ji t- 6'- 4 6C^C- t CFW 85-02
THE INFLUENCE OF HUMANITY ON THE COASTAL LANDSCAPE OF FLORIDA:
The Indian River as a Case Study
Center For Wetlands
University of Florida
Gainesville, Florida 32611
The coastal landscape has attracted ever increasing numbers of people
since the very early days of Florida's history. In no other area of Florida
is the presence of humanity more visible. It is estimated that well over
70% of Florida's total population lives within the coastal zone. The
ecological impacts of accommodating ever increasing numbers of individuals
within the coastal zone are not well understood and as a consequence in most
cases are not considered as decisions are made concerning growth of the
region. Only after symptoms of a declining environmental quality are
noticed is there sufficient public attention drawn to the issues of growth
management and environmental planning to achieve some measure of protection
of the landscape components and processes that are threatened. For example,
experience has shown that only after marked declines in commercial and
sports fisheries is there enough public awareness of the problem to foster
enough support to achieve some reversal of the trend. However, in many cases
not enough is known about the causes of the declines much less what manage-
ment strategies are necessary, so little if anything is done of lasting
Again and again attention is focused because of some symptom...loss of
sport fisheries, eutrophication of water bodies, near extinction of species,
or salt water intrusion....and resources are directed at solving the
symptom, not the problem. The problem, in most cases is the development of
the landscape with little attention given to the "system" of the landscape.
Little awareness is shown of the structural and functional "wholeness" that
is the landscape system of wetlands and uplands, dry lands and water bodies,
and developed lands and natural lands. Development patterns recognize
individual property rights, and the infrastructure of urbanization, but pay
little heed to the "infrastructure of nature".. the storage, movement, and
discharge of surface and ground waters, the movements and budgets of
nutrients, or the currents, eddies, and tides of marine waters.
Any plans to manage growth, or solve the myriad problems associated
with the existing web of the urbanized coastal zone must have as a basis an
understanding of Florida's landscape as an integrated whole system.
Development regulations, plans for infrastructure expansion, and public
policy need to reflect a new awareness of the landscape as a whole system,
where wetlands are recognized for their values of water storage and
Proceedings of the Indian River Resourcesi Symposium : 1-13
purification, where watersheds are left intact, where waters are recycled
and conserved, where the interconnections between uplands and estuaries are
recognized, and where humanity lives in a balanced economy of nature and
Whole Systems Approach
Understanding the whole landscape as one system may be a method of
beginning to solve some of the complex problems that face decision makers,
managers, and regulators. A whole systems approach sees the landscape of
uplands and estuaries as one interconnected system, and the development of
inland areas as directly affecting the health and well-being of the coastal
To understand any component of a landscape, such as the estuary, one
must first look to the larger system in which it is embedded, and the
driving forces that shape and sustain it. For like all of nature, the
landscape is organized as systems within systems. The estuary is a marine
system embedded within a much larger marine environment, interfacing with
the terrestrial environment and driven by forces generated at the global
scale. From the seaward side come the forces of waves, winds, and tides
that shape barrier islands, carve inlets and flush the estuary. From the
landward side come runoff waters from abundant rainfall, carrying nutrients
and organic matter that sustain long pyramidal food chains. From above,
sunlight penetrates the clear waters providing the energy for photosynthesis
of the abundant plant life.
In all, the estuary can be thought of as the interface of land and
water, where the energies and materials of the landscape are concentrated
and where the energies of the sea are dissipated. It is at this interface
that marine productivity is highest and the attraction for humanity to
congregate is greatest, and where the delicate balance of inputs from the
land and inputs from the sea is easily disrupted....where changes in the
quantities of water, nutrients, or organic matter, or changes in flushing by
tidal action can cause major changes in the structure of the estuary.
THE INDIAN RIVER BASIN
Shown in figure 1 is a map of the watershed of the Indian river system
as detailed by Conover and Leach (1975). The total area of the drainage
basin is given by Hughes (1978) as 3605 km2. Average elevation and highest
elevation are about 8 and 27 meters above MSL respectively. The basin
stretches approximately 134 kilometers from the Ponce de Leon Inlet on the
north to the St. Lucie Inlet at its southern extreme. At its widest point
near the Brevard/ Indian River County line, the basin is about 27 kilometers
(measured from the Indian River inland). For much of its length the basin
averages less than 3 kilometer in width.
Historically, the watershed:for the Indian River was probably much
narrower in the area of central Indian River and southern Brevard counties,
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ta?' |jI~ X ST. LUCIE
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Figure 1. The Indian River watershed. In recent years
the watershed boundaries have been altered through
development activities, especially in southern
Brevard and Indian River counties.
where extensive ditching and drainage canals have routed waters eastward
into the estuary. These waters probably were part of the St. Johns marsh
and flowed northward and westward, forming part of the headwaters of the St.
Brooks (1981) describes the physiography of the basin as part of the
eastern flatwoods district, consisting of five distinct sub-districts that
originated during the late Pleistocene. Generally, the basin is a series of
well drained ridges interspersed with relic inlets and terraces. The
extreme coast is dominated by offshore barrier islands perched on top of
middle and late Pleistocene coquina and sand shell ridges. Where the basin
is widest, drainage canals have increased the basin's western limits to
include areas of poorly drained flatwoods and organic soils of the St. Johns
Driving Energies of the Estuary
The estuary is a complex system whose main driving energies come from
both the sea and land (see Figure 2). From seaward come the driving forces
of wind, waves, and tides that continually shape and reshape the coastal
beach and dunes systems; the most energy intensive of Florida's ecological
systems. The never ending surf and tidal cycles and the ever changing winds
buffet the seaward edge of the dune causing less than ideal conditions for
life. The vegetation that colonizes and lives on the dune has adapted to
life in a very harsh environment. Sometimes considered fragile, the plants
that have adapted to these conditions are actually quite hardy. However,
stabilization of the high energy coastline is a demanding role that leaves
little excess energy to cope with additional stress. As a consequence, a
small amount of additional stress is usually all it takes to begin the
processes of decline, ending in their erosion from winds, waves or tides.
Figure 2. The estuary is a complex ecological system whose most
important sources of energy are the flushing by tidal
cycles, and the inflow of nutrient maiden runoff from
Landward from the frontline defensive ecological systems of the
coastal beach and dune are less fragile communities, that benefit greatly
from the continual cycles of tides and storms. Salt marshes and mangrove
forests line most of the coastal areas where wave energies are not too
strong and where tidal influence is sufficient to keep the environment
saline. The organic matter produced by these communities represents the
single greatest food source for estuarine food chains.
The most important sources of energy to the estuarine environment are
the tides that flush nutrients, organic matter, and larvae in and out again,
and the inflow of waters laden with nutrients and organic matter from the
terrestrial environment. Their physical energies shape the contours of bay
bottoms, scouring tidal channels, and depositing sand bars, develop tidal
creeks shaped to insure flushing even at their farthest reaches, and open
and close ocean inlets as the yearly cycles of wet seasons and spring tides
trade influence. Carried by these two intertwining waters are the chemical
energies of nutrients that are required by vegetation for growth, and the
seeds, larvae, and juvenile fish that insure the estuary remains a diverse,
resilient, and productive soup.
Driving Energies of the Upland Landscape
Of the main renewable driving energies of the upland landscape rain is
the dominant force. Given in figure 3 is a diagram of the hydrologic cycle
showing the relative percentages of rainfall that are evaporated, transpired
by vegetation, recharged, and that portion that is runoff. The amount of
rainfall, its cycle through the landscape, and the periodicity of the wet
and dry seasons control many of the processes of Florida's landscape mosaic
and coastal estuarine resources. Nearly 70% of total rainfall returns to
the atmosphere either as evaporation or as transpiration from vegetation.
Of the remaining rainfall, about 10% recharges ground waters, and 20% runs
off the landscape.
Because of their importance, the contributions of fresh water from
rainfall, runoff and sewage are compared in table 1. Rainfall and runoff
contribute a total of 592 billion gallons (2.2 billion cubic meters) of
fresh water per year to the Indian River. Historically, runoff was probably
less than 1/2 of its current value, since the water basin boundaries have
changed through construction of drainage canals. By comparison, if it is
assumed that the sewage from all the populations of Brevard, Indian River
and St. Lucie counties were discharged to the Indian River, the total
additional fresh water would amount to only 26 billion gallons (98 million
cubic meters) per year, or about 4.4% of the total freshwater input to the
The final columns in table 1 show nutrient contribution to the Indian
River based on average concentrations of total phosphorus in rain, surface
water runoff, and treated sewage effluent. A different picture emerges when
relative contributions of nutrient sources are compared. The contribution
of sewage is greater than rainfall and runoff combined (bear in mind that
sewage estimates are based on estimated population serviced by sewage plants
that discharge to the estuary; the actual sewage flows may be somewhat
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Figure 3. Diagram of the hydrologic cycle showing the relative
portions of rainfall that are evapotranspiration,
runoff, and infiltration.
Figure 4 is a conceptual drawing of the landscape showing the inland
areas of flatlands with scattered wetlands, intermingled with sloughs, and-
rivers and streams that flow slowly to the estuary. The dry season ends
with the onslaught of wet season rains that first fill the scattered
isolated wetlands to overflowing, in turn filling the sloughs, and
eventually sending excess runoff slowly to the estuary. Through sloughs,
streams, and finally rivers the water gently meanders, always moving slowly
through the vegetated channels whose friction acts to minimize runoff
velocities and hold the water on the landscape.
Water is held back on the landscape and released only very slowly to
obtain maximum benefit from its life-giving moisture and the nutrients it
carries. Ground waters are maintained at high levels whenever rainfall is
retained on the landscape. When runoff and infiltration are great, local
ground water levels are deep. In these instances, during dry seasons,
vegetation show signs of drought stress, wilt, drop their leaves, and if the
drought continues for long enough, even die.
Table 1. EstiLates of Yearly Inflows of Fresh Water
and Nutrients to the Indian River Nstuary
Source Fresh Water Nutrients (Tot. P)
Gallons Cubic Meters Pounds Kilograms
(x 109) (x 109) (x 103) (x 103)
Rain1 349.4 1.3 171.6 78.0
Runoff2 243.6 0.9 404.8 184.0
Sewage3 26.4 0.1 615.3 279.7
1. Area of Indian River taken as 995 km2, rainfall taken as
1.33 m/yr, and average concentration of Tot. P in rain-
fall as .06mg/l.
2. Average runoff per year taken as 0.256m/yr, area of
basin as 3605 km and average Tot.P concentration of
3. Sewage estimate based on total population of 482,000
people, average daily sewage generation of 568
liters/person, and Tot.P concentration of 4mg/l.
Figure 4. Conceptual diagram of th.e organization of the
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Figure 4. conceptual diagram of the organization of the
Florida landscape, showing inland wetlands that
contribute wet season runoff slowly to rivers
The "primitive" Florida Landscape resembled that shown in Figure 4, and
was organized around the dominant energy associated with rainfall. In the
primative landscape there were no quick ways to the ocean. Every water
course was a gentle one, meandering and winding ever so slowly to the sea,
providing ample opportunity for waters and nutrients to do the work of the
landscape and for the maintenance of high water tables. Nutrients were
removed from surface waters as they flowed gently to the sea through complex
channels of wetlands, sloughs, and floodplain swamps. This insured that
over-enrichment of the downstream estuaries did not occur. The nutrients
that did arrive were organic nutrients, that acted much like time release
fertilizers, releasing their energy to the estuary slowly over time to
minimize the potential of over-enrichment.
A balanced system, the estuary ebbed and flowed over the centuries,
receiving wet season runoff and the organic nutrients it carried, processing
them and developing long complex food chains based on them. With the
influences of humanity in the landscape, many of these relationships have
been changed: most inadvertently, for the relationships of inland
development on the quality and productivity of the estuary were not well
understood, or considered.
Effects of Landscape Reorganization
Rainfall, the main renewable driving energy of the landscape, is also
the main force that humanity must "control" when developing the Florida
landscape. Excess wet season rains must be dealt with to minimize flooding
of developed lands, and in many areas ground waters must be lowered to
insure adequate "drainage and control" of storm waters. Unfortunately,
these alterations of the existing conditions extend far beyond the property
boundaries of the development. Neighboring lands and downstream water bodies
are forever altered as well. Canals and drainage ditches lower ground water
levels in adjacent lands for distances as great as 1 mile on either side of
the ditch, and carry increased amounts of runoff of poorer quality to down
stream water bodies.
Figure 5. Diagram showing the natural landscape and
effectsof channelization. When channelized
as in the drawing on left, landscape values
are disrupted. Water tables are lowered,
vegetation suffers drought, and pollutants
are carried to estuaries without the benefit
of treatment by floodplain wetlands.
When sloughs and streams are channelized as in figure 5, the friction
that was caused by meanders and vegetated channels is lost. Waters then flow
with greater velocity, causing greater erosion of banks and decreasing the
ability of vegetation to filter nutrients, metals and other pollutants.
The net result is increased loads of sediments and nutrients as well as
other pollutants in the receiving estuaries. Increased sediment and nutrient
loads decrease available light within the estuarine water column, having the
overall effect of reducing photosynthetic activity, which in turn has a
direct negative impact on fisheries. Increased pollutant loads have direct
impacts on the viability of the marine environment.
Not only does the estuarine environment suffer, but the terrestrial
environment suffers as well, for the loss of nutrients as they are leached
and flushed from the landscape decreases productivity of vegetation.
Lowered water tables as a result of the straightening and deepening of
streams decreases water availability and increases the likelihood of drought
stress during the dry season. In all, the straightening and deepening of
streams has little positive benefit to the environment, although it does
help to alleviate flooding of urbanized areas by increasing the rate and
velocity of runoff.
Strongly related to the problems associated with the channelization of
streams are the problems associated with increased impervious surface within
watersheds. Shown in figure 6 are typical runoff hydrographs for a natural
watershed and one that has a large amount of impervious surface. As the
amount of impervious surface increases, the amount and speed of waters
running off the land increases. The end result of such changes is increased
velocity of runoff waters, and greatly diminished purity. Couple increased
impervious surface with channelization of streams, and the overall result is
a fast decline in the quality and resiliency of the receiving estuaries.
ao / A<^I | Natural Lands
0 Time (Since Rainfall Event)
Figure 6. Typical runoff hydrograph for developed and natural
lands, showing the increase in volume and rate of
discharge after a rainfallbecauseof the increased
area of impervious surface.
Both the physical reorganization of the landscape during development
and the reorganization that results from the release of by-products as
development is complete, have a profound effect on structural and functional
characteristics of the landscape and its components. When lands are paved,
sodded, and built upon, and when canals are dug for "storm water control",
the amount and timing of runoff are changed. When septic tanks, sewage
treatment plant outfalls, and fertilizer are allowed to enter surface waters
without further treatment, the quality of runoff waters and receiving water
bodies are greatly affected. The lowering of ground water tables to
accommodate development lowers productivity of ecological systems, decreases
storage of waters, and increases the need for irrigation of crops and lawns.
In all, as the landscape is reorganized to better "fit" the needs and
desires of humanity, the overall effects on the wider environment are not
considered. Humanity now controls the destiny of the landscape through the
release and control of energies that shape, move, and dig the earth, and
energies that build and maintain clusters of buildings and their
inhabitants. The high energy concentrated by-products of the urbanized
landscape released to the environment develop new ecological systems at
outfall points and reorganize other existing systems through which they
pass. Without an overall landscape perspective, one that integrates into
"wholes" rather than dissects into pieces, the task of managing the environ-
ment is rendered almost hopeless. Resource management strategies must
include the wider setting within which the resource is embedded. Management
must start with the watershed, and the use, reuse, and reorganization of the
landscape at that level must be dealt with first, before any realistic
management strategy can be outlined for the parts.
Protecting Wetland Values
Wetlands, andthe vital functions they perform, are worthy of special
mention in any management strategy. Unconstrained development in the past
has lead to the loss of untold acreage of wetlands, but more importantly, it
has lead to the loss of vital services and wildlife habitat.
The consequences of insensitive and unconstrained development on
Florida's wetlands are well documented. Since the turn of the century,
approximately 40% of the wetlands within the state have been drained,
converted to agricultural uses, or developed as urban lands. Little
understood in the public forum however, are the secondary impacts on the
public health and well being.
When wetlands are eliminated from the landscape, or when wetland
functions are severely impaired through insensitive development techniques,
much more is lost than just a "few worthless swamps". Wildlife habitat is
lost that directly affects species that depend on those areas for survival.
The near extinction and endangerment of wildlife species is due for the most
part from loss of habitat, rather than over-hunting or poaching.
The loss of wetland functions, like water storage and water quality
enhancement, directly affect the health, safety and well-being of humanity.
As storage is lost and urbanization increases, downstream floodingresults,
requiring ever increasing expenditures of money and energy to mitigate.
Valuable water is shunted to the estuaries, increasing nutrient loads and
contaminants. Without.the filtering that wetlands perform, ground waters
and runoff waters become increasingly contaminated with an array of
nutrients, metals, and toxins, threatening public water supplies, and
the quality of receiving water bodies.
Present state and federal laws affect only a portion of Florida's
wetlands and leave to ultimate destruction the majority of Florida's most
valuable natural assets. The role of comprehensive planning in protecting
Florida's wetlands is very important, for only through the stated objectives
and goals of community comprehensive plans can the value of wetlands to the
community at large and their value in enhancing the public's health and
well-being be asserted. Without comprehensive planning that recognizes the
values of wetlands and that protects these values, individual values in
almost all cases overpower the values associated with wetlands and the
Sound landscape management is a prerequisite to managing down stream
systems of lakes, rivers, streams, and estuaries. To accomplish this the
following concepts and principles are suggested as a means of guiding
development within the Indian River watershed.
1. Prohibit the lowering of ground water tables, and instead, encourage
development to raise elevations of roads and housing to minimize flooding.
2. Discourage any increases in impervious surfaces, and encourage the use
of surfaces of parking lots, low intensity roads, and walkways that allow
water to percolate into the soil.
3. Prohibit the channelization of streams or creeks, and encourage
vegetated swales for the management of storm waters.
4. Require that all storm water management systems be designed to
accommodate vegetation in all channels, swales, and retention basins.
5. Encourage "nonstructural" solutions to stormwater management and the use
of wetlands (whether natural of artificial) for storm water discharge.
6. Determine acceptable levels of freshwater input to the estuary and
develop an overall management plan to insure that these inputs are met. In
some areas the increased flushing brought on with increased fresh water
loads may be beneficial to off-set other negative consequences of
development within the watershed; in other areas, increased inputs may be
7. Prohibit any development seaward of the secondary dune, recognizing the
shifting character, and high energy nature of the beach and dune system, and
encourage management practices that will enhance the integrity of these
8. Let no additional structures be constructed that will interfere with
tidal flushing or currents.
9. Discourage the construction of seawalls, especially where there are none
at present, or where there is heavy boat traffic or likelihood of wind-
10. If additional waterways are dug for boat basins, etc. design channels
that taper in width from mouth to farthest landward extent to increase tidal
flushing. Design channel sides that do not require seawalls by ensuring
that natural vegetation can colonize to stabilize banks.
11. Recognize the exceptional value inherent in wetlands as filters,
recharge areas, water conservers, and wildlife sanctuaries and prohibit any
further development of all wetlands, whether or not considered
jurisdictional by the state.
12. Since terrestrial environments, especially wetlands, are inherently
more productive than estuarine systems, and are capable of absorbing high
nutrient wastes of urbanized areas, develop plans to reroute nutrient-rich
sewage inland to the interior wetlands of the St. Johns River, which has had
so much of its base flow diverted.
13. Encourage a BASIN WIDE approach to comprehensive planning, and develop
a single, integrated plan that will encourage cooperation between the
numerous governmental agencies that now have fragmented jurisdiction over
the basin and its resources.
14. And finally, develop a renewed interest in the management of the
landscape, and commit the resources necessary to attract professional
engineers, ecologists, and planners that will be capable of developing
creative solutions and enforcing necessary regulations to ensure a high
quality environment for all citizens of the Indian River Basin.
Conover, C.S. and S.D. Leach. 1975. River Basin and Hydrologic Unit Map of
Florida. Map Series no. 72, Fl Dept. of Natural Resources, Bureau of
Hughes, G.H. 1978. Runoff From Hydrologic Units in Florida. Map Series no.
81, Fl. Dept. of Natural Resources, Bureau of Geology. Tallahassee.
Brooks, H.K. 1981. Guide to the Physiographic Divisions of Florida.
Institute of Food and Agricultural Sciences, University of Florida.