfall patterns in the region, and the restoration project components must be designed and operated to mimic this natural variability. For example, the FWS is assisting the Corps and the South Florida Water Management District in revising the regulation schedule for Lake Okeechobee. Regulation of Lake Okeechobee is central to water management in the rest of the C&SF system. This provides an opportunity to not only improve habitat conditions within the littoral zone of Lake Okeechobee, but also influences conditions in connected areas, including the St. Lucie and Caloosahatchee estuaries and the Water Conservation Areas.
DOI is particularly concerned about the potential harm to fish and wildlife from contaminants that might be released as a result of CERP projects. The rehydration of lands previously used for agriculture, water stored in underground aquifers, or water diverted or reclaimed from urban areas may reintroduce contaminants from the soils. This issue is not addressed as part of the water quality targets for CERP projects but must be addressed as part of the stewardship responsibilities of DOI.
DOI is also interested in improving fish and wildlife habitat and recreational potential of water storage reservoirs and other constructed features in ways consistent with the water management functions of the project features.
DOI collaborates with the USACE and SFWMD on three primary activities:
Overview of Science Support for DOI Managers
South Florida has one of the most extensive hydrologic and ecological data collection and analysis efforts in the country, with contributions from numerous federal and state agencies, including DOI. The collected field data support modeling efforts that convert large amounts of technical information into planning and evaluation tools. These tools directly support project design and adaptive management. In order to meet the modeling challenges of the CERP, DOI should be an active and important participant in the Interagency Modeling Center (IMC), which was established to provide an environment to conduct work in an open and collaborative technical environment.
Hydrologic Research and Modeling
While the NSM provides a picture of the historic, predrainage Everglades, the South Florida Water Management Model (2 x 2 Model) provides a picture of how the regional water management system works. At a scale of 2 square miles, this landscape-scale model simulates regional predictions of the hydrologic conditions that would occur given changes in water management in South Florida. The 2 x 2 Model has been used for nearly two decades to evaluate the consequences of modifications to the C&SF Project. The acquisition of the basic data needed to support the model (evaporation, rainfall, geology, vegetation, water levels, topography, etc.) has been a priority for many years, and the model is "complete," although it is continuously updated. Groundwater flows have been added to improve some simulations of hydrologic conditions, but all the subsurface simulations end at the mainland shoreline rather than extending to the continental margin. The NSM Model is derived from the 2 x 2 Model and is continuously updated with that model to ensure that the inputs to each are the same.
A next generation hydrologic model that uses higher resolution in key areas, known as the South Florida Regional Simulation Model (RSM), is being developed by the SFWMD. Two higher resolution (500 x 500 meters) hydrologic models, known as the TIME and SICS, are available for the southern Everglades and are being used to predict salinity in the coastal wetlands. Additional models, particularly at local levels, and linkages among models are needed for the detailed design and adaptive management of individual projects.
Changes in the hydrology of the South Florida ecosystem will ultimately cause changes in downstream estuaries and embayments. Because hydrologic models used to design the CERP do not accurately represent groundwater and surface water flow without uncertainties, surface water and groundwater inputs into coastal estuaries such as Florida and Biscayne Bays, many questions remain regarding the link between changes in water management and the salinity and water quality in these estuaries. The Florida Bay Interagency Science Program is integrating the research, modeling, and monitoring projects needed to understand how the bay currently functions and how it will function in the future as part of the South Florida ecosystem. DOI interests in projects affecting Florida Bay and Biscayne Bay are addressed for each individual project.
Ecological Research and Modeling
Computer models are used to project and evaluate how vegetation and wildlife in the South Florida ecosystem will respond to changes in hydrology and land use. These models combine detailed spatial information about elevation and current vegetation patterns with landscape-scale models of hydrology and include assumptions about ecological processes, such as nutrient transport and vegetative succession. It is important that the scale of models applied for ecological restoration match the scale of the problem being addressed.
During the development of the CERP, a set of ecological models were used to predict ecological responses to various water management scenarios in the Everglades ecosystem. These models were driven by the 2 x 2 Model and the higher resolution hydrologic models developed for the southern Everglades. New models are being developed that will output hydrologic data in different forms, which will enhance the compatibility between the hydrologic and the ecological models. While not yet as mature as the hydrologic models, the ecological models are useful for projecting the effects of hydrologic change on biotic communities and certain endangered species.
Three general kinds of ecological models are used to predict the ecological effects of the various CERP projects: Models of vegetative production, habitat suitability index (HSI) models, and faunal demographic models. HSI models produce maps indicating the spatial pattern of habitat suitability for particular species. Demographic models project how population size may change through time as a function of the changing environment. Such models are essential for performing population viability analyses to determine the risk of extinction.
As individual projects are designed and implemented, they will be based on the most up-to-date scientific knowledge currently available. As models are improved and additional models are developed, projects will be adaptively managed to increase the potential for restoration success.
Water Quality Research and Modeling
WRDA 2000 authorizes the USACE to adaptively manage the ongoing CERP program to continuously incorporate new scientific and technical information into projects. This adaptive assessment and monitoring program will be used to refine and improve the design and operation of CERP projects and to determine whether the CERP is achieving its overarching objective of recovering healthy and sustainable ecosystems in South Florida. The adaptive management program is being carried out by "RECOVER," which is an interagency team of scientists and technical staff being led jointly by the USACE and the SFWMD. DOI scientists and technical staff serve on the RECOVER leadership group and co-chair some of the RECOVER subteams.
A RECOVER Adaptive Assessment Team (AAT) has developed a systemwide Monitoring and Assessment Plan (MAP), which establishes a framework for (1) measuring and understanding systemwide responses to CERP projects, (2) determining how well the CERP is meeting its goals and objectives, and (3) identifying opportunities for improving the performance of the CERP where needed. The MAP will provide a single, integrated plan for participating agencies, including DOI, to measure systemwide responses and the performance of the CERP.
Two key assumptions have been made that will be critical to the success of MAP implementation: (1) Existing monitoring will continue with existing funding sources (i.e., the MAP does not replace other agency efforts). (2) Partnering agencies will contribute funding and/or will participate in implementation of the MAP.
The MAP addresses only responses expected from implementation of CERP projects and does not include all of the components necessary to achieve long-term restoration of the South Florida ecosystem. Examples of ongoing monitoring activities that are independent of the MAP include weather and water stage monitoring stations (USGS), salinity monitoring networks in Everglades and Biscayne Bay National Parks (NPS), and the American alligator survey network (CESI).
Organization of Water Projects
The remainder of this chapter discusses 21 projects designed to improve the quantity, quality, timing, and distribution of water flows in the region. The project-specific science needs are identified for each project. The projects are organized into the following six subdivisions:
In addition, a summary of the "Landscape-Scale Science Needed to Support Multiple CERP Projects" is provided at the end of this chapter. This science includes
U.S. Department of the Interior, U.S. Geological Survey
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Last updated: 15 January, 2013 @ 12:43 PM(KP)