CONTENTSINTRODUCTION .......................... 1

GOALS .................................. 1

UPLANDS ............................... 1Pine-Palmetto Forest ........................ 1Hammocks and Tree Islands ................. 3Policies ................................... 4

INTERIOR WETLANDS ................... 4The East Everglades ...................... 6Policies ... ............................. 8Southern Everglades Coastal Marsh ........... 8Policies ................................ 9Everglades National Park ................... .10Policies ................................... 10

ESTUARIES ....... ...................... 10Estuarine Mangrove and Coastal Marsh ....... 12Policies ................................... 13Marine Grass Beds ........................ 14Policies .......................... ...... 16Estuarine Water Quality .................... 16Policies ................................... 17

BEACHES AND BARRIER ISLANDS ......... 17Policies ................................... 21

MARINE WATERS ......................... 21Policies ................................... 26

OTHER ENVIRONMENTAL ISSUES ........ .30Endangered and Threatened Species . ......... 30Policies .............................. 30Hurricane Hazard ......................... 30Policies .......................... ...... 31

The preparation of this document was financed in part througha comprehensive planning grant from the U.S. Departmentof Housing and Urban Development.

INTRODUCTIONNatural environmental systems perform vitalservices in supporting human life and the economicactivities upon which the people of the Regiondepend. These services include water supply, wastedisposal, food production, hurricane and floodprotection, air quality, climate, and the unique andbeautiful environment that has attracted visitorsand residents in unprecedented numbers. Likeother complex systems, natural systems canoperate efficiently only if they are maintained in afunctional state. If vital components are destroyed,or if the system is overstressed, breakdown willoccur and the system will fail. Technology can beused to increase the capacity of the natural system,but this requires expenditure of energy and capitalto do work that was formerly performed free.

If appropriate technology and/or sufficientcapital are not available to relieve stress on naturalsystems they deteriorate and the quality of lifedeclines. Examples in the Region are: loss ofbeaches to erosion; degradation of water quality,both for water supply and for recreation; declineof fish and shellfish harvests; increasing traveldistances to recreation and wilderness areas; anddecrease of water available for both natural systemsand human use.

Large areas of South Florida are naturallysuitable for urban development. It is most costefficient to manage other areas as natural supportsystems for supplying vital services and protectionfor the built environment. It makes economic senseto use each system for the function to which it isbest suited, and to achieve optimum use of both thenatural and built environments through intelligentmanagement.

GOALS1. Manage natural systems to insure that their

valuable services to the people of the Region arenot lost. These services include maintenanceof water supply, water quality, hurricane andflood protection, recreation, food production,air quality, climate, and the environment thatcontinues to attract tourists, commerce andindustry.

2. Direct development to locations that areadvantageous for development with the leastundesirable impact on both the natural andthe built environment.

3. Require sound development practices topreserve valuable natural system services andamenities, while providing a safe and beneficialhuman environment.

UPLANDSThe uplands of the Region are on the Atlanticcoastal ridge, which has a maximum elevation of 20feet. It extends from the northern boundary of theRegion, paralleling the coast south to the Miamiarea, where it turns southwestward away from theshore. The ridge terminates at Homestead in southDade County, with a few outcrops in EvergladesNational Park.

The underlying geological formation islimestone, covered by a thin layer of sand. In placesthe limestone is exposed at the surface, and rainfalleither penetrates the ground rapidly, or runs off tolower elevations. The limestone contains numeroussolution holes, both surficial and subterranean,which may create localized problems for construc-tion, but has a sponge-like water bearing capacity.

Value of UplandsEarly settlements were located on the ridge becauseof its higher elevation and desirable coastallocation. Geologic and soil conditions were alsogenerally favorable for building, and these naturaladvantages attracted continuing development.Except for agricultural areas in south Dade County,most of the ridge has now been urbanized. Asavailable high land became scarce, developmentspread westward into drained Everglades andeastward into the mangrove fringe. This was madepossible by drainage and flood control projects, andby dredging and filling of former wetlands.

PINE-PALMETTO FORESTOnce the dominant plant community of the coastalridge, the pine-palmetto community is largelyreplaced by urbanization and agriculture, and itmay become the rarest of formerly common plantcommunities. This open forest community of slashpine, with under-story vegetation including sawpalmetto and over 100 species of grasses, shrubsand herbaceous plants, prefers drier areas and/orshallow soils. It will not tolerate standing water,and where it is wet or very humid, hardwoodhammocks or cypress are found among the pines.

Pineland is maintained by periodic firesthat kill invading hardwoods, but spare the fire-resistant pines and saw palmettos. Fire hasbeen curtailed, however, near development,and hardwoods - particularly the less desirablepoisonwood and albizzia - are successfullyinvading pine forests near urbanized areas.Change from pine forest to hardwood hammocktakes about 25 years.

Development practices in pineland mustreflect the extreme susceptibility of pinesto damage. If the roots or bark are injured by

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clearing, trucking, or operation of heavyconstruction equipment, the tree is susceptible toinvasion by pine bark beetles, which kill the tree infive to ten years. It is common to see pines thatwere left but damaged during urban developmentbecome yellow, lose their needles and die in a fewyears. One method of avoiding such injury is toleave a protective ring of saw palmetto around thepines, incorporating them both into the landscapedesign.

HAMMOCKS AND TREE ISLANDSHammocks, heads, and tree islands are small,dense hardwood areas that stand out against thesurrounding vegetation as islands of trees.They may occur on the ridge among pines andpalmettos, or in wetlands on slightly elevated areas.There are about 100 species of trees and shrubsfound in eleven types of hammocks in southernFlorida. Temperate zone hammock species aremore common in the northern part of the Region,giving way to more tropical Caribbean speciestoward the south, and becoming purely tropical inthe Florida Keys.

Hammocks and tree islands are often namedfor their dominant tree - bay heads, willow heads,cypress heads, oak hammock, and mahoganyhammock are examples. "Heads" and "treeislands" are usually found in wetlands and"hammocks" on the ridge. The terminologyoriginated in local usage, and is not a scientificclassification.

The hammocks on the coastal ridge form ona small elevation under slightly more humidconditions, often near a sinkhole which holds wateryear-round. As a hammock develops, the densevegetation tends to hold high humidity, creating amicroclimate that is warmer in winter and cooler insummer than the surrounding area. Leaf litterbuilds up on the ground, forming moist hammockpeat soil a foot or more deep. The combinationof high humidity and moist soil keeps out mostpineland fires.

On the exterior edge, the typical hammock isfringed by a thicket of shrubs or saw palmetto thatappears to be impenetrable, and helps keep interiorhumidity high. This edge is where pioneer ham-mock species begin to invade the surroundingpineland. The hammock interior, however, is a tallcanopy with an open understory where ferns andepiphytic "air plants" and orchids are abundant.

More than 500 hammocks once dotted thepineland ridge in Dade County alone, but most

have been eliminated by fire, land development,and lowering of the water table. Remaining ,hammocks can be preserved by public acquisitionor by careful planning of private development.Hammocks within large development tracts arevaluable features that should be retained andutilized. Access can be created so that the hammockcan be used as a private park for the residents.Buildings can be clustered and construction limitedto preserve the viable portions of forest. Roads andparking should be kept to a minimum. Removal ofthe perimeter shrub thicket increases air circulationand reduces temperature and humidity. Someplant species would probably be adversely affected,particularly air plants and orchids, but mostwould survive.

Environmental alteration in the uplands hashad impact on other systems, as well as degradingthe quality of the uplands themselves. Asdevelopment has progressed, runoff from urbanand agricultural uplands has increased, reducingwater quality in both freshwater wetlands andcoastal environments. Extensive land clearance hasremoved vegetation that formerly slowed runoffwater and filtered pollutants. Nutrients frompastures and lawns, sewage outfalls, and fertilizershave altered natural communities, and causedfrequent fish kills. Pesticides from urban andagricultural lands, as well as trace metals and othertoxins contained in urban runoff have long-termeffects that are only beginning to be understood.Land management and development practices inthe uplands can and should be improved tominimize the impacts on sensitive environmentalsystems. It should be emphasized, however,that the uplands are the most suitable for urbandevelopment.

Almost all of the pine forest that once extendedover the ridge has been logged, cleared away forurban and agricultural use, or destroyed by fire.The scattered pinelands that remain are essentiallysecondary growth. Most of the hundreds ofhardwood and oak hammocks have been partiallyor totally eliminated. Lowering of the water tableand alteration of the fire cycle have significantlychanged the remaining native upland plantcommunities. Roadsides, levees, and abandonedfarmlands provide habitats for establishment ofintroduced vegetation, especially those which caninvade and out-compete native species. Brazilianpepper, Australian pine, and melaleuca areparticularly aggressive invaders, but other speciesare also involved in specific areas. Management of

clearing, trucking, or operation of heavyconstruction equipment, the tree is susceptible toinvasion by pine bark beetles, which kill the tree infive to ten years. It is common to see pines thatwere left but damaged during urban developmentbecome yellow, lose their needles and die in a fewyears. One method of avoiding such injury is toleave a protective ring of saw palmetto around thepines, incorporating them both into the landscapedesign.

HAMMOCKS AND TREE ISLANDSHammocks, heads, and tree islands are small,dense hardwood areas that stand out against thesurrounding vegetation as islands of trees.They may occur on the ridge among pines andpalmettos, or in wetlands on slightly elevated areas.There are about 100 species of trees and shrubsfound in eleven types of hammocks in southernFlorida. Temperate zone hammock species aremore common in the northern part of the Region,giving way to more tropical Caribbean speciestoward the south, and becoming purely tropical inthe Florida Keys.

Hammocks and tree islands are often namedfor their dominant tree - bay heads, willow heads,cypress heads, oak hammock, and mahoganyhammock are examples. "Heads" and "treeislands" are usually found in wetlands and"hammocks" on the ridge. The terminologyoriginated in local usage, and is not a scientificclassification.

The hammocks on the coastal ridge form ona small elevation under slightly more humidconditions, often near a sinkhole which holds wateryear-round. As a hammock develops, the densevegetation tends to hold high humidity, creating amicroclimate that is warmer in winter and cooler insummer than the surrounding area. Leaf litterbuilds up on the ground, forming moist hammockpeat soil a foot or more deep. The combinationof high humidity and moist soil keeps out mostpineland fires.

On the exterior edge, the typical hammock isfringed by a thicket of shrubs or saw palmetto thatappears to be impenetrable, and helps keep interiorhumidity high. This edge is where pioneer ham-mock species begin to invade the surroundingpineland. The hammock interior, however, is a tallcanopy with an open understory where ferns andepiphytic "air plants" and orchids are abundant.

More than 500 hammocks once dotted thepineland ridge in Dade County alone, but most

have been eliminated by fire, land development,and lowering of the water table. Remaininghammocks can be preserved by public acquisitionor by careful planning of private development.Hammocks within large development tracts arevaluable features that should be retained andutilized. Access can be created so that the hammockcan be used as a private park for the residents.Buildings can be clustered and construction limitedto preserve the viable portions of forest. Roads andparking should be kept to a minimum. Removal ofthe perimeter shrub thicket increases air circulationand reduces temperature and humidity. Someplant species would probably be adversely affected,particularly air plants and orchids, but mostwould survive.

Environmental alteration in the uplands hashad impact on other systems, as well as degradingthe quality of the uplands themselves. Asdevelopment has progressed, runoff from urbanand agricultural uplands has increased, reducingwater quality in both freshwater wetlands andcoastal environments. Extensive land clearance hasremoved vegetation that formerly slowed runoffwater and filtered pollutants. Nutrients frompastures and lawns, sewage outfalls, and fertilizershave altered natural communities, and causedfrequent fish kills. Pesticides from urban andagricultural lands, as well as trace metals and othertoxins contained in urban runoff have long-termeffects that are only beginning to be understood.Land management and development practices inthe uplands can and should be improved tominimize the impacts on sensitive environmentalsystems. It should be emphasized, however,that the uplands are the most suitable for urbandevelopment.

Almost all of the pine forest that once extendedover the ridge has been logged, cleared away forurban and agricultural use, or destroyed by fire.The scattered pinelands that remain are essentiallysecondary growth. Most of the hundreds ofhardwood and oak hammocks have been partiallyor totally eliminated. Lowering of the water tableand alteration of the fire cycle have significantlychanged the remaining native upland plantcommunities. Roadsides, levees, and abandonedfarmlands provide habitats for establishment ofintroduced vegetation, especially those which caninvade and out-compete native species. Brazilianpepper, Australian pine, and melaleuca areparticularly aggressive invaders, but other speciesare also involved in specific areas. Management of

these changing natural and artificial environmentalsystems will require large-scale and innovativetechniques which are yet to be developed.

Use of non-native (exotic) plant species in newlandscaping should be avoided. Some exoticsrequire frequent irrigation during drought periods,and heavy use of pesticides and fertilizers that maycause water pollution. Low maintenance exotics,on the other hand, tend to escape from cultivation,invading and even replacing natural vegetativecommunities. Many species of native vegetationare admirably suited for landscaping, and sincethey are adapted to the South Florida soils andrain cycle, they do not require much watering orfertilizer once they are established. They alsoprovide food and habitat for native songbirds andsmall mammals.Policies1. The upland areas of the Region are most suitable

for urbanization; therefore, future develop-ment should be directed first to the coastal ridgeand existing filled areas before more costlydevelopment in lower-lying areas is encouraged.

2. Require new developments in native pinelandsand hammock forests to use ecologically sounddesign practices, such as clustering of buildings,and selective clearing of native vegetation.

3. Local governments should prohibit thedeliberate planting of particularly undesirableexotic species, including melaleuca, casuarina,and Brazilian pepper.

4. Use native plants in new landscaping tominimize use of water, pesticides and fertilizer.

5. Develop stormwater and groundwater manage-ment techniques and regulations, includingdesign criteria for new development to improvethe quality of water discharged to canals andother surface waters.

6. Alternatives to direct discharge of stormwater,such as grassed swales, berms, and retentionponds, are preferred.

7. Conduct construction activity, includingapproved clearing and grading activities, in amanner which minimizes adverse impactson natural vegetation and avoids degradationof air and water quality.

INTERIOR WETLANDSFree-flowing streams in well-defined channels,such as are found in other parts of the State, are rarein South Florida. Instead, much of the abundant

rainfall penetrates directly down into the shallowaquifers, and the remainder either flows slowlysouthward across the land as sheet flow, or standsin the wetland swamps, ponds and sloughs that area prominent feature of the landscape. The lack ofslope prevents rapid runoff, and the slow drainageresults in seasonal or year-round flooding. Theextent of the 1947 floods (Figure 2) are believed to beapproximately the boundaries of the naturalwetlands prior to the digging of canals. Naturaluplands prior to drainage were located mainly onthe coastal ridge.

Lake Okeechobee has been called the wateryheart of South Florida. Before drainage began at theturn of the century, this shallow lake periodicallyoverflowed to the northern Everglades, and,augmented by rainfall, flooded the wetlands to thesouth. When the potential of the rich organicEverglades soils was recognized, drainage foragricultural development began. The St. Lucie andCaloosahatchee rivers were extended by canals toconnect Lake Okeechobee to the Atlantic and theGulf in order to lower its water level. Other canalswere dug southward from the Lake across theEverglades, and eastward through the transverseglades of the coastal ridge, lowering former peakwater levels by as much as six or seven feet. Saltintrusion at the coast, and drought and fire inthe Everglades soon followed. Yet, wet years stillbrought disastrous floods to urbanized areas.Construction of flood control works was thenbegun. Three water impoundment lakes - thewater conservation areas - were enclosed by dikesand levees, intercepting surface flow. Canalscarry water from these reservoirs to recharge thewellfields of coastal cities, and the excess is divertedto the Atlantic. The South Florida drainage basinis now an artificially controlled system.

Value of WetlandsWetlands serve many important functions. Becauseof their capacity to hold water, they reduce theimpact of flooding on developed areas by acting asstorage basins for flood waters. This is particularlyimportant near urban areas, where pavementand buildings waterproof the land surface andincrease stormwater runoff. Wetlands also act asgroundwater recharge areas where they areunderlain by shallow surface aquifers. A vitalfunction of wetlands is their ability to filterpollutants from water before it enters the aquifer orsurface water bodies. Studies of marshes indicatethat a significant reduction in amounts of pollutionand sediment occurs by the time water has passed

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through the marsh.Wetlands are one of the most productive

natural systems; some having been found to equalor exceed the productivity of intensively farmedcropland. Fish and waterfowl production isparticularly important economically, both forrecreation value, and for harvest. Wetlands are alsoessential for wildlife, as many rare or endangeredspecies are wetland dependent.

An additional substantial value of wetlandsystems is recreational. Fishing, hunting, andsimple relaxation and enjoyment of the spectacularwater birds and unparalleled diversity of life formsare wetland resources that are irreplaceable.

The plants and animals of the Everglades aredependent on a yearly rhythm of flooding anddrying, and the timing of the cycle is important, asis the total water quantity. Too much water atnesting time can prevent reproduction of certainbirds, for example. Plant communities also havecritical requirements. In the cypress community, forexample, the seeds sprout on moist soil in thewinter, after the water recedes, and grow rapidlythe first year to remain above the level of floodingthe following year. Short periods of floodingcan be tolerated, but long submergence will killthe seedling, as will prolonged dry periods.

Many other species have equally specific needsif they are to reproduce and survive. EcologistArthur Marshall has described these complexinterrelationships:

Heavy tropical rains come to southFlorida in the summer and fall throughoutthe Everglades waterway. The water risesout of its shallow, scattered depressions -lakes, rivers, ponds, and sloughs. It sheetsover the southern Everglades marshes inthe form of a very broad river whichhistorically was seven or eight feet deep atsummer flood.

Regenerative processes bloom withthe rising spread of the water under thewarm summer sun. Plant germinationand growth flourish. Many aquaticorganisms - insects, crayfishes, killifishes,reptiles - engage in an orgy ofreproduction and in a few weeks theirprogeny can be seen in all reaches ofthe summer river.

After the rains let up, the sheet waterrecedes into the deeper ponds andsloughs and concentrates the summer'sproduction of small organisms, making

them available in essential densities to thewaiting large predators. This phenomenonof flood-bloom-recession-concentrationis a marvel of synchronization - for thesummer's organic products are thusserved up to the flocks of colonial birdswho are then fledging their young and tothe young and adults of many marinefishes which invade the brackish andfresh waters of the lower Everglades toforage there.The major freshwater wetland system of the

South Florida Region, the Everglades, has beensubdivided by flood control works and by urban,agricultural and park development, into four majorsubunits:1. Water Conservation Areas. These are shallow

artificial water storage lakes, managed by theSouth Florida Water Management District.

2. East Everglades. Semi-drained wet prairieand sawgrass marsh east of the ConservationAreas, between the levees and the urbanizedcoastal ridge.

3. Southern Everglades Coastal Marsh. A broad,low freshwater marl prairie lying between thecoastal ridge and the saline mangrove fringe insouthern Dade County.

4. Everglades National Park and Big CypressFreshwater Preserve. Occupying much ofwestern Dade and all of mainland Monrcecounties, these federal preserves also include thesouthern fringe of the Big Cypress Swamp.

THE EAST EVERGLADESThe eastern Everglades, the area in Broward andDade counties between the coastal ridge in the eastand the flood control levees and EvergladesNational Park in the west, is an area of former wetprairie and sawgrass marsh that was flooded partof the year. Much of this area, now extensivelydrained, has been altered for urban developmentor agriculture. The area was formerly part ofthe Everglades watercourse but is now isolated byconservation area levees to the west, and peakwater levels are 2 to 4 feet lower than they wereprior to canal drainage.

The former wetland community is beinginvaded by non-native species, and the peat soilshave been burned away in places by fires, or havepartially oxidized by exposure to air. These changesresult from lowering of the water table andshortening of the flood period. Where agricultural

/7

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FIGURE 3DIRECTIONS OF NATURAL SURFACEDRAINAGE

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or urban development has occurred, runoff hasimpacted water quality.

When development is absent, however, thearea functions as an important aquifer rechargearea due to the filtering capacity of organic mucksoil and the permeability of the underlying geologicformations. Although the natural habitat value ofthe area has been lessened by alteration, it still actsas an important buffer zone between the urbanizedcoastal strip and the natural communities of theconservation areas, which have high environmentaland recreational value.

There is increasing pressure for developmentin the east Everglades, and large tracts have alreadybeen committed for future residential projects.The proposal for a major jetport in north Dade isstimulating proposals for industrial development.If extensive development proceeds, the capacityof the area to retain flood waters would be reduced,as would its essential aquifer recharge capability,because additional filling and drainage would benecessary for flood protection of new development.If the remaining natural value of the area is to beretained, it is necessary to limit the amount of fill ortopographic disturbance which takes place, and tominimize removal of existing organic soils. Thecumulative effect of demucking and fill is a decreasein total aquifer recharge, and lower quality of bothsurface and ground water.

A particular concern is control of land useadjacent to the conveyance canals which supplywater to municipal wellfields, and land uses nearwellfields themselves. All major conveyance canalsflow through portions of the east Everglades, andcan influence ground water movement one-halfmile or more from their banks. Similarly, the zone ofinfluence of a major wellfield extends outwardfrom the well, the distance depending on rate ofpumping, adjacent rock formations, and seasonalfluctuation of the water table. Preliminary EPAstudies have shown that urban runoff andindustrial waste have already contaminatedground water in the vicinity of at least one majormunicipal wellfield. Local government land useregulations, water quality management programs,and requirements for sound development practicesare essential to protect the water supply.

The upper drainage basin of Taylor Slough lieswithin the east Everglades, outside the boundariesof Everglades National Park. It is a seasonallyimportant feeding area for birds which nest in thePark, but its chief importance is in the flow of waterprovided to the Slough itself, and to its down-stream estuaries which support 90 percent of

the United States populations of Americancrocodile and Cape Sable sparrow, 50 percent of thenesting egrets and roseate spoonbills in Florida,and significant populations of brown pelicans, baldeagles, and ospreys, as well as juvenile life stagesof many sport and commercial fishes.

Land use in the Taylor Slough drainage basinmust be carefully planned and regulated to avoidcutting off the vital flow of water to the Park andFlorida Bay.

Policies8. Allow only those uses and intensities in the

eastern Everglades that minimize adverseimpacts on water quality, surface flow,hydroperiod, soil cover, aquifer recharge, andthe natural, wildlife, and recreational valuesof the Conservation Areas, and EvergladesNational Park and Florida Bay.

9. When adequate public services are available orprogrammed, priority should be given todevelopment within the generally urbanizedarea, followed by staged growth outward fromthe urbanized area.

10. Develop areas which have already been filledor otherwise significantly disturbed, beforealteration is permitted in less disturbedareas. An exception would be areas in whichalteration has caused damage to vitalenvironmental systems; such areas and theirfunctions should be restored if feasible.

11. Develop special land use and landdevelopment controls for areas which arewithin the zone of surface or groundwaterinfluence of existing or proposed publicwellfields and their conveyance canals.

SOUTHERN EVERGLADESCOASTAL MARSHThis area of salt and freshwater marshes occupiessouthernmost Dade County as shown on Figure 1.Everglades National Park forms the western border,and Card Sound, Barnes Sound, and Biscayne Bayform the boundary on the south and east.

Elevations range from a maximum of five feetnear the Park entrance, grading imperceptiblydown to sea level at the coast. The majority of thearea is less than three feet above mean sea level,making it extremely prone to hurricane flooding.Soils are primarily marl over bedrock or marl overpeat. Mangrove peat underlies the estuarine areasalong the coast, where the elevation is generallyless than one foot above mean sea level.

In the past the area was characterized duringhigh water periods by uninterrupted overlandflow of freshwater from the ridge in the vicinity ofFlorida City, southward and eastward into thecoastal mangrove estuaries. Most of the area isflooded yearly to a depth of at least one foot.Inundation in the southern portions is morefrequent and longer lasting than in the north.Management of existing canals in the area providesa semblance of natural water flow to the coastalestuaries.

Predominant vegetation includes spikerush,beakrush, and sawgrass, typical of wet prairies.South of the C-111 canal, widely dispersed sloughssupport the growth of shrubs and stunted trees.The algal mat or periphyton is a dominant feature,and forms the foundation of the biologicalcommunity of the freshwater marshes. It also playsan important role as a water filtering agent and soilbuilder. The wildlife habitat value of this area isextremely high, and several endangered speciesinhabit the area. The overland flow of freshwatermaintains the valuable brackish water habitat areasand carries nutrients to the important fish andshrimp nurseries of the mangrove estuaries.

Environmental changes within this area havebeen primarily caused by drainage canals andalteration of surface flow, and by the Florida Powerand Light Company cooling system in the easternportion. Canal 111, in addition to its drainagefunction, was intended to be used as a waterway forbarge traffic. However, at the insistence of variousagencies and organizations, both public andprivate, Canals 109 and 110 were left with earthenplugs, thus preventing the drainage of thesevaluable wetlands, and C-111 was equipped withgated control structures.

Although the area has been altered by anumber of canals, levees and roads, it is still highlyproductive biologically. If no additional obstructionto sheetflow occurs, it can continue to function as awet prairie from which nutrient-laden waters flowinto the mangrove estuaries along the south andsoutheastern coast. This wetland is also vital as afeeding ground for animals inhabiting andprotected by Everglades National Park, but whichnest and feed in this area outside the Park.

The area is also important as a freshwaterrecharge area for prevention of further saltwaterencroachment into the aquifer. This function iscritical, since the intrusion line penetrates furtherinland in south Dade County than anywhere else inthe Region.

The Turkey Point nuclear power plant, andthe proposed South Dade nuclear facility site arelocated in the eastern portion of the area, andprecautions should be taken to limit developmentin their vicinity and monitor their impact in thisenvironment.

Much of the southern Everglades coastalmarsh has been designated as an EnvironmentalSensitivity Zone, or Conservation Zone by theDade County Comprehensive DevelopmentMaster Plan, and implementation of resourcemanagement objectives now underway by DadeCounty should adequately protect this area.These guidelines address varied environmentalconcerns (drainage, flood control, water qualityand quantity, vegetation) and reflect the area'sunique and vulnerable hydrological, soil andvegetative conditions.

Policies12. Future land use in the Southern Everglades

should be consistent with the area's highbiological value, recognizing the extremevulnerability of the area to flooding andhurricane damage.

13. Precautions should be taken to prevent furtherdisruption of the flow of surface water to theestuaries. Preservation of sheetflow is vital formaintenance of the area's endangered wildlifespecies and for the marine communities of theestuaries (fish and shrimp).

14. No new drainage canals should be permitted inthe coastal marshes as further drainage orchanged salinity will adversely affect importantbiological functions and ecosystems.

15. Limit inappropriate development inthe vicinity of existing and proposed nuclearpower facilities.

16. Implement the resource management guide-lines (environmental guidelines) proposed inthe Dade County Master Plan (Part 2) toprotect "environmental sensitivity zones" (i.e.Southern Everglades Coastal Marshes).These guidelines address varied environmentalconcerns (drainage, flood control, water qualityand quantity, vegetation) and reflect the area'sunique hydrological, soil and vegetativeconditions.

17. Restore, to the extent practical, the naturalwater flow disturbed by drainage structureswhich are unneeded where these obstructionsare detrimental to the functioning of the naturalsystem.

EVERGLADES NATIONAL PARKEverglades National Park was officiallydesignated in 1947. The original statute creatingthe Park directed that:

The land area or areas shall bepermanently preserved as awilderness, and no development ofthe project or plan for theentertainment of visitors shall beundertaken which will interfere withthe preservation intact of the uniqueflora and fauna and the essentialprimitive natural conditions nowprevailing in this area(16 U.S.C. 410c).Shark River Slough and the coastal

mangrove estuaries comprise the major portionof Everglades Park. Part of the water flow to theSlough, the major drainageway of the Park, hasbeen cut off by flood control levees and isregulated by control structures along thesouthern boundary of Conservation Area 3A.The timing and quantity of water allocated tothe Park from the Conservation Area has longbeen a subject of controversy. The effects ofdrydown or flooding that is out of phase withthe natural hydroperiod has caused habitatalteration, change in plant and animalcommunity, composition, and disruption orfailure of wildlife reproduction cycles. The Parkis dependent for its survival upon high qualitywater of sufficient quantity flowing from thenorth, timed to correspond to the life cycles andprocesses of the plants and animals.

Only the southeastern fringe of the BigCypress watershed lies in the Region, partly withinthe boundaries of Everglades National Park, andpartly in the area which has been designated forpurchase as the Big Cypress Freshwater Preserve.The eastern portion of the Big Cypress is relativelypristine - probably the most undisturbed portionof the South Florida peninsula - and is vital tothe continuing viability of the western part ofEverglades Park.

The entire southern Florida peninsula hasbeen vastly altered by drainage and flood controloperations during the past 50 years, which havechanged the water flow patterns and drained awaymuch of the surface water which would haveotherwise flowed to and through Everglades Park.Since the Park contains only a segment of theEverglades system, and the subsystems of theEverglades are so interrelated and dependent upon

the sheet flow of freshwater, the National Park doesnot include enough area to assure the preservationof even this small remnant of the total Evergladessystem. Conditions within the Park are profoundlyaffected by activities outside the Park and beyondthe control of Park officials. Land and watermanagement decisions around the National Parkwill determine the survival of this single"preserved" area of the Everglades ecosystem.

The major issue, then, is water supply to thePark, including quantity, quality, and timing.Its management is a challenge to decision-makersand institutions.

Policies18. Quantity, quality, and timing of water flow to

Everglades National Park should be as close tonatural conditions as possible, as an integralpart of the regional water management plan.

19. Land use in areas of the Shark Slough andTaylor Slough drainage basins which lie outsidethe Park boundaries should be consistent withsound management of the valuable biologicaland recreational resources of the Park and theFlorida Bay estuaries.

ESTUARIESHigh productivity, diversity of plants and animals,and unique environmental characteristics makeestuaries one of the most valuable natural systems.These areas, where fresh water from the land mixeswith sea water, provide a lower salinity nurseryground for many important species of sport andcommercial fish and shellfish.

The estuaries in the Region are locatedbehind long, narrow barrier islands. Biscayne Bay,including Card and Barnes sounds, is locatedin Dade and Monroe counties. Smaller estuarineareas in Broward County are connected by theIntracoastal Waterway. Many were freshwaterlakes and wetlands until the Waterway wasconstructed and various inlets were dug to connectto the sea.

The estuaries of Florida Bay and the Gulf coastare different from those of the east coast. They arepart of a complex swamp shoreline composed ofmany mangrove-covered islands. Numerousshallow rivers, sloughs, and tidal channels bringfreshwater from the Everglades and Big CypressSwamp to the many small estuarine water bodies.Unlike the highly urbanized east coast, thisshoreline is relatively natural, and west of BarnesSound it is part of Everglades National Park.

UPLAND ASURBANIZESEASTERN

EVERGLAISSOUTHEREVERGLA

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FIGURE4 o 4 8 12 16 20 24FIGUREMILESCCrrCnwI~ WLILAN AXLA

rrrESWAI Tlt WT I LANU AREASOF THE SOUTH FLORIDA REGION

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Value of EstuariesSub-tropical estuaries support a high degree ofbiological diversity and productivity, with complexlife patterns and closely interdependent species.Estuaries rank with tropical rainforests and coralreefs as highly productive ecosystems. They areusually more productive than either the seaon one side or the freshwater drainage area on theother. This high natural productivity is due to acombination of characteristics.

Shelter: An estuary is protected fromwave action, allowing bottom dwellingorganisms to attach, seagrasses and algaeto become established, and nutrientsand floating organisms to remain. Lowersalinity also deters marine predators.Large ocean predators are deterred by theshallow depth.

Sunlight: Shallow depth allows lightto penetrate to the bottom, supportingphotosynthesis by bottom vegetation.Turtle grass and other seagrasses are themajor primary producers in the foodchain of warm-water estuaries.

Salinity: The reduced salinity of theestuarine environment provides suitablehabitat for young of the many marinespecies which cannot survive oceansalinity as juveniles.

Nutrient storage: Nutrients aretrapped within the estuary in the stemsand leaves of plants, and later slowlyreleased as detritus (tiny particlesproduced as the plant parts are brokendown by fungi, algae, protozoans,and small shellfish).

Tidal Zone Vegetation: Anotherimportant source of nutrients is thedetritus originating in tidally flushedmangrove swamps and coastal marshes.The small organisms which break downthe detritus are a vital link in the foodchain. The most productive part of theestuarine nursery is the tidal zone andadjacent shallow water zone. This is alsothe first part of the estuary to be effectedby land-based activity.

Tidal Action: Detritus, nutrients,small organisms, and waste are swept outof the intertidal zone by the tide, andtransported to other parts of the estuarinesystem. Tides also eventually carry excessnutrients to the sea, where they are usedin offshore systems.

The interaction of sea, land, tides, and sunlightin estuaries creates some of the richest foodproducing areas in the world. The system is basedon the detritus mentioned above - nutrients fromdecaying vegetation. In the North River estuaryof the Everglades, biologists found that detritusaccounts for 80- 90% of the food of crabs, worms,insect larvae, and small fishes. These smallanimals in turn are the food for over sixty juvenilefish species which depend on the estuarineenvironment for part of their life cycle. Amongthem are tarpon, snook, ladyfish, and gray snapper.Other game fish which use the mangrove estuariesare sea trout, crevalle jack, and jewfish. Shrimp arealso detritus feeders, as are mullet and blue crab.

Estuarine value can be partially measured inthe economic yields of the tourist industry andcommercial fisheries. In 1969, Florida tourists spent$5.5 billion on sport fishing - almost one quarterof personal income in the State. The NationalMarine Fisheries Service found that the value ofcommercial marine landings for 1972 was $57million, and in 1973 statewide income from shrimpalone exceeded $26 million.

All components of the estuarine system, andtheir interactions, must be considered to protectestuarine function:

Protection of estuarine resources dependsnot on the protection of a point (grassflat)but on the protection of a process.(Marshall)Protection of estuarine systems can be

facilitated by establishing a 50' coastal constructionsetback in estuarine areas. This would allow for anatural vegetative buffer between the mean highwater line and any structures. This vegetativebuffer, 50' landward of the mean high water level,will cleanse upland run-off before it entersestuarine waters, provide for shore stabilization,and protect life and property.

The main components of estuarine systemsdiscussed below are:1. The tidally flushed mangrove or coastal marshes2. Marine grassbeds and other bottom vegetation3. The water body itself.

ESTUARINE MANGROVE ANDCOASTAL MARSHIn southern Florida mangroves occur intermittentlyalong the entire coast, primarily in quieter estuarinewaters. Coastal marshes are found adjacent to themangroves, but are more common in northernFlorida, where frost limits the spread of mangroves.

In southern Florida, both mangroves and coastalmarshes cover large areas because they are able towithstand contactwith seawater.

The term "mangrove" refers to tree species notclosely related but generally found in the mangroveforest. There are many species of mangrove, butthe only three found in southern Florida are the red,the black, and the white mangrove.

Red mangroves usually occupy the outer orseaward zone. They are distinctive in appearance,with arching prop roots projecting from the trunkor branches down into the water. They producecigar-shaped seedlings that sprout while attachedto the parent tree, and after they drop into the waterand float away, they become rooted if caught indebris or in a mudbank in shallow water. Redmangroves can grow in shallow offshore areaswhere the roots are always under water, or onshorewhere the soil surface is barely under water at thehighest tide. The seedlings can also be carried farinland, where they may grow in dwarf form inisolated clumps, or up tidal rivers where they formtall forests in the floodplain.

The middle zone, at slightly higher elevations,is dominated by black mangrove in associationwith salt marsh plants. This zone is usually floodedduring high tide. Black mangroves may some-times be found at the edge of the water with nointervening band of red mangrove. Often thesetrees are old and large, remaining after the redshave been washed away by a storm.

The most landward zone is affected onlyby the highest spring and storm tides. The whitemangrove is found here in association withthe buttonwood (not a mangrove) and marshvegetation.

Estuarine mangroves perform several valuablefunctions. Their leaves are a major source ofnutrients for the many estuarine-dependent animalspecies, particularly sport and commercial fishesand shellfish.

They also act as soil-builders. Mangroveforests are associated with deposits of peat. Theleaves that fall on the soil decompose and arereduced to detritus in about a year, or are washedaway by tides. The roots, however, resist decay insaturated soil, forming peat that has been found todepths of 12 feet. These deposits have kept pacewith the rising sea at a rate of 1 inch each hundredyears.

The mangroves, in their role as buffers tostorm winds and tides, prevent devastation of thecoastline by absorbing the energy of storms.This protects the upland, but in the process the

mangroves may be damaged or destroyed. In somecases natural recovery takes place, but in othersa new shoreline replaces the old. Where uplanddevelopment needs protection, carefulmanagement of the mangrove forest is necessary.

One form of management is the planting ofmangroves in new areas, as was done to stabilizeportions of the Florida Overseas Railway causeway.Numerous experimental plantings have beensuccessfully started in South Florida and elsewhere.

Experimental work by the Florida Departmentof Natural Resources in Tampa Bay showed that theblack mangrove is at least as important as the red inshoreline protection and land building. The blackmangrove has the added advantage of beingtolerant to lower temperature as well as to adversesoil conditions, such as may be found in man-madeshorelines. It can also tolerate some covering bypumped materials by producing new sprouts, andit can survive heavy top damage by hurricanes orfrost. It is also quicker to develop a root system toprotect the soil from erosion. Both red and blackmangroves respond well to pruning, whichsuggests that they could be used as waterfronthedges, even to protect seawalls or possibly replacethem.

Where possible, mangroves and theirassociated upland should be left alone to performtheir protective functions. Generation andregeneration of mangrove forests occurs onwilderness shorelines without the interference ofman, but where impacted by human activity,problems arise. Florida mangroves, however, arewell suited for careful management. The redmangrove is recognized as the most importantspecies for fisheries productivity. It also serves as asoil producer and stabilizer as well as a storm buffer.The black mangrove is important for shorelinestabilization, both as a secondary defense behindthe red mangrove, and because its root systemdevelops more rapidly than that of the red.Policies20. To provide for shore stabilization, cleanse

upland run-off, and protect life and property,the State should establish a constructionsetback line for estuarine shorelines, similar tothe existing State program (Ch. 161, E.S.) forbeach and dune setbacks. This setback lineshould be a minimum of 50' upland of the mostlandward mean high water line (consistent withCh. 161, ES.) unless an analysis of topography,vegetation, and other environmentalcharacteristics indicates a more appropriatesetback.

21. Route surface runoff in the upland throughgreen swales, ponds, mangroves and othervegetated buffer zones before release intoan estuary.

22. Locate marinas in upland rather than wetlandareas, preferably adjacent to existing waterbodies. They should be designed to take fulladvantage of tidal exchange. Deposit spoilexcavated for construction or maintenanceupland, not in wetlands.

23. Slope perimeters of marinas, canals, and otherartificial water bodies to minimize slumpingand erosion. If stabilization is required, riprapof indigenous rock rubble should be used toprovide a relatively natural surface on whichmarine organisms can grow.

24. Where development in upland mangrove areasis deemed acceptable, selective clearing canmaintain water quality and natural productivityof the mangrove system, while allowing theupland area to be developed. Mangrovesseaward of the mean high water line areprotected by state law. Selective clearing inmangrove and marsh areas should followthese minimum guidelines until the State candevelop performance standards.A. Leave tidally flushed mangrove forest

intact, with a landward buffer strip at least50' wide.

B. Riverine forest. Where there is some tidalflushing, leave tall red mangroves intact,with a landward buffer at least 50' wide.Channels may be cut through to increasetidal flushing. Where there is no flushing,the tall red mangroves may be selectivelycleared without affecting most marinesystems.

C. Fringe forest. Along the coast, andbordering canals and streams, leave fringingmangroves intact in a buffer zone at least 50feet inland of the mean high-water line.

D. Dwarf forest. Leave dense areas borderingthe coast and canals intact, as in the fringeforest. Tidal .channels may be cut throughthe forest and may actually increaseproductivity. Where growth is sparse andtrees are so far apart that their branches donot touch, dwarf mangroves are not veryproductive and do not contribute "significantly to the marine environment.

E. Coastal marsh. Preserve buffer zones similarto those recommended for the mangrovesin the coastal marsh. Leave 50 foot buffer ofmarshland inland of all water bodies andstreams.

25. Avoid lake excavation, sewage disposal andrefuse disposal in estuarine mangroves orcoastal marshes. In all areas seaward of the 1000isochlor line (groundwater), allow theseactivities only after careful consideration ofeffects upon saltwater intrusion and waterquality.

MARINE GRASS BEDSThe major submerged plant and animalcommunity in estuaries is associated with seagrasses. These include turtle grass, Cuban shoalgrass and manatee grass, as well as interspersedclumps of marine algae. Their location depends onwater depth, with denser zones found near theshore. A complex assortment of algae are foundgrowing on the older sea grass blades, and togetherwith the grasses, are a source of primaryproductivity that exceeds that of the mangroves.

Many estuarine life forms are part ofthe marine grass community, or dependent onit, including shrimp, sea urchins, conch, seacucumbers, molluscs, fishes, turtles, and manatee.The food web starts with photosynthesis by thegrasses, followed by growth of algae anddecomposition of old blades, their consumption bybottom-dwelling organisms, which are consumedin turn by larger fishes. Many of the bottomanimals are filter feeders that keep the water clear,while processing the remains of decomposition.

Sea grasses are vulnerable to human activity,and management is necessary to prevent loss of thediverse and productive estuarine communityassociated with them. Their importance to marinefisheries is not as well studied as that of mangroves,but is thought to be similar or greater.

Dredge and fill activities have the greatestimpact on sea grasses, but thermal effluents,sewage, oil, heavy metals, and pesticides also affectthem adversely. Since seagrasses are densest closeto shore, they are affected first by land basedactivities in estuaries. Binding and stabilization ofbottom sediments is an important function ofseagrasses. Where they have been destroyed orremoved, re-establishment has been successful inexperimental plantings in Biscayne Bay. Their usein stabilization of borrow areas and canals is also apossibility.

Dredging in estuarine waters is usually done tocreate or maintain canals, navigation channels,turning basins, harbors and marinas, for layingpipelines, as a source of material for fill, or to createconstruction sites. Since estuaries are much moreproductive than the open ocean, providing foodand shelter for most species of commercial and

WORLD DISTRIBUTION OF PRIMARY PRODUCTION

MUUN FTAIN FORESTS I t jCONTINETALSOME AGRICULTU. -' SHELF WATER -.MOIST FORESTS 9

SECONDARY COMMUNITIES OME ESTUARIES, SPRINGS,CORAL REEFSHALLOW LAKES TERRESTRIAL COMMUNITIES ON ALLUVIAL PLAINS

MOIST GRASSLANDS AGRICULTURE ENERGY - SUBSIDIZED AGRICULTURE

The world distribution of primary production in terms of annual gross production (in thousands of- kilocalories per square meter) of major ecosystem type. Only a relatively small part of thebiosphere is naturally fertile. (After E.P. Odum, 1963.)

GROSSPRIMARY

AREA PRODUCTIVITYECOSYSTEM (I 06KM2)(KCAL/M 2/Year)

MAR/NEOpen ocean 326.0 1,000Coastal zones 34.0 2,000

*Upwelling zones 0.4 6,000Estuaries and reefs 2.0 20,000SUBTOTAL 362.4 -

TERRESTRIALDeserts and tundras 40.0 200Grasslands and pastures 42.0 2,500Dry forests 9.4 2,500Boreal coniferous forests 10.0 3,000Cultivated land with little or no energy subsidy I 0.0 3,000Moist temperate forests 4.9 8,000Fuel subsidized (mechanized) agriculture 4.0 12,000Wet tropical and subtropical (broadleaved evergreen) forests 14.7 20.000SUBTOTAL 1 35.0 -TOTAL for biosphere (not including ice caps)( round figures) 500.0 2,000

ESTIMATED GROSS PRIMARY PRODUCTION (ANNUAL BASIS) OF THE BIOSPHERE AND ITS DISTRIBUT-ION AMONG MAJOR ECOSYSTEM

FIGURE 5COMPARISON OF ESTUARINE PRODUCTIVITY WITH OTHERECOSYSTEMSSOURCE= E.P. ODUM, 1971

sport fish, the effects of estuarine dredging aresimilar to but more serious than those of offshoredredging:* Removal of the bottom sediments removes plant

and animal habitat.* Sedimentation reduces the productivity of

biological communities by lowering oxygenlevels.

* Turbidity inhibits photosynthesis by reducingwater clarity.

* Water pollution is increased when dredgingactivity stirs up bottom sediments that haveabsorbed many kinds of pollutants, includingheavy metals and pesticides from canals andboth urban and agricultural runoff.

* Creation of basins or channels by dredging alsochanges water circulation, eventually causingchanges in water temperature, salinity, dissolvedoxygen, sediment accumulation and ultimatelyproductivity.

Channel and basin dredging necessarilyproduces spoil that has to be disposed ofsomewhere. Spoil disposal through sidecastingin estuarine waters or through direct disposalin offshore ocean waters can smother bottomorganisms and lower oxygen levels, which reducesthe productivity or even kills bottom communities.Extensive disposal in a given area, particularly inestuarine waters, can cause shoaling and adverselyaffect water circulation. Open water disposal canalso increase turbidity and sedimentation. If thespoil is polluted, its release in open water will causeoxygen depletion. Polluted spoil may also be toxicbecause of the presence of heavy metals, pesticides,and other chemicals.

While the creation of spoil banks or islandsmay reduce subsequent sedimentation, thismethod of spoil disposal is directly destructive ofwetlands or bottom communities. Spoil banks orislands adjacent to navigation channels may alsoadversely affect water circulation. In addition, thesedisposal areas may be aesthetically unpleasingand produce obnoxious odors.

Policies26. Align navigation and access channels to

avoid shellfish beds, seagrass flats, or otherproductive areas whenever feasible andwith preference for degraded areas.

27. New canals and channels should be dredgedonly when in the public interest and to provideaccess to common marina facilities with.publicaccess and should be designed to maximizeflushing action.

28. Prohibit new finger-fill canals, or other canaldesigns which result in stagnant water.

29. When repairing existing bulkheads, place rockriprap seaward of the repaired bulkhead, to aheight appropriate for local tides in order toprovide a more durable shoreline. This providesa surface suitable for estuarine plants andanimals to become established. It also reducesthe force of waves, thereby reducing erosionand allowing marine grasses to becomeestablished.

30. Plant mangroves in rip-rap, where practical.31. When favorable conditions are re-established

replant marine grasses in areas where theyhave been destroyed by dredging or bypollution.

32. The cumulative impacts of numerous smallprojects should not be overlooked. Thedredging and bulkheading of a thousand feet ofshore and bottom in one large development isno more harmful than a dozen small projectscovering a similar length. Small projects shouldbe reviewed in the context of a managementplan which addresses the problem ofcumulative effects, and considers existingconditions on a large-scale basis, and notproject-by-project as applications are filed.

33. In order to minimize the necessity or pressureto alter viable natural shoreline areas, requireboat dockage facilities as shorelineredevelopment occurs, and where conditionsare already suitable.

ESTUARINE WATER QUALITYThe alteration of drainage patterns by canals hashad important effects on coastal estuaries. Prior todrainage, freshwater reached the coast by overlandflow, through the wetlands of the Everglades orthrough the transverse glades of the lower coastalridge. Other wetlands, drained by the natural riversof the Region, slowed the flow and cleansed thewater before it reached the estuary. Freshwaterflow was more evenly distributed, both spatiallyand over time.

Canals now channel freshwater rapidly tothe coast and into the estuaries according to floodconditions in the interior and capacity for backpumping into the Conservation Area and LakeOkeechobee. The canals thus become concentratedsources of freshwater which enters the estuaries in"pulses," depending on artificial regulation, ratherthan in rhythm with the seasonal rains.

The first spring rains wash over the landsurface, carrying the dry season accumulation of

pesticides, oil and grease, coliform bacteria, andother substances to the canals, some of which stillserve as receiving waters for sewage outfalls. Theseartificial waterways, in turn, carry the water rapidlyto the coastal control structures, and into estuarinewaters. As spring rains continue, it becomesnecessary to open the control structures to regulatewater levels inland. This releases a "pulse"of water and sediments which may contain heavyconcentrations of nutrients, trace metals andpesticides.

Estuarine water quality depends on acomplicated balance between the rate of pollutantinputs and the rate of their removal. Rate of input isa function of polluted runoff from the land, andwater quality management. Removal rate dependson the capacity of the estuary to assimilatepollutants, and on its flushing rate.

Studies in Biscayne Bay by Lee and Rooth,show that shallow bays are very poorly flushedby tides. The result of limited flushing is thatpollutants discharged into the estuary willaccumulate there, and pollutant removal dependsprimarily on the assimilative capacity of theestuarine system itself. A healthy system withadequate populations of shoreline and bottomplants and animals can assimilate limited amountsof pollutants. When the number of plants andanimals is reduced or when there are morepollutants than they can assimilate the waters maybecome turbid and nutrient laden, with the seriousdegradation indicated by algal blooms, odors,fish kills and low species diversity.

Alterations which decrease the ability of anestuary to assimilate pollutants include:* Removal of mangrove or coastal marsh vegetation.* Destruction of bottom vegetation, such as sea

grasses, by dredging, filling, changes in salinity,temperature, or bottom scouring by currents(such effects may result from new inlets orchannels).

* Changes in circulation and/or salinity, resultingfrom construction of causeway fills or spoilislands, or changes in inlets or in the amount orrate of runoff from the land.

* Destruction of plants and animals by introductionof toxic substances or smothering by dredgespoil.

* Reduction of plant photosynthesis due toincreasing turbidity of the water, throughdredging or boat traffic.

Canals are a major source of estuarinepollution. A study of the Environmental ProtectionAgency made a comparison of the nutrient load ofBroward County sewage outfalls with that of its

primary canals, which discharge to the estuarinewaters of the Intercoastal Waterway. The totalnutrient load carried by the canals is about 10,000pounds per day, while that of the Pompano andHollywood outfalls is only about 3,000 poundsper day. These findings emphasize the importanceof ending the pollution of inland canals if theestuarine environment is to be protected.Policies34. Design and implement a county level sampling

program for estuarine waters to monitor trendsin water quality, to measure the effectiveness ofpollution abatement programs - nonpoint aswell as point sources - and to serve as earlywarnings in areas where pollution may not besuspected.

35. Manage the canal system to minimize theadverse effects of canal discharge on estuarinewaters.

36. Water management agencies should addressthe issue of timing and quantity of freshwaterflow. Concentrated pulses of freshwater havean adverse impact on an estuary, acting as apollutant, particularly in those which havelimited circulation or which are naturallysomewhat saline. If the productivity of theRegion's estuaries is to be protected orenhanced, a more natural freshwater regimemust be re-established.

BEACHES ANDBARRIER ISLANDSThe southern tip of the Florida peninsula issurrounded by hundreds of islands. They can begrouped into three categories:1. The sedimentary barrier islands of the east coast,

extending from Key Biscayne north.2. The Florida Keys, a chain of coral and oolitic

rock islands extending from Soldier Key southto Key West.

3. The Ten Thousand Islands and the islandsof Florida Bay, along the southern and westerntip of the peninsula.

In geological terms, a barrier island is a long,narrow, offshore sandbar or bank. The ocean side isgenerally a beach area with adjoining sand dunes,and the landward side is an estuary or tidal lagoon.These highly mobile sand banks shelter themainland from the severest impact of ocean wavesand storms, and are maintained by vegetationacting against the forces of wind, storms, currents,and wave action.

A(NATURAL) scrub forest

B(BULKHEADED)

DISTANCE FROM SHORE (Ft.)

"Bulkheading" destroys the most important part of the estuarine "nursery ground"andencourages the building of housing developments that are vulnerable to hurricanes

and other storms. Diagram redrawn from Mock (1966),who reports that 10 months of

Intensive sampling yielded 2.5 times more brown shrimp and 14 times more white shrimp

(the two chief commercial species) from a natural area in the Texas estuary (A in the

diagram) than could be harvested from a bulkheaded area in the same estuary(B in thediagram).

FIGURE 6EFFECTS OF THE DESTRUCTION OF ESTUARINENURSERY GROUNDS

SOURCE: E.P. ODUM,1971

- -

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)0

The islands of Key Biscayne, Virginia Key, andMiami Beach were formed by deposition of sandover a rock base which is a submerged extension ofthe Florida Keys formation. North of Miami Beachthe "islands" are separated from the mainland bythe Intracoastal Waterway, a canal which was dugto provide an inland navigation route along thecoast. The Waterway connected various smallinland lakes and wetlands (some formerly freshwater), producing an artificial estuarine system aswell as navigable waterway. Although classificationof the latter islands as true barrier islands isquestionable, the natural forces now operating aresimilar.

Value of Beaches and Barrier IslandsBarrier islands, beaches and dunes occupy a verysmall part of the Region's land area, but are soattractive and desirable that they have become thesymbol of the regional way of life. Beaches form anarrow band along the seaward side of barrierislands; behind them are found coastal strandforests, and wetlands of estuarine waters.

A study by the State Division of Recreationand Parks reported that most tourists have definiteexpectations of the vacation experience that avisit to Florida will provide. Outdoor recreationexperiences are the type most desired, and beachesare mentioned most often - by 76 percent of thosearriving by auto and 56 percent of those arrivingby plane. It is essential to the Region's economy tocontinue to provide this type of experience andenvironment, and to protect barrier islands andbeaches from further damage and erosion.

In addition to their traditional role as recreationsites, beaches and dunes also serve to protectupland development. They are built and rebuilt bythe forces of ocean currents, storms and tides. Theyare essentially temporary, since the forces that builtthem can also alter them beyond recognition -sometimes during a single storm.

Needs for public beach facilities are increasingfaster than the population, as increased leisure timeand mobility allow a greater amount of use perperson. The problems which must be addressed,therefore, are twofold: first, both public and privatebeaches should be protected from erosion andpollution; second, public access and/or acquisitionof beachfront land should be increased to meetincreasing demand for resident and touristrecreation.

Barrier islands are dynamic systemsmaintained or altered by the interaction of:* vegetation* wind, storm, and wave action* currents* sea level rise

* availability of sand* biological activity, including man's

A barrier island system is ever-changing.During the season when the longshore currenttransports sand grains toward the south, thenorthern end of the island tends to erode, whilesand is deposited to the south. Although at anothertime of the year the process may be reversed, inFlorida the dominant direction of sand flow issouthward. Under natural conditions, erosion fromone island or sand bar means deposition else-where. Beaches and dunes store sand for naturalmaintenance and replenishment. A storm mayremove sand from the beach, and simultaneouslymove sand from the shifting dune to replenish thebeach. Then wind action gradually restores thedune.

The sea is rising at a rate of about .01 inch peryear (one inch per hundred years) and as waterdepth increases waves reach further inland, andwith them, erosion. For a given rise in sea level, theseaward shoreline may retreat a distance two orthree times that magnitude. For example, with anocean rise of one foot the island would retreat 100 to1,000 feet per century - a significant distance.Erosion of barrier islands is accelerated by stormwinds and tides.

A major source of sand for Florida barrierislands is quartz sand washed down from themountains of Appalachia and transported to thecoast by the rivers of Georgia and South Carolina.From the river mouths it is swept southwardalong Florida beaches by the longshore current.Reservoirs and dams constructed on theserivers have restricted the flow of quartz sand and,with the source reduced, Florida beaches areexperiencing a net loss of sand. The quantity ofsand moving past given points is shown below.Note that the further south the lower the amount.

ESTIMATED NET LITTORAL DRIFT RATE:FLORIDA-GEORGIA LINE TO KEY WEST

Net average annualLocation drift rate

(cubic yards)St. Johns River, Duval County 500,000Ponce de Leon Inlet 500,000Canaveral Harbor 350,000Fort Pierce Inlet 200,000-250,000St. Lucie Inlet 230,000Lake Worth Inlet 230,000Hillsboro Inlet 120,000Port Everglades 50,000Ocean entrance, Miami Harbor 10,000Key West Negligible(U.S. Army Corps of Engineers)

BERM

M.H.W.

Profile B-INITIAL AT'I'ASTORM WAVES

.l,>.\ PROFILE A

- EROS/ON ^STORM TL E M. LW

le C - STORM WA:E " : :.ATTACK OF FOREDUNE : : -MA.W

ACCRETIONPROFILE A

STORM

ACCRETION

FIGURE 7DIAGRAM OF STORM WAVE ATTACK ON BEACH AND DUNESOURCE: U.S. ARMY CORPS OF ENGINEERS

1971

I

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Inlets play an important part in barrier islanddynamics. The area around an inlet is unstable, andrapid large scale changes can occur, causing existinginlets to migrate or close entirely, and newones to open. Dredging and stabilization projects,necessary to maintain navigation, interfere withnatural inlet processes which are important tobarrier island maintenance. Jetties built to preventshoaling of inlets cut off the southward flow ofsand, causing sand to accumulate north of the jetty,but eroding the downstream beaches. Sandtransfer facilities, which pump the accumulatedsand across the inlet to the eroding side, can helprestore some semblance of natural sand transport.

The beach itself is very tolerant to recreationaluse. Foot traffic will not harm it, and it can be safelyused for the traditional activities of swimming, sunbathing, fishing, and strolling. It is important toallow enough room between structures and theshoreline so that if natural erosion occurs, naturaldeposition can restore the beach without harmingstructures in the process.

The dunes, both primary and secondary, areextremely fragile. The stabilizing vegetation mustbe maintained since even a small break in plantcover can be quickly enlarged by the wind until amajor break is formed. No clearing or majorstructures should be allowed. Foot traffic alsodestroys dune vegetation, but this can be preventedwith raised walkways across the dunes.

Behind the stable secondary dune, conditionsare favorable for upland vegetation to becomeestablished. If mature trees exist landward of thesecondary dune it is an indication that stabilizationhas occurred and the secondary dune, ifundisturbed, will continue to provide protectionagainst ordinary storms and tides; however,unusual storm conditions still cause destructionfrom time to time.

Because of their aesthetic and locationalattractiveness, the pressures of urbanization areenormous, and barrier islands have beenintensively developed. High density developmentas close as possible to the ocean is a continuingthreat. Efforts to place permanent and stablebuildings on the shifting, moving barrier beachplace man in direct conflict with these naturalforces.

The National Shoreline Study (U.S. ArmyCorps of Engineers, 1971) designated all of thebeaches of the Region as areas of significant orcritical erosion. The barrier island system survivesby its flexibility. Unfortunately, when property lines

are drawn and buildings built, property ownerswish to halt the natural processes which maydiminish their holdings. Many engineeringsolutions have been attempted, but their effect hasgenerally been to increase erosion. Groins andjetties block the littoral drift of sand, starving thebeaches downstream. These structures temporarilyimprove the upstream situation, but storm tideseventually carry the excess sand out and over theedge of the continental shelf, where it can no longerbe picked up and redeposited by subsequent waveswells. While a naturally sloping beach dissipateswave energy, a vertical sea wall deflects the energydownward, creating a scouring action near thebottom of the wall. This causes the underminingand eventual collapse of the wall. The same is trueof foundations of buildings constructed too close tothe shore. Poorly located channel cuts create similarconditions and can cause erosion of the shorelineand collapse of onshore structures.

The effect of these processes are accelerated onthe beaches of the Region. The bottom slope ismuch steeper here, and the continental shelf is onlytwo or three miles wide. Even under naturalconditions, some of the southward flow of sandwould be lost off the edge of the shelf into the depthof the Florida Straits. This would be tolerable if thebeaches were still being replenished naturally;however, the northern sources of sand are beingcut off. Therefore, it is imperative to conserveexisting beaches. Planning strategy in the coastalenvironment must recognize the dynamics ofbeach and dune formation, and maximize thesenatural defenses. Once they are destroyed,man-made defenses must be substituted, and theseare expensive and do not provide long-termsolutions.

Beach and dune restoration is extremely costly.Costs have been as high as $1,000,000 per mile, withyearly maintenance costs up to $100,000 per mile.If the conditions that caused the original erosionremain unchanged, restored beaches will belost again.

Beach restoration operations can also destroysea bottom contours near shore which would havetrapped eroded sand until the next storm carried itback to the shore. Dredging and resultant siltation,associated with both urban development and beachrestoration projects may destroy shell beds, whichare a prime source of new sand, and bottomvegetation, which stabilizes sediment contours andreduces sand loss. The Crandon Park-Virginia Key

restoration project in Dade County was followed byloss of 50 percent of the near shore sea grass bedssince 1969.

Despite these adverse impacts, beach res-toration and nourishment is probably the mostacceptable shore protection method in areaswhich are already developed.

On the landward side of barrier islands there isgenerally an enclosed shallow estuary whichseparates the mainland from the island. Thesesensitive estuarine waters afford food sources formarine life, as well as nesting and feeding area formarine birds. In South Florida, particularly, theseareas are ecologically valuable as well as vital to theeconomic viability of commercial and sport fishing.Threatened by intense development, theseestuaries and mangroves are frequently destroyedby dredging and filling, and other associatedbuilding activities.

In addition to problems associated withnatural systems, the man-made infrastructure isan issue of concern on the barrier islands. Themajor problems include obtaining adequatedrinking water, sewage treatment facilities, andtransportation access to the islands. The hazard ofstorm destruction of life and property wheredevelopment has taken place is another problem inmanagement and protection of the barrier islands.

The necessity of comprehensive man-agement strategies is emphasized by the fact thatpublic funds and programs have inadvertentlycontributed to stimulate development on barrierislands. Examples are three major Federalprograms: flood insurance, which has madebuilding in high-risk coastal areas more attractive;Environmental Protection Agency fundingof sewage treatment plants; and the granting ofbridge permits by the Coast Guard.Policies37. Manage barrier islands, beaches, and dunes to

protect them from damage and erosion, topreserve their value to tourism and recreation,and to maintain their ability to protect uplanddevelopment.

38. Locate development sufficiently back from andabove mean high water to insure optimumprotection from flood damage, and the leastpossible harm to natural beaches, dunes, andvegetation which can help protect against suchdamage.

39. Development on islands should not be

encouraged unless sufficient public facilitiesand flood hazard protection (includinghurricane shelter or evacuation routes) areavailable.

40. Public access and acquisition of beachfront landshould be investigated as a major strategy forenhancing tourism and thus the viability of theregional economy as well as meeting the needsof residents.

41. Coastal erosion management and controlshould give preference to strategies whichare imitative of natural processes. Beachnourishment, restoration and dunestabilization projects should be givenpreference over jetties, groins, seawalls,and other structural approaches.

42. Proposed beach restoration projects should becarefully evaluated to avoid damage to viablereef areas. Project design should include asminimum objectives:a) adequate pre-dredging surveys of the

biological value and amount of availablesand in the proposed dredging site; and

b) monitoring throughout the project, todetermine the quality and suitability of thedredged material, and to prevent damageto biologically valuable areas.

MARINE WATERSThe continental shelf is narrow off the coast ofsoutheast Florida, ranging from a maximum ofabout 65 km (40 mi.) off Cape Canaveral, narrowingto about 3 km (2 mi.) off Palm Beach. South of PalmBeach it roughly parallels the coastline, graduallywidening again east of Miami and south of theFlorida Keys. Throughout the Region, the shelf ischaracterized by reef communities of great diversityand productivity.

It was formerly thought that the Florida reefsterminated in the northern Keys because of thelower temperatures and sand drift found north ofMiami. More recent investigations, however, haverevealed reef-like structures parallel to the fulllength of the southeast Florida coastline. The exactnature of these structures is not known. They maybe true coral reefs, or they may consist of a recentlyformed coral veneer over rock formations.Investigation of the geologic structure of theseridges is not yet complete, but biologicinvestigations reveal a well developed coral

community extending beyond the northernboundary of the Region.

The typical zonation of the south Florida reefsis shown in Figure 7. The back reef zone includesthe reefs closest to shore, and is not as welldeveloped as the outer reefs. In many places thefirst reef is composed of beach stone or coral rubble,with few living components. It has not beendetermined whether these were once healthy reefsthat have deteriorated, or if natural conditions havealways prevented full coral development in theback reef zone. There are well developed back reefs300 feet off the highly urbanized coast of the FortLauderdale-Pompano Beach area, but the ones offBoca Raton consist mostly of beach rock.

The patch reef is usually separated from thefirst or back reef by a wide intervening zone ofmostly barren sand. The shifting of this sand bed bystorms may cover considerable portions of patchreef. The stress of this environment may be thereason that the corals of the patch reefs are smallerand not as well developed as those on the outerreef. The patch reefs are also greatly affected bybeach restoration projects, since the usual sourcesof dredge sand are the sand pockets and bedssurrounding the patch reefs.

The outer reef, usually separate from the patchreef by another zone of sand beds, is at the edge ofthe continental shelf, where reef growth is best.Here currents and wave action create amplecirculation to oxygenate the water and bringessential nutrients.

Value of Marine SystemsLiving coral reefs are an extremely important partof the marine system of the continental shelfof southeast Florida. They are among the mostproductive of all ecosystems, and many sport andcommercial species of fish and shellfish dependon the reefs for food or shelter.

The reef is built by colonies of small, flower-likeanimals - coral polyps - that secrete calciumcarbonate (limestone) to create a protective shelterfor themselves, and thus form the solid structure ofthe reef. They need clear, relatively shallow waterto allow penetration of sunlight, and a fairly stablewater temperature. They survive best wherecurrent and wave action is high. The edge of thecontinental shelf in the western Atlantic satisfiesthese requirements and corals are found fromBermuda to Brazil.

Worm rock reefs (vermitid reefs) also occur inthe Region. Often pieces of these reefs are broken

off and washed ashore, and the fragments havethe appearance of fossilized "spaghetti." They areprevalent locally in the inshore zone in Browardand Palm Beach counties, and in Florida Bay. Theyact as barriers to beach erosion, and, like coral reefs,provide a habitat and food source (in the larvalstage) for numerous marine organisms.

Coral reefs create a habitat suitable for manyother life forms. Reef communities together withestuarine systems produce many of the fisheryspecies of southeast Florida. Species which spendtheir juvenile stages in the estuarine mangroves orsea grass beds may also depend on the reef inlater stages of their life cycle.

The economic value of the reefs can bemeasured in commercial fishery productivity,income from sport fishing activities, and in theincome from tourists who come to view and enjoythe spectacle of reef life. In Monroe County alone,the market value of commercial fishery productsin 1973 was estimated by the Division of StatePlanning to be between $70 and $90 million. Inaddition, the value of sport fishing to the Keyseconomy was about $25 million annually. The reefalso attracts tourists, and in 1973 John PennekampCoral Reef State Park alone recorded 376,000visitors.

The reef also functions as a natural breakwaterand sand trap. Both normal currents and tropicalstorms create wave forces that can erode theupland. The wave energy is considerably reducedas the surge passes over the reef. The coral headsand reef structure may be broken and damaged, buta living reef can repair itself over time. A dead reef,on the other hand, erodes and disintegrates. Waveand storm damage will then increase on the shore.

Another function of the reef is the trapping ofsand in the depressions landward of the outer reef.These sand beds serve as reservoirs for naturalbeach renourishment, and sands in waters less than30 feet deep are carried back inshore as part of thebeach cycle. Where the continental shelf is narrow,as it is in southeast Florida, sand eroded from thebeach is often lost to the deep ocean trenches if nottrapped by the various reef structures. Capturedand retained by the living reef, the sand can berecycled naturally to the beach by ocean currents orstorms, or will remain available for artificialrenourishment. Most artificially restored beacheserode significantly after renourishment and someof the lost sand can be redredged from the sandbeds near shore, if reefs are there to trap it.

The reefs of South Florida may be at thenatural limits for reef growth. Temperature isknown to be a limiting factor for coral reefs ingeneral. This natural stress, when increased bystress from human activity, may be beyond thelimits of reef survival. If the coral animals die, sodoes the reef community. The other reef inhabitantsleave if they are mobile, or die if they are attached tothe bottom. Much localized reef damage has beendone by collectors of coral or tropical fish. Pry barsand blasting, although prohibited, have been used,and boat anchors can tear away large pieces of reefat a time. Sewage outfalls located in reef areasdestroy the reef community, which is smothered bythe effluent and replaced by a brown hairlike algalgrowth and a few sewage-tolerant marine worms.

Aside from this significant but localizeddamage, there are extensive areas where the reefsare dying from unknown causes. A study by theFlorida Coastal Coordinating Council describedareas in the Keys where over 80 percent of reefcorals and 77 percent of other life forms were dead.Since the northern reef tract has not yet been aswell-studied as the Keys tract, it is not knownwhether similar damage is occurring.

Some authorities point to siltation fromnear-shore dredging and silt-laden runoff fromupland clearing and development as a cause of reefdecline. Sediment released by such activities canphysically smother the coral, interfering withphotosynthesis by substantially decreasing thepenetration of sunlight. Turbidity also occursnaturally, when winter storms stir up bottomsediments and turn the water milky for days. Thewater does clear between storms, however, and thecorals can secrete a mucous coating thatentraps and removes limited amounts of sediment.Prolonged or continuous sedimentation, on theother hand, does not allow such recovery.

There are other clues to the reasons for coralreef mortality. The outer reefs are in better conditionthan the inner, or patch reefs. This may be a result ofnatural limits, as mentioned above, or may be theresult of poorer quality waters near shore. The reefsin the northern Keys are in worse condition thanthose in the lower Keys. Again, these are closer tothe land-based impacts of land clearing, septic tankeffluent, and within southward flowing currentswhich may carry sewage effluent and urban andagricultural runoff from the mainland.

The cause of reef mortality, aside from localareas, is unknown at present. It may be that it is acombination of the natural stresses to which the

reefs have adapted, made lethal by the additionalimpacts of reduced water quality and physicaldamage.

Major management problems of the south-east Florida continental shelf environment includedredging for beach restoration, and marinedumping of sewage effluents. Both activities canbe managed to produce minimal impacts onthe marine environment, but if precautions areignored, the impacts can be serious.Dredging for Beach RestorationBeach erosion control projects were monitored bythe U.S. Army Corps of Engineers in Palm Beachand Broward counties and results showed thatdamage to coral reefs was directly related to thenature of the area dredged and the methods ofdredging. In the area from Pompano toLauderdale-by-the-Sea, and in Deerfield Beach,dredging for beach restoration did no observableecological damage. The investigators suggestedthat three major factors were responsible for thenegligible damage. First, there was enough sand inthe borrow areas so that there was only slightscouring of reef areas. Second, the borrow areas didnot immediately border viable reefs, so sedimenttransport by currents from the dredging sites to thereefs was light. Third, the reef is far enough offshoreand is washed by north-south, nearshore currentsso that settling of sediments on the reef was slight.

Observations at the Hallandale restoration siterevealed that the reef was substantially damaged inand adjacent to the borrow areas. The reasonsappeared to be a lack of sufficient sand in thebottom areas, location of borrow areas near thereefs, scouring of reef edges, and careless handlingof dredging equipment. Interestingly, HallandaleBeach was originally to have been nourished withsand imported by barge from Sandy Cay in theBahamas. Apparently the discovery of sand nearbyled to abandonment of the original proposal. In thelight of the damage done by overdredging ofmarginal sand beds, the original proposal hadsignificant merit, despite the greater initial cost.

Every effort should be made to protect viablereefs, both before and during beach restoration andnourishment projects. Ecological mopitoringshould be included as part of such projects, andadequate analysis of the proposed borrow siteshould be undertaken before any final decision ismade to proceed with dredging. If the proposedborrow area is found to be suitable, the monitoringshould continue through the project to ensure

Meters

General zonation and morphology of the reefs off thesoutheast Florida coast.

FIGURE 8TYPICAL ZONATION OF SOUTH FLORIDA REEFS

SOURCE: GOLDBERG, 1973

L

_____-a

$F~FS

that the dredging contractor takes adequate precau-tions to avoid reef areas and protect them fromsedimentation and physical damage. If damageoccurs, appropriate measures should be takenimmediately to correct the procedure and protectreef resources.

It should be emphasized that beach restorationand nourishment is less environmentally damagingin the long run than any other method of shoreprotection now available. If adequate planning isdone beforehand, and sufficient care is takenduring the operation, damage will probably beslight and will repair itself over time. The operationcan be devastating, however, unless there isadequate consideration of the total system of beach,dune, nearshore bottom, and reef, and the damagecaused may be permanent and irreversible.

Ocean OutfallsThe issues to be considered in the question ofocean disposal of sewage are well summarized byBascom:

There is good reason to restrict theamount of nutrient material that isdischarged into lakes and rivers, whereoxygen is limited and a reducingenvironment can be created. The ocean isanother matter. It is an essentiallyunlimited reservoir of dissolved oxygen,which is kept in motion by currents and isconstantly being replenished by naturalmechanisms.

It is nonetheless possible tooverwhelm a local area of the ocean with ahuge discharge of nutrient material thatmay form a deposit on the sea floor if thelocal conditions are not carefullyconsidered. The materials must bepresented to the ocean in the right placesand at reasonable rates. Among the waysof achieving that objective are the use ofdischarge pipes that lead well offshoreand have many small diffuser ports and, ifthe volume of discharge is exceptionallylarge, the distribution of the effluentthrough several widely dispersed pipes.

Problems caused by the addition ofnitrogen and phosphate to inland waters,which they overfertilize, do not apply tothe ocean. There they could be helpful byproducing the equivalent of upwelling,the natural process that brings nutrientsfrom deep water to the surface waterswhere most marine organisms are found.

As Issacs has pointed out, "the sea isstarved for the basic plant nutrients, and itis a mystery to me why we should beconcerned with their thoughtfulintroduction into coastal seas in anyquantity that man can generate in theforeseeable future." (Bascom, 1974)

Carefully planned disposal of nutrients in thesea may not be harmful, but heavy metals andpesticides pose a different problem:

Some industries discharge substantialquantities of heavy metals and complexorganic compounds into municipalwastewater systems whose effluentreaches the ocean. Certain of the metals(mercury, chromium, lead, zinc,cadmium, copper, nickel and silver) arenotably toxic and so are subject tostringent regulation. The most dangeroussubstances, however, are syntheticorganic compounds such as DDT andpolychlorinated byphenyls. Thedischarge of these substances as well asthe heavy metals must be prevented.(Bascom, 1974)Studies by the Environmental Protection

Agency in the South Florida Region have shownthat sewage outfalls, when properly designed andoperated, are probably not harmful to the marineenvironment. The most significant considerationsare: 1) sufficient length and depth to preventonshore winds and currents from carrying theeffluent plume back to shore, and 2) avoidance ofsuch sensitive marine communities as estuaries,marine grass beds, or coral reefs.

Existing outfalls in the Region presentlydischarge in shallow waters, too close to shore.Studies have shown that effluent is sometimescarried back to bathing beaches by onshore windsand currents. Capital improvement programs areunderway, however, to improve treatment ofeffluent, and to extend the outfalls to safer depths.Policies43. Research should be undertaken to identify the

causes of coral reef decline in areas where noreasons are apparent.

44. Enforcement of existing State and Federalregulations for protection of coral in Floridawaters should be funded.

45. Phase out ocean outfalls adversely affectingcoral reef areas.

46. Implement appropriate engineering optionswhen needed to improve existing oceanoutfalls. Examples are:a) extension of existing outfalls to lower depthsb) installation of diffusers to help mixingc) dilution of effluent with saltwater prior to

discharged) improved treatment prior to ocean discharge

47 Evaluate long-range sewage disposalalternatives, including recycling of wastes toinsure protection of quality of coastal andestuarine water resources.

48. Consider importation of sand from environ-mentally acceptable areas as alternativesto dredging in local areas where the sandsupply is marginal or insufficient, or wherelocal sand is unsuitable for beach fill.

OTHER ENVIRONMENTALISSUESENDANGERED AND THREATENEDSPECIESOnly a remnant of South Florida wildlife remains,since half of the original wetlands have beendrained, and the other half substantially altered.Wildlife depends on suitable habitat for survival,and the key to preservation of wildlife species isprotection of sufficient habitat. The completedomestication of wilderness areas makes them fitonly for man, and those animals which can adapt tourbanization - lizards, opossum, squirrels, andrats. Some animals can survive in urbanized areasthat are carefully managed by man. Moderate sizedareas left in a natural state will provide habitat forsongbirds, turtles, rabbits, foxes, and waterfowl.Other animals, such as the Florida panther andblack bear, need true wilderness, and must retreatto the remotest parts of the Big Cypress swamp.Estuarine habitat is essential for at least 65 percentof all marine organisms during some portionof their life cycle. Marine turtles require relativelyundeveloped, dark beaches for nesting, and themanatee must have access to warm inland waters.

The Florida Committee on Rare andEndangered Plants and Animals (FCREPA), agroup of Florida biologists, has prepared anexhaustive inventory of the habitats of rare andendangered species. Figures 8 through 12 show thecomposite habitats of threatened and endangeredplants and animals, compiled from maps forindividual species included in the FCREPAinventory. The inventory is valuable as a reference,and should be consulted in the early stage of any

planned development, so that sensitive habitatsharboring endangered species may be totallyavoided. In other, less sensitive areas, human useand survival of rare or endangered species canbe achieved.

Decisions to permit development in an areaof rare or endangered species habitat should bebased on the sensitivity of the species to humanproximity. Some habitats can be managed for bothhuman use and wildlife. Ospreys, for example,can live near development if sufficient productiveponds or sloughs are left undisturbed for theirfeeding, if sufficient natural cover is allowed toremain, and if tall trees or nesting boxes on polesare provided. Other species may need greaterprotection through strict regulation or outrightpurchase of habitat. Planners need the expertiseand assistance of biologists and ecologists todetermine whether a proposed development oractivity has adequately provided for such protectivemeasures, and to evaluate the sufficiency of themeasures proposed.

Policy46. The appropriate State agencies and universities

shall compile management techniques forinsuring survival of rare, threatened, andendangered species, and establish criteria forevaluating proposed activities which mightadversely impact those species. Thesetechniques and criteria, which can be basedon existing knowledge, can then be used bylocal planning agencies and elected officialsin evaluating proposed development activitiesin their jurisdictions.

HURRICANE HAZARDSouth Florida's coastal zone varies in elevation fromnear sea level in the southern coastal marsh, toalmost 20 feet in areas along the coastal ridge. Muchof this low-lying area is prone to flooding, bothfrom rainfall accompanying hurricanes, and fromstorm-generated tidal surges. The NationalWeather Service estimates that a hurricane can beexpected to pass through the Region every six toeight years.

Hurricane storm surge impact on a coastalarea depends on several factors: the size of thehurricane, the direction from which it approaches,wind speed, shoreline configuration, continentalshelf slope, and the height of the prevailing(normal) tide at the time. A NOAA study calculatedthat a hurricane of the intensity of Camille, withwinds of 200 mph, would cause a maximum storm

tide of 20 feet above mean sea level in Biscayne Bay.The highest land elevation around Biscayne Bay is20 feet in Coconut Grove.

Several hurricane-related factors should beconsidered in planning for the location of coastaldevelopment.1. Shoreline configuration: On a convex shoreline,

tidal surge tends to be dissipated. Concaveshorelines, especially bays which are partiallyenclosed by barrier islands or causeways, sustaina much greater impact because the flood water istrapped and prevented from flowing quicklyback to sea. Water entering the bay through aninlet may be forced back out to sea across theback of the barrier island, depending on localcircumstances.

2. Coastal elevation: The rate of fall-off of storm tideis about one foot per mile inland. A twenty footstorm tide could theoretically penetrate 20 milesinland in the absence of mitigating factors. Thecoastal ridge or stable dunes paralleling theshore can effectively protect inland areas. It isestimated that a ridge ten feet high or more, andfive miles wide would probably prevent moststorm tides from washing over to the interior.Channels through the ridge, either naturalformations or man-made canals, however, allowstorm elevated waters to penetrate inland.

3. Coastal vegetation: Dense coastal vegetation,such as mangroves, or coastal hammock forest,can moderate storm surge by increasing surfacefriction and absorbing wave energy. In theprocess, much of the forest may be destroyed,but impacts on the upland are lessened. The

forest will probably repair itself over time, or itcan be replanted or otherwise managed torecover more quickly.

4. Evacuation of coastal residents: Total evacuationof a threatened urban area is generally notpossible, particularly from islands where onlyone road provides access to the mainland. TheKeys are the most vulnerable example. Othermeasures, such as designated refuges in safehigh rise buildings, should be incorporated into aregional emergency preparedness plan. Thepopulation of south Florida has increased greatlysince the last severe hurricane, and the greatmajority of residents have never experienced asevere hurricane. Many of them live in newdevelopments in low-lying coastal areas that areat risk in a major storm.

Policies50. Natural systems which protect against

hurricane storm surge must be protected. Thecoastal ridge, mangrove fringe, and the dunesand their stabilizing vegetation cover areexamples.

51. Locate future development where the potentialfor hurricane damage is as low as possible.

52. Design projects to mitigate storm damage. Forexample: elevating buildings on stilts instead offill to permit passage of storm water; reducingto a minimum any canals or other breaks innatural storm barriers; construction ofnecessary bridges on pilings instead ofcauseway fill to avoid trapping flood waters.

DADE

9F HABITAT FOR:D ANDD PLANTSMONROE

KEY WEST.,.o o.IJC,=...

II E

cill i ~ In iBROWARD UFORT

LAUDERDALE

I (~CATtAIU AF HRITTmVA IOv V I HAI TT

FOR THREATENED ANUENDANGERED FISH

DADEIIAMI

MONROE

SOURCE: FLA. COMMITTEE ON RARE AND

ENDANGERED PLANTS AND ANIMALS

1976/__

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HABITATNED ANDBIRDS

FIGURE 12B A A. .Im...

LV AI IUN 0VFOR THREATEENDANGERECAND REPTILE

SOURCE = FLA. COMITAND ENDANGERED PLANIMALS, 1976

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HABITATNED ANDBIRDS

FIGURE 12a AA - A I

LOCATIO IUN OFOR THREATEENDANGEREDAND REPTILE

SOURCE= FLA. COMITAND ENDANGERED PLANIMALS, 1976

ERDALE

13 W:

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FIGURE 13LOCATION OF HABITAT FOR THREATENEDENDANGERED MAMMALS

SOURCE: FLA.COMMITTEE ON RARE AND

ENDANGERED PLANTS AND ANIMALS,1976

AND

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