Watersheds, hydraulic engineering
and a law of unintended consequences.
By Joseph Siry
narrative starts | table of watershed changes | adaptableness schematic | conceptual models used | middle narrative | later narrative | conclusion
“A river is a unit from its source to its mouth.”Gifford Pinchot, c. 1908.
The paper explores how recovering an ecological condition before some human modification was made requires a new metaphor concerning human alteration of physical conditions and geographical contours. The essay considers hydraulic engineering and dam building as a means to convey how and why humans create new circumstances of existence. As an inquiry into the best means of reviving ecological patterns for more than just economic, cultural or spiritual reasons, an argument is made for language’s role in fostering a learning deficiency. Unable to employ an adaptive management approach to ecological resources’ allocation, we still search for an accurate vocabulary to describe the history, social models and scientific evidence that clearly speak to us.
The setting is the major tributary watershed of the St.
Johns River. Outside of the northeast coast of Florida the watershed is
oldest settled portions of the interior of the state. The Ocklawaha River
Valley, like the St. Johns flows from south to north. It rises in the east
central Florida lakes region and flows through troughs in the Ocala Limestone,
fed by numerous springs until it turns abruptly east and conjoins with
the wider St, Johns River in a series of braided streams amidst riparian
swamps west of Welaka. First dammed for flood control and agricultural
drainage in the 1920s the river became the preferable site for a “Panama
Canal” across the state in the 1930s during the Great Depression. In 1968
it was the preferred waterway for the Army Corps of Engineers to instead
dredge the Cross Florida Barge Canal. Dams were created at Rodman and Eureka
sites to flood the lower river in order to lift barges over a 120 feet
high section of the central Florida Ridge between Silver Springs, on the
east, and Lake Rousseau, on the west.
The watershed today is characterized by a rapid conversion of acreage from largely agrarian to more urban and suburban land use patterns. Recent US Geological Survey studies of water quality suggest a doubling of nutrient levels in the spring fed Silver River attesting to the upstream development’s consequences on the major tributary of the Ocklawaha River. Between 1954 and 2000 nitrate levels for example doubled in sampling of Silver Springs.
Percent of land use changes in the Ocklawaha River Watershed
"The City of Ocala, located in the River Basin, has the highest numerical urban sprawl index in the US in terms of current population density and change in population density during the 1990s. (El Nasser & Overberg, 2001)"
|Types of Land Use
|Transport, et al.
|Urban and Built up
Nitrates in the Ocklawaha River Basin, Florida (Draft)
University of Florida, Department of Environmental Engineering
Since 1970, in one county alone, Marion County, (Ocala) 82 per cent of all housing units have been built. The unpublished speculation of the USGS findings is that in some proportion, urban and suburban runoff, sewage treatment, septic tanks and agricultural runoff all account for the doubling on nitrate levels and the presence of other “cultural” nutrients in the spring fed Silver River. Like the longer and larger Ocklawaha, changes in agricultural practices, growth in suburban land use and spreading impervious surfaces due to transportation needs have disturbed the water quality of these two principle waterways in the basin.
Thus there is also a complex subject of how best to conceptualize technical engineering projects with respect to the environmental advantages and disadvantages these changes inflict on fisheries, wildlife and cultural patterns of subsistence. While humans share with termites and beavers the capacity to alter considerable areas to their immediate advantage, humans have begun to understand the unintended trans-boundary and even planetary impacts some changes in land use are having.
These impacts are largely, but not exclusively, interfering with the rate of biogeochemical cycles that move nutrients from the air into the ground, the ground into the air and water, the water into the air, or the air into the water. Some rates of turnover such as nitrogen, sulfur, carbon and phosphorus can have unintended consequences on air masses or water bodies. These impacts’ mass, duration and frequency are having profound implications for our economies, new engineering projects and the stewardship of biological wealth.
In addition to these unintentional disturbances, intellectual conjecture about nature, due to discoveries in biology, chemistry, geology and physics, is shifting human understanding of existence. Particularly with respect to the carrying capacity of a watershed and the assimilative capacity of air and water resources, new measures of human disturbances have revealed a more pressing need to restore what George P. Marsh referred to in 1864 as “disturbed harmonies” in the human relationship to nature. While Marsh called for restoration under the terms of geographical regeneration in the Civil War period, ecology only coalesced as a discipline in the early 20th century and restoration biology as a discipline in the late 20th century.
We live in the midst of rapid changes in thoughts about natural objects because of the speed of population growth, technological change, and conversion of existing physical surroundings. In Florida, population has doubled roughly every twenty years since the 1920s decade. Once considered ubiquitous in the state, alligators were placed on the endangered species list in 1974 and later removed, as populations rebounded in 1984. Sea cows or manatees (Trichechus manatus) were once considered nuisances in water bodies, are now cherished by some and as endangered species—are scientifically used to assess water quality and habitat conditions since they graze on tons of aquatic vegetation everyday as herbivores. Black bear (Ursus major) populations in the state have fallen and they too are on the endangered list, together with the Florida panther, American crocodile, and red cockaded woodpecker. Due largely to a damage, loss or degradation of their ranges, habitat fragmentation or water drainage, these creatures are treated as “sentinel” or symbolically important creatures, indicative of adverse changes in ecological conditions.
Out of the physical or material world emerges a biologically active ingredient called life, or the living world. Some species of this living menagerie, such as the Florida Scrub Jay, live no where else and have such particular living conditions that without habitat conservation plans, their populations plummet, and they may become locally extinct across much of their historic range. As a composition of organic and inorganic conditions of existence, as Darwin suggested, in aggregate that this living world is best understood as a dynamic, self organizing and unbelievably ancient existence characterized by cycles, flows of essential nutrients and potentially enormous differences in how various creatures persist, sustain themselves and often other species. For example the Florida gopher tortoise burrows in the dry sand areas and creates tunnels that are used by the indigo snake, gopher frog and other assorted co dependent creatures. Without these re-contour specialists whose habit for “remodeling” habitat creates areas for other species to live, a diverse part of the natural world will disappear. Called keystone species, because other animals and plants depend on their presence in an area, the gopher tortoises in dry areas, or alligators in wet and seasonally dry areas sustain other populations by maintaining certain conditions in the habitat conducive to one another’s dependent species.
In yet another case, the scrub jay eats a certain type of caterpillar that feeds on a type of fire tolerant if not fire induced-- vegetation restricted to arid sand hills, and requiring several acres per breeding pair. The scrub jay reintroduction literature suggests the birds may travel great distances to find suitable living conditions, although breeding pairs that mate for life, usually do not stray far from their home territories. So significant are these creature’s habits that some counties, such as Sarasota County have drafted ordinances that create incentives for owners of sand hill or sand-scrub and other rare habitats, to leave these areas open and free from agricultural or urban development. All of these species, save for the crocodiles, make their homes, or had historically been residents of the Ocala National Forest. Unlike an incentive program, or a conservation easement, this forest like state or county owned land uses the traditional means of owning property in order to protect, otherwise vulnerable, yet valued resources. This forest is in eastern Marion County, forms a necessary riparian and upland component of the Ocklawaha Valley watershed and is the oldest protected federal forest acreage in the state. Significant stretches of scrub, longleaf pine and bottomland hardwood swamp, all very scarce forms of natural areas in the state, persist in the protected areas of this National Forest. Originally set aside for watershed protection and sustained yield forestry of sand pine for pulp and paper manufacturing, the multiple-use forestry act (197?) has broadened, if not always deepened the mandate of the forest service to wisely steward the plant, wildlife and fishery stocks found on federal land for the various benefits of a wider public who demands recreation and not just lumber from its commonly owned forest lands.
Over the last two centuries biologists who study living things have been struck by many often-subtle characteristics of how species adapt to the changing conditions of existence. But among their observations, paramount is the growing and widespread belief that the pace of changes underway since the 17th century has had an accelerating and unavoidably disturbing affect on the adaptive responses and variety of adjustments that species can make to altered surroundings. It may be perplexing to bird lovers, but sand hill cranes and wood storks have been seen to feed in artificial retention ponds, created to capture highway or other urban storm water runoff from paved over land. Clearly some creatures, such as raccoons, opossum’s and squirrels may increase in number due to human modification of land and water patterns, while scrub jays clearly do not. Some creatures such as the gopher tortoise can be readily relocated from harms way and placed in reserved natural lands. Similarly, fresh water fish have been stocked in lakes and streams by artificial selection in the employment of fish hatcheries. In Florida, however, with the construction of dams for flood control and later the barge canal, shad and striped bass were blocked from spawning upriver (like salmon in the Pacific Ocean) and the American eel fishery was adversely affected since these creatures live up river but must spawn in the Atlantic Ocean.
In the long memory of genetic adaptive responses of living creatures to physical existence, earthquakes, floods, fires, volcanic eruptions, hurricanes, tsunamis and glacial changes have all undoubtedly refined life on earth. In the sense of E. O. Wilson’s comment that our ancestor’s genes “have eaten the storms,” his metaphor can be extended. Life today is the product of our ancestral species having adapted and thus enfolded into their genetic repertoire of possible responses all the disasters that have and will continue to require life to readjust to new conditions. Since the work of Alvarez in the 1970s we have even added the catastrophic impact of asteroids, meteors or space debris to the disturbances that have inevitable molded the adaptive responses of life on earth to chronic, acute, or lasting changes in physical existence.
So why it can be asked are human intrusions any worse than geological events with respect to life on earth? More specifically how is the convergence of human demographic growth, technological disturbance and the actual physical reassembly of our surroundings any worse than say the ice age in the Pliocene, or an asteroid that ended the Cretaceous period and the ubiquitous diversity of dinosaurs on earth? In one sense these questions are not appropriate to ask. By simply answering the wrong question, we can say that current human impact may not be as bad as an asteroid falling into the Gulf of Mexico. But we have just made an irrational comparison between two unlike impacts. The question is a wrong one to ask because it attempts to place humans outside of the physical and biological milieu within which we find ourselves embedded. If humans are part of a living matrix that persists in a physically optimal condition, then treating human impacts an glacial or astronomical impacts as similar distorts our understanding.
Like all life on earth human beings and civilizations depend upon common geochemical materials that over time the earth accumulates from the tread of life upon its surface. Aside from the argument that large mouth bass may thrive in a dammed reservoir (converted river bed and flood plain), other species, including shad, striped bass, blue crabs, or eels may cease to exist. More significantly, the transformation of the adjacent watershed has altered the chemical composition of both spring fed and swamp fed rivers in the Ocklawaha Valley. Thus, human impacts have a physical, biological and intentional character that make such impacts different from physical collisions or climate changes. We can change out behavior, whereas glaciers and asteroids are without volition. Through conscious choices in land use and water permitting, the human use of the upland, whose receiving waters are the Silver and Ocklawaha Rivers, is having discernible downstream impacts on water, vegetation and fisheries.
More explicitly humans, the species we depend upon and the species that depend upon us all have to live with the consequences of growing cultural disturbances. These cultural disturbances are what biologists, like Wilson have envisioned genetically and referred to their combined impacts as a bottleneck in biological existence. This narrowing of genetic futures, or bottlenecks through which all species’ gene pools must pass, is the reason for the use of such a term. These constricted passages from the present gene pool to some future more limited pools, exist due to the changes in human demography, technical capabilities and character of our lingering disturbance. When a species such as the Ivory billed wood pecker, once inhabitants of Florida’s remote forests, become extinct, we say that they as a species have failed to transit through the bottleneck which Wilson envisions as an artificial gauntlet run by all species. Humans have a choice, in one sense that asteroids, glacial advances and volcanic explosions do not, to rehabilitate plats and animals, even wild settings, so as to widen the constrictive bottlenecks in the transmission of wild gene pools from one generation to the next.
Historians who use ecological methodology and biological
findings to understand the relation of humans to natural history have developed
two or three powerful descriptive metaphors concerning impacts generally
of civilization on ecology and a place’s ecological resilience to changes
experienced by other creatures to the human civilizing impulse. These generalizations
reduce the complexity of human ecological conditions to ecological, economic,
or geographical models. All of the models are dynamic in that they stress
interdependency, extractive response, and feedback functions in the way
creatures and conditions are shaped and shaped by each other’s presence.
1. The earth is not a stage but an active partner in human endeavors dynamically shaping and being shaped by the interaction of civilization in a series of ecological revolutions. (Crosby, Merchant, et. al.)
2. The principle cultural mechanism for converting natural objects into resources for human use is understood through economics and by their labor and ingenuity humans extract what they desire, need, or can afford to from their physical surroundings with various degrees of damage, destruction, or improvement. (Worster, Steingraber, Jackson.)
3. As agents of change like glaciers, volcanic eruptions or other geological forces human civilization emerged by the 19th century as an active ingredient in altering the face of the earth. By measuring such land use and land use changes in forests (LULUCF) or other long lived features humans can better understand their impact to mitigate, if not fully avoid harmful or unhealthy alterations of the planet’s feedback mechanisms. (Marsh, Toynbee, Wilson)
Each of these metaphors: partnership arenas, extractive markets, or geophysical panopticon, can be helpful in understanding how our ideas about nature, biological wealth and our own species’ health changes over time. They are also complementary means of reducing the complexity of ecology and evolution for more effective human comprehension of our impact’s consequences.
These perspectives suggest that there is a range of human responses to and alterations of their surroundings. Simplistically these range from passive to active adaptive responses and from more to less maladaptive responses.
|Fish weirs, snares, controlled burn, forest fires
|Living in a flood plain
|Slash and burn agriculture
|Radioactive nuclear fallout
Where then does the ideal of biorestoration, or ecological restoration fit into this schematic framework for understanding the human role in natural history? In reviewing the necessity of reintroducing salmon populations and salmon diversity (of species) into the Columbia River watershed, Kai Lee, an agency and science policy specialist has argued for the application of social learning strategies and bounded conflict as a means to employ adaptive management techniques to resolve the disputes among practitioners.
Underlying these disputes over legal obligations for water, fisheries and forests in the Columbia River are the seeming intractable conditions imposed on natural resources by hydro electrical dams and salmon spawning and growth requirements. Salmon are an anadromous or ocean living fish that must return to fresh water to breed, much as the striped bass, or shad in the Ocklawaha river. As such the life cycle of the species requires the entire length of the river, its flood plain and estuary in order for the ocean stock to remain numerous and genetically viable enough for wildlife or people to catch.
Social learning requires that different specialties
learn to speak each other’s use of language. I will call these differences
in expert languages, dialects and emphasize that they create a problem
across disciplinary gaps and with political discussions. For instance David
H. Davis, a political scientist argues that, because air “pollution affects
everyone in a region. The social science term for this concept is ‘collective
good.” He then points out that, “Economists use the term public good,”
but political scientists refrain from using this word, because it is too
easy to confuse ‘public’ with ‘governmental’.” (1998, p. 28.) This is just
a simple example that does not involve chemistry, biochemistry or ecosystem
management where the use of the same word, may logically have different
meaning to experts. Professional dialects exist as barriers to understanding
impede the exchange of expertise, and more importantly inhibit our conversations
with the public in a vocabulary that everyone can understand.
With respect to adaptive management a contrast between
the Rodman Dam reservoir and the Bonneville Dam reservoir is instructive.
Unlike Bonneville Dam, the Rodman Dam is not used to provide water for
agricultural irrigation, or electrical power. Instead it holds back a shallow,
9000-acre reservoir managed by the state of Florida for a single species,
a largemouth bass fishery. Once the home of anadromous shad and striped
bass fisheries, the Rodman dam now keeps these fish, eels and manatees
from ascending upriver. The reservoir floods 16 miles of river upstream
burying 20 springs and drowning a diverse array of habitats. These habitats
include, flood plain marshes, wet prairies and the more diverse bottomland
hardwood swamps beside the river. Bonneville dam has much of the same impact
on riparian vegetation of the Columbia basin, but it does have fish ladders,
a fish hatchery, while providing subsidized electrical power and cheap
water for irrigation in an otherwise arid region. Many upstream users have
an interest in how Bonneville is managed. Boat fishing enthusiasts as opposed
to bank fishers have an interest I how Rodman is managed.
Adaptive management is now a readily used means in wetland restoration, or bioremediation practice to test actual field observations against models or anticipated results when attempting to engineer, manage or guide a natural or ecologically functional system from the status quo to some more desirable state of existence. Adaptive management is used in the Columbia River basin. At each step in the process, the natural field site is used to experiment in such a way that unforeseen impacts can be documented and the disturbances assessed before system wide damages weaken the capacity or rivers to assimilate waste, or habitat to accommodate more wildlife, grazing animals or stocks of fish. In a limited sense, “what if” questions are asked and when suitable, experiments derived from those realistic questions can be tested and monitored in the field, lake, stream or river. This allows practitioners to learn from their mistakes without an endless and costly process of random trial and error where species may be lost or their viability impaired.
Unlike adaptive strategies, random trial and error in Florida has had its benefits and social costs. From making a canal of the Kissimmee River for grazing and flood control to the diking of Lake Okeechobee for farming and the drainage of the Everglades, trial and error approaches have revealed important information about aquatic -- if not estuarine ecosystems. But the cost of each of these lessons in Florida has had to be shared by all of the nation’s taxpayers because water diversion has had adverse consequences for municipalities and wildlife alike. The advantage of adaptive management lies in reducing the costly mistakes we are undoubtedly on the verge of making as we expand the area in which people dwell, increase the state’s population and attempt to meet the steadily increasing per capita demand for water.
Adaptive management in the case of the Rodman reservoir would mean that as one moves from single to multiple resource management of the impounded waters, that as water levels are lowered or raised, the necessary experiments are performed for water quality, revegetation, and spring flow, to compare field based observations with computer models. This means that at every stage in the retrieval of a flowing stream from a reservoir a series of data points can be generated and plotted to better inform modelers on the relationship of nutrients to vegetation growth, fisheries and seasonal fluctuations. Thus the Rodman pool, where approximately one third of the runoff accumulated over the year evaporates from the shallow surface waters can serve as an aquatic laboratory. As such it becomes a means of restoring multiple use and a measure of what we do not know when it comes to re-engineering an ecological system from one cultural condition to a more diverse situation with respect to species, habitats, and hydrological conditions.
While adaptive management is the tactical means to the strategic end called ecosystem management, neither of these words evokes, I think, a suitable metaphor to inform us. Nor can they guide us in our thinking about the impact of building or removing dams from rivers, or recreating the stream and underground water flow of an extensive wetland, or breaching a barrier island to assist the tidal flushing of a lagoon constricted by five or so causeways that thwart tidal currents’ flow. Michael Polan, in using the example of a forested village commons in Connecticut, a decade ago, argued that wilderness is an insufficient metaphor to describe the condition of this White Pine forest as it was taken over by an invasive exotic called Japanese honeysuckle vine, or when it was leveled by a tornado. The natural disaster led to the township arguing over what to do with the downed trees and the “adversely” altered forest. While Polan suggests that garden is as likely a metaphor as any to replace the neo-romantic ideal of wilderness, I am not entirely sure that Bonneville or Rodman reservoirs are gardens. Nor are we in any way assisted by thinking of them this way.
In the case of Rodman reservoir consider some facts. The state refers to the impoundment of water behind Kirkpatrick (Rodman) Dam as “Lake Ocklawaha.” Water quantity flowing into the very shallow impoundment is diminished by evaporation to the extent that about one third of the flow evaporates from the surface before it moves through the dam. The water quality in the reservoir is such that three times in the past, millions of fish have died from anoxic conditions, now requiring variation of the water levels. This means periodically the water is lowered to deny aquatic weeds space to grow. Once the weeds die, the water levels are returned to 18 feet behind the dam. The organic material, called detritus, created by altering water levels sinks to the bottom of the impoundment. From the perspective of fish species, largemouth bass populations are the basis of this regimen, not the other species of migrating fish or mammals that would thrive if there were a way through or over the earth filled dam. Wading bird populations that also populate southern riversides have been selected for by this water regime. These then are the facts in summary a 9,000-acre impoundment, flooding sixteen miles of river beneath 18 feet of water is simultaneously a lake, a reservoir, and a fish farm.
Is it any wonder that the public might be confused? The late Marjorie Harris Carr, for whom the cross-Florida greenway is named, used to say that an evaporative pan is not a reservoir, let alone a lake. One is tempted to call this impoundment an immense birdbath, but that too is only a partial, if not impartial observation of the whole. Advocates of “saving” Rodman reservoir as a largemouth bass fishery insist that the as an “ecosystem” the impoundment should be “preserved.” There is more than just competing dialects at work here for describing the same place, but I am really not alluding to economic motivations for different advocacy positions. Nor am I suggesting that it is helpful to see two competing extractive modes of recreation in a tug of war over what to do with the place.
What is clear is that if this area is a forest, a greenway or an impounded waterway, we do not as yet have a precise enough vocabulary to describe this alteration of the watershed. To the extent we have a vocabulary, precision thought can help solve problems. In the absence of even an imaginative metaphor, the single-purpose management of a fishery stands in relief from the Forest Service ideal of a multiple use approach to resource management. Stuck in the discourse of an extractive model, advocates on all sides of the question have seized pieces of the ecological model to wield as clubs in a public policy forum, where the lack of clarity compounds decision-making. In the wake of complications, it may be said that decision-making entities, like courts, frequently opt for the simplest, narrowest, or least harmful means of preserving the status quo. Adaptive management based on geographical realities, hydrological complexities and biological wealth is never simple. It may even challenge the concept of an unchanging existing status, since existence by its very definition is an arena where change has one of several discernable (observed, hence a panopticon where many alternatives are observable) outcomes.
The late Paul Shephard, of the Clermont Colleges, argued that we use metaphors as a means to transcend opposite, or unlike conditions with a single complex image. He further conjectured that in losing our religious upbringing in a more secular educational climate where commercial media commands most of our attention, the capacity for people to understand metaphors might atrophy. By this he meant that expressions of faith encompass rich metaphors that force the learner to leap over significant differences. For example “virgin birth.” In the Christian, Coptic and ancient Egyptian mythic traditions the concept of birth being associated with virginity, the very opposite of fertility, is an article of faith wrapped in a metaphor that reveals a mystery of existence. If we lose our ability to understand, let alone formulate appropriate metaphors, and Shephard is correct, then the suitable metaphor to encompass alteration of the living world fades away. It disappears at the very time we need better words to effectively describe existing conditions. Be this a “biogenetic bottleneck” through which we are living or a “geophysical hysterisis,” we lack a fitting descriptive metaphor to reveal our actions’ consequences. Hysteresis is a term in physics that describes a condition once thermally altered that is impossible to materially recreate because the metal is compositionally changed. So, by analogy, to restore a reservoir to better water quality is as difficult to conceptualize, as it is to restore a flowing river. Instead we use words that sound the same but describe radically different situations.
The emphasis here on the material and ecological conditions of natural areas, rivers and streams should not be the only consideration in understanding the human interdependence on the biological wealth of the physical world. There are cultures that envision a transcendent, metaphorical and even non-material relationship among all living beings. While our society is not dominated by such beliefs, even Christians understand the symbolism of water in baptism’s sacramental ritual. Such a ritual, after all, is an attempt to re-establish a divinity in the material elements that compose our world and us. Water, Leonardo da Vinci reminded us, is “the driver of life.” For Christians water is a symbol of the redemptive spirit of creation and the means of uniting humankind with its creator. Along the banks of the Ocklawaha River, in Marion County just below the confluence of the Silver River, is a site called by early settlers, Baptism Bluff. It marks the place where rural practitioners of Christianity baptized their faithful. The Kwakiutl people of the Pacific Northwest imbued the salmon with a sacred spirit of renewal that was observed in seasonal rituals to encourage the annual migrations of these species. Expressions of transcendent beliefs amidst the material of existence reveal a human capacity to accurately convey hidden conditions.
The historic transformation of the Ocklawaha Valley from agrarian to industrial and eventually into suburban settings is no trading of agrarian for mechanized “Arcadias.” No, at a deeper sense the forty year persistence of Rodman reservoir behind Kirkpatrick dam suggests that some events lack a precise explanatory vocabulary. The case of the transformation of the lower Ocklawaha Valley by the canal persists as a testament to the power of minority rights in a state where progress is still measured by to what extent the land can be physically altered. Although we are connected in ecological, extractive and geographical ways there is more to this intimacy than we can imagine. Our language and society may lag behind understanding what our tools have wrought. It would behoove use to move with more caution, always testing our assumptions. For biorestoration to aver the same mistakes that single purpose engineering fostered, social learning and adaptive management to promote biological diversity requires a new natural metaphor. If humans are to become more able stewards, we require some growth in their imaginations and expressions to convey the opportunities, obstacles and consequences of our daily dialogue with a dynamic and diverse ecology.
Watershed's value | New York City's Watershed
Version 4: 3/17/03
return to top of page