Final Restudy PMs Details

Attachment B

Performance Measure Documentation

Category

Ecological

Performance Measure

Seasonal Distribution of Overland Flow Volume, Mid Shark River Slough

Date Submitted/Revised

June 1988

General Planning Objective

This performance measure is linked to the Everglades Sloughs Conceptual Model developed by the SERA Natural Systems Team, and addresses several hydrologic and ecologic planning objectives identified by the Governors's Commission for a Sustainable South Florida in the C&SF Project Restudy Conceptual Plan.

Region

The seasonal distribution of overland flow volume is applied as a performance measure only to the cross section in mid Shark River Slough.

Restoration Goal

The re-distribution of flow into Shark River Slough, with subsequent restoration of extended duration of uninterrupted flooding, brief duration of dry conditions, water depth pattern, and overland flow volume and timing characteristic of the pre-drainage system is among the highest priorities of ecosystem restoration in the southern Everglades.

Problem Addressed

Restoration of the seasonal timing of flow down Shark River Slough is important to extend the duration of flooding in the Slough and to provide seasonal salinity patterns in the estuaries as they would have occurred in the natural system

Model Target

The target is a cumulative deviation that does not exceed that indicated by NSM45F.

Model Output Format

The overland flow volume across the cross-section in mid Shark River Slough that occurs each month of the year is calculated as the percent of the annual flow volume and is averaged over the 31-year period of record. The performance measure is the cumulative deviation of the monthly percent of annual flow under a given alternative from the monthly percent of flow under NSM45F, summed over the 12 months of the year. It is given a weighting of one when averaged with the other performance measures for Shark River Slough because of the higher level of uncertainty in NSM45F simulations of flow compared to other parameters.

Evaluation Tools

The South Florida Water Management Model and Natural System Model should be used to evaluate a cross section evaluate a cross-section taken across the entire width and depth of flow in mid Shark River Slough.

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Performance Measure

Florida Bay Performance Measure Suite:

Frequency of Stages of 6.3+ feet MSL at Gage P33

Frequency of Stages of 7.3+ feet NSM at Gage P33

Cumulative Salinity Differences from High Levels, March-June

Cumulative Salinity Differences from Low Leves, August-October

Date Submitted/Revised

June 1998

General Planning Objective

These performance measures are linked to the Florida Bay Mangrove/Estuarine Conceptual Model developed by the SERA Natural Systems Team.

Region

All four measures target Florida Bay coastal basins.

Restoration Goal

Ecological values and indicators of restoration success in the Florida Bay mangrove estuary and coastal basins that are linked to the above hydrology/salinity performance measures in the conceptual model include 1) increased production of low-salinity mangrove fish and invertebrates, 2) re-establishment of coastal nesting colonies of wading birds and wood storks and eastern Florida Bay colonies of roseate spoonbill, 3) delay (syn) in coastal colony formation by wading birds and wood storks, 4) resumption of the return frequency of wading bird and white ibis super colonies, 5) increased growth and survival of juvenile American crocodiles, 6) increased cover of low-to-moderate salinity aquatic macrophyte communities in coastal lakes and basins, 7) return of seasonal waterfowl aggregations to coastal lakes and basins, 8) enhanced nursery ground value for sport fishes and pink shrimp in coastal basins, and 9) persistence and resilience of the mangrove, salt marsh and tidal creek vegetation mosaic.

Problem Addressed

Ecological restoration of the estuary requires a reduction in the frequency of high salinity events that have been identified for each coastal basin through the conceptual model process. Another restoration criterion is to increase the frequency of low salinity events that have been identified for each coastal basin.

Table 1. Lower and upper salinity levels identified for coastal basins. It is desirable to decrease the frequency that salinity exceeds upper levels, and to increase the frequency that salinity drops below lower levels.

Basin Lower Level Upper Level

Joe bay 5 ppt 15 ppt

Little Madeira Bay 15 ppt 25 ppt

Terrapin Bay 25 ppt 35 ppt

Garfield Bight 25 ppt 35 ppt

North River Mouth 5 ppt 15 ppt

The strategy for ecological restoration of the estuary is to maintain freshwater heads and flows in the Everglades at the upstream end of the salinity gradient in order to achieve desirable salinity regimes in the Florida Bay coastal basins at the downstream end of the salinity gradient. Regression analyses demonstrated inverse relationships of salinity in the coastal basins to water level upstream in the Everglades. The regressions indicated that stages of 7.3 and 6.3 feet msl at the P33 gage in central Shark River Slough produce the lower and upper salinity levels for Joe Bay, Little Madeira Bay, Terrapin Bay, Garfield Bight, and North River Mouth.

Model Target

Number of months NSM4.5F provided stages of 6.3 or above

Number of months NSM4.5F provided stages of 7.3 or above

Reduce the cumulative salinity difference to a value that does not exceed the cumulative difference produced by NSM4.5F.

Model Output Format

The Florida Bay Mangrove/Estuarine Conceptual Model identifies high salinity concentrations for the coastal basins of Florida Bay which should not be exceeded more frequently than NSM45F would indicate. Stages equaling or exceeding 6.3 feet msl at the P33 gage in mid Shark River Slough correspond to a reduced frequency of those high salinity events in the the Florida Bay coastal basins from Joe Bay to North River Mouth. This performance measure is the number of months during the 31-year period of record when stages at P33 rose to, or above, 6.3. A reduced frequency of high salinity events is given a high priority in the ecological restoration of the coastal basins, thus the frequency of 6.3+ stages is given a weighting of two when averaged with the other performance measures.

The Florida Bay Mangrove Estuarine Transition Conceptual Model identifies low salinity concentrations for the coastal basins of Florida Bay which should be attained as frequently as NSM45F would indicate. Stages equaling or exceeding 7.3 feet msl at the P33 gage in mid Shark River slough corresponded to an increased frequency of those low salinity events in the coastal basins of Florida Bay. The performance measure is the number of months during the 31-year period of record when stages at P33 rose to, or above, 7.3. An increased frequency of low salinity events is given a lower priority than a reduced frequency of high events, thus the frequency of 7.3+ stages is given a weighting of one when averaged with the other performance measures for the coastal basins.

The transition from the late dry season to the early wet season during March through June is a critical period to estuarine organisms in the Florida Bay coastal basins regarding the frequency and duration of high salinity events. Salinity is estimated based on relationships between mean monthly salinity in the coastal basins and water stage at the P33 gage in mid Shark River Slough. The cumulative salinity difference (ppt) from the high salinity levels that have been identified for Florida Bay coastal basins is summed during the dry/wet season transition months of March-June. Differences are summed over five coastal basins (Joe Bay, Little Madeira Bay, Terrapin Bay, Garfield Bight and North River Mouth) and over the 31-year period of record. Differences above the specified high salinity levels are given a positive value, and differences below the high salinity levels are given a negative value. This measure is given a weighting of two when averaged with the other performance measures for the coastal basins because the avoidance of high salinity events is considered more important than the attainment of low salinity events.

During the August-October transition from the late wet season to the early dry season, it is important to achieve low salinity levels in the Florida Bay coastal basins to provide the seasonal environment for low-salinity estuarine organisms and to postpone the onset of high salinity events further into the dry season. Salinity is estimated based on relationships between mean monthly salinity in the coastal basins and water stage at the P33 gage in mid Shark River Slough. The cumulative salinity difference (ppt) from the low salinity levels that have been identified for the Florida Bay coastal basins is summed during the wet/dry season transition months of August-October. Differences are summed over the five coastal basins and over the 31-year period of record. Differences above the specified low salinity levels are given a positive value, and differences below the low salinity levels are given a negative value. This measure is given a weighting of one when averaged with the other performance measures for the coastal basins because the attainment of low salinity events is considered less important than the avoidance of high salinity events.

Evaluation Tools

The South Florida Water Management Model and Natural System Model should be used to evaluate P33 stages. Priority is given to the P33 stage of 6.3 and the March-June cumulative salinity difference, which pertain to the avoidance of high salinity levels, over the P33 stage of 7.3 and the August-October cumulative salinity difference, which pertain to the achievement of low salinity levels

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Category

Ecological

Performance Measure

Model Lands/C-111 Performance Measure Suite

High Water

Low Water

Extreme Low Water

Relative Dry Period Slope

Wet Season Inundation Pattern

Late Wet Season Inundation

Date Submitted/Revised

March 1998/July 1998

General Planning Objective

Meets planning objective criteria identified by the SERA Natural System Team and by the Governor’s Commission for a Sustainable South Florida.

Region

The term Model Lands, for C&SF Restudy planning purposes, applies to three areas: (1) wetlands immediately north of the C111 Canal, (2) the land between U.S. 1 and Card Sound Road, and (3) land east of Card Sound Road and south of the Mowry Canal (C-103). These areas correspond to Indicator Regions 4 (C-111 Perrine Marl Marsh), 5 (Model Lands South), 6 (Model Lands North), and 47 (North C-111).

Restoration Goal

Reduce artificial hydrological barriers between indicator regions, minimize the amount of time exceedingly high and low water levels stress natural vegetation communities, and restore more natural hydropatterns.

Problem Addressed

The Model Lands/C-111 region encompasses freshwater (predoninantly marl prairie) wetlands, a transition zone, and coastal wetlands. This area has been subdivided and hydrologically isolated from the regional system by primary and secondary canals and major and minor roads. The result has been widespread overdrainage and a reduction in the amount of freshwater reaching the coastal mangroves and nearshore estuarine waters as overland flow.

A study by Meeder et al. (1996) compared recent vegetation to vegetation mapped during the 1940’s by Egler (1952). Their work indicated that a zone of low plant cover and low primary productivity, which is observable as a “white zone” on aerial photographs, has expanded inland by as much as 300 meters since 1940. Meeder et al. (1996) associated the inland expansion of this zone with saltwater intrusion.

Surface water connection between the vast freshwater wetlands in this region has been disrupted and runoff to the coastal bays and sounds have been blocked or diverted by U.S. 1, Card Sound Road and borrow ditches, canal levees, and other man-made structures. Ishman’s (1998) paleoecologic study of Manatee Bay suggests that the bay supported a lower salinity fauna in the early part of this century than it does today. Although large quantities of fresh water are sometimes flushed to Manatee Bay through the C-111 Canal (S-197), the point source delivery and pulsed manner in which this water moves into Manatee Bay has proved harmful to marine and estuarine life. Most of the time Manatee Bay receives little freshwater inflow.

Model Target

The Natural System Model (NSM) was not used to set performance targets for this region. NSM is not a good indicator of pre-drainage hydrologic conditions in the Model Lands area, as evidenced by NSM predictions of lower dry-season water levels than the 1995 Base. If current water levels were higher than pre-drainage water levels, it is unlikely that the “white zone” would have expanded to the degree that it has since 1940. Additionally, there had to have been sufficient freshwater flows to Manatee Bay at most times of the year to support a brackish water fauna, which does not exist in modern times. Four indicator regions in the Model Lands area were established for the study of alternative management scenarios. Specific target water levels and hydroperiods were defined for these indicator regions based on known topography and projections of future restored vegetation. Vegetation zones adapted from Meeder et al. (1996) were the basis for establishing target water levels. The collective professional experience of a team of biologists from federal, state, and local agencies and businesses was the basis for setting desired maximum ponding depths, minimum water levels, and hydroperiods for each vegetation zone. Indicator regions and the projected desired hydrologic parameters are shown below, followed by the vegetation zones applicable to each indicator region. Maximum and minimum water levels are relative to ground level.

Indicator Region	Region Name	SFWMM Cells	Max Ponding Depth - Wet Season	Min Water Level - Dry Season	Average Hydroperiod	Vegetation Zones Included
4	C-111 Perrine Marl Marsh	R8, C26-27 R7, C26-27	< 2.0 ft	> 0.5 ft	10 - 12 months	3
5	Model Lands South	R8, C29-30	< 2.0 ft	> 0.5 ft	10 - 12 months	3
6	Model Lands North	R10, C29-30	< 1.75 ft	> 0.25 ft	8 - 12 months	2 + 3
47	North C-111	R9, C26-27	< 1.5 ft	> 0 ft	6 - 9 months	2

Vegetation zones used as the basis for establishing targets

Zone	Descriptive Name	Desired Wet Season Maximum Water (relative to ground elevation)	Desired Dry Season Minimum Water (relative to ground elevation)	Desired Average Hydroperiod
0	Agriculture/Open Land Buffer	N/A	N/A	N/A
1	Shrub-dominated Freshwater Marshes	< 0.5 ft	> -0.5 ft	Driven by downstream hydrology
2	Muhly/Sawgrass or Sawgrass Mosaic with Tree Islands	< 1.5 ft	> 0 ft	6 - 9 months, no wet season reversals
3	Sawgrass Marsh with Freshwater Swamp Forests	< 2.0 ft	> 0.5 ft	10 - 12 months, no wet season reversals
4	Mixed Graminoid with Dwarf Mangroves	Driven by upstream maxima	> 0.5 ft	12 months
5	Ecotone - “White Zone”	*	*	12 months
6	Fringing (aka Coastal) Mangroves	**	**	12 months
7	Downstream Marine Areas	N/A	N/A	N/A

Water level not a useful indicator; 0 - 3 ppt salinity desired. year round.

** Water level not a useful indicator; 0 - 5 ppt salinity desired. year round.

Model Output Format

High Water: The proportion of time that water levels are below the high water level which has been specified for the indicator region.

Low Water: The proportion of time that water levels are below the low water level which has been specified for the indicator region.

Extreme Low Water: The proportion of time that water levels stay above one foot below the low water target.

Relative Dry Period Slope: Relative measure of the steepness of the slope for the stage duration curve during dry periods.

Wet Season Inundation Pattern: Proportional measure of how many times during the 31 year simulation that water levels drop below surface elevation during the July-October portion of the wet season.

Late Wet Season Inundation: Proportional measure of how many times during the 31-yr simulation that autumn periods of inundation ended during the months of November and December.

This was applied only to Indicator Region 5 (Model Lands South), which includes habitat critical for Roseate Spoonbill feeding.

Evaluation Tools

South Florida Water Management Model

Literature Cited

Egler, F.E. 1952. Southeast saline Everglades vegetation. Florida and its management. Veg. Acta Geobot. 3: 213-265.

Meeder, J.F., M.S. Ross, G. Telesnick, P.L. Ruiz, and J.P. Sah. 1996. Vegetation analysis in the C-111/Taylor Slough Basin. Final report on Contract C-4244. Southeast Environmental Research Program, Florida International University, Miami, Florida.

Ishman, S.E., T.M. Dronin, L. Brewster-Wingard, and D.A. Willard. 1998. Paleoenvironmental record from Manatee Bay, Barnes Sound, Florida. Poster presentation at the USGS Paleoecology Workshop, Key Largo, Florida, January 22-23, 1998.

Authors & Contributors

Authors: Joan Browder and Gwen M. Burzycki

Contributors: South Dade Wetlands Team: Individuals will be listed

******************************************************************************

Category

Ecological

Performance Measure

Wood Stork Nesting Patterns

Date Submitted/Revised

May 1998

General Planning Objective

Meets SERA objectives to (1) Restore the natural annual and multi-year patterns of native plant and animal distribution, abundance, seasonality and richness to the natural areas of the southern Everglades region, and (2) Provide for self-sustaining and self-regulating populations of native plant and animal species with special attention to threatened, endangered and species of special concern (includes both state and federally listed species).

Meets general planning objectives of the Conceptual Plan for the C&SF Restudy Project, of the Governor's Commission for a Sustainable South Florida, to (1) Improve and protect habitat quality, heterogeneity, and biodiversity in coastal and associated marine ecosystems, and (2) Provide for sustainable populations of native plant and animal species with special attention to threatened, endangered, or species of special concern.

Region

Southern Everglades & Big Cypress Subregions

Restoration Goal

Recover healthy, sustainable Wood Stork nesting colonies to the Everglades basin.

Problem Addressed

The number of Wood Storks nesting in colonies in the central and southern Everglades has declined from 5,000-8,000 birds prior to the C&SF Project (numbers are for 1931-1946) to 250-1,000 birds since 1986 (Ogden 1991, 1994, Gawlik & Ogden 1996). During this same spread of years (1931-1996) the timing of colony formation (initiation of nesting) by storks has shifted from November & December for most years prior to 1970, to February & March for most recent years (Ogden 1994). Earlier forming colonies were larger and more successful than late forming colonies (e.g., means of 2,250 pairs in November colonies, and 450 pairs in March colonies; successful in 7 of 9 years between 1953-1961, but successful only 6 of 28 years between 1962-1989. Early forming colonies were located almost entirely within the mainland, mangrove forest zone downstream from the freshwater Everglades drainage, or along the mangrove-freshwater ecotone in the southern Everglades. Recent stork colonies mostly have been located on willow and pond apple islands in the south-central Everglades.

The hypothesis which best explains the changes in nesting patterns by storks is that, as a result of substantial reductions in freshwater flow into the mainland estuaries, the production and availability of the size classes of fishes which are essential prey for nesting storks has deteriorated to the point where the mangrove zone can no longer support nesting by storks (Ogden 1994). Storks now "wait" until water levels in the later-drying interior sloughs drop low enough for fish to be adequately concentrated to support nesting activity. Interior, late-forming colonies often fail because, (a) fish stocks also are relatively low because of increased frequencies of slough dry-outs in the managed system, (b) interior colonies lack the range of foraging habitat conditions found in estuarine systems, and (c) late colonies are still active when summer rains disperse local prey concentrations.

Model Target

To recover healthy, sustainable nesting colonies of Wood Storks in the Everglades basin, storks must return to nesting in the area of the mainland estuaries, with colonies forming no later than January. The historical pattern was for storks to forage primarily in the mainland estuarine region during the early dry season at the time of colony formation, and to forage in the drying freshwater sloughs during the later dry season during the nestling and fledging stages of reproduction.

In addition to recovery of traditional location and timing patterns, the Science Sub-Group of the South Florida Ecosystem Restoration Task Force and Working Group set a ecosystem restoration target of 3,000 - 5,000 nesting storks for the Everglades and Big Cypress colonies combined (Ogden et al. 1997). This numerical target is consistent with the target set in the revised Wood Stork Recovery Plan for delisting the stork: 2,500 pairs (5,000 birds) nesting in south Florida in a total population of 10,000 pairs (U.S. Fish and Wildlife Service, 1996).

Model Output Format

The two hydrological indicators which best measure the recovery of optimum foraging conditions for storks for the restoration targets described above, are, (a) the measures of the volume of flow into the mainland estuaries downstream from the southern Everglades and Big Cypress (three flow lines; one across the southern Shark Slough; one across the southern Taylor Slough/Craighead Basin; and one across the Lostman's Slough), and (b) the measure of mean duration of uninterrupted surface hydroperiod in the central and southern Shark Slough (indicator regions 10 and 11). The target is to meet NSM 4.5 predicted flow volumes and hydroperiod durations, respectively. The "score" for each alternative plan and base condition will be the simple mean of the percentages of NSM targets for the five hydrological parameters (3 flow lines and 2 indicator regions). This calculation results in greater weight for the estuarine target, because three of the five values are for measures of flow into the estuaries. Greater weight for the estuarine target is appropriate because achievement of the desired colony timing and location patterns may be dependent of estuarine conditions.

Evaluation Tools

Uses output from the South Florida Water Management Model and the Natural Systems Model (4.5), for Indicator Regions 10 and 11 in the central and southern Shark Slough, and 3 Flow Lines at the freshwater/estuarine ecotone (Taylor Slough, Shark Slough, Lostmans Slough).

Literature Cited

Gawlik, D.E. & J.C. Ogden (eds.). 1996. 1996 late-season wading bird nesting report for south Florida. South Florida Water Management District. West Palm Beach, FL.

Ogden, J.C. 1991. Wading bird colony dynamics in the central and southern Everglades. An annual report. South Florida Research Center. Everglades National Park.

Ogden, J.C. 1994. A comparison of wading bird nesting colony dynamics (1931-1946 and 1974-1989) as an indication of ecosystem conditions in the southern Everglades. Pp. 533-570 in, Everglades. The ecosystem and its restoration (S.M. Davis & J.C. Ogden, eds.). St. Lucie Press, Delray Beach, FL.

Ogden, J.C., G.T. Bancroft & P.C. Frederick. 1997. Ecological success indicators: reestablishment of healthy wading bird populations. In, Ecologic and precursor success criteria for south Florida ecosystem restoration. A Science Sub-group report to the Working Group of the South Florida Ecosystem Restoration Task Force. U.S. Army Corps of Engineers, Jacksonville, FL.

U.S. Fish and Wildlife Service. 1996. Revised recovery plan for the U.S. breeding population of the Wood Stork. U.S. fish and Wildlife Service. Atlanta, GA. 41 pp.

Authors & Contributors

Submitted by: John C. Ogden, South Florida Water Management District

******************************************************************************

Category

Ecological

Performance Measure

Viable Populations of the Endangered Cape Sable Sparrow

Date Submitted/Revised

November, 1998

General Planning Objective

Meets Governor’s Commission planning objective in the C&SF Project Restudy Conceptual Plan; to provide for sustainable populations of native plant and animal species with special attention to threatened, endangered, or species of special concern.

Region

Everglades National Park and Big Cypress National Preserve

Restoration Goal

For the sparrow to survive in the long‑term, there must be three healthy sub‑populations, each averaging at least 2000 birds.

Problem Addressed

The Cape Sable sparrow is a Federally listed endangered species found only within the southern Everglades. First found early in this century, its exact range was not known completely until an extensive survey was completed in 1981. Approximately 6500 existed at that time, grouped into three areas. The one west of Shark River Slough (A) was the most numerous, followed by a slightly smaller population east of the Slough and west of Taylor Slough (B). The remaining birds were scattered in populations to the north and east of these two areas (C through E). In 1992, the second annual survey found similar numbers, though the northeastern birds had declined. In 1993, the western population declined precipitously and has remained at low levels since. Population B has remained more or less constant. The remaining populations have been marked by declines and local extinction (Curnutt et al.,l998)

Analysis of the causes of these declines rule out chance fluctuations in numbers (which can be large for similar grassland sparrows) and Hurricane Andrew, which passed over some of the populations in 1992 (Curnutt et al., l998) Persistent high water levels during the bird's breeding season (mid‑March to mid‑June) are the cause of the decline in the western part of the range. High water levels ‑ caused principally by discharges across the S12 structures during the early months of the year ‑ prevented breeding in 1993 and 1995 and allowed only limited breeding in 1994, 1996, and 1997 (Nott et al., l998). Rainfall during the breeding season has a much smaller effect on the water levels in this area. In the north and east of the sparrow's range, frequent fires caused the decline in sparrow densities. Fires as often as once a year preclude breeding, and sparrow numbers increase as fire frequencies decline to once in seven years. This frequency is the limit of the data. It seems possible that the diversion of water flows from northeast Shark Slough is partly responsible for the drier conditions there, which could result in more frequent fires and, in turn, the decline of the sparrow population.

Model Target

An area of 30 square kilometers in the west should remain dry (water level at or below ground level) for a least 40 days during the period mid‑March to mid June. This will allow the birds to complete one clutch. This is a minimum safe standard for wet years, not an average value. Under average conditions, an area of approximately 100 square kilometers would be dry and part of this area would be dry for at least 80 days ‑ the time taken to complete two clutches.

In the northeast part of the sparrow's range, the water levels need to be raised during the pre‑breeding season in a way necessary to reduce fire frequencies across the area to a safe minimum standard of no more than one dry season fire in three years.

The first requirement is that the water level at NP205 should be at or below ground level on April 1st of each year. This will ensure that sufficient breeding habitat is available for the population west of Shark River Slough.

The second requirement is that water levels in the marl prairies to the east of Shark River Slough and north of Long Pine Key should be raised at the end of the rainy season by about 12 cm (= 5 inches) above recent averages.

Model Output Format

Evaluation Tools

ATLSS

Literature Cited

Curnutt, J.L., A.L. Mayer, T.M. Brooks, L. Manne, O.L. Bass, Jr., D.M. Fleming, and S.L. Pimm. (in press). Population dynamics of the endangered Cape Sable Seaside‑Sparrow. Animal Conservation.

Nott, M.P., O.L. Bass, Jr., D.M. Fleming, S.E. Killeffer, N. Fraley, L. Manne, J.L. Curnutt, T.M. Brooks, R. Powell , and S.L. Pimm. (in press). Water levels, rapid vegetation changes, and the endangered Cape Sable Seaside‑Sparrow.

Anonymous. 1997. Balancing on the Brink: The Everglades and the Cape Sable Seaside Sparrow. Report , U.S. Department of the Interior. 23pp.

Authors & Contributors

Stuart L. Pimm

Department of Ecology and Evolutionary Biology

The University of Tennessee

Knoxville, TN 37996

******************************************************************************

Category

Ecological

Performance Measure

Inundation Pattern (number and mean duration of inundation periods)

Date Submitted/Revised

September 1997/June 1998

General Planning Objective

Recovery of historical hydroperiods was identified by the SERA Natural Systems Team as the highest priority for the ecological restoration of the slough/peat system, and was identified as one of the general planning objectives established by the Governor’s Commission for a Sustainable South Florida in the Conceptual Plan for the C&SF Restudy Project.

Region

Northern and Central Everglades:

Loxahatchee National Wildlife Refuge (WCA-1)

Holey Land and Rotenberger WMAs

WCA-2A and 2B, WCA-3A and 3B

Pennsuco Wetland

Restoration Goal

A functionally restored system should mimic natural system inundation frequencies and duration.

Problem Addressed

Inundation patterns in the managed Everglades system have been substantially altered from pre-drainage patterns due to water management practices. The ecological impacts of this are detailed in one of the four critical ecological pathways suggested by the Everglades slough conceptual model. This pathway links reduction in water storage capacity and shortened hydroperiods (hydrologic stressors) with ecological responses that include reduced production and survival of aquatic animals, degraded plant community structure and composition, and the spread of exotic vegetation.

Model Target

Target values for duration of inundation and number of events were those predicted by NSM 4.5 Final with two exceptions: (1) Indicator Region 17’s performance was evaluated by comparing values to the average of NSM values for Indicator Regions 14 and 18; this was because the NSM depths in this Indicator Region had been identified during evaluation of Alternatives 1-3 as being lower than desirable for this relatively pristine marsh area; (2) in LNWR, the targets were 1995 Base values, in keeping with the refuge’s current regulation schedule.

Model Output Format

The average depth during a given week in a given year is calculated for each 2x2 grid cell, and these values are averaged over the set of grid cells within an indicator region to obtain an average depth for the indicator region for that week. The duration of inundation for a year is then calculated as the maximum number of sequential weeks in that year during which water depths averaged above zero for the indicator region. Note that this PM differs from the “hydroperiod” measure used in previous planning efforts, in that here only continuous sequences of inundation are scored, whereas the previous measure calculated percent of the year during which water levels were greater than zero, regardless of whether or not the inundation period was interrupted by a dry out. Results are presented in tabular form and also as the two-part graphic “Inundation Pattern 1965-1980, and 1981-1995”.

Evaluation Tools

Output from the South Florida Water Management Model and the Natural System Model 4.5 should be used for the following indicator regions: (groupings correspond to areas with distinct hydrologic performance.)

Loxahatchee NWR (Indicator Regions 26 & 27)

Holey Land & Rotenberger WMAs (Indicator Regions 28 & 29)

WCA-2A (Indicator Regions 24 & 25)

WCA-2B (Indicator Region 23)

NW WCA-3A (N of Alligator Alley & W of Miami Canal; Indicator Regions 20 & 22)

Northeastern WCA-3A (N of Alligator Alley & E of Miami Canal; Indicator Region 21)

Eastern WCA-3A (S of Alligator Alley, E of Miami Canal; Indicator Region 19)

Central & Southern WCA-3A (S of A. Alley, W of Miami Canal; Indicator Regions 14, 17 & 18)

WCA-3B(Indicator Regions 15 & 16)

Pennsuco Wetlands (Indicator Regions 52 & 53)

Literature Cited

Final Draft: Natural Systems Team Report to the Southern Everglades Restoration

Alliance. July 30, 1997.

Bales, J. D., J. M. Fulford, and E. Swain. 1997. Review of selected features of the Natural System Model, and suggestions for applications in South Florida. USGS Water-Resources Investigations Report 97-4039. Raleigh, North Carolina

Authors & Contributors

Originated by SERA Natural Systems Team

Drafted by J. Ogden

Revised by L. Heisler and W. Park

******************************************************************************

Category

Water Supply/Resource Protection

Performance Measure

Preventing Salt-Water Intrusion of the Biscayne Aquifer: Percent Time Canal Stage <Salt-Water Intrusions Criteria> 1 Week for Primary Coastal Canal at Selected Structure

Date Submitted/Revised

September 1997

General Planning Objective

Minimum Flows and Levels – SFWMD; Control salt-water intrusion into freshwater aquifers – GCSSFL; Ensure adequate water supply and flood protection for urban, natural and agricultural needs – GCSSFL

Region

Lower East Coast Service Area – Eastern portions of Palm Beach, Broward and Miami-Dade Counties

Restoration Goal

Prevent further encroachment of salt-water interface into the Biscayne aquifer

Problem Addressed

The principal threat to the maintaining the long-term functions of the Biscayne aquifer is salt-water intrusion, i.e. contamination of the aquifer by saltwater. The Biscayne aquifer is located along the eastern edge of Palm Beach County, underlies the majority of Broward County and almost all of Miami-Dade County. Along the aquifer’s eastern edge, its fresh water is in contact with the salt water originating from the ocean. The constant westerly flow of fresh water from the Everglades helps to keep the salt water stationary. However, when groundwater levels adjacent to the fresh water/salt water interface are lowered, salt water can potentially move inland replacing the fresh water (Swift et al. 1998). The higher density salt water tends to remain inland for long periods of time causing a permanent loss of that portion of the aquifer. Along the Lower East Coast, lowering of the groundwater table due to overdrainage and increased well field withdrawals has allowed salt water to invade and contaminate the Biscayne aquifer during periods of drought (Parker et al. 1955). Salt water intrusion of the Biscayne aquifer is considered one of the greatest threats to the long-term water supply of South Florida.

In order to minimize the inland migration of the saline interface, a sufficient head of fresh water must be maintained within the aquifer. Loss of the fresh water head that previously existed west of the Atlantic Coastal Ridge is considered the primary cause of the inland migration of salt water in South Florida ( Parker et al. 1955; Fish and Stewart, 1991). The groundwater hydrology of South Florida’s Lower East Coast has been permanently altered by urban and agricultural development and construction of the Central and Southern Florida Project. Construction of a series of canals has drained both the upper layer of the Biscayne aquifer and the fresh water mound west of the Atlantic Coastal Ridge. This drainage has reduced the volume of groundwater flowing east and has resulted in the inland migration of saline interface along the entire edge of the aquifer during dry periods. Localized saltwater intrusion has resulted from large coastal wellfields, five of which were partially lost in1939 while others are still threatened today. Construction of coastal canal water control structures, beginning in the 1940s, has helped to stabilize or slow the advance of the saline interface.

Water levels in the coastal canals largely govern the expected inland migration of the saline interface. Managing coastal canals at appropriate water levels during drought periods is a viable option for stabilizing the salt water interface and preventing further inland migration (Swift et al. 1998). The control elevations have been set for the primary canals that receive water from the regional system and have sufficient canal conveyance capacity to receive water from outside their drainage basins.

Model Target

Maintain elevations of primary coastal canals at control structure

Canal - Structure	Canal Stages (ft NGVD)
North New River @ G-54	3.50
Hillsboro Canal @ G-56	6.75
C-51 @ S-155	7.75
C-18 @ S-46	5.00
C-2 @ S-22	2.00
C-4 @ S-25B	2.00
C-6 @ S-26	2.00
C-14 @ S-37B	6.50
C-15 @ S-40	7.75
C-16 @ S-41	7.75
C-9 @ S-29	2.00
C-13 @ S-36	4.00

Model Output Format

Table indicating the target and the number of times and percentage of time the target was not met.

Evaluation Tools

Use output from the south Florida Water Management Model

Literature Cited

Literature Cited: Swift, David, et al. 1998. Draft Proposed Minimum Water Level Criteria for Lake Okeechobee, the Everglades, and the Biscayne Aquifer within the South Florida Water Management District. West Palm Beach, FL

Authors & Contributors

Originated by LEC Subteam of the AET. Drafted by Brenda Mills; Revised by Jeff Giddings

******************************************************************************

Category

Ecological

Performance Measure

Extreme Events:

High Water Extremes

Low Water Extremes

Date Submitted/Revised

September 1997/June 1998

General Planning Objective

The extreme events performance measures address the priority criteria submitted by the SERA Natural Systems Team; the elimination of regulatory operational schedules which cause unnatural depth and duration of flooding patterns. These measures also address several planning objectives identified by the Governor’s Commission for a Sustainable South Florida in the C&SF Project Restudy Conceptual Plan; to restore more natural organic and marl soil formation processes and arrest soil subsidence, to provide for sustainable populations of native plant and animal species, to restore and, where appropriate improve, functional quality of natural systems, and to restore more natural hydropatterns.

Region

Northern and Central Everglades:

Loxahatchee National Wildlife Refuge (WCA-1)

Holey Land and Rotenberger WMAs, WCA-2A and 2B, WCA-3A and 3B

Pennsuco Wetland

Restoration Goal

Prevention of peat loss resulting from extreme low water events and protection and recovery of tree-island communities that are degraded during extreme high water events.

Problem Addressed

As illustrated in the Everglades sloughs conceptual model, water management practices have generated hydrologic stress on the system in the form of regulatory releases and shortened hydroperiods. The ecologic response to this stress includes flooded tree islands and alligator nests, soil subsidence, spread of exotic vegetation, and ultimately the degredation of plant community structure and the reduction in numbers of native fauna. The extreme events performance measures assess the frequency and duration of water levels that exceed values associated with two major sources of ecological damage in the slough/sawgrass/peat system, namely, muck fires and microbial oxidation during extreme low-water events, and death of tree-island organisms during prolonged high water.

Model Target

Target values for extreme events in LNWR were 1995 Base values, in keeping with the refuge’s current regulation schedule. The high water performance target for all other indicator regions in the Northern and Central Everglades was that the number and duration of events be less than or equal to NSM values. For low water extremes, the performance target was to minimize frequencies and duration of events.

Model Output Format

The extreme events measures assess the frequency and duration, for different alternatives, of periods of extreme high and low water. The basic variable calculated is the number of weeks during the period of record during which water levels exceeded a criterion high or low, and the average duration of these events. These counts are obtained for each cell within an indicator region, and then averaged over the cells in the region to obtain an average number of extreme events and an average duration of these events for the entire period of record for that indicator region. Results are presented in tabular form.

Evaluation Tools

Output from the South Florida Water Management Model and the Natural System Model 4.5 for the following indicator regions is used: (groupings correspond to areas with distinct hydrologic performance.)

Loxahatchee NWR (Indicator Regions 26 & 27)

Holey Land & Rotenberger WMAs (Indicator Regions 28 & 29)

WCA-2A (Indicator Regions 24 & 25)

WCA-2B (Indicator Region 23)

NW WCA-3A (N of Alligator Alley & W of Miami Canal; Indicator Regions 20 & 22)

Northeastern WCA-3A (N of Alligator Alley & E of Miami Canal; Indicator Region 21)

Eastern WCA-3A (S of Alligator Alley, E of Miami Canal; Indicator Region 19)

Central & Southern WCA-3A (S of A. Alley, W of Miami Canal; Indicator Regions 14, 17 & 18)

9. WCA-3B(Indicator Regions 15 & 16)

10. Pennsuco Wetlands (Indicator Regions 52 & 53)

Literature Cited

Dineen, J. W. 1974. Examination of water management alternatives in Conservation Area 2A. Central and Southern Florida Flood Control District In Depth Report, Vol. 2, No. 3. (July-August, 1974).

McPherson, B. J. 1973. Vegetation in relations to water depth in Conservation Area 3, Florida. Open File Report No. 73025. US Geological Survey.

Southern Everglades Restoration Alliance (SERA). July 30, 1997. Final Draft:

Final Draft: Natural Systems Team Report to the Southern Everglades Restoration

Alliance. July 30, 1997.

South Florida Water Management District. August 14, 1997. Draft minimum water level criteria for Lake Okeechobee, the Everglades Protection Area, and the Biscayne aquifer within the South Florida Water Management District.

Authors & Contributors

Originated by SERA Natural Systems Team

Drafted by J. Ogden; revised by L. Heisler and W. Park

******************************************************************************

Category

Water Supply/Resource Protection

Performance Measure

Preventing Salt-Water Intrusion of the Biscayne Aquifer: Stage Duration Curves for selected control structures

Date Submitted/Revised

May 1998

General Planning Objective

Region

Lower East Coast Service Area 3– Eastern portions Miami-Dade County

Restoration Goal

Prevent further encroachment of salt-water interface into the Biscayne aquifer in South Miami-Dade County. Evaluation methodology described herein is to facilitate evaluation and comparison of alternatives and not to supplant the research and analysis necessary to determine the control elevations to slow salt-water intrusion.

Problem Addressed

In order to minimize the inland migration of the saline interface, a sufficient head of fresh water must be maintained within the aquifer. Loss of the fresh water head that previously existed west of the Atlantic Coastal Ridge is considered the primary cause of the inland migration of salt water in South Florida (Parker et al. 1955; Fish and Stewart, 1991). The groundwater hydrology of South Florida’s Lower East Coast has been permanently altered by urban and agricultural development and construction of the Central and Southern Florida Project. Construction of a series of canals has drained both the upper layer of the Biscayne aquifer and the fresh water mound west of the Atlantic Coastal Ridge. This drainage has reduced the volume of groundwater flowing east and has resulted in the inland migration of saline interface along the entire edge of the aquifer during dry periods. Localized saltwater intrusion has resulted from large coastal wellfields, five of which were partially lost in1939 while others are still threatened today. Construction of coastal canal water control structures, beginning in the 1940s, has helped to stabilize or slow the advance of the saline interface.

At this time, salt-water intrusion criteria do not exist for the major canals in southern Miami‑Dade County. Generally the canals are cut directly into the most pereable portions of the Biscayne aquifer. It is difficult to maintain canal stages for extended periods of time without using significant volumes of water from regional storage. However, it is important to evaluate water levels in these canals because encroachment of the salt front into the Biscayne aquifer has occurred previously in this area. Plus, major public water supply wellfields are located in southern Miami‑Dade County. This area was evaluated by using the stage duration curves for the following structures: C‑100A @ S‑123, C‑1 @ S‑21, C‑102 @ S‑21A, and C‑103 @ S‑20F. The stage duration curves were used to evaluate the alternatives in two ways: 1) the distance by which an alternative's water level fails to reach two feet NGVD at the 90th percentile of the stage duration curve; and 2) the percentile at which an Alternative's stage duration curve meets the 50th percentile of the 1995 Base’s stage duration curve.

In the first scenario, two feet NGVD was used for comparison in keeping with the Ghyben‑Herzberg relationship which estimates that one foot of freshwater head is required to protect forty feet of aquifer. The aquifer along the coast in southern Miami‑Dade is approximately eighty feet that would require two feet of freshwater head. The 90th percentile of the stage duration curve was used since that percentile reflects lower stages of the dry season when the risk of salt-water intrusion is increased. The score is calculated from the distance of the base conditions and alternatives to the two feet NGVD on the stage duration curve. Alternatives that equaled or exceeded the target scored 100% (no extra credit was given for exceeding the target).

Score = [(2 ‑ Distance/2)] x 100 = % of meeting 2 foot target

The second scenario used the 50th percentile of the 1995 Base to evaluate performance since it represents approximately the midpoint between the wet and dry seasons and can be viewed as "average conditions" for the 1995 Base. The score reflects the percentile at which a base condition or alternative meets or exceeds the water level at the 50th percentile of the 1995 Base. Salt-water encroachment has occurred in the period of record and, therefore, exceeding the 50th percentile is considered an improvement but may not prevent further encroachment.

Model Target

Maintain elevations of primary coastal canals at control structures. These targets are the current operational criteria. The canal stages need to be examined further to develop appropriate targets and operation criteria to prevent encroachment of the salt water into the surficial aquifer.

Canal - Structure	Canal Stages (ft NGVD)
C-100A@ S-123	2.00
C-1@ S-21	2.00
C-102 @ S-21A	2.00
C-103 @ S-20F	2.00

Model Output Format

Model Output Format: Stage Duration Curves for four control structures: C-100A@S-123, C-1@S-21, C102@S21A and C-103@20F

Evaluation Tools

Use output from the south Florida Water Management Model

Literature Cited

Swift, David, et al. 1998. Draft Proposed Minimum Water Level Criteria for Lake Okeechobee, the Everglades, and the Biscayne Aquifer within the South Florida Water Management District. West Palm Beach, FL.

Authors & Contributors

Originated by Sue Alspach, Miami-Dade County, DERM of the LEC Subteam. Drafted by Brenda Mills; Revised by Jeff Giddings

******************************************************************************

Category

Ecological

Performance Measure

Seasonal Distribution of Overland Flow Volume, Mid Shark River Slough

Date Submitted/Revised

June 1988

General Planning Objective

Region

The seasonal distribution of overland flow volume is applied as a performance measure only to the cross section in mid Shark River Slough.

Restoration Goal

Problem Addressed

Model Target

The target is a cumulative deviation that does not exceed that indicated by NSM45F.

Model Output Format

Evaluation Tools

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Category

Ecological

Performance Measure

Duration of Uninterrupted Flooding

Date Submitted/Revised

June 1998

General Planning Objective

The duration of uninterrupted flood events is the highest priority hydrologic performance measure for ecological restoration in the Everglades. Conceptual models of both the ridge and slough landscapes and the marl prairie/rocky glades landscapes identify duration of uninterrupted flooding as the single hydrologic parameter that affects all the plant and animal attributes that are considered to be indicators of ecological health in the Everglades.

Region

Duration of uninterrupted flooding is applied as a performance measure to the Shark River Slough. and Rockland Marl Marsh (Indicator regions 8, 9, 10, and 11).

Restoration Goal

Increased nesting success and abundance of American alligators and a corresponding increase in the number of occupied alligator holes to serve as drought refugia and to increase habitat heterogeneity, 2) increased population density of aquatic fauna, 3) increased abundance of wading birds and wood storks, 4) re-establishment of coastal nesting colonies of wading birds and wood storks, 5) delay (syn) in timing of colony formation by wading birds and wood storks, 6) resumption of the return frequency of wading bird and white ibis super colonies, 7) enhanced production and community composition of periphyton, 8) accelerated accretion of marl and peat soils, 9) persistence and resilience of macrophyte and tree island plant communities including the cessation of sawgrass expansion into wet prairies and sloughs, and 10) increased nesting success and population size of Cape Sable seaside sparrows.

Problem Addressed

Due to water management practices, inundation frequency and duration in Shark River Slough and the Rockland Marl Marsh landscapes have been altered from pre-drainage patterns. The re-distribution of flow into Shark River Slough, with subsequent restoration of extended duration of uninterrupted flooding, brief duration of dry conditions, water depth pattern, and overland flow volume and timing characteristic of the pre-drainage system is among the highest priorities of ecosystem restoration in the southern Everglades.

Model Target

The target is the mean duration of flooding indicated by NSM45F.

Model Output Format

Only flood events when the mean water depth equals or exceeds 0.2 feet are measured because depths less than 0.2 feet have been observed to impair the establishment of populations of aquatic organisms. The mean duration of all such flood events during the 31-year period of record is the performance measure. It is given a weighting of 3 when averaged with the other performance measures for these regions.

Evaluation Tools

The South Florida Water Management Model and Natural System Model should be used to evaluate Indicator Regions:

Rockland Marl Marsh

SW Shark Slough

Mid Shark Slough

NE Shark Slough

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Category

Ecological

Performance Measure

Duration of Dry Conditions

Date Submitted/Revised

June 1998

General Planning Objective

The re-distribution of flow into Shark River Slough, with subsequent restoration of extended duration of uninterrupted flooding, brief duration of dry conditions, water depth pattern, and overland flow volume and timing characteristic of the pre-drainage system, is among the highest priorities for ecosystem restoration in the southern Everglades. The conceptual models identify drought severity as the second most important hydrologic variable for ecological restoration in the Everglades.

Region

The mean duration of dry events is applied as a performance measure to the Shark River Slough and Rockland Marl Marsh indicator regions.

Restoration Goal

Problem Addressed

Drought severity affects the ability of aquatic fauna to survive dry conditions in alligator holes and solution holes, the intensity of wild fires, and the loss of peat soil in the Everglades.

Model Target

Mean duration of dry events indicated by NSM45F

Model Output Format

Drought severity is most clearly indicated by 2X2 model output as the duration of dry conditions. Dry events are defined as times when the water level drops either to zero or a negative value below the ground surface. Two dry events that are separated by a flood event when the water level rises to less than 0.2 feet above the ground surface are grouped as one dry event because such a minor flood event has been observed to impair the establishment of populations of aquatic organisms. In that case, the duration of the dry event is calculated as the sum of the two dry events and the intermittent flood event. The performance measure is the mean duration of all dry events during the 31-year period of record. It is given a weighting of two when averaged with the other performance measures for these regions.

Evaluation Tools

The South Florida Water Management Model and Natural System Model should be used to evaluate Indicator Regions:

Rockland Marl Marsh

SW Shark Slough

Mid Shark Slough

NE Shark Slough

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Category

Ecological

Performance Measure

Number of Dry Events

Note: Since reduction in the number of dry events became a priority in the modeling leading to Alternative D13, it was added as a performance measure to replace mean duration of flooding.

Date Submitted/Revised

June 1998

General Planning Objective

The conceptual models identify drought severity as the second most important hydrologic variable for ecological restoration in the Everglades

Region

Number of dry events is applied as a performance measure to the Shark River Slough..

Restoration Goal

Increased nesting success and abundance of American alligators and a corresponding increase in the number of occupied alligator holes to serve as drought refugia and to increase habitat heterogeneity, 2) increased population density of aquatic fauna, 3) increased abundance of wading birds and wood storks, 4) re-establishment of coastal nesting colonies of wading birds and wood storks, 5) delay (syn) in timing of colony formation by wading birds and wood storks, 6) resumption of the return frequency of wading bird and white ibis super colonies, 7) enhanced production and community composition of periphyton, 8) accelerated accretion of peat soils, 9) persistence and resilience of macrophyte and tree island plant communities including the cessation of sawgrass expansion into wet prairies and sloughs.

Problem Addressed

Drought severity affects the ability of aquatic fauna to survive dry conditions in alligator holes and solution holes, the intensity of wild fires, and the loss of peat soil in the Everglades.

Model Target

The target is not to exceed the number of dry events indicated by NSM45F.

Model Output Format

Dry events are defined as times when the water level drops either to zero or a negative value below the ground surface. Two dry events that are separated by a flood event when the water level rises to less than 0.2 feet above the ground surface are grouped as one dry event because such a minor flood event has been observed to impair the establishment of populations of aquatic organisms. In that case, the duration of the dry event is calculated as the sum of the two dry events and the intermittent flood event. This performance measure calculates the number of dry events during the 31-year period of record.

Evaluation Tools

The South Florida Water Management Model and Natural System Model should be used to evaluate Indicator Regions:

SW Shark Slough

Mid Shark Slough

NE Shark Slough

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Category

Ecological

Performance Measure

Mean Depth During Flooding

Date Submitted/Revised

June 1998

General Planning Objective

The water mean depth during periods of flooding was identified in the Everglades Sloughs Conceptual Model as relevant to the community composition of wetland vegetation, to the establishment, survival and community composition of aquatic fauna, and to the freshwater head driving flows toward Florida Bay. While the mean depth during flooding is important in these regards, it is not considered to be as high a priority in the restoration of ecological values as duration of flooding or drought severity in the southern Everglades

Region

The mean depth during flooding is applied as a performance measure only to Shark River Slough (Indicator Regions 9, 10 and 11).

Restoration Goal

Increased nesting success and abundance of American alligators and a corresponding increase in the number of occupied alligator holes to serve as drought refugia and to increase habitat heterogeneity, 2) increased population density of aquatic fauna, 3) increased abundance of wading birds and wood storks, 4) re-establishment of coastal nesting colonies of wading birds and wood storks, 5) delay (syn) in timing of colony formation by wading birds and wood storks, 6) resumption of the return frequency of wading bird and white ibis super colonies, 7) enhanced production and community composition of periphyton, 8) accelerated accretion of peat soils, 9) persistence and resilience of macrophyte and tree island plant communities including the cessation of sawgrass expansion into wet prairies and sloughs.

Problem Addressed

Shark River Slough represents the largest drainage basin in the southern Everglades and contains most of the ridge and slough peatland landscape within Everglades National Park. Pre-drainage Shark River Slough was the classic river of grass, a nearly continuously flowing and flooded peatland. Multi-year periods of flooding in Shark River Slough, punctuated by infrequent and brief dry conditions, provided a year-round aquatic ecosystem that produced peat deposits, drove the hydrology of adjacent rockland and marl marshes, provided a drought refugium for aquatic organisms from the adjacent shorter-hydroperiod wetlands, and influenced the salinity regimes in the coastal basins of Florida Bay. The re-distribution of flow into Shark River Slough, with subsequent restoration of extended duration of uninterrupted flooding, brief duration of dry conditions, water depth pattern, and overland flow volume and timing characteristic of the pre-drainage system, is among the highest priorities for ecosystem restoration in the southern Everglades.

Model Target

The target is the mean depth indicated by NSM45F.

Model Output Format

To be consistent with the definition for the duration of flooding, only events when the water depth averaged at least 0.2 feet are included in the calculation. The performance measure is the mean depth of all flood events during the 31-year period of record. It is given a weighting of one when averaged with the other performance measures for Shark River Slough.

Evaluation Tools

The South Florida Water Management Model and Natural System Model should be used to evaluate Indicator Regions:

SW Shark Slough

Mid Shark Slough

NE Shark Slough

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Category

Ecological

Performance Measure

Wet Season Water Level Reversals

Date Submitted/Revised

June 1998

General Planning Objective

This performance measure is linked to the Marl Prairie/Rocky Marl Marsh Conceptual Model developed by the SERA Natural Systems Team, and addresses several hydrologic and ecologic planning objectives identified by the Governors's Commission for a Sustainable South Florida in the C&SF Project Restudy Conceptual Plan.

Region

The number of wet season reversals is applied as a performance measure only to the Rockland Marl Marsh, since reversals were not found to apply to Shark River Slough in the model outputs

Restoration Goal

Recover natural system pattern of wet season reversals.

Problem Addressed

A wet season water level reversal is defined as an incident during a period of flooding when water depth recedes to less than 0.2 feet, but then rebounds to greater than 0.2 feet, without the marsh drying completely. A reversal is distinguished from a dry period in that during a reversal, water depth does not drop to or below the ground surface The Marl Prairie/Rocky Glades Conceptual Model identifies a critical ecological pathway triggered when water depth drops to less than 0.2 feet during a period of flooding; aquatic fauna population densities decline, survivors retreat to refugia in solution holes or alligator holes, and population recovery is slowed

Model Target

The target is not to exceed the number of reversals indicated by NSM45F.

Model Output Format

The performance measure is the total number of reversals during the 31-year period of record. It is given a weighting of one when averaged with the other performance measures for the Rockland Marl Marsh.

Evaluation Tools

The South Florida Water Management Model and Natural System Model should be used to evaluate the Rockland Marl Marsh (Indicator region 8)

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Category

Ecological

Performance Measure

Total Annual Overland Flow Volume, Mid Shark River Slough

Date Submitted/Revised

June 1998

General Planning Objective

Region

The total annual overland flow volume is applied as a performance measure only to a cross section in mid Shark River Slough.

Restoration Goal

The re-distribution of flow into Shark River Slough, with subsequent restoration of extended duration of uninterrupted flooding, brief duration of dry conditions, water depth pattern, and overland flow volume and timing characteristic of the pre-drainage system.

Problem Addressed

The annual overland flow volume down Shark River Slough provides a measure of the total contribution of the Slough to freshwater inputs to the Gulf of Mexico and Florida Bay estuaries. Flow volume also relates to duration of flooding and water depth within the Slough..

Model Target

The target is the annual overland flow volume indicated by NSM45F.

Model Output Format

The monthly volumetric flow rate is simulated as the volume passing a section perpendicular to the direction of flow. The cross-section is taken across the entire width and depth of flow in mid Shark River Slough. The total annual flow volume is determined by summing the monthly flow values. The total annual flow volume is averaged over the 31-year period of record. The performance measure is the mean annual flow volume expressed as percent of the NSM45F flow volume. It is given a weighting of one when averaged with the other performance measures for Shark River Slough because of the higher level of uncertainty in NSM45F simulations of flow compared to other parameters

Evaluation Tools

The South Florida Water Management Model and Natural System Model should be used to evaluate a cross-section taken across the entire width and depth of flow in mid Shark River Slough.

Literature Cited

Authors & Contributors

Author: Steve Davis

Contributors: South Florida Water Management District and Everglades National Park staff (Final document will identify individual contributers)

******************************************************************************

Category

Ecological

Performance Measure

Salt Intrusion Front Movement and Groundwater Flows to Biscayne Bay

Date Submitted/Revised

August, 1998

General Planning Objective

This measure addresses Governor’s Commission for a Sustainable South Florida general planning objectives: 1) Restore more natural hydropatterns, including associated sheetflow, and 2) Provide more natural quality and quantity, timing and distrubutuion of freshwater flow to and through the natural Everglades

Region

This performance measure addresses groundwater flows into Biscayne Bay and affects LEC Service Area 3

Restoration Goal

The restoration target is to restore, to the extent possible, the hydraulic head which drives groundwater flows to Biscayne Bay. Preliminary analysis of the existing Miami-Dade County water quality database for Biscayne Bay indicates that some groundwater flows may occur during periods of high rainfall or during wet years. This is an indication that it may be possible to increase groundwater flows to the bay by raising watershed groundwater levels to the extent possible without triggering flood control measures.

Problem Addressed

Biscayne Bay historically received a large portion of its freshwater inputs from groundwater. Groundwater seeps and springs were/are located throughout the bay and historically, freshwater entered the bay in a more or less distributed manner. Drainage of the watershed for flood control lowered regional groundwater levels and reduced the hydraulic head west of the Atlantic Coastal Ridge which drove these flows. The result has been a reduction in the freshwater inputs from groundwater and an increase in the proportion of the freshwater budget which is provided through surface water flows from the canals. The current surface water flows constitute a point source discharge and although the freshwater is required to maintain estuarine conditions, the distribution and timing of the point source discharges cause large local variations in salinity which are harmful to marine and estuarine biota.

Model Target

The following target groundwater levels, which are based on the Ghyben-Herzberg relationship, would therefore represent the direction in which groundwater levels need to be raised in order to create a more desirable hydraulic head for driving increased groundwater flows to Biscayne Bay. Alternatives that improve conditions over base or future base (i.e. where the groundwater levels more closely approach the Ghyben-Herzberg relationship) are preferable to those where conditions are equal to or worse than base or future base. It should be noted that direct comparisons of target groundwater levels calculated with the Ghyben-Herzberg relationship and the LEC Minimum Levels should not be made. The LEC Minimum Levels are for canal stages at the specified structures; the groundwater levels for the surrounding land will be higher.

Cell Cluster	Approximate Depth to the Base of the Biscayne Aquifer *	Target Groundwater Levels based on the Ghyben-Herzberg Relationship	Average Topography for Cell Cluster (from Topography for SFWMM)	LEC Minimum Flows and Levels - Canal/Structure
North Bay #1	180 ft. between G-3300 and the Snake Creek (C-9) Canal	4.5 NGVD	9.61 NGVD	2.00 - C-9/S-29
North Bay #2	130 ft. at mouth of the Miami Canal	3.25 NGVD	8.25 NGVD	2.50 - C-6/S-26
Central Bay	110 ft. at Snapper Creek	2.75 NGVD	10.26 NGVD	2.50 - C-2/S-22
South Bay	85 ft. at G-3316	2.13 NGVD	5.1 NGVD	None Set

Source: Fish, J.E. and M. Stewart 1991. Hydrogeology of the Surficial Aquifer System, Dade County, Florida. U.S. Geological Survey Water Resources Investigations Report 90-4108, 50 pp.

Model Output Format

Area of Interest: Four blocks of WMM model cells distributed along the western shoreline of Biscayne Bay. The cell clusters are as follows:

North Bay Block #1: R28, C36; R27, C36; R27, C35; R26, C35

North Bay Block #2: R24, C34; R23, C34

Central Bay Block: R21, C33; R20, C33; R20, C32; R19, C32; R19, C31

South Bay Block: R14, C30; R13, C30; R12, C30; R12, C29

North Bay #1 is centered over the Atlantic Coastal Ridge, is bisected by the Biscayne (C-8) Canal, and is composed predominantly of higher elevation uplands. North Bay #2 is centered over the Miami River but intersects the Atlantic Coastal Ridge at the extreme north and south ends, and therefore is composed predominantly of moderate to low-lying uplands. Central Bay Block is centered over the Snapper Creek (C-6) Canal and is composed predominantly of higher elevation uplands. South Bay Block is located between Cutler Ridge and the north end of the Model Lands Basin and is composed almost entirely of low-lying uplands and wetlands.

Groundwater stage hydrographs (weekly averages) and groundwater stage duration curves over the period of record, averaged for each of the cell blocks. Average elevation for each cluster and the Ghyben-Herzberg relationship for that location (based on the aquifer depth at that location - provided below) should be displayed as horizontal lines superimposed on the hydrographs and stage duration curves. Although similar to the salt intrusion performance measures for the LEC, this measure is different because it looks at area groundwater levels rather than canal stages.

Bar graph showing the number of times weekly average groundwater levels equal or exceed the Ghyben-Herzberg relationship for that cell block over the period of record. Alternatives with higher numbers of events would provide higher groundwater flows to Biscayne Bay than alternatives with lower numbers or no events.

Although more appropriate for a static aquifer, the Ghyben-Herzberg relationship (depth to the saltwater interface (below sea level) in a coastal aquifer is 40 times the elevation of the water table above sea level at the same location) can be used as a first approximation for the groundwater levels necessary to maintain freshwater conditions to the base of the aquifer. The LEC Water Supply Plan Committee proposed minimum canal stages for the C-9, C-6, and C-2 to prevent salt intrusion to the Biscayne Aquifer, but modified the levels projected by this relationship based on information that the equation would overestimate the head needed in a flowing system (SFWMD 1997).

Evaluation Tools

SFWMM

Literature Cited

Mulliken, , J.D. and J.A. VanArman, eds. 1995. Biscayne Bay Surface Water Improvement and Management Technical Supporting Document. South Florida Water Management District, West Palm Beach, FL. 178 Pp. plus appendices.

Parker, G.G., G.E. Ferguson, S.K. Love, and others. 1955. Water Resources of Southeastern Florida. Water Supply Paper 1255. U.S. Geological Survey, Washington, D.C. 965 Pp.

Authors & Contributors

Gwen Burzycki (DERM)

Contributors: Kevin Kotun (DERM)

******************************************************************************

Category

Flood Control

Performance Measure

End of Month Stage Duration Curve1983-1993

Date Submitted/Revised

February, 1998

General Planning Objective

This performance measure addresses the general planning objective identified by the Governor’s Commission for a Sustainable South Florida in the Conceptual Plan for the C&SF Project; establish levels of provided flood protection in terms of frequency, depth, and duration

Region

C-111 Basin

Restoration Goal

Provide flood protection to the area east of the L-31N and C-11 canals and south of Richmond Drive.

Problem Addressed

The property east of the L-31N and C-111 canals, south of Richmond Drive, was provided a beneficial level of flood protection during the 1983 to 1993 period by the way those two canals were operated. During that period, water levels were raised during the dry months without causing increased water levels during the wet periods. Limited data from 1994-1996 indicate that Experimental Water Deliveries Program tests 6 and 7 have not achieved this objective. Farmers in the area have experienced a decreased ability to eliminate excess stormwater from their fields.

An occurrence of ground water stage within two (2) feet of the ground surface for a duration of greater than 24 hours is considered a flood event with the potential for causing agircultural crop loss. The SFWMM has no capability to directly measure flood control on individual fields or during relatively short events. Peak stage difference maps have been developed to provide a general indication of the estimated changes in simulated peak stages that result from an alternative scenario. They cannot be used as a performance measure for changes in flooding risk at a particular location for a specific storm event.

Model Target

The 1983-93 portion of the stage duration curve taken from the model calibration and validation runs for each of the five (5) indicator cells in the southern Dade area.

Model Output Format

Stage duration curve described above.

Evaluation Tools

SFWMM

Literature Cited

Authors & Contributors

Tom MacVicar, Carol Drungil, Linda McCarthy, SFWMD’s Agricultural Advisory Committee, Lorraine Heisler, Cal Neidrauer.

******************************************************************************

Category

Ecological

Performance Measure

Daily Hydrograph with Spring Water Recession Windows

Date Submitted/Revised

January 14, 1998

General Planning Objective

This performance measure addresses one of the preferred options for ecosystem restoration of the Lake Okeechobee Area identified by the Governor’s Commission for a Sustainable South Florida; to restore more natural fluctuations of lake levels with no significant impacts to the littoral zone. It also addresses several general planning objectives identified in the conceptual plan for the C&SF Project Restudy; improve habitat quality and heterogeneity, and restore more natural hydropatterns.

Region

Lake Okeechobee

Restoration Goal

Optimize intra-year variation in lake levels to provide a healthy ecosystem for wading birds and other wildlife.

Problem Addressed

Research conducted in the comprehensive Lake Okeechobee Ecosystem Study (LOES) indicated that a certain degree of seasonal variation in lake levels is necessary to maintain a healthy ecosystem (Aumen and Wetzel 1995). In particular, studies dealing with wading bird nesting and food resource (forage fish) utilization indicated that a spring (January through May) recession in lake levels from near 15 ft to below 12 ft, with no reversal greater than 0.5 ft during that period, would optimize the health of those animal populations (Smith et al. 1995, Smith and Callopy 1995). Receding lake levels in spring serve to concentrate prey resources at a time when birds are searching for food for their offspring. Avoiding reversals during that time period is critical, because birds select nesting sites on the basis of current lake levels, and their sense of where lake levels are going in the future. Reversals (sudden increases in lake level following a period of decline) are unexpected events that can flood out and destroy nests. Reversals also can interfere with the reproductive cycle of other animals (e.g., the apple snail) which lay eggs on emergent plant stems. Spring lake level recessions to below 12 ft also benefit the ecosystem by invigorating willow stands (a critical nesting habitat for wood stork) and allowing fires to burn away cattail thatch.

Model Target

The general goal is to achieve a hydropattern for the lake that results in as many years as possible with spring lake level recessions falling within the “windows” of the performance indicator graph. However, it is unclear how many total years out of 30 would be the ideal case.

Model Output Format

A 30-year daily stage hydrograph for the 1995 and 2050 base conditions and each water supply Alternative, overlaid by “windows” spanning the 12-15 ft depth and Jan-May seasonal ranges.

Evaluation Tools

SFWMM

Literature Cited

Aumen, N.G. and R.G. Wetzel. 1995. Ecological studies on the littoral and pelagic systems of Lake Okeechobee, Florida (USA). Archiv fur Hydrobiologie, Advances in Limnology, Volume 45. 356 pp.

Smith, J.P. and M.W. Callopy. 1995. Colony turnover, nest success and productivity, and causes of nest failure among wading birds at Lake Okeechobee, Florida (1989-1992). Archiv fur Hydrobiologie, Advances in Limnology 45: 287-316.

Smith, J.P., J.R. Richardson and M.W. Callopy. 1995. Foraging habitat selection among wading birds at Lake Okeechobee, Florida, in relation to hydrology and vegetative cover. Archiv fur Hydrobiologie, Advances in Limnology 45: 247-285.

Authors & Contributors

Karl E. Havens and Barry H. Rosen, South Florida Water Management District

Contributors: Robert Pace (USFWS), Lorraine Heisler (GFC)

******************************************************************************

Category

Ecological

Performance Measure

Similarity in Duration of Lake Stages >15 ft

Date Submitted/Revised

January 14, 1998

General Planning Objective

This performance measure is linked to the Lake Okeechobee Conceptual Model.

It addresses the general planning objective, improve habitat quality and heterogeneity, identified in the conceptual plan for the C&SF Project Restudy.

Region

Lake Okeechobee

Restoration Goal

Minimize the frequency of prolonged events (lake stages exceed 15 ft for more than 12 continuous months) that may limit light penetration to the lake bottom .

Problem Addressed

Prolonged moderate high lake levels (>15 ft) are harmful to the lake’s ecological and societal values, including the recreational fishery, birds and other wildlife, the native vegetation mosaic, recreation, ecotourism and water quality (Havens and Rosen 1997). Such events result in loss of submerged plant communities due to light limitation (Steinman et al. 1998), increase the lake-wide phosphorus concentrations (Havens 1998), and may cause an increased frequency of algal blooms in near-shore areas (Maceina 1993).

Model Target

The objective is to avoid prolonged high water level conditions that result in the adverse impacts described above, in order to protect the lake’s ecological and societal values. From the standpoint of these objectives, the optimal output would be a “box” spanning the range from approximately 0 to 90 days (3 months), and “whiskers” not reaching beyond 180 days (6 months).

Model Output Format

“Box-whisker” plots showing duration statistics (median, maximum, minimum, 25 and 75th percentile duration in days) for lake stages in excess of 15 ft for a historic period, the 1995 and 2050 base cases, and each proposed water supply Alternative for the 30 year period of record. Each lake regulation schedule alternative will be compared to the period of historical record (1950-1972).

Evaluation Tools

SFWMM

Literature Cited

Havens, K.E. 1997. Water levels and total phosphorus in Lake Okeechobee. Lake and Reservoir Management 13: 16-25.

Havens, K.E. and B.H. Rosen. 1997. A conceptual model for Lake Okeechobee. Society for Ecological Restoration Conference, Ft. Lauderdale, Florida.

Maceina, M.J. 1993. Summer fluctuations in planktonic chlorophyll a concentrations in Lake Okeechobee, Florida: the influence of lake levels. Lake and Reservoir Management 8:1-11.

Steinman, A.D., R.H. Meeker, A.J. Rodusky, W.P. Davis and S-J. Hwang. 1998. Ecological properties of Charophytes in a large subtropical lake. Journal of the North American Benthological Society, in press.

Authors & Contributors

Karl E. Havens and Barry H. Rosen, South Florida Water Management District

Contributors: Robert Pace (USFWS), Lorraine Heisler (GFC)

******************************************************************************

Category

Ecological

Performance Measure

Similarity in Duration of Lake Stages <12 ft.

Date Submitted/Revised

January 14, 1998

General Planning Objective

This performance measure is linked to the Lake Okeechobee Conceptual Model.

It addresses the general planning objective, improve habitat quality and heterogeneity, identified in the conceptual plan for the C&SF Project Restudy.

Region

Lake Okeechobee

Restoration Goal

Minimize the frequency of prolonged events (lake stage falls below 12 feet for longer than 12 continuous months) that substantially reduce the littoral area available as wildlife habitat, and promote exotic plant expansion.

Problem Addressed

Prolonged moderate low (<12 ft) lake levels are harmful to the lake’s ecological and societal values, including the recreational fishery, birds and other wildlife, the native vegetation mosaic, recreation, ecotourism and water quality (Havens and Rosen 1997). At lake levels below 12 ft, over 70% of the marsh is dry, and cannot function as a habitat for fish, birds or other wildlife (SFWMD 1997). These conditions also are favorable for expansion of exotic plants into native plant-dominated regions of the marsh (Thayer and Haller 1990, Lockhart 1995).

Model Target

The objective is to avoid prolonged low water level conditions that result in the adverse impacts described above, in order to protect the lake’s ecological and societal values. From the standpoint of these objectives, the optimal output would be a “box” spanning the range from approximately 0 to 90 days (3 months), and “whiskers” not reaching beyond 180 days (6 months).

Model Output Format

“Box-whisker” plots showing duration statistics (median, maximum, minimum, 25 and 75th percentile durations in days) for lake stages below 12 ft for a historic period, the 1995 and 2050 base cases, and each proposed water supply Alternative for the 30 year period of record. of each lake regulation schedule alternative will be compared to the period of historical record (1950-1972).

Evaluation Tools

SFWMM

Literature Cited

Havens, K.E. and B.H. Rosen. 1997. A conceptual model for Lake Okeechobee. Society for Ecological Restoration Conference, Ft. Lauderdale, Florida.

Lockhart, C.S. 1995. The effect of water level variation on the growth of Melaleuca seedlings from the Lake Okeechobee littoral zone. MS Thesis, Florida Atlantic University, Boca Raton, Florida.

SFWMD. 1997. Surface water improvement and management (SWIM) plan – update for Lake Okeechobee. South Florida Water Management District, West Palm Beach, Florida.

Thayer, P.L. and W.T. Haller. 1990. Fungal pathogens, Phoma and Fusarium, associated with declining populations of torpedo grass growing under high water stress. Proceedings of the European Water Research Society, 8^th Symposium on Aquatic Weeds, pp. 209-214.

Authors & Contributors

Karl E. Havens and Barry H. Rosen, South Florida Water Management District

Contributors: Robert Pace (USFWS), Lorraine Heisler (GFC)

******************************************************************************

Category

Ecological

Performance Measure

Similarity in Duration of Lake Stages <11 ft

Date Submitted/Revised

January 14, 1998

General Planning Objective

This performance measure is linked to the Lake Okeechobee Conceptual Model.

It addresses the general planning objective, improve habitat quality and heterogeneity, identified in the conceptual plan for the C&SF Project Restudy.

Region

Lake Okeechobee

Restoration Goal

Minimize the frequency of extremely low lake stages (<11 ft) that result in a loss of the littoral zone as habitat for aquatic biota, and promote expansion of exotic plants into pristine native-plant dominated regions of the lake.

Problem Addressed

Extreme low lake levels (<11 ft), of any duration, are harmful to the lake’s ecological and societal values, including the recreational fishery, birds and other wildlife, the native vegetation mosaic, recreation, ecotourism and water quality (Havens and Rosen 1997). Low lake levels dry out critical marsh habitat, and may permit the more rapid expansion of exotic plants (Meleleuca and torpedo grass) into regions still occupied by native plant communities (Thayer and Haller 1990, Lockhart 1995). At lake levels 11 ft, nearly 95% of the littoral zone is dry, including the Mooneshine Bay region. This region is of particular concern, since it is a prime habitat for snail kite, and a last refuge for these federally-endangered birds (as well as other species) during regional droughts (Bennetts and Kitchens 1997). At present, Moonshine Bay is an excellent habitat because it is dominated by spike rush (Eleocharis) and bladderwort (Utricularia), which provide considerable open-water habitat for forage fish, and substrates for apple snail eggs. If the region should be overtaken by torpedo grass, whose expansion into new areas appears to be hindered by standing water (Thayer and Haller 1990), these habitat values could be lost.

Model Target

The objective is to avoid the extreme low water level conditions that result in the adverse impacts described above, in order to protect the lake’s ecological and societal values. From the standpoint of these objectives, the optimal output would be no such events; i.e., all attributes of the box-whisker plot below zero.

Model Output Format

“Box-whisker” plots showing duration statistics (median, maximum, minimum, 25 and 75th percentile durations in days) for a historic period, the 1995 and 2050 base cases, and each proposed water supply Alternative for the 30 year period of record. of each lake regulation schedule alternative will be compared to the period of historical record (1950-1972).

Evaluation Tools

SFWMM

Literature Cited

Bennett, R.E. and W.M. Kitchens. The demography and movements of snail kites in Florida. Technical Report 56, United States Geological Survey, Biological Resources Division, Talahassee, Florida.

Havens, K.E. and B.H. Rosen. 1997. A conceptual model for Lake Okeechobee. Society for Ecological Restoration Conference, Ft. Lauderdale, Florida.

Lockhart, C.S. 1995. The effect of water level variation on the growth of Melaleuca seedlings from the Lake Okeechobee littoral zone. MS Thesis, Florida Atlantic University, Boca Raton, Florida.

Authors & Contributors

Karl E. Havens and Barry H. Rosen, South Florida Water Management District

Contributors: Robert Pace (USFWS), Lorraine Heisler (GFC)

******************************************************************************

Category

Ecological

Performance Measure

Similarity in Duration of Lake Stages >17ft

Date Submitted/Revised

January 14, 1998

General Planning Objective

This performance measure is linked to the Lake Okeechobee Conceptual Model.

It addresses the general planning objective, improve habitat quality and heterogeneity, identified in the conceptual plan for the C&SF Project Restudy.

Region

Lake Okeechobee

Restoration Goal

Minimize the frequency of extreme high lake stage events (>17ft) that may cause wind and wave damage to the shoreline plant communities, and transport phosphorus-laden pelagic water into pristine interior regions of the littoral zone.

Problem Addressed

When lake levels reach this extreme high, the following impacts can be expected, in addition to those occurring when lake levels exceed 15 ft; damage to bulrush and other shoreline plant communities by wind and waves, and transport of nutrients into the pristine littoral marsh, with nutrient-induced changes in periphyton, plant, and animal communities

Model Target

The goal is to have zero events.

Model Output Format

“Box-whisker” plots showing duration statistics (median, maximum, minimum, 25 and 75th percentile durations in days) for a historic period, the 1995 and 2050 base cases, and each proposed water supply Alternative for the 30 year period of record. Each lake regulation schedule alternative will be compared to the period of historical record (1950-1972).

Evaluation Tools

SFWMM

Literature Cited

Bennett, R.E. and W.M. Kitchens. The demography and movements of snail kites in Florida. Technical Report 56, United States Geological Survey, Biological Resources Division, Talahassee, Florida.

Fry, B., P.L. Mumford, F. Tam, D.D. Fox, G.L. Warren, K.E. Havens and A.D. Steinman. 1998. Trophic position and individual feeding histories of fish from Lake Okeechobee, Florida. Canadian Journal of Fisheries and Aquatic Sciences, in review.

Havens, K.E. 1997. Water levels and total phosphorus in Lake Okeechobee. Lake and Reservoir Management 13: 16-25.

Havens, K.E. and B.H. Rosen. 1997. A conceptual model for Lake Okeechobee. Society for Ecological Restoration Conference, Ft. Lauderdale, Florida.

Havens, K.E., T.L. East, S-J. Hwang, A.J. Rodusky, B.Sharfstein, and A.D. Steinman. 1998.

Algal responses to nutrients in a littoral mesocosm experiment. Oikos, in review.

Lockhart, C.S. 1995. The effect of water level variation on the growth of Melaleuca seedlings from the Lake Okeechobee littoral zone. MS Thesis, Florida Atlantic University, Boca Raton, Florida.

Maceina, M.J. 1993. Summer fluctuations in planktonic chlorophyll a concentrations in Lake Okeechobee, Florida: the influence of lake levels. Lake and Reservoir Management 8:1-11.

Authors & Contributors

Karl E. Havens and Barry H. Rosen, South Florida Water Management District

Contributors: Robert Pace (USFWS), Lorraine Heisler (GFC)

******************************************************************************

Category

Water Supply

Performance Measure

Agricultural and urban water supply using the Monthly Supply-Side Management Report and Simulated Annual Demands not Met per Year (for each coastal service area).

Date Submitted/Revised

January 1998

General Planning Objective

Soon after the C&SF Comprehensive Review Study (Restudy) process was initiated, SFWMD’s Lower East Coast Regional Water Supply Plan staff made a decision to defer planning and making recommendations on phase 2 water supply projects due to potential conflicts with the Restudy results. The phase 2 projects are needed primarily to address environmental goals and agricultural water supply needs that were not met by the LEC WSP projects proposed in phase 1 of the plan. Subsequent to that decision, WRDA 1996 shortened the time period in which the Restudy would be conducted. In 1997, the Florida Legislature modified Florida law (HB 715) and included some clarification of how the Water Management Districts were to do water supply planning. The Districts’ regional water supply plans now must contain a “level-of-certainty planning goal associated with identifying the water supply needs of existing and future reasonable-beneficial uses shall be based upon meeting those needs for a 1-in-10 year drought event” (Chapter 373.0361(2)(a)(1), F. S.). Since a portion of SFWMD’s water supply planning was deferred and is now taking place in the Restudy process, it’s expected that the goal stated in Florida law be adopted as the Restudy goal.

Region

The Lake Okeechobee Service Area includes the Everglades Agricultural Area, the Caloosahatchee Basin, the St. Lucie Basin, the S-4 Basin, the L-8 Basin and the Seminole Indian (Brighton and Big Cypress) Reservations

Restoration Goal

Water shortage restrictions for the Lake Okeechobee Service Area should be limited to not more than three in the 31-year simulation period.

Problem Addressed

Chapter 373.246, F.S., requires that the Water Management Districts develop a water shortage plan to protect the water resources from serious harm during droughts, and to restore them to their previous condition. In the present water shortage rule, cutbacks in water usage are triggered by either a saltwater intrusion event (well triggers) or by a low-Lake-Okeechobee event. The regional system is operated so that deliveries to the coast are made to either halt or slow down saltwater intrusion. Deliveries are made first from the Water Conservation Areas, then from Lake Okeechobee, depending on what their respective water levels are and on what basin is experiencing the shortage. Under the water shortage plan, provisions for variances and alternative measures to prevent undue hardship and ensure equitable distribution of water resources may be included.

With the present configuration of the C&SF System, Lake Okeechobee is the only reliable water supply source of significance during extended droughts. The Lake Okeecheebee Supply-Side Management Plan was designed to establish a procedure for supply allocation during periods of shortage. The allocation method that was developed recognized the need to hold water in reserve for anticipated high-demand periods, and recognized the actual physical limitations of the delivery system. Water supply releases during dry periods are determined by a set of water shortage management zones. Each of the zones represents storage levels with assigned probabilities of shortage. Some of the assumptions of the original methodology are: 1) that a stage of 13.5 ft on October 1 as being the level which must be exceeded to defer supply-side management; and 2) water deliveries from the Lake would be based on a weekly formula that allocated the available water in the Lake above a stage of 11 feet. The Governing Board would decide each month on additional steps necessary to manage available supplies during the shortage.

The volume of water between 11 ft and 10 ft. is reserved for the purpose of preventing saltwater intrusion in the Lower East Coast wellfields. Because of downstream physical limitations, water cannot be removed from the lake when it falls below 9.5 ft. These operational Arules@ are being used in the SFWMM model runs for the Restudy alternatives.

A second issue that adds to the difficulty of defining “1 in 10” is deciding what to assume the effect of implementing minimum flows and levels (MF&Ls) will be on how the regional system will be operated. There is potential the water shortage plan and supply-side management plan could be modified, depending on how future policy and legal decisions are made. If the outcome of future minimum flow and level-related rule development, lawsuits, changes to current law, require the operational rules of the regional system to be changed from what is assumed in the Restudy, the “1-in-10” definition used for this phase of the Restudy also could change.

The Alternatives Evaluation Team (AET) formed a subcommittee to discuss approaches and make a recommendation on how to define a “1 in 10” year LOC performance measure for the purposes of the Restudy. During the development of SFWMD=s Upper East Coast Regional Water Supply Plan, a statistical “1 in 10 year drought” year, based on rainfall, was constructed for use using basin models. The SFWMM cannot be used in the same manner, so one of the goals of the subcommittee was to try to decide how to describe an equivalent LOC for the Lake Okeechobee Service Area and the Lower East Coast. Discussions are still occurring on potential ways to run the SFWMM to try to determine if it’s possible to calculate the volume of water that would be needed from the regional system by each basin to meet water supply needs during a “1-in-10 year drought”. The District’s modeling staff does not have time to design and run the SFWMM for this purpose before April 1998. Discussions are also continuing on if or how to describe a “1 in 10 year drought event”. In the interim, the subcommittee agreed to use the frequency and severity of entering into supply-side management events for the agricultural basins in calculating a 1-in-10 year drought LOC. For the Lower East Coast Service Areas, the number of years the lake triggers a water shortage will be used in addition to the number of locally triggered events in calculating a 1-in-10 year drought LOC.

Model Target

To meet all demands (or needs). Recognizing that this may not be feasible, to meet a “1 in 10 year drought” level of certainty; measured by using the frequency of entering into supply-side management operations. An event should not last longer than 7 consecutive months.

Defining the “1-in-10 year drought event” level-of-certainty (LOC) is problematic because of the distribution capability of the regional system, and could be done in any number of ways. Different areas/basins of the District could be in a 1-in-10 year drought event as defined by rainfall at different times, but could receive sufficient water supply via deliveries through the regional system. Assuming that all service areas are experiencing a 1-in-10 year drought at the same time would in fact be an event that would occur less frequently than 1 in 10 years.

Model Output Format

Using the supply-side management reports, count the number of SSM with cutback events that occur. Months with days in SSM without cutbacks are not included. If the total percent cutback for any month is less than 10%, or the number of days with cutbacks is less than 7, the event is not counted. A water year, beginning October and ending September, is used to count events. An event is defined as any year that has a cutback occurrence as described above. For the coastal service areas: use the “simulated annual demands not met due to water restrictions per year” performance indicator, and count the number of events where demands were not met due to Lake Okeechobee. The target would be no more than three events over the simulated period. (Note: Demands not met caused by local well triggers are not considered in the LOSA.)

EAA and LOSA demands – dry years; C43 and C44 Basin Regional irrigation supply and demand not met; Other LOSA supplemental irrigation supply and demands not met; Total irrigation supply and shortages for Seminole Tribe, Big Cypress Reservation; Mean annual EAA/LOSA irrigation demands and demands not met; Report Cumulative total demand, cut-back volume, and cut-back over period of simulation; Lake Okeechobee daily stage hydrograph; Stage hydrographs and depth duration curves for reservoirs

Evaluation Tools

SFWMM

Literature Cited

Authors & Contributors

Linda McCarthy, Jeff Giddings, Steve Lamb, Fred Rapach, Pat Gleason, Brenda Mills, Carl Woehlcke, Roy Reynolds.

******************************************************************************

Category

Ecological

Performance Measure

Flows to Lake Worth Lagoon

Date Submitted/Revised

January, 1998

General Planning Objective

This measure addresses several general planning objective identified by the Governor’s Commission for a Sustainable South Florida in the Conceptual Plan for the C&SF Project Restudy; provide more natural quality and quantity, timing, and distribution of freshwater flow to estuaries and coral reef ecosystems, and improve and protect habitat quality, heterogeneity, and biodiversity in coastal and associated marine ecosystems

Region

Lake Worth Lagoon, C-51

Restoration Goal

The restoration target is to create estuarine conditions, to the extent possible, in the Lake Worth Lagoon.

Problem Addressed

Lake Worth lagoon historically was a predominately freshwater system that became estuarine periodically through ephemeral inlets opened by hurricanes. The salinity range in the Lake worth Lagoon varies from 0 parts per thousand (ppt) to approximately marine conditions (36 ppt). This is not normally an estuary that becomes hypersaline.

Model Target

An estuarine salinity envelop of 23 ppt to 35 ppt has been chosen as the target salinity range. This is a viable salinity range for a number of organisms many of that are commercially and recreationally important. To attain this salinity a maximum flow needed to be developed. Previous hydrodynamic modeling displayed that 500 cfs creates a steady state salinity of 23 ppt. For the low flow part of the salinity envelop, 0 cfs is the target. Enough groundwater occurs that should still allow estuarine conditions. Based on past modeling, this flow range of 0-500 cfs should create the salinity range of 23 ppt - 35 ppt.

Model Output Format

Mean wet/dry season flows to Lake Worth through S40, S41 & S155 for the 31 year simulation period.

Number of times salinity envelope criteria were not met for the Lake Worth Lagoon (mean monthly flows 1965-1995)

Evaluation Tools

SFWMM

Literature Cited

Day, J.W. 1989. Estuarine Ecology.

Indian River Lagoon SWIM Plan.

Lake Worth lagoon Draft SWIM PLan.

Haunert, D.E., and R. Chamberlain. 1994. St. Lucie and Caloosahatchee estuary performance measures for alternative Lake Okeechobee Regulation Schedules. SFWMD Memorandum.

Authors & Contributors

The Water Quality subcommittee for the Lake Worth Lagoon

Steve Traxler, Dave Swift, Allen Treffry, Harvey Rudolf, Dick Tomosello, Dawn Whitehead, Jim Barry, Brian Gentry

******************************************************************************

Category

Ecological

Performance Measure

Continuity: Water Surface Elevations across Barriers

Date Submitted/Revised

January, 1998

General Planning Objective

This performance measure addresses several general planning objectives for the restudy identified by the Governor’s Commission for a Sustainable South Florida; improve connectivity and fragmentation of habitats and restore more natural hydropatterns.

Region

Total System

Restoration Goal

Recover spatial and temporal continuity in water depth patterns, across any levees remaining internal to the natural system, consistent with NSM predictions of regional hydropatterns.

Problem Addressed

Canals and levees are widely used to manage the flow of water in south Florida and it is highly unlikely that they will all be removed. Unfortunately, they have several negative effects on wildlife. The deep-water habitat in canals favors larger, predatory fish over smaller, prey species, canals allow exotic fish to reach the Everglades interior easily, and the warmth of the deep water allows these tropical exotics to overwinter farther north than in the past. Both canals and levees physically restrict the movement of smaller species of wildlife, and levees attract terrestrial predators into the marsh interior. More wide-ranging species took advantage of the fluid range of opportunities presented by the wetting and drying cycles in the natural system. Suitable habitat could usually be found somewhere within the system regardless of the season or amount of rain. In the managed system, however, artificial barriers have disrupted these patterns.

Artificial barriers tend to create markedly different water regimes on their upstream and downstream sides. Water usually pools on the upstream side causing the area downstream to become drier. Water quality parameters also may differ widely. Smaller species that do manage to cross a barrier may find inhospitable conditions on the other side. Larger species such as wading birds that feed at particular depths for example, may have to travel much further to feed.

This performance measure addresses the differences in water surface elevations on either side of major artificial barriers in the remaining Everglades.

Model Target

The target condition is water elevation differences across each barrier similar to that predicted by the NSM. Differences of more than one depth class from NSM predictions are considered poor.

Model Output Format

By selecting groups of SFWMM grids on either side of a barrier and comparing the mean water surface elevation classes of the two groups, an indicator of continuity of landscape can be derived. Groups of cells were used to avoid the pitfalls inherent in single cell comparisons. Many of the barriers in the SFWMM are artificially located on the boundary between cells. In those cases, adjacent cells on either side were used. In other cases, cells containing barriers were excluded to avoid the anomalous elevation values resulting from the influence of the barrier. Adjacent cells were selected so they would have similar soils, vegetation and hydrology. Of course, cells across boundaries may naturally differ in soil, vegetation and hydrology. This measure seeks to evaluate not whether differences exist, which they undoubtedly do, but whether those differences are consistent with NSM predictions.

Comparisons are made to sets of cells on either side of the following barriers: Tamiami Trail (east), Tamiami Trail (west), L-67, and L-28, Alligator Alley, the levee/canal between WCA-2 and WCA3 and the divide between WCA1 and WCA-2A. Cells within the groups are pooled on either side of the barrier by determining the time series of mean weekly water elevations for each set of cells. The difference between these values for the two groups is then compared to the difference between the same groups of cells predicted by the NSM. Water surface elevations are used instead of depth estimates because depth estimates inherently have more error than water elevations, especially across levees where there may have been differential soil loss or accretion and where the collection of topographic data may not be similarly accurate on either side. Comparing water surface elevations instead eliminates this source of error. Additionally, the model is calibrated to water surface elevations and not to depths.

The Performance Measure is a list of mean weekly water surface elevations, upstream minus downstream for each barrier for each alternative next to those predicted by the NSM and a histogram showing the total number of weeks in which the upstream-downstream water elevation differences were: 1) within 0.0 to 0.249 feet of NSM, 2) greater than 0.25-0.49 feet different, 3) less than 0.25-0.49 feet different, etc. using whatever increment best illustrates the range of data for the model runs.

Selected cells are listed below. Superscript G = gauge, IRn = Indicator Region Cell

Divide between Loxahatchee NWR (WCA-1) and WCA-2A.

Upstream:

NSM: Ridge and Slough

1995 Land Use: Modified Ridge and Slough I. Cattails along the barrier, nearby Sawgrass Plains

Projected 2050 Land Use: Same as 1995

Cells: R46C29, R45C29^G, R45C30^IR26, R44C30^IR26, R44C31

Downstream:

NSM: Ridge and Slough

1995 Land Use: Mixed Cattail/Sawgrass, Cattails along barrier, and nearby Sawgrass Plains

Projected 2050 Land Use: Same as 1995 but with expanded cattails and irrigated pasture and row crops at the south end.

Cells: R45C28^G,IR25, R44C28^IR25, R44C29^IR25, R43C29, R43C30

Levee and canal between WCA-2A and WCA-3A

Upstream

NSM: Sawgrass (north), Ridge and Slough (south).

1995 Land Use: Modified Ridge and Slough I, Sawgrass, Mixed Cattail/Sawgrass, Cattail

Projected 2050 Land Use: Sawgrass Plains (north), Modified Ridge and Slough I (south), Cattails along barrier

Cells: R41C26, R41C27, R40C27, R39C27, R39C28, R38C28

Downstream:

NSM: Sawgrass (north), Ridge and Slough (south)

1995 Land Use: Sawgrass Plains, Mixed Cattail/Sawgrass, Cattails along barrier

Projected 2050 Land Use: Same as 1995

Cells: R41C25, R40C25^IR21, R40C26, R39C26, R38C26, R38C27^G

L-67 WCA-3A to WCA-3B

Upstream:

NSM: Ridge and Slough system.

1995 Land Use: Sawgrass plains (northeast), Modified Ridge and Slough I (southwest)

Projected 2050 Land use: Same as 1995

Cells: R29C25, R28C24, R27C24^G,IR15, R27C23^G, R26C23, R25C22, R24C22

Downstream:

NSM: Ridge and Slough

1995 Land Use: Wet Prairie

Projected 2050 Land use: Same as 1995

Cells: R29C26, R28C25, R27C25^IR15, R26C24^G , R25C24^IR15, R25C23, R24C23^IR15

Miami Canal

Upstream:

NSM: Ridge and Slough system.

1995 Land Use: Sawgrass plains, Cattails, Modified Ridge and Slough I near L-67

Projected 2050 Land use: Same as 1995

Cells: R41C19, R40C20, R39C20, R38C21, R34C24, R33C25, R32C26

Downstream:

NSM: Ridge and Slough

1995 Land Use: Sawgrass Plains, Wet Prairie, a few Cattails at Alligator Alley

Projected 2050 Land use: Same as 1995

Cells: R41C17^IR22, R40C18^G,IR22, R39C18^IR20, R38C19^IR20, R33C23, R32C23, R31C24

L-28

Upstream (WCA-3A):

NSM: Predominantly Ridge and Slough

1995 Land Use: Predominantly Modified Ridge and Slough I

Projected 2050 Land use: Same as 1995

Cells: R29C17^IR17, R28C17^IR17, R27C17, R26C17, R25C17^IR14,

Downstream (BICY):

NSM: Forested wetlands (north), Wet Prairie (south)

1995 Land Use: Same as NSM

Projected 2050 Land use: Same as NSM

Cells: R29C15, R28C15, R27C15, R26C15, R25C15,

Alligator Alley West of L-28 Interceptor:

Upstream

NSM: Forested Wetlands.

1995 Land Use: Same as NSM

Projected 2050 Land use: Same as NSM

Cells: R37C10, R37C11, R37C12, R37C13

Downstream:

NSM: Forested Wetlands

1995 Land Use: Same as NSM

Projected 2050 Land use: Same as NSM

Cells: R35C10, R35C11, R35C12, R35C13

Alligator Alley East of L-28 Interceptor, north of WCA-3A:

Upstream

NSM: Ridge and Slough

1995 Land Use: Some Wet Prairie, Mostly Sawgrass Plains

Projected 2050 Land use: Same as 1995

Cells: R36C18^G,IR20, R36C19, R36C20 and R36C24, R36C25, R36C26

Downstream:

NSM: Ridge and Slough

1995 Land Use: Wet Prairie west of Miami Canal, Sawgrass to the east, cattails at intersection of canal and road

Projected 2050 Land use: Same as 1995

Cells: R34C18^IR18, R34C20^IR18 R34C20^IR18, R34C24^IR19, R34C25^IR19, R34C26^IR19

East Tamiami Trail - WCA-3B to ENP

Upstream

NSM: Ridge and Slough system.

1995 Land Use: Wet Prairie (west), Modified Ridge and Slough I (east)

Projected 2050 Land use: Same as 1995

Cells: R23C23^IR15, R23C24^G,IR16, R23C25^IR16, R23C26^G,IR16

Downstream:

NSM: Ridge and Slough

1995 Land Use: Modified Ridge and Slough II

Projected 2050 Land use: Same as 199 5

Cells: R22C23^G, R22C24, R22C25, R22C26^G

Tamiami Trail WCA-3A to ENP

Upstream:

NSM: Ridge and Slough system.

1995 Land Use: Modified Ridge and Slough I

Projected 2050 Land use: Same as 1995

Cells: R23C17^IR14, R23C18^IR14, R23C19^IR14, R23C20^IR14

Downstream:

NSM: Marl Marsh.

1995 Land Use: Some Marl Prairie (west), mostly Modified Ridge and Slough II

Projected 2050 Land use: Same as 1995

Cells: R22C17, R22C18^G, R22C19^G, R22C20

Tamiami Trail west of L-28

Upstream:

NSM: Forested Wetlands, Wet Prairie between levee and 50-Mile Bend

1995 Land Use: Same as NSM

Projected 2050 Land use: Same as NSM

Cells: R26C11, R26C12^IR37, R26C13

Downstream:

NSM: Forested Wetlands, Wet Prairie between levee and 50-Mile Bend

1995 Land Use: Same as NSM

Projected 2050 Land use: Same as NSM

Cells: R24C11^IR40, R24C12, R24C13

Evaluation Tools

SFWMM

Literature Cited

Authors & Contributors

Drafted by Cheryl Buckingham (USFWS)

Contributors: John Ogden (SFWMD), Lorraine Heisler (FGFWFC), Winifred Park (SFWMD)

******************************************************************************

Category

Ecological

Performance Measure

Fragmentation: Miles of Canals and Levees Affecting Natural Areas

Date Submitted/Revised

February, 1998

General Planning Objective

Region

Total System

Restoration Goal

Fill in artificial water features, remove barriers or otherwise make these structures biologically invisible to the surrounding landscape.

Problem Addressed

In its effort to control floodwaters and provide water supply, the C&SF Project created miles of canals, levees, and water control structures with associated deep pools. Canals and levees usually coexist; construction of a canal usually means a spoil levee exists alongside it just as a levee requires a borrow canal. Roadway construction usually involves combinations of levees and canals, sometimes with culverts to allow water to flow underneath. Water control structures are usually even more complex, involving combinations of levees, canals and deep pools. In some places, multiple canals, levees and water control structure form intricate patterns - and formidable barriers to wildlife.

When levees block the flow of water, they also restrict the movement of aquatic and semi-aquatic life forms in the water. Land-based predators use the levees to invade the marsh interior, preying upon animals that try to cross the intrusive fingers of terrestrial habitat. Levees also act as conduits, allowing terrestrial plants to invade. Canals act as corridors particularly for non-native animals and plants that can extend their ranges rapidly from points of introduction and can move into wetlands where they can alter habitats and affect food webs (Loftus and Kushlan 1987; Loftus 1986). Artificial, deep-water habitats provide thermal and spatial refuge to large numbers of both non-native and native aquatic predators in the dry season, enhancing their survival and ultimate population sizes. During the dry season, these predators prey heavily on small marsh fishes and invertebrates moving in from the adjacent wetlands (Howard et al. 1995). Alternatives that accomplish their purpose without adding to the present array of levees, canals, culvert pools, and borrow ponds in the system are considered to do no further harm but do not “restore” connectivity. Alternatives that fill in artificial water features, remove barriers or otherwise make these structures biologically invisible to the surrounding landscape are considered a positive step towards restoration. Alternatives that require a net addition of structures are detrimental.

Model Target

Minimize the extent of canals and levees internal to the remaining natural system.

Model Output Format

Outputis a table showing the number of miles of canals and, levees bordering or bisecting natural areas for each alternative.

Evaluation Tools

SFWMM

Literature Cited

Loftus, W. F. and J. A. Kushlan. 1987. Freshwater fishes of southern Florida. Bulletin of the Florida State Museum, Biological Sciences 31: 147-344.

Loftus, W. F. 1986. Distribution and ecology of exotic fishes in Everglades National Park, pp. 24-34 IN L. K. Thomas (editor). Management of exotic species in natural communities. Proceedings 1989 conference on Science in the National Parks, Ft. Collins, Colorado.

Howard, K. S., W. F. Loftus, and J. C. Trexler. 1995. Seasonal dynamics of fishes in artificial culvert pools in the C-111 basin, Dade County, Florida. Final Report to the U. S. Army Corps of Engineers as Everglades N. P. Cooperative Agreement #CA5280-2-9024.

Authors & Contributors

Drafted by Cheryl Buckingham (USFWS)

Contributors: Joan Browder, NFMS/NOAA, Cheryl Buckingham, USFWS, William F. Loftus, NPS, John Ogden (SFWMD), Agnes McLean (SFWMD)

******************************************************************************

Category

Ecological

Performance Measure

Sheetflow: Volumes Across Transects in the WCAs and Everglades National Park

Date Submitted/Revised

February, 1998

General Planning Objective

This performance measure addresses several general planning objectives for the restudy identified by the Governor’s Commission for a Sustainable South Florida; restore more natural hydropatterns, including associated sheetflow, and improve connectivity and reduce fragmentation of habitats.

Region

Total System

Restoration Goal

Restoring the appropriate volume and direction of sheet flow to large areas of the freshwater marshes will allow the system to once again naturally shape tree islands, take up nutrients, precipitate phosphorus and calcium carbonate into the substrate, and retain water into the dry season. Restoring volumes of flow to Shark River Slough (the largest drainage in the system) and across the marl prairies of southern Everglades and through the system of creeks ringing Florida Bay will increase freshwater inputs into the Bay. Restoring freshwater flows into the Bay, particularly during the dry season, is badly needed to recreate the proper salinity patterns and circulation needed to restore the ecology of the system.

Problem Addressed

Sheet flow is one of the defining characteristics of the pre-drainage Everglades. Water once continuously flowed from the shore of Lake Okeechobee through the Everglades to Shark River Slough and on into Florida Bay. In the managed system, the Lake and the Water Conservation Areas have been impounded. Flow patterns out of Lake Okeechobee have shifted from primarily wet season flows in response to rainfall to dry season flows in response to urban and agricultural water supply demands.

While depths may be similar to the pre-drainage system, the River of Grass is now stagnated. The Water Conservation Areas, divided by levees and canals, are now a series of pools where water travels with less velocity and in different directions of flow. “Ponded systems favor certain species and flowing systems favor others. There are many physicochemical differences in the two systems: food types and sources, migration of macroinvertibrates, dispersion of nutrients, aeration and diffusion of gases in water, particulate suspension, and thermal stratification are some examples. Ponding in the WCAs amounts to regulation for certain species—the zoo approach that is not an ecosystem approach. From a water conservation perspective, ponding may be wise; and in a water-limited system, ponded water for fish is a real improvement over no water for fish. Is would be possible to match regulated hydroperiods month to month with natural hydroperiods and still have a completely different ecosystem due to the difference in water movement. This is another reason why a hydroperiod analysis is singularly insufficient to create the intended biological conditions.” (U. S. Corps of Engineers, 1994).

System-wide, there has also been a loss of dry season lag flows from the dense sawgrass plain that formerly covered the present Everglades Agricultural Area. “Impoundment of water in the Water Conservation Areas and diversion of surface water flows to the east, combined with groundwater and levee seepage loses eastward in the modified system, have significantly contributed to reduced flows and the resultant loss of persistent hydroperiods in the southern Everglades flows and the resultant loss of persistent hydroperiods in the southern Everglades.” (Davis and Ogden 1994).

The overall flow pattern has changed, too, now that the deepest part of the system, east of the Dade-Broward levee, has become an urban landscape. More water is forced through the remaining area, creating excessive depths in the impounded areas. In Florida Bay, decreased freshwater flow and increased salinity have contributed to the deterioration of estuarine productivity in Florida Bay. Pink shrimp, snook, redfish and recruitment have been reduced. Reproductive success of ospreys, great white herons, and many wading birds that nested in the estuarine ecotonal areas have been lowered. Wading bird colonies have collapsed as once-persistent pools in lower Shark River Slough have dried. Mortality in seagrass beds and mangroves has also been linked to reduced freshwater flows.

Model Target

Flow volumes across selected groups of transects predicted by NSM version 4.5 Final.

Model Output Format

A relative value for improvement in sheetflow in the Everglades marshes was obtained by comparing flow volumes across a number of transects in the north, central and southern Everglades and Big Cypress with those predicted by the NSM version 4.5 Final. Twenty-six transects were chosen throughout the Water Conservation Areas, Big Cypress, and Everglades National Park. The average annual volumes of flow for the wet season and dry season for each alternative were compared to the wet season and dry season volumes from NSM version 4.5 Final. Dry season volumes were considered more important. The 26 transects were grouped into five categories representing their general area: Big Cypress Group (T24, T25, T26), Central Everglades (WCA-3A) Group (T7, T8, T12), Southern Everglades Group (T21, T23A, B, &C), Tamiami Trail Group (T17, T18) and the L-67 Group (T13, T14). Then for each group, an index was calculated for each transect based on the wet season and dry season average annual overland flows. For each base condition and plan, the flow value was divided by the NSM value to obtain wet season and dry season proportions, which were then scaled. Scaling, using the same curve formula described above was used to obtain values between 0.0 and 1.0. In cases where the proportion of wet season flows exceeded NSM, they received a value of 1.0. For dry season flows, excess flows were treated the same as insufficient flows.

Evaluation Tools

SFWMM

Literature Cited

Science Sub-group. Federal Objectives for the South Florida Restoration. Prepared for the South Florida Management and Coordination Working Group of the South Florida Ecosystem Task Force. 1993.

Central & Southern Florida Review Study Team. Comprehensive Review Study Reconnaissance Report. U. S. Army Corps of Engineers, Jacksonville, Florida. 1994.

Everglades: The Ecosystem and its Restoration. Edited by S. M. Davis and J. C. Ogden. Delray Beach, Florida: St. Lucie Press. 826 pp. 1994.

Authors & Contributors

Drafted by Cheryl Buckingham (USFWS)

Contributors: Ken Tarbotton (SFWMD), John Ogden (SFWMD), Agnes McLean (SFWMD)

******************************************************************************

Category

Ecological

Performance Measure

Maintenance of desirable salinity conditions within the St. Lucie Estuary

# of months with mean monthly flow < 300 cfs

# of months with mean monthly flows > 2,800 cfs

# of months with mean monthly flows were > 4,500 cfs

# of months with mean monthly flows > 2,800 cfs (local basin runoff)

additional # of months with mean monthly flows > 2,800 cfs (Lake Okeechobee regulatory releases)

Date Submitted/Revised

June, 1998

General Planning Objective

This performance measure suite is linked to the St. Lucie and Caloosahatchee conceptual model (Grey and Haunert). It addresses several general planning objective identified by the Governor’s Commission for a Sustainable South Florida in the Conceptual Plan for the C&SF Project Restudy; provide more natural quality and quantity, timing, and distribution of freshwater flow to estuaries and coral reef ecosystems, and improve and protect habitat quality, heterogeneity, and biodiversity in coastal and associated marine ecosystems

Region

Caloosahatchee Estuary

Restoration Goal

Reduce high volume and minimum discharge events to the estuary to improve estuarine water quality and protect and enhance estuarine habitat and biota.

Problem Addressed

The Caloosahatchee Estuary is located on the southwest coast of Florida, and discharges into Charlotte harbor, and then into the Gulf of Mexico. The Caloosahatchee is also connected to Lake Okeechobee through the C-43 canal (Caloosahatchee River), and there are a series of smaller drainage works in association with substantial agriculture development in the watershed. The construction of a water control structure (Franklin Lock and Dam) downstream of Lake Okeechobee has decreased the tidally influenced portion of the estuary, allowing for a convenient use of the C-43 as a potable water supply.

Model Target

# of months with mean monthly flow < 300 cfs : Target minimum mean monthly flows to the estuary are 300 cfs to protect Vallisneria, tape grass and support juvenile fish populations. This flow could come from the watershed (including groundwater), Lake Okeechobee (via S-79), or a combination of the two. The results of hydrologic modeling indicate that the optimum scenario would have no more than 60 months of mean monthly flows of <300 cfs. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

b. High Discharge Criteria, # of months with total mean monthly flows > 2,800 cfs : The results of hydrologic modeling indicate that the optimum scenario would have no more than 22 months of mean monthly flows of >2,800 cfs. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

High Discharge Criteria, # of months with total mean monthly flows were > 4,500 cfs : The results of hydrologic modeling indicate that the optimum scenario would have no more than 6 months of mean monthly flows of >4,500 cfs. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

# of months with mean monthly flows > 2,800 cfs (C-43 basin runoff) : The results of hydrologic modeling indicate that the optimum scenario would have no more than 22 months of mean monthly flows of >2,800 cfs. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

additional # of months with mean monthly flows > 2,800 cfs (Lake Okeechobee regulatory releases, Zone A discharges) : The results of hydrologic modeling indicate that the optimum scenario would have no additional months of mean monthly flows of >2,800 cfs (from Lake Okeechobee). The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

Model Output Format

# of months with mean monthly flow < 350 cfs

# of times the 14-day moving average flow is > 2800 cfs (local basin runoff)

additional # of times the 14-day moving average flow is > 2800 cfs (Lake Okeechobee releases)

High Discharge Criteria, # of times mean monthly flow is > 2800 cfs

High Discharge Criteria, # of times mean monthly flow is > 4500 cfs

Evaluation Tools

SFWMM

Literature Cited

Chamberlain, R., and D. Hayward, 1996. Evaluation of water quality and monitoring in the St. Lucie Estuary, Florida. Water Resources Bulletin. 32(4) 681-696.

Espey, Jr. W.H. and P.G. Cobbs (eds). Proceedings First International Conference, Water Resources Engineering, American Society of Civil Engineers (ASCE). 1506-1510.

Haunert, D., and R. Chamberlain. 1994. St. Lucie and Caloosahatchee Estuary Performance Measures for Alternative Lake Okeechobee Regulation Schedules. SFWMD Memorandum.

Haunert, D.E., 1986. Proposed supplemental water management strategy to enhance fisheries in the St. Lucie Estuary, FL (Draft). SFWMD.

Haunert, D.E. and J.R. Startzman, 1980. Some seasonal fisheries trends and effects of a 1,000 cfs freshwater discharge on the fisheries and macroinvertebrates in the St. Lucie Estuary, Florida. SFWMD Tech. Pub. 80-3.

Haunert, D.E. and J.R. Startzman, 1985. Short term effects of a freshwater discharge on biota of the St. Lucie Estuary, Florida. SFWMD Tech. Pub. 85-1.

Indian River Lagoon SWIM Plan, 1996.

Morris, F.W. 1987. Modeling of hydrodynamics and salinity in the St. Lucie Estuary. South Florida Water Management District: Technical Publication 87-1.

Otero, J. M., and Floris, V. (1994). Lake Okeechobee Regulation Schedule Simulation: South Florida Regional Routing Model. SFWMD. Special Report prepared for the U.S. Army Corps of Engineers, Jacksonville, Florida.

Otero, J.M., J.W. Labadie, D.E. Haunert and M.S. Daron, 1995. Optimization of managed runoff to the St. Lucie Estuary. Water Resources Engineering, Vol. 2.

Steinman, A. 1996. Letter from SFWMD dated April 2, 1996 to U.S. Army Corps of Engineers, Jacksonville District.

Authors & Contributors

Dan Haunert, Susan Grey, Liz Manners

Coordinator: Steve Traxler, Winnie Park

******************************************************************************

Category

Ecological

Performance Measure

Maintenance of desirable salinity conditions within the St. Lucie Estuary

# of months with mean monthly flow < 350 cfs

# of months with mean monthly flows > 1,600 cfs

# of months with mean monthly flows were > 2,500 cfs

# of times the 14-day moving average flow is > 1600 cfs (local basin runoff)

additional # of times the 14-day moving average flow is > 1600 cfs (Lake Okeechobee regulatory releases)

Date Submitted/Revised

January, 1998

General Planning Objective

Region

St. Lucie Estuary

Restoration Goal

Reduce high volume discharge events to the estuary to improve estuarine water quality and protect and enhance estuarine habitat and biota.

Problem Addressed

The St. Lucie Estuary is located on the southeast coast of Florida, and discharges into the Indian River Lagoon and Atlantic Ocean at the St. Lucie Inlet. The estuary encompasses about eight square miles, and the historic watershed was estimated to be about 1/3 the size of its present configuration. Due to extensive agricultural and urban drainage projects beginning in the 1910s, the present day watershed area has been expanded to almost 775 square miles. Major canals in the watershed include the C-23 and C-24 canals, part of the Central and South Florida Flood Control Project. In addition, the estuary is linked to Lake Okeechobee by the C-44 canal that is utilized for both navigation and the release of floodwaters from Lake Okeechobee.

To determine appropriate water quantity inflows to the estuary, biological indicators with definable salinity preferences were chosen. A favorable range of salinities for the estuary were determined (referred to as the salinity envelope) based on the requirements of SAV and oysters. Woodward-Clyde, in a literature review report developed for the District in 1998, summarizes the approximate salinity tolerances for selected SAV and American oyster. A report on the abundance and type of SAV species by Phillips and Ingle (1960), provided the most complete source of information on SAV occurrence and abundance in the St. Lucie Estuary. This survey of SAV which was conducted from September 1957 to March 1959 revealed that the three most commonly found species of SAV in the estuary at the time were shoal grass (outer and middle estuary), manatee grass (outer estuary), and widgeon grass (north fork). They also reported on the salinity tolerance, normal, common and optimum range for all species. The normal tolerance range for shoal grass is 5-55 ppt; for manatee grass, 17-44 ppt; and for widgeon grass, 0-45 ppt. These numbers were based on reviewed literature, and all species can withstand even greater salinity fluctuations for short periods of time. The salinity tolerance ranges were also summarized for the different life cycle stages of the American oyster. The optimum range for adults and juveniles is 10-20 ppt, 20-23 for spat, 23-27 for larvae and embryos and 15-20 ppt for a sustainable population (Woodward-Clyde 1998). These favorable ranges of salinity (salinity envelope) have been related to volumes of freshwater flow to the estuary and a target range of flows was determined. In order to meet the salinity envelope criteria the surface water flows coming from the watershed as well as from ground water should be in the range of 350cfs - 1600cfs

Model Target

The performance measures have targets based on flow that would support optimum hydrologic conditions conducive of optimum quality habitat for fish, wildlife, and other aquatic resources. The targets are based on optimization model outputs, natural variation that would occur during the period 1965-1995, and desirable salinity conditions for existing and potential aquatic resources within the St. Lucie Estuary. The target salinity gradients in St. Lucie Estuary were determined by a hydrodynamic salinity model (Morris 1987) combined with estimates of salinity requirements for two indicator species in the estuary, Halodule wrightii (shoal grass) and Crassostrea virginica (American oyster).

# of months with mean monthly flow < 350 cfs : Target minimum mean monthly flows to the estuary are 350 cfs to protect oysters near the Roosevelt Bridge, promote brackish aquatic plant growth, and support juvenile fish populations. This flow could come from the watershed (including groundwater), Lake Okeechobee (via S-80), or a combination of the two. The results of hydrologic modeling indicate that the optimum scenario would have no more than 50 months of mean monthly flows of <350 cfs. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

# of times the 14-day moving average flow is > 1600 cfs (local basin runoff) : Historically, the high flow events have been the most destructive. The results of hydrologic modeling indicate that the optimum scenario would have no more than 13 events of 14-day moving average flows of >1600 cfs. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

# of times the 14-day moving average flow is > 1600 cfs (Lake Okeechobee releases) : The results of hydrologic modeling indicate that the optimum scenario would have no months of 14-day moving average flows >1600 cfs from Lake Okeechobee releases. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

# of times mean monthly flow is > 1600 cfs : The results of hydrologic modeling indicate that the optimum target would have no more than 9 months of mean monthly flows of >1600 cfs. This target dictates a maximum flow that will provide suitable habitat for important benthic communities. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

# of times mean monthly flow is > 2500 cfs : The results of hydrologic modeling indicate that the preferred scenario would have no more than 3 months of mean monthly flows of >2500 cfs. Mean monthly flows above 2500 cfs result in freshwater conditions throughout the estuary causing severe impacts to estuarine communities. The estuary data for the alternatives is taken from the performance measures bar graphs and tables.

Model Output Format

# of months with mean monthly flow < 350 cfs

# of times the 14-day moving average flow is > 1600 cfs (local basin runoff)

additional # of times the 14-day moving average flow is > 1600 cfs (Lake Okeechobee releases)

# of times mean monthly flow is > 1600 cfs

# of times mean monthly flow is > 2500 cfs

Evaluation Tools

SFWMM, optimization modeling for the S. Lucie basins

Literature Cited

Chamberlain, R., and D. Hayward, 1996. Evaluation of water quality and monitoring in the St. Lucie Estuary, Florida. Water Resources Bulletin. 32(4) 681-696.

Espey, Jr. W.H. and P.G. Cobbs (eds). Proceedings First International Conference, Water Resources Engineering, American Society of Civil Engineers (ASCE). 1506-1510.

Haunert, D., and R. Chamberlain. 1994. St. Lucie and Caloosahatchee Estuary Performance Measures for Alternative Lake Okeechobee Regulation Schedules. SFWMD Memorandum.

Haunert, D.E., 1986. Proposed supplemental water management strategy to enhance fisheries in the St. Lucie Estuary, FL (Draft). SFWMD.

Haunert, D.E. and J.R. Startzman, 1985. Short term effects of a freshwater discharge on biota of the St. Lucie Estuary, Florida. SFWMD Tech. Pub. 85-1.

Indian River Lagoon SWIM Plan, 1996.

Morris, F.W. 1987. Modeling of hydrodynamics and salinity in the St. Lucie Estuary. South Florida Water Management District: Technical Publication 87-1.

Otero, J.M., J.W. Labadie, D.E. Haunert and M.S. Daron, 1995. Optimization of managed runoff to the St. Lucie Estuary. Water Resources Engineering, Vol. 2.

Steinman, A. 1996. Letter from SFWMD dated April 2, 1996 to U.S. Army Corps of Engineers, Jacksonville District.

Woodward-Clyde Consultants, 1998. St. Lucie Estuary Historical, SAV, and American Oyster Literature Review. Prepared for the South Florida Water Management District, West Palm Beach, Florida.

Authors & Contributors

Dan Haunert, Susan Grey, Liz Manners

Coordinator: Steve Traxler, Winnie Park

******************************************************************************

Category

Ecological

Performance Measure

Canal Discharges to Biscayne Bay

Date Submitted/Revised

May, 1998

General Planning Objective

This performance measure addresses several planning objectives identified by the Governor’s Commission for a Sustainable South Florida in the Conceptual Plan for the C&SF Project Restudy; Improve habitat quality and heterogeneity, Provide more natural quality and quantity, timing and distribution of freshwater flow to estuaries, and improve and protect habitat quality, heterogeneity, and biodiversity in coastal and associated marine ecosystems.

Region

For this performance measure, Biscayne Bay is considered to be bounded by Snake Creek to the north (Oleta River State Park) and the southern border of Biscayne National Park to the south.

Based on historical accounts and scientific studies, Biscayne Bay has been classed as a positive, shallow, tidal, bar-built estuary (Kohout and Kolipinski 1967). The term positive refers to the condition of salinity being less than seawater (Hela et al. 1957). The salinity gradient that established estuarine habitat in Biscayne Bay is dependent on both surface and ground water flows (Fatt and Wang 1987). The effect of regional drainage projects on these flows has been to disrupt salinity patterns and impair coastal ecosystem function by altering the timing and amounts of freshwater input to the bay.

Restoration Goal

Reduce excessive canal discharges to the bay, provide a stable brackish water habitat during the wet season, and provide more water during dry periods to prevent hypersaline conditions from impacting important marginal wetlands and nearshore habitats.

Problem Addressed

While accomplishing the goal of flood control, the presence and operation of the canals has had profound hydrological and ecological consequences on Biscayne Bay (Teas et al. 1976, Thorhaug et al. 1976, Hoffmeister 1974). The temporal and spatial pattern of freshwater inflow to the bay was fundamentally altered to one of point source discharges (canal mouths) that are characterized by abrupt periods of high discharge and minimal or no discharge to the bay. Although the general pattern of wet and dry seasons still persist, operation of coastal water control structures results in rapid changes in local salinity gradients that may occur on a daily basis and over several months, particularly during the rainy season (Fatt 1986). During the dry season, hypersalinity has been observed as a result of evaporation, retention of canal flow, and bay circulation (Lee 1975). While abrupt changes in salinity can occur naturally in nearshore habitats, they usually result from infrequent events such as hurricanes and tropical storms. The effects of salinity changes have been documented for fish (e.g. Davenport & Vahl 1975, Provencher et al. 1993, Serafy et al. in press) and for invertebrates (e.g. Brook 1982, Montegue and Ley 1993, Irlandi et al. in press). The presence and operation of the canals and construction of permanent oceanic inlets has resulted in a loss of estuarine function and shifted Biscayne Bay to more of a lagoon, adversely impacted from freshwater pulses and highly variable salinities. These conditions have been at least partly responsible for the loss of historically abundant estuarine species, such as red drum, black drum, and eastern oyster, the loss of juvenile fish habitat, and the significant increase in stress-tolerant fish species such as the gulf toadfish (Serafy et al., in press).

Model Target

Model results were compared to surface water budget targets that were considered appropriate to achieving restoration of the Biscayne Bay ecosystem. These targets consist primarily of the existing average annual inflow to Biscayne Bay as defined by the 1995 Base hydrologic period, with a 2% increase in total inflow budget to be applied in the dry season to the Central and South Bay regions.

A separate target for Snake Creek (S29) was also developed based on canal discharge that would maintain salinities for oyster survival. average salinity (measured at one meter depth) near the mouth has averaged less than 20 ppt. since 1988. Viable oyster communities appear to thrive in the area forming the headwaters of the Oleta River. By use of linear regression modeling, a total monthly volume of 13,300 acre-feet equates to 20 ppt. salinity concentration. This should be viewed as a minimum monthly flow. Excessive flow does not seem to be problem in general.

Model Output Format

Based on SFWMM hydrologic model output, the bay was divided into five regions from north to south, based on the mean monthly discharge from water control structures in these regions. The regions were Snake Creek (S29), North Bay (G58, S28, S27), Miami River (S25, S25B, S26), Central Bay (G97, S22, S123), and South Bay (S21, S21A, S20F, S20G). Model output for each alternative provides results as the sum of discharge from the structures in each region in terms of a mean annual wet season and dry season volume.

Evaluation Tools

SFWMM

Literature Cited

Alleman, Richard W. 1995. Surface Water Improvement and Management Plan for Biscayne Bay. Planning Document, South Florida Water Management District, West Palm Beach, Florida.

Brook, I. M. 1982. The effect of freshwater canal discharge on the stability of two seagrass benthic communities in Biscayne National Park, Florida. Proc. Int. Symp. Coastal Lagoons, Bordeaux, France. Oceanol. Acta 1892:63-72.

Davenport, J. and O. Vahl. 1979. Responses of the fish Blennius pholis to fluctuating salinities. Mar. Ecol. Prog. 1:101-107.

Fatt, J. C. 1986. Canal impact on Biscayne Bay salinities. MSc thesis, Univ. of Miami, Coral Gables, FL.

Fatt, J. C. and J. D. Wang. 1987. Canal discharge impacts on Biscayne Bay salinities, Biscayne National Park. Research/Resources Management Report SER-89, National Park Service, Atlanta, Georgia.

Hela, I., J. K. McNulty, and C. A. Carpenter. 1957. Hydrography of a positive, shallow, tidal, bar-built estuary. Bull. Marine Sci. Gulf Caribbean 7:47-99.

Hoffmeister, J. E. 1974. Land from the sea: the geologic story of South Florida. University of Miami Press, Coral Gables, FL.

Irlandi, E., S. Macia, and J. Serafy. In press. Salinity reduction from freshwater canal discharge: effects on mortality and feeding of an urchin (Lytechinus variegatus) and gastropod (Astrea tecta). Bull. Mar. Sci.

Kohout, F.A. and M.C. Kolipinski. 1967. Biological zonation related to groundwater discharge along the shore of Biscayne Bay, Miami, Florida. Estuaries 19:488-499.

Lee, T. N. 1975 Circulation and exchange processes in southeast Florida’s coastal lagoons. University of Miami, Rosentiel School of Marine and Atmospheric Science. Technical Report to US Energy Research and Development Administration, ID No. ORO-3801-9.

Montegue, C. L. and J. A. Ley 1993. A possible effect of salinity fluctuation on abundance of benthic vegetation and associated fauna in Northeastern Florida Bay. Estuaries 16:707-717.

Provencher, L., J. Munro, J. D. Dutil. 1993. Osmotic performance and survival of Atlantic cod (Gadus morhua) at low salinities. Aquaculture 116: 219-231.

Serafy, J. E., K. C. Lindeman, T. E. Hopkins, J. S. Ault. In press. Effects of freshwater canal discharge on fish assemblages in a subtropical bay: field and laboratory observations. Mar. Ecol Prog. Ser. In press.

Teas, H. J., H. R. Wanless, and R. Chardon. 1976. Effects of man on the shore vegetation of Biscayne Bay. In: A. Thorhaug (ed.) Biscayne Bay: Past, Present, and Future. University of Miami Sea Grant Special Report No. 5. 315 pp.

Thorhaug, A., M. A. Roessler, and D. C. Tabb. 1976. Man’s Impact on the Biology of Biscayne Bay. A. Thorhaug (ed.) Biscayne Bay: Past, Present, and Future. University of Miami Sea Grant Special Report No. 5. 315 pp.