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Landscape Change In The South Prong Alafia River Basin by Kimberly Sarah Koenig A thesis submitted in partial fulfillment of the requirements for the degree of Master of Arts Department of Geography College of Arts and Sciences University of South Florida Major Professor: Robert Brinkmann, Ph.D. Mark R. Hafen, Ph.D. Graham A. Tobin, Ph. D. Date of Approval: December 6, 2006 Keywords: phosphate mining, aerial photos, west-central Florida, Bone Valley, reclamation Copyright 2007, Kimberly Sarah Koenig
ACKNOWLEDGEMENTS I would first like to thank Dr. Brinkm ann for your constant support throughout this endeavor and for always providing posit ive energy in the department. Dr. Tobin, thank you for setting and adhering to high standards, and for your guidance in this thesis. Dr. Hafen, thank you for always providing help, support, and reality-checks when needed, in this thesis and throughout my gra duate experience. The academic and moral support found in many of my fellow stude nts has helped tremendously throughout graduate school. Sara, thank you for all of your help and friendship. Craig, thank you for your friendship, technical assist ance, and help remaining sane through this journey. Clay, thank you for your friendship, moral support, and for taking me on the tour de phosphate that sparked my passion. Heather, your ex ceptional work and dedication serves as a shining light for many of us. April, Melis sa, Dan, Grant, Erin, and Spencer I have enjoyed your company and help throughout this experience. I would especially like to thank my family for their love and suppor t throughout school and life. Thank you for being exceptional role models and for teaching me to live for what I believe in. A special thank you must go to John, Jordin, Rosalie, Matt, Pete, Sabrina, Jenny, and Darrell for your friendship, encouragement, and humor. And Kellan, your constant love and support has made the challenges of life and school seem minor. The dedication and excellence that you maintain in your work has served as a constant reminder of th e capabilities of an individual. Thank you fo r everything.
TABLE OF CONTENTS List of Tables iii List of Figures iv Abstract v Chapter 1 Background 1 Introduction 1 Literature Review 2 The Drainage Basin 4 Landscape Alteration 5 Land Use/Cover Change Analyses 7 Florida Geology, Geomorphology, and Hydrology 8 Florida Geology 8 Florida Geomorphology 10 Florida Hydrology 11 Landscape Alteration in Florid a 13 Environmental Pressures 13 Land Use 15 Phosphate in Florida 16 Formation 16 Mining 18 Landscape Alteration 19 Chapter 2 Study Area 24 Physical Geography 24 Human Geography 26 The Alafia River and Phosphate Mining 28 The South Prong Alafia River 29 Chapter 3 Data and Methodology 32 Data 33 Landscape Classification 35 Analysis 41 Chapter 4 Results and Discussion 45 Landscape Composition 45 Composition: 1940 Group 45
Composition: 1970 Group 47 Composition: 2004 Group 47 Surface Hydrology 52 Surface Hydrology: 1940 Group 53 Surface Hydrology: 1970 Group 55 Surface Hydrology: 2004 Group 57 Phosphate Mining 59 Phosphate Mining: 1940 Group 59 Phosphate Mining: 1970 Group 61 Phosphate Mining: 2004 Group 63 Landscape Change 65 Composition 66 Surface Hydrology 81 Chapter 5 Conclusion 91 Conclusions 91 Limitations 93 Implications 95 Future Research 97 References Cited 99 Appendix 107
LIST OF TABLES Table 1. Aerial Photo Set Information. 34 Table 2. Georeferencing Data. 35 Table 3. Mining Feature Classes and Background Information. 37 Table 4. Landscape Classes and Background Information. 38 Table 5. Study Period Rainfall Information. 39 Table 6. 1940 Landscape Composition. 46 Table 7. 1970 Landscape Composition. 48 Table 8. 2004 Landscape Composition. 50 Table 9. 1940 Surface Hydrology. 53 Table 10. 1970 Surface Hydrology. 55 Table 11. 2004 Surface Hydrology. 57 Table 12. 1940 Phosphate Mining. 59 Table 13. 1970 Phosphate Mining. 62 Table 14. 2004 Phosphate Mining. 63 Table 15. General Landscape Change. 66 Table 16. Results of Difference Between 2 Proportions Tests, Anthropogenic Activity. 74 Table 17. Results of Difference Between 2 Proportions Test, P hosphate Mining Activity. 76 Table 18. Changes to Surface Hydrology. 81 Table 19. Length of Streams & Drainage Density, 1940, 1970, & 2004. 81
LIST OF FIGURES Figure 1. Florida Geology. 9 Figure 3. Bone Valley Phosphate Deposit. 19 Figure 4. Mandatory Reclamation Phosphate Lands. 22 Figure 5. Alafia River Drainage Basin. 25 Figure 6. Annual Rainfall Alafia Basin 1930 2005. 26 Figure 7. Study Area. 30 Figure 8. 1940 General Landscape Composition Map. 46 Figure 9. 1940 Landscape Proportions. 47 Figure 10. 1970 General Landscape Composition Map. 48 Figure 11. 1970 Landscape Proportion. 49 Figure 12. 2004 General Landscape Map. 51 Figure 13, 2004 Landscape Proportion. 52 Figure 14. 1940 Surface Hydrology Map. 53 Figure 15. 1970 Surface Hydrology Map. 56 Figure 16. 2004 Surface Hydrology Map. 58 Figure 17. 1940 Phosphate Mining Map. 60 Figure 18. 1970 Phosphate Mining Map. 62 Figure 19. 2004 Phosphate Mining Map. 64 Figure 20. General Landscape Change. 67 Figure 21. Mining 1940, 1970, & 2004 68 Figure 22. Water 1940, 1970, & 2004. 69 Figure 23. Urban 1940, 1970, & 2004. 70 Figure 24. Agriculture 1940, 1970, & 2004. 71 Figure 25. Undisturbed / Other 1940, 1970, & 2004. 72 Figure 26. Natural Lands Lost to An thropogenic Activity 1970 2004 & 1940 2004. 73 Figure 27. Natural Lands Lost to Phosphate Mining 1970 2004 & 1940 2004. 75 Figure 28. 1940 Landscape Evolution Example. 78 Figure 29. 1970 Landscape Evolution Example. 79 Figure 30. 2004 Landscape Evolution Example. 80 Figure 31. Surface Hydrology 1940, 1970, & 2004. 82 Figure 32. 1940 Hooker's Prairie Landscape Change Example. 85 Figure 33. 1970 Hooker's Prairie Landscape Change Example. 86 Figure 34. 2004 Hooker's Prairie Landscape Change Example. 87 Figure 35. Surface Hydrology Lost to An thropogenic Activity 1940 2004 & 1970 2004. 89 Figure 36. Surface Hydrology Lost to Phosphate Mining 1940 2004 & 1970 2004. 90
Landscape Change in the South Pr ong Alafia River Drainage Basin Kimberly Koenig ABSTRACT West-central Florida has supplied much of the national and global demand for phosphate for over 100 years. The two main trib utaries of the Alafia River, the North and South Prongs, have been extensively modi fied by the strip mining, benefaction, and chemical processing activities associated with the phosphate mining industry. Using aerial photos, an analysis of landscape change in the South Prong Alafia River drainage basin (357.4 km 2 ) between 1940, 1970, and 2004 was conducted. A modified Florida Land Use, Land Cover, and Forms Classifica tion System code (FLUCCS) was used to classify and measure change through the st udy period. Change in the study area is characterized by a dramatic decline in the area covered by natural lands and an increase in the area covered by anthropoge nic activity. Increasing 43.8 km 2 from 1940 1970 and 199.96 km 2 from 1970 2004, phosphate mining activ ity is the primary force of landscape alteration in the study area. The historic h eadwaters of the main stream, Hookers Prairie, is completely replaced by mining-induced landforms in 2004. Net change in landscape composition from 1940 2004 is 1) phosphate mining (+243.76 km 2 ), 2) surface hydrology (-113.13 km 2 ), 3) urban (+2.42 km 2 ), agriculture (+19.76 km 2 ), and undisturbed / other (-139.66 km 2 ). The results of this study indicate that the regional environment and hydrology have b een heavily impacted by phosphate mining
activity. The critical management of the industrys environmental impacts and reclamation practices is essential for the current and future health of the local environment and its inhabitants.
CHAPTER 1: BACKGROUND Introduction The largest reserves of phosphate in the world are located in central Florida (PCBOCC, 2006). Over 120 years of openpit phosphate mining has caused great landscape disturbance, particularly in the we st-central portion of the state. A primary concern related to the industry is the e ffect of mining activit ies on local hydrology (Brown, 2005). The management and reclam ation of phosphate-disturbed lands is a critical issue for the future of Floridas natural environment as well as for population sustainability. This research project focuses on analyz ing the spatial and temporal rates of landscape changes due to phosphate mining in the drainage basin of the South Prong Alafia Drainage Basin of west -central Florida. Details of landscape composition, before and after modification from phosphate mini ng, can guide restoration and reclamation efforts. Additionally, the examination of preand post-phosphate disturbed lands may provide insight into the effects of the i ndustry on local ecologi cal and hydrological functions. The research objectives are: To understand landscape composition, with an emphasis on phosphate mining and surface hydrology, in 1940, 1970, and 2004. To understand landscape change, with an emphasis on phosphate mining and surface hydrology, in 1940, 1970, and 2004.
This research was driven by the following research questions: How has the landscape composition of th e drainage basin of the South Prong Alafia River changed from 1940 2004? How has the surface hydrology of the study area changed from 1940 2004? How has phosphate mining altered the landscape of the study area from 1940 2004? These research questions were addres sed through aerial photointerpretation and GIS analysis. Aerial photos sets used in this analysis include a 1940 Group (1938 & 1941), a 1970 Group (1968 & 1973), and a 2004 Group (2004). The final product of this research is 1) a geodatabase, for each group of photos, of landscape composition, surface hydrology, and phosphate mining activity, 2) a mo rphometric and qualitative description of the features mapped in each group of photos, and 3) an analysis of landscape change throughout the study period. Literature Review Global history has seen an exponential in crease in population, development, and technological innovations. Turner and others (2001) identify two important trends related to land use throughout history: the total la nd area dedicated to human uses has grown tremendously, and the use and control of the la nd has intensified as a result of increased production of goods and services. A burgeoni ng world population both contributes to and exacerbates these trends. Land use activi ties such as developm ent, agriculture, and mining activities dramatically alter natural landscapes. Given the increase in land altered
by human use, there is heightened concern for the effects of land use on the natural environment. Water is a vital and increasingly scare resource. World wide, natural hydrologic features are polluted, altered, and even lo st. A large and growing world population coupled with the increased area affected by human use places water resources under great pressure. Public and private entities as well as scientists from a vari ety of disciplines are concerned with the protection and integrit y of hydrologic features of the natural landscape. Globally, water resource issues are in the forefront. The natural environment of Florida is one of the many places in which intensive and extensive human use has resulted in a si gnificantly altered landscape. Floridas natural hydrologic regime has undergone substa ntial modification. Federal, state, and local governments are actively planning a nd conducting restoration efforts throughout Florida. Also, there is a strong focus rega rding water resource management throughout Florida focused on conservation, reclamation, and restoration. There is an overall need for more data to aid in these efforts. A major issue related to Floridas water resource and land management is the phosphate mining industry (Brown, 2005). Flor ida is the nations leading producer of phosphate (FIPR, 2004). Phosphate mining in Florida is extremely land-intensive (BMR, 2004). The rate of land disturbed by phosphate throughout the state is 4,000-6,000 acres per year (FIPR, 2004). The natural landscape of the state has been and continues to be severely modified by phosphate mining activ ities. The natural hydrologic regime of phosphate mined areas is one of the primary issues related to the quality and functionality of the post-mined landscape (Brown, 2005). This research seeks to add to the existing
knowledge regarding landscape composition be fore and after alteration from phosphate mining activity. Additionally, this research seeks to provide insight into the rate and extent of landscape modification from phosphate mining activity in the South Prong Alafia River Drainage Basin. The Drainage Basin This research was developed and conducte d under the theoretical context of the drainage basin system A systems approach focuses on objects, the origin and development of objects, and the interaction between objects (Thorn, 2005). In a system, everything is connected to varying degrees Within physical sciences, such as geomorphology and hydrology, a systems approach has clarified the importance of and the interaction between form and pro cess (Gardiner, 1975) and emphasized the importance of the total environment and the elements within that environment (Gregory and Walling, 1973). The drainage basin is an open system in which there is the flow of mass and energy (Knighton, 1998; Wasserman 1990); there is self-regu lation and a tendency to promote equilibrium between the elements within the system (Wasserman, 1990). Within the drainage basin, it is well-estab lished that downstream consequences have upstream causes (Knighton, 1998, p. 65). The behavior and characteristics of the fluvial system at any location are reflective of the collective effects of upstream controls; these controls include geology, land use, and basin physiography (Knighton, 1998). Thus, changes to these controls will result in modified behavi or within the drainage basin system.
As a system, the drainage basin serves as an ideal set ting for understanding hydrologic alterations. The extent of anth ropogenic activities on the river channel and hydrologic functions is largely dependant on the nature of the activ ities as well as the proportion of the directly affected drainage basin (Park, 1977). Modifications to the fluvial environment result in changes to physical behavior and ecosystem dynamics (Levy and others, 2006; Po ff and others, 1997). Anthropogenic modifications in the hydrologi c regime of a drainage basin are the result of either direct channel modifications or indirect channel modifications (Gregory, 1977; Park, 1977) Direct channel modifications include channelization, levee construction, dam and reservoir construction, irrigation diversions, and bank modification (Gregory, 1977). Indirect modifications include changes in land use such as urbanization, land clearing, and mining. Through excavation and processing activiti es, phosphate mining results in both direct and indirect modification of Florida s streams. The industry has impacted the states hydrology for over a century. The stre ss of the phosphate mining industry on the hydrologic system exacerbates the regions water supply issues. Landscape Alteration The rate of land use and land cover cha nge has rapidly incr eased in the last several decades. The area affected by such changes has greatly incr eased (Solecki, 2001; Rembold and others, 2000). The terms land use and land cover are closely related, but represent different phenomena. Land use refers to the ways in which humans utilize the land and its resources. Land cover refers to the habitat and/ or vegetation present (Turner
and others, 2001). Worldwide, the rate of land cover alteration and land use change continues to accelerate. Concern for land use and land cover change s has heightened in recent years (Park, 1977). Socio-economic and environmental i ssues related to land use and land cover change have been frequently highlighted in recent research (Rembold and others, 2002). Landscape alteration studies include analyses of both cultural and environmental changes and a combination of the two. Landscape altera tion has recently incl uded research themes such as the role of economics in land use and land cover change (for examples, see Solecki, 2001; Walker, 2001), socioeconomic activities, land use dynamics, and effects on land cover (for examples, see Rembold and others, 2000; Soini, 2005; and Hladnik, 2005), alterations to natural hydrology and subs equent changes in th e hydrologic system and native land cover (for examples, s ee Merdonca-Santos and Claramunt, 2001; Maekawa and Nakagoshi, 1997; Ford and Brooks, 2002; Davies and others, 2005; White and Greer, 2006), as well as effects of mi ning activities on hydrology (for examples, see Kondolf and others, 2002; Graf, 1979; Rowan and others, 1995; Broring and Wiegleb, 2005). Direct human use represents the principa l factor in landscape alteration (Turner and others, 2001). Such activities include ag riculture, livestock activ ities, silviculture, urbanization and development, and mining. The majority of the total open landscape area is affected by human use. Of the land area regularly affected by human use, nearly 65% is accounted for by agriculture, forestry, mine ral extraction practices, transportation and urban development (Hladnik, 2005). Land use is directly linked to environmental quality (Redding and Perry, 1972; Solecki, 2001).
The concept of disturbance is a key to understanding landscape changes (Quattrochi and Pelletier, 1991). Disturbances can be natural (i .e. wildfire) or driven by human forces (i.e. drainage of wetlands). Disturbance refers to phenomena that disrupt the structure of ecosystems, communities, and/or population stru ctures and change resources and/or the physical environment (Turner and Dale 1991). Social, political, and economic forces largely dictat e disturbances in landscapes that are dominated by human use (Dunn and others, 1991). Land and resour ce management activi ties should critically consider the causes, patterns, dynamics, and consequences of natu ral and human-induced disturbances (Turner an d others, 2001). As the growth of global population conti nues and associated changes in land use and land cover accelerate, there will be a conti nued increase in issues between water use, development, and environmental change (Herrm ann and others, 1998). Land Use/Cover Change Analyses The study of land use and land cover ch anges is largely driven by applied problems and resource management needs (T urner and others, 2001). Landscapes are not static, but rather change ove r space and through time. Thus space and time are critical elements for understanding change at the landscape scale (Wien, 2002; Merdonca-Santos and Claramunt, 2001). Data for the analysis of landscape change are generally confined to three categories: 1) aerial photos, 2) satellite imagery, and 3) archival data. The current trend is towards the use of satellite-based imager y and automated raster analysis. However, aerial photos remain as prime source of lands cape-scale data for a majority of the 20 th century. Photointerpretation has some draw backs which include quality and availability
of aerial photographs as well as the time involved in the pr ocess (Dunn and others, 1991). Digital remote sensing provides elaborate me thods of analysis, but costs are relatively high and historical data are l acking. Archival data, such as census reports and historic soil surveys, can be used for qualitativ e analysis and can supplement aerial photointerpretation and digital remote se nsing analyses (Dunn and others, 1991). Florida Geology, Geomorphology, and Hydrology Prior to discussing landscape alteration in Florida it is important to put the state in a geologic, geomorphic, and hydrologic context. Florida is frequently misunderstood as a flat, featureless plain. This is far from the truth. A variety of la ndforms occur throughout Florida. Florida has a rich geological histor y that has resulted in the diverse landscape present today. Florida Geology The state of Florida is lo cated in the Coastal Plain physiographic province. The province is a region characteri zed by low relief that is und erlain by unconsolidated to poorly consolidated sediments as well as ha rdened carbonate rocks (Berndt and others, 1998). Floridas highest eleva tion is 345 feet above sea le vel in Walton County (FDEP, 2002). Most of the surface of Florida is cove red by deposits of sand that overlie a thick sequence of limestone and dolomite (Berndt and others, 1998). Florid as overall lack of natural exposures hinders ge ologic investigations in the state (Scott, 1992). Surface sediments in Florida range in age from the Eocene to the Holocene epochs (Lane, 1994). Figure 1 depicts the surface geology of Florida. The surface of Florida is dominated by Pliocene to Holocene siliciclastic-bearing se diments that were deposited in response to late Tertiary and Qu aternary Period fluctuations in sea level
Figure 1. Florida Geology.
(Scott, 1992). Precambrian Cambrian i gneous rocks, Ordovician Devonian sedimentary rocks, and Triassic Jurassic vol canic rocks occur thousands of feet below the surface of Florida and comprise what is known as the Florida Basement (Scott, 1992). Florida Geomorphology Peninsular Florida is the exposed porti on of the Florida Platform. Florida is located on the eastern portion of the platform (Schmidt, 1997). The platform extends over 100 miles west of Tampa and only approximately 3 miles east of West Palm Beach (Lane, 1994). The Florida Platform was formed by a combinati on of volcanic activity and the deposition of marine sediments over 500 million years ago (FLMNH, 2006). Geological evidence indicates that Florida was first formed together with the northwest coast of Africa before they were separa ted by tectonic rifting (Lane, 1994). Marine forces have dominated the geom orphologic history of Florida (Schmidt, 1997). Sea levels fluctuated numerous times since the formation of the Florida Platform (Lane, 1994). At times of higher sea leve ls, the platform was shaped by the shallow marine environment and associated erosiona l and depositional forces (Schmidt, 1997). Various relict shorelin es can be observed throughout the state. The landscape of Florida continues to be modified through coastal, fluv ial, chemical and aeolian forces. Floridas last documented emergence occurred approximately 35 million years ago (FLMNH, 2006). Florida was once separa ted from North America by the Gulf Trough. The trough was filled by siliciclastic sediments derived from the Appalachian Mountains during the Miocene Epoch (Lane, 199 4). With time, these sediments covered the carbonate platform.
Florida Hydrology Florida has a rich and diverse set of hydrological resource s. Figure 2 is a simplified depiction of Floridas surface hydrology. Average annual rainfall in the state is 53 inches; spatial and temporal variations in rainfall are present (Patton and Dehan, 1998). Freshwater is replenished by preci pitation as well as in flow of groundand surface water from Alabama and Georgia (Mille r, 1997). With high amounts of rainfall, runoff, evapotranspiration, and groundwater leve ls, the landscape of Florida is dominated by hydrologic processes (Gross, 1991). The peninsula has over 1,190 miles of coastline, more than 7,700 lakes, greater than 1,700 streams, 3 million acres of wetlands, and 320 springs (Patton and Dehan, 1998). The landscape of Florida is covered by highly permeable soil and rock at or near the surface (Miller, 1997). Karst terrain is present throughout much of the state (Lane, 1994). Manifestations of karst terrain throughou t the state include a high occurrence of sinkholes and springs, the presen ce of caves, disappearing str eams, and a well-established underground drainage network (FDEP, 2002). The high water table, low topographic relief, and proximity to sea le vel of Florida results in a higher number of streams than are generally present in karst areas (Mossa, 1998). The hydrology of Florida includes a uni que system of groundwater and surface water features. Combined, the surficial sands of Florida and the thick underlying limestone and dolomite form an extensive groundwater reservoir (Berndt and others, 1998). There are five principal aquifer syst ems in Florida that result in abundant groundwater resources (Miller, 1997). Stat ewide spring discharge exceeds 8 billion gallons per day (FDEP, 2002). The Floridan an d Biscayne Aquifers represent the largest
sources of water for the state of Florida. A majority of lakes and streams interact with groundwater (FDEP, 2002). Landscape Alteration in Florida One of the states primary problems rests in the need for a sustainable relationship between the human environmen t and the natural environment (Winsberg, 1996b). Population growth and development characterizes much of the history of Florida (Fernald and May, 1996). The states mo st significant population boom was fully underway by the 1950s and it continues today (W insberg, 1996a). Florida is currently home to over 17,000,000 people (USCB, 2006) with over 40,000,000 annual visitors (Winsberg, 1996b). Environmental Pressures Throughout the history of Florida, the st ates urbanization has frequently been at odds with the health of the natural envir onment (Fernald and May, 1996). The rate and scale of growth within the state threaten to destroy much of the beauty of Florida and to irreparably damage its ecology (Patton, 1996). Much of what attracted people has been altered and degraded by thei r presence. Widespread drai nage of wetlands, miles of artificial waterfront, hazardous waste discharges, and unplanned urban sprawl are among some of the results of population growth with scant regard to the he alth of the natural environment (Patton, 1996). Floridas species are among the most endangered in the nation, largely due to the destru ction of habitats (Whitney and others, 2004), as well as habitat fragmentation (Kautz and others, 1998).
The natural hydrologic regime of Florida has been subjected to an exceptional amount of modification. Of Floridas 51,858 miles of stream s and rivers, approximately half are ditches and canals (FDEP, 2002). Ex tensive levee and canal construction began in the 1920s. Wetlands were drained on a large scale for flo od control and to accommodate agriculture and development (Walker, 2001). Streams were channelized for navigation and development, altered by da ms and reservoirs, and stressed by large withdrawals for various huma n uses. Floodplains were alte red by development (Kautz and others, 1998). Floridas coastline is heavily populated and its estuarine and marine habitats suffered greatly; many of the natura l communities are not healthy (Whitney and others, 2004). Lakes were directly altered by land use change and urbanization as well as indirectly affected by groundw ater withdrawals (Kautz a nd others, 1998). As the principal supply for public, domestic, and indus trial water uses, groundwater is in high demand (Berndt and others, 1998). The Federal, state, and local governme nts are actively undertaking projects to restore the natural functions of much of the states natura l landscape (Patton and DeHan, 1998). The natural hydrology of Florida has undergone extensive a lteration and many hydrologic features have been de graded, with some f eatures lost altogether. The Florida Department of Environmental Protection identif ies water quantity and quality issues to be of primary concern for the 21 st century (FDEP, 2002). Two of the largest restoration efforts ever conducted, the Ki ssimmee River Restoration Proj ect and the Comprehensive Everglades Restoration Plan, ar e currently being undertaken in the state. Both projects focus on restoring natural hydrologic functions.
Phosphate mining has been a major force of alteration in th e states hydrologic and terrestrial landscape. The restorati on of Floridas phosphate-mined lands could potentially cover over 300,000 acres and is sim ilar to the Everglades Restoration project in scale and complexity (Brown, 2005). Land Use Florida supported a large and grow ing population throughout most of the 20 th century and into today. An expanding ec onomy accompanied this explosive population (Patton, 1996). The rapid land use and land cover changes in Florida are driven by agricultural development, industrial purpos es, commercial development, residential needs, and transportation (Solecki, 2001) Developing sustainable communities continues to be a challenge. Floridas three largest industries ar e tourism, agriculture, and mining (IMC phosphates, undated). The very nature of these industries causes them to alter the natural landscape of Florida. Florida is widely know n for its ability to produce subtropical and out of season crops (Patton 1996) as well as its many tourist attractions, both constructed and natural. Although Florid a ranked fifth nationwide in terms of non-fuel mineral production in 2003 (USGS, 2003), the mining industry of Florida is not as well-known as the tourism and agriculture industries. The mineral industry of Florida is diverse in nature and is important to the states economy. Mining in Florida is undertaken exclusively by open-pit methods (Lane, 1994). Phosphate, cement, stone, sand, and gravel production repres ents approximately 88% of mining activities th roughout the state (McClellan and Eades, 1997). Other mining activities include fullers earth, palygorskite clays, pe troleum and natural gas, and
rutile (Campbell, 1985). All mining in Florida is subjecte d to reclamation requirements (BMR, 2004). Phosphate mining accounts for ap proximately 50% of Floridas mineral value (McClellan and Eades, 1997) and repres ents the most land-intensive commodity mined in the state (BMR, 2004). Phosphate in Florida Of the four phosphate-producing states throughout the nation, Florida leads in production (USGS, 2003). Worldwide, onl y Morocco produces more phosphate than Florida (Livingston and others, 1998). Th e phosphate reserves of Florida contribute approximately 75% of the nations supply and approximately 25% of the worlds supply of phosphate (Brown, 2005; IMC Phosphates, unda ted). As the third largest industry in the state, phosphate mining and processing is of vital importance to the economy of Florida (IMC Phosphates, undated). Phosphate is a limited, non-renewable re source (FIPR, 2004; Slansky, 1986). A majority (90%) of phosphate mined in Florida is used in the production of fertilizer. Phosphorus is one of the three primary plant nutrients essential for growth (FIPR, 2004; Slansky, 1986). There are no substitutes for phosphorus in agricultu re (Jasinski, 2005; Slansky, 1986). With a rising world population and the need for dependable food supplies, global phosphate demand is expect ed to increase (Jasinski, 2006; Slansky, 1986). Phosphate is also used in a variety of products such as plasti c, food preservatives, animal feed, soft drinks, toothpaste, and vitamins (Lane, 1994; Campbell, 1985). Formation Phosphorite is a term used to describe sedimentary rocks that contain an economic amount of phosphorus (Compton, 1997). Larg e, economic phosphorite deposits, such as
those found in Florida, are rare due to the st rict conditions necessary for their formation (Compton, 1997; Riggs, 1980). The formation of such deposits requires a sufficient fluctuation of organic matter to provide the phosphorus necessary to form phosphorite. Once formed, a physical process to remove or ganic matter and fine-grained sediments is necessary to yield concentrated phosphorite (Compton, 1997). The origin of the phosphorite reserves of Florida lies in Miocene marine sedimentation (Compton, 1997; Riggs, 1980). P hosphorite-bearing sediments of Florida, for the most part, belong to the Hawt horn Group and the Bone Valley Member (Compton, 1997). Fluctuations in sea le vel during the Miocene provided the shallowwater coastal and shelf marine environmenta l conditions necessary for the formation of Floridas phosphate reserves (Riggs, 1980; Scott, 1997). Re-working of these reserves during the Pliocene high -stand resulted in the high con centrations of phosphorus present in much of Floridas phosphate deposits today (Slansky, 1986). A majority of the phosphorus in Floridas phosphorite derives from francolite. Crandallite and wavellite contribute a minor portion of the phosphorus in the phosphorite reserves of Florida; these minerals form from extensively weathered francolite (Compton, 1997). The topography of Florida guided the Mi ocene sedimentation of phosphate, and thus, the distribution of the states current reserves (Compton, 1997). Low-lying areas were submerged, providing the necessary mari ne environment, and the topographic highs of the state provided struct ural guidance for the sedimentation and subsequent concentration. Topographic highs of greatest influence during this process were the Ocala Upland and the Sanford High (Riggs, 1980). Other influential positive features
included the St. Johns Platform, the Central Florida Platform, and the Brevard Platform (Compton, 1997). Mining Over 300,000 acres in Florida are domi nated by phosphate mining activities (Brown, 2005). Phosphate mining has taken plac e in Florida for nearly 120 years. The discovery of high-grade hard rock phospha te ore near Dunnellon in 1889 triggered a phosphate boom. By 1892, there were over 215 phosphate mining companies operating in the state (FIPR, 2004). Currently, three co mpanies mine land pebble phosphate in the state. Land pebble is favored for mining becau se of the large size of the deposits as well as the ease in mining and low be nefaction costs (Campbell, 1985). The Bone Valley Deposit in Central Florida is the largest phosphate deposit in the world (PCBOCC, 2006). This deposit encompasses approximately 500,000 acres throughout Polk, Hillsborough, Manatee, and Ha rdee Counties and has been the primary source of phosphate in the st ate (Jasinski, 2005). The location of the Bone Valley Deposit is depicted in Figure 3. The Hawthorn Formation is also being mined in Hamilton County in north Florida and areas adjacent to the Bone Valley Deposit (FIPR, 2004). Phosphate mining in Florida takes the form of open pit mining, utilizing large draglines and buckets to rem ove vegetation and the overburde n, which is typically 30 feet thick (Brown, 2005). The buckets, which ar e large enough to hold a truck or van, are also used to mine the phosphate matrix (FIPR, 2004). The pits created in the phosphate
Figure 2. Bone Valley Phosphate Deposit. extraction are generally 200-300 feet wide and several thousand feet in length (Yon, 1983). The phosphate ore zone is generally 5 to 50 feet thick and is a combination of clay, quartz sand, and phosphate (Yon, 1983). After excavati on, high pressure water is utilized to slurry the phosphate matrix fo r transport to the benefaction plant. The phosphate is then separated from the matrix through benefaction and shipped to chemical processing facilities for the production of fertilizer (FIPR, 2004). Landscape Alteration Phosphate mining activity results in a landscape that is severely modified (Brown, 2005, p. 324). Annually, phosphate mining disturbs 4,000-6,000 acres (FIPR,
2004). Mining for phosphate alters the topograp hy, the stratigraphy of geology and soils, and the hydrologic regime of the natural landscape of Florida (Riekert and others, 1991). The nature of landscape alteration from phosphate mining results from excavation as well as processing. In fact, some of th e primary issues asso ciated with phosphate mining are its waste products. The two ma in waste products from phosphate mining are clay settling areas and phos phogypsum. The following is a brief summary of these waste products. Clay Settling Areas (CSAs) produced through benefaction; typically occupy 40 60% of the post-mined landscape (B rown, 2005). High-pressured water is utilized to separate the phosphate matrix and results in clay by-products that occupies a much larger area post-proce ssing. CSAs shift and settle over time, resulting in increased de pression storage and evapor ation and decreased runoff (Lewelling and others, 1998). Additiona lly, CSAs hinder groundwater recharge (Lewelling and others, 1998). Phosphogypsum Stacks phosphogypsum is produced from chemical wet processing of phosphoric acid at a rate of 30 million tons/year (FIPR, 2004). Approximately 5 tons of phosphogypsum results from the production of 1 ton of phosphoric acid (Long and Orne, 1990) Phosphogypsum contains radium, fluoride, and acids and is re quired to be stored in gi ant gyp stacks (Dooris and others, 2000). Over 1 billion tons of phosphogypsum is currently stored in 25 stacks in Florida (FIPR, 2004). Gyp st acks can reach 200 feet high and cover 400 600 acres; the smallest stack weighs approximately 5 million tons (Dooris and others, 2000).
The hydrologic regime is particularly a ffected by phosphate mining activities. In 1998, the regional water demand for the industry was 200 million gallons/day (SWFWMD, 1998). Approximately 25-30% of lands annually disturbed by phosphate extraction activities are wetlands (FIPR, 2004). In addition to the wetlands directly destroyed by mining, other wetlands are aff ected due to disconnection from natural systems, altered hydrology, and increased tu rbidity (HCEPC, 2006). Streams have been relocated to allow phosphate mining (Robert son, 1987). Effects of phosphate mining on the hydrology of Florida include the reduction or elimination of base flow, reduced surface runoff, lowered water levels in the U pper Floridan aquifer, and replacement of natural surface drainage by modified topography and reclaimed ditches and swales (Lewelling and others, 1998). The landscape that remains after phospha te mining takes place is virtually barren (Brown, 2005, p. 326). Reclamation of phosphate mined lands is mandatory for all lands mined after July 1, 1975. Lands mi ned prior to July 1, 1975 were reclaimed on a voluntary basis; a majority of mined land in rural central Florida was not reclaimed (FIPR, 2004). The location of Mandatory Re clamation phosphate la nds is depicted in Figure 4. Reclamation research is considered a top pr iority related to th e industry in Florida (FIPR, 2004). It is estimated that without human interven tion, the post-mined landscape will take approximately 500 years to undergo natural restoration (Brown, 2005). It is important to note that reclamation does not mean the restoration of the natural communities that were in existence prior to mining activity. Reclamation entails returning lands to a beneficial use, whereas restoration entails rest oring ecological and
Figure 3. Mandatory Reclamation Phosphate Lands.
hydrological functions (Brown, 2005). Altern ative ecosystems, differing significantly from the original ecosystems, usually result from reclamation activit ies (Pratt and others, 1985). Phosphate mining is frequently promot ed as a temporary land use by the industry (Mosaic, 2005). However, finding pr oductive uses for reclaimed phosphate land often presents a major problem (PC and UFIFAS, 1994). Public concern and debate has often surrounded the effects of phosphate mining on Floridas wetlands, rivers, and natural landscape (Pratt and others, 1985). There is currently a large public concern regarding the industrys inten tions to move south as the Bone Valley deposit is mined out. The ecological and hydrologi cal health of the Peace River is a major focus of public resistance to additional mining. For over a century, phosphate mining has been a significant force of landscape modification and resource consumption in the region. Critical management of this industry is necessary for future sustainability of the region. A great er understanding of the role of phosphate mining in land use/land cover change and environmental health is essential for the current and future task of regulation and management of Floridas phosphate industry.
CHAPTER 2: STUDY AREA This project focuses on a sub-basin of th e Alafia River, which has been heavily impacted by phosphate mining activities. Th e South Prong of the Alafia River was chosen for this analysis due to the scale of impacts from mining on this sub-basin. The following sections explore geography of the Al afia River and highlight the interaction of the phosphate industry with the Alafia River watershed. The final section specifically examines the South Prong Alafia River sub-basin. Physical Geography The Alafia River drains approximately 1,093 square kilometers in Hillsborough and Polk Counties (Kelly and others, 2005). The location of the Alafia River Drainage Basin is depicted in Figure 5. The Alafia River is formed by the confluence of its two main tributaries, the North and South Pr ong Alafia Rivers, in eastern Hillsborough County. It flows 38.6 kilometers west into lower Hillsborough Bay (SWFWMD, 2001). The Alafia River watershed is surrounded by the Peace River watershed to the east, the Little Manatee River watershed to the south, and the Hillsborough River watershed to the north (Kelly and others, 2005). The climate of this area is humid subtropi cal, with a mean annual temperature of 72.2 0 F (SWFWMD, 2001). Mean annual rainfa ll is 52 inches, with a majority of precipitation occurring as convective thunders torms from June September (Kelly and others, 2005). Figure 6 is a graph of annua l rainfall of the basin from 1930 2004.
Figure 4. Alafia River Drainage Basin. Annual evapotranspiration for the Alafia Rive r drainage basin is 39 inches (SWFWMD, 2001). Land cover in the Alafia River watershed was historically a variety of coastal, wetlands, and upland habitats (SWFWMD, 2001). The lower portion of the Alafia River drains part of the Gulf Coastal Lowlands, while the remainder of the river flows through the Polk Upland (Kelly and others, 2005). Primary soil groups in the Alafia River watershed include the My akka-Basinger-Holopaw association, the Candler-Lake association, and the Winder-Chobee-St. Johns (SWF WMD, 2001). The soils of the Polk County portion of the watershed are dominated by Arents-HaplaquentsQuartzipsamments, a man-made soil type that is the result of phosphate mining (Kelly and others, 2005).
Figure 5. Annual Rainfall Alafia Basin 1930 2005. (Data Source: SWFWMD Comprehensive Watershed Management su mmary rainfall data) The water level of the Alafia River is often below the potentiometric surface of the underlying aquifers, resulting in numer ous springs and seeps along the river and floodplain (Dames and Moore, 1975). Tw o second-magnitude springs, Lithia and Buckhorn Springs, contribute approximately 35 million gallons/day to the Alafia River (Champion and Starks, 2001). Approximately 14 % of the combined flow of Lithia and Buckhorn Springs is diverted to phosphate chemical processing facilities (SWFWMD, 2001). Human Geography The Alafia River is located within the large and rapidly developing urban area of Tampa Bay. Urban areas within the waters hed include parts of Lakeland, Plant City, Mulberry, and Brandon (Kelly and others, 2005). Watershed population in 2000 was
estimated to be 232,227 (SWFWMD, 2006). Agriculture and phosphate mining are major economic activities in the watershed. Rates of habitat dest ruction within the watershed have been high since the 1 920s and 1930s (SWFWMD, 2001). The current area covered by natural systems is declining, habitats are being fragmented, and changes in hydrology and degraded water quality are leading to damage in areas not directly altered by anthropogenic activity (PESI, 2002). The Alafia River watershed is a major water source for public supply, industrial uses, agriculture, and phosphate mining (SWFWMD, 2001). Both surface and ground water are used for water supply. For exam ple, approximately 99.6 million gallons/day were withdrawn from the watershed in 1998. Of these withdrawals, agriculture accounted for 30% and phosphate mining accounted for 28% (SWFWMD, 2001). Additionally, the recently completed C.W. B ill Young Reservoir utilizes the Alafia River as a primary source of water (TBW, 2006). As urbanization and industrial growth continue in the drainage basin and surrounding areas, pressures on water supply are expected to increase (SWFWMD, 2001). This is especially important given th e history of water supply shortages in the Tampa Bay region. For over 40 years, the region has experienced political battles over water resource supply and demands (Rand, 2003). Water quality and qua ntity continue to be an issue in the region. PESI (2002) identifies the following as the primary sources of pollutant loading to the Alafia River: 1) phosphate mining and processing, 2) nitrate lo ading from Lithia and Buckhorn Springs, 3) periodic spills from phosphate CSAs and gypsum stacks, 4) urbanization, 5) agriculture, and 6) sewage disposal.
The Alafia River and Phosphate Mining The Alafia is home to both phosphate mini ng and processing and is thus impacted by the land disturbance, clay and phos phogypsum waste, and water quality issues associated with the industry. Phosphate mining activity has been an inherently intrusive and destructive practice with respect to the natural habitat within the watershed (SWFWMD, 2001, p. 6-15). In 1999, mining activity accounted for at least 35.9% of the total land area within th e drainage basin (Kelly and othe rs, 2005). A majority of the mining activity is concentrated in the eastern half of the watershed, particularly in the North and South Prongs of th e river (SWFWMD, 2001). The headwaters of both the river and its two main tributaries are located in the phosphate mining district of Hillsborough and Polk counties (Dames and Moore, 1975). The mouth of the river was dramatically altered by dredge and fill activities associated with the need for shipping access from a phos phate mining facility to the main shipping channel in Tampa Bay. The historic mouth of the river has since been reduced to a small tidal creek with minimal to no conn ection to the river (PESI, 2002). Widespread changes to the physiography a nd drainage patterns of the basin have resulted from phosphate mining as natural lands have been cl eared, excavated, and partially reclaimed (SWFWMD, 2001). The origin of many of the open water systems in the eastern portion of the basin lies in phosphate mining activity (Kelly and others, 2005). The largest wetland in the basin, H ookers Prairie (Dames and Moore, 1975), has undergone near total modification by phosphate mining. Phosphate reclamation efforts within the basin have yielded mixe d results (SWFWMD, 2001).
Phosphate mining activity acc ounts for a majority of the water quality issues that the watershed has experienced (HCEPC, 1998), and represents bot h point and non-point sources of pollution (SWFWMD, 2001). Pollutants that result from the mining process include strong acids, phosphates, fluorides, sulfates, ammonia, and radionuclides (PESI, 2002). Both phosphogypsum and clay settling area failures have occurred numerous times on the Alafia River, ofte n with ecologically devastating results. These spills can threaten human health, wildlife, and ecosystems (SWFWMD, 2001). An example of such spills occurred on December 7, 1997 when the dike of a gypsum stack failed and released approximately 50 million gallons of acidic process water into a tributary of the North Prong of the Alafia River (HCEPC, 1998). The spill resulted in the death of most of the aquatic life (ranging from alligators to fish to microscopic plankton) for the remaining length of the river (HCEPC, 1998). The South Prong Alafia River The South Prong Alafia River, one of the tw o main tributaries of the Alafia River, drains approximately 357 square kilometers (88,303 acres) (Kelly and others, 2005). The location of the South Prong Alafia River Drai nage Basin is depicted in Figure 7. The channel of the South Prong is poorly define d, flowing through marsh and swamp areas (SWFWMD, 2001). The headwaters of this stre am are in Hookers Prairie, northeast of Brewster in Polk County (Dames and Moore, 1975). Watershed land use in 1999 (utilizing the FLUCCS code) was dominated by phosphate mining activity (65%) and agricu lture (17.3%), with small amounts of wetlands (10.9%), uplands (5.5%), open water (1.5%), and urban usage (2.3%) (Kelly
Figure 6. Study Area. and others, 2005). Urban activity is concen trated in Bradley Junction, a phosphate community circa 1896 (FIPR, 2004). Over half of the mined land in the Alafia River watershed is located in the South Prong sub-basin (Kelly and others, 2005). T opographic maps indicate that much of the area within the basin is barren land, a re sult of extensive phosphate mining activity (SWFWMD Exec Summary). Phosphate mining is considered the major pollutant source for the South Prong drainage basin (SWFWM D, 2001). The headwaters of the South Prong Alafia River (Hookers Prairie) have been greatly impacted by phosphate mining activity. A sawgrass reclamation project in the Hookers Prairie area won the Bureau of Mine Reclamations Outstanding Wetland Project award in 2000 (Mosaic, 2005).
However, the mining tract that covers the H ookers Prairie area was not yet released by FDEP in 2003. There is a lack of understanding regardi ng the impacts of an thropogenic activity, and particularly phosphate mining, on the Alafia River Drainage Basin. This research seeks to contribute to the knowledge rega rding the impacts of phosphate mining on the South Prong Alafia River Drainage Basin. Additionally, this research seeks to enhance the understanding of the dynamics of landscape change in the region and the associated implications for population and environmental sustainability.
CHAPTER 3: DATA AND METHODOLOGY This research seeks to understand landscap e change to the drainage basin of the South Prong of the Alafia River, utilizing the earliest comprehensive da ta set available. The objectives of this research are: To understand landscape composition, with an emphasis on phosphate mining and surface hydrology, in 1940, 1970, and 2004. To understand landscape change, with an emphasis on phosphate mining and surface hydrology, in 1940, 1970, and 2004. This research was driven by the following research questions: How has the landscape composition of th e drainage basin of the South Prong Alafia River changed from 1940 2004? How has the surface hydrology of the study area changed from 1940 2004? How has phosphate mining altered the landscape of the study area from 1940 2004? These research questions were addresse d through the interpre tation of sequential aerial photographs. Given that aerial photogr aphs provide a holistic view of the landscape (Lo, 1976) and represent the only comp rehensive source of data for the early 20 th century, aerial photos were ideal for this study. Analysis of archival data, such as historic soil surveys and topographic maps, wa s utilized to enhan ce the quality of the aerial photointerpretation and resulting data. The utilization of mu lti-temporal sets of
aerial photos allowed for the exploration of th e spatial and temporal dynamics related to phosphate mining in the study area. Data The two-county nature of the drainage basin provided a challenge to the acquisition of comprehensive sets of aerial photographs for the years of interest. Photos were taken in different, but near, years in each of the two counties. In order to utilize the earliest photos available for the study area, 1938 Hillsborough County and 1941 Polk County aerial photos were acquired. This gr oup of photos will be referred to as the 1940 Group. Table 1 outlines information for each set of photos used in this analysis. 1968 Polk County and 1973 Hillsborough County photos were chosen for analysis in order to gain a better understanding of the temporal dynamics associat ed with change in the study area. This group of photos will be referred to as the 1970 Group. The final photos, taken in 2004, were chosen for analysis in order to understand the contemporary composition of the study area. This group of phot os will be referred to as the 2004 Group. While the multi-year groupings are not desirable, they provided the only way to capture full drainage basin characteristics during particular time periods. Due to the non-static nature of drai nage basin boundaries and many issues associated with delineating them, spatial data were acquired from the SWFWMD regarding the current South Pr ong Alafia River drainage ba sin. This basin boundary was used in each year of analysis. In many places, the basin boundary is defined by anthropogenic features. County Road 555 form s the entire eastern boundary of the basin and State Highway 674 forms part of the southern boundary. Additionally, many parts of
the basin boundary are formed by phosphate mi ning features that in clude clay settling areas of various ages and stages of reclamation and gypsum stacks. Table 1. Aerial Photo Set Information. Photo Group Photo Set Data Source Date Additional Info Required Georeferencing 1938 Hillsborough Florida Center for Community Design and Research (FCCDR), University of South Florida November 1938 January 1939 Georeferenced by FCCDR under a grant from Hillsborough County No 1940 Group 1941 Polk University of Florida March 1941 Originally taken by the Department of Agriculture Yes 1968 Polk University of Florida January February 1968 Originally taken by the Department of Agriculture Yes 1970 Group 1973 Hillsborough Environmental Protection Commission of Hillsborough County No 2004 Group 2004 Polk & Hillsborough FDEPs Land and Boundary Information System (LABINS) December 2003 April 2004 Orthophotos No All analysis was conducted within the Al bers Equal Area Conical Projection in order to preserve areal inte grity of the data. Where needed, georeferencing was conducted within ArcGIS. Due to the rural na ture of the study ar ea in the early photos and the extent of landscape al teration over the study period, an array of spatial data were utilized to ensure quality georeferencing. Tabl e 2 outlines the data that were utilized in the georeferencing process.
Table 2. Georeferencing Data. Data Information Data Source Topographic Maps USGS 7.5 minute; created 1987 LABINS Roads 1: 24,000 roads; created 1998 Florida Geographic Data Library Hydrography 1: 100,000 surface hydrology; created 2003 Florida Geographic Data Library Gypsum Stacks Phosphogypsum stack locations; created 2003 FDEP Mandatory, NonMandatory, and Hybrid CSAs Compilation of all data regarding clay settling areas; created 2003 FDEP Landscape Classification Data analysis was conducted within ArcG IS. All data were managed within a geodatabase. The three groups of photo sets provided the basis for the creation of the database. The features of interest were for each study period and subsequently analyzed landscape changes. A classification system wa s created and uniformly applied to each set of photos. The creation of this classification system was guide d by a review of the nature of phosphate mining in central Florida as well as the Florida Land Use, Cover, and Classification System (FLUCCS) Handbook. The FLUCCS code was developed by the Florida Department of Transportation to pr ovide a uniform basis for land cover and land use classification. The identification of features of intere st was performed through the utilization of the fundamental principles of image interp retation. These are size, shape, location, shadow, tone and color, texture, pattern, height and depth, site, situ ation, and association (Jensen, 2000). An inherent challenge to qua ntifying landscape change is the notion that
the landscape is a continuum rather than a series of discrete landscape classes and problems arise in landscape classificati on regardless of the survey methodology employed (Taylor and others, p. 2749,1999). I attempted to best account for this challenge through the utilization of a variety of archival data and constant data quality and assurance monitoring. To assure quali ty landscape classification, historic and contemporary soil surveys, topographic maps, and the pertinent avai lable spatial data were used to guide interp retation of the photos. A pilot study, covering 50 sq km in Polk County, was conducted April May 2006. This study area was chosen because of the existence of both mining and natural features in the historic landscape. The goa l of the pilot study was to test and fully develop the methods and classification scheme proposed for this study. The pilot study was successful in this regard. Minor modifi cations in the classification scheme were made as a result of this study. The study ar ea was successfully mapped by land use. The landscape classes and specific features ut ilized in this analysis were chosen to fully embrace the nature of landscape alterati on from phosphate mining as well as to meet the goals of this study. Tables 3 and 4 outline the landscape features and basic criteria for their identification used in this analysis. Special attention was placed on wetland delineation. A wetland is defined as an area that is periodically i nundated or saturated by surface or ground water on an annual or seasonal basis, that displays hydric soils, and that typically suppor ts or is capable of supporting wetland hydrophytic vegetation (Black, 1991, p. 133). However, true wetland delineation was in this case difficult due to the inability to test soils, water, and vegetation
Table 3. Mining Feature Classes and Background Information. LU/LC Category Feature ID Feature Type Classification Mining 110 Mining Facilities Industrial facilities on mining land Processing began in 1950s (Long & Orne, 1990) 120 Gypsum Stacks A by-product of processing, gypsum stacks are located near processing facilities FDEP shapefiles used as guidance in case of discrepancy 130 Open Pits Active Adjacent pits and steep-sloped piles Mine pits are easily observable on aerial photos (SWFWMD, 2001) 140 Clay Settling Areas CSAs that retained shape were placed under this classification CSAs easily observable on aerial photos (SWFWMD, 2001) FDEP shapefiles were used as guidance in case of discrepancy 150 Old Clay Settling Areas CSAs that have not retained their shape and/or were heavily vegetated were placed under this classification FDEP shapefiles were heavily utilized as guidance for this feature classification 160 Tailings/ Spoil Piles Generally located in areas of recent and active mining Tailings now utilized in reclamation efforts; represent a temporary landscape feature in current photos 170 Mining Lakes & Ponds Region has many water-filled former mine pits (SWFWMD, 2006) Water bodies on mined land not falling into other categories were placed under this classification 180 Disturbed Mining Land Mining scars apparent and/or documented from earlier photo sets Mining land not falling into other terrestrial mining classes was placed under this classification 190 Reclaimed Land/Converted to other Land Uses Mined land in areas of mandatory reclamation and classified as released by FDEP was placed under this classification Mined land that was converted to other uses (agriculture & urban) and observed through the interpretation of earlier photos was placed under this classification
Table 4. Landscape Classes and Background Information. at each site for each year of analysis. To compensate for this difficulty, soil surveys and topographic maps were used for guidance. Th e complications associ ated with identifying wetlands from aerial photos may have led to the inclusion of some undisturbed land in this land use category. Data quality check ing and assurance wa s conducted after the completion of each year of landscape clas sification as well once all years were completed. LU/LC Category Feature ID Feature Type Classification Water 210 Streams Much of the channel is undefined, flowing through marsh and swamp (Dames and Moore, 1975) Topographic maps and FDEP shapefiles were used for guidance Streams were combined with wetlands for areal measurements 220 Wetlands Natural wetland systems Topographic maps and soil surveys were used for guidance 230 Lakes and Ponds Natural lakes and ponds Water bodies placed under this classification have little to no vegetation 240 Karst Depressions Mapped only in areas not classified as wetlands These features have little to no water Urban 300 Urban Urban or Built Up Agriculture 400 Agriculture Agricultural activity apparent Undisturbed / Other 500 Undisturbed / Other All lands not falling into the above categories were placed under this classification. Although most of these lands were undisturbed, some rangeland was likely placed into this category due to its general lack of distinctive landforms and/or borders
Due to the dynamic nature of the precipitation regime and hydrological system, it is likely that features mapped as karst depressions in drier conditions may be mapped as lakes/ponds in wetter conditions, and vice ve rsa. The stream floodplains are densely vegetated and the streams often disappear in the aerial photos. To ensure accurate measurements in landscape coverage, streams and wetlands were combined for areal calculations. Streams were digitized as line files in order to determine total stream length and drainage density. These parameters were ex amined to provide a ge neral understanding of the defined drainage in the study area th roughout the study period. The fine scale of analysis necessary for accurate hydrologic modeling was unattainable due to the large size of the study area and difficulties encount ered in stream definition. Understanding changes to surface h ydrology is difficult due to the dynamic nature of the hydrologic regime. This ch allenge was addition ally given special consideration due to the time between the photo sets used for the 1940 Group (1938 & 1941) and the 1970 Group (1968 & 1973). Table 4 provides summary data regarding annual basin rainfall during the study period. Table 5. Study Period Ra infall Information. (Data So urce: SWFWMD, CWM, 2006). Study Period Rainfall Data Group Year Rainfall (inches) 1938 48.63 1940 Group 1941 57.55 1968 50.44 1970 Group 1973 55.28 2004 Group 2004 68.80 Mean 1930 2005 52.32 Standard Deviation 1930 2005 8.76
The land use category of undisturbed / other served as a catch-all for lands not falling in any of the anth ropogenic land use categories or lands with no clearly identifiable hydrological characteristics. Mo st of these lands ar e likely undisturbed uplands. However, there is a possibility that some rangelands were included in this classification category due to the frequent lack of physical evidence associated with historic cattle farming. The available spatial data regarding phos phate mining landforms were used as guidance in classification. P hosphate mining-associated data are generally limited to post-1975, when reclamation became mandato ry. However, there has been a considerable effort by various state agencies to compile spatial information regarding clay settling areas that were present prior to mandatory reclamation. These data were especially helpful due to the sometimes unc learly defined boundaries of clay settling areas in the historic photos. Consistent with the need to clearly de fine landscape classes and specific feature classes, specifications were developed as to what lands would be included in the reclaimed land category. Spatial data rega rding reclamation status are available on a scale that is consistent with individual mining operations, which modernly cover broad expanses. Most of the study area is contem porarily mined out; nearly all of the mined land in the study area is classi fied by FDEP as under reclam ation. Land was classified as reclaimed only if 1) the mining tract wa s officially released by FDEP according to the 2003 shapefile, or 2) conversion to other land uses (i.e. urban or agriculture) was observed in the aerial photos thr ough the study period.
Analysis In 1940, missing and/or poor quality photos led to the classification of 14.5 sq km of the basin as no data. This area represen ts 4.5% of the basin. To ensure a consistent study area, these areas were treated as exclus ion layers in the subsequent years. All results and maps are based on the basin with the appropriate areas excluded. However, information regarding all available data is also presented in the results tables for each step of analysis for the 1970 and 2004 groups. The area of each feature was calculated within ArcGIS. These figures were used in calculating the total extent of each la ndscape class and feature class. General landscape composition is analyzed based on th e five broad landscape classes generated for this analysis (mining, water, urban, ag riculture, and undisturbed / other). For the purpose of understanding the ro le of anthropogenic activity in the landscape change dynamics, the five landscape classes were grouped into the categor ies of natural and anthropogenic land uses. Anthropogenic land uses include mining, urban, and agricultural lands. Natural lands include water and undisturbed / other. After the examination of general la ndscape composition, surface hydrology and phosphate mining activity were analyzed in gr eater detail based on th e specific feature classes generated for this anal ysis (Table 4). Areal calculations were used to gain an understanding of the role of each feature within surface hydrology and phosphate mining. Additionally, landscape organization was vi sually examined for patterns. Areal calculations were then used to explore land use change from 1940 1970, 1970 2004, and overall from 1940 2004. To explore landscape evolution, land use maps were generated for each general landscape class for 1940, 1970, and 2004. To
further examine the role of anthropogenic activ ity in the loss of na tural lands, layers of natural and anthropogenic land uses were generated for each 1940, 1970, and 2004. The intersect function in ArcGIS was then used to determine which natural lands present in 1940 were replaced with anthropogenic lands in 1970. This operation was subsequently repeated to determine natural lands lost to anthropogenic activity from 1970 2004, and overall from 1940 2004. The significance of the change in the proportion of the basin covered by anthropogenic activity was st atistically explored thr ough the Difference Between Proportions Two Sample Z-test. This statis tic tests for a significance different between two proportions from different populations, at the desired level of significance (McGrew and Monroe, 2000). The standardized test statistic for the Difference Between Proportions Two Sample z-test is: ) 11 ( )() (21 21 21nn qp pppp z Erro r Standard difference ed Hypothesiz diff Observed z Where: p 1 = the number of successes (proportion of the total study area) accounted for by the variable of intere st in the population 1 p 2 = the number of successes (proportion of the total study area) accounted for by the variable of interest in population 2 n 1 = the total population 1 (study area) n 2 = the total population 2 (study area)
p = the amount of the variable of inte rest in population 1 + the amount of the variable of interest in population 2 / the to tal study area of populat ion 1 + the total study area of population 2 q = 1 p (McGrew and Monroe, 2000) To further examine the role of phosphate mining activity in the loss of natural lands, layers of phosphate mining activity were generated for each data set in 1940, 1970, and 2004. The intersect functi on in ArcGIS was then used to determine which natural lands present in 1940 were replaced with phosphate mining activity in 1970. This operation was subsequently repeated to determ ine natural lands lost to phosphate mining activity from 1970 2004, and overall from 1940 2004. The Difference Between Proportions Two Sample Z-test was again used to explore th e significance of the change in the proportion of the basin covere d by phosphate activity from 1940 1970, 1970 2004, and overall from 1940 2004. Areal calculations were then used to explore changes to su rface hydrology from 1940 1970, 1970 2004, and overall from 1940 2004. Change in total stream length and drainage density were also explored. To understand hyd rological evolution in the study area, land use maps were generated fo r the specific surface hydrological features for 1940, 1970, and 2004. The role of anthropogenic activity in the loss of surface hydrology was explored using the intersect function in ArcGIS. The intersect function was first used to determine the area of surface hydrology in 1940 that is replaced by anthropogenic
activity in 1970. This operation was subseque ntly repeated to determine the area covered by surface hydrology lost to anthropogenic activity from 1970 2004, and overall from 1940 2004. The role of phosphate mining in the loss of surface hydrological features was examined using the intersec t function described above.
CHAPTER 4: RESULTS & DISCUSSION Landscape Composition It is well documented that the landscape of the South Prong Al afia River drainage basin has been dramatically altered by intensive land use ac tivity, most notably phosphate mining and processing. However, detailed data regarding the sp atial and temporal dynamics of this alteration are lacking. A total of 1717 landscape features were delineated for this analysis. The following information is the result of the dig itization of the 1940 Group, 1970 Group, and 2004 Group aerial photographs. Composition: 1940 Group The general land use map generated for th e 1940 Group is located in Figure 8. A total of 14.5 sq km, representing 4.05% of the study area, was treated as no data in the 1940 classification due to missing and/or poor quality photos. Table 6 summarizes the spatial extent and lands cape proportion for the genera l landscape classes in 1940. Minimal anthropogenic activity was observed in the 1940, and thus this photo set provided a basis for understanding lands cape composition in the study area under natural conditions. Figure 9 represents proportional landscape composition for the 1940 Group. Anthropogenic activities accounted for 10.89% of the study area in 1940. Agriculture, covering a mere 27.25 sq km, was the major activity present. Small patches of agricultural land uses were located ad jacent to wetlands throughout the study area.
Table 6. 1940 Landscape Composition. 1940 Land Use Class Area (square km) % of study area Mining 11.55 3.23 Water 152.26 42.57 Urban 0.19 0.05 Agriculture 27.25 7.61 Undisturbed / Other 151.96 42.49 Exclusion / No Data 14.50 4.05 Total 357.1 100 Urban activity, covering 0.19 km sq, occurred as a small group of st ructures adjacent to agricultural activity Phosphate mining activity, whic h occurred in small groups on the periphery of the eastern portion of the basin, accounted for 11.55 sq km. Figure 7. 1940 General Landscape Composition Map.
A majority of the study area (85.06%) wa s covered by natural landscape classes. Water features, including streams, wetlands, lakes and ponds, and karst features, covered 152.26 sq km. Undisturbed / other lands c overed 151.96 sq km. These landscape classes were interspersed and occurred ubiq uitously throughout the study area. Figure 8. 1940 Landscape Proportions. Composition: 1970 Group Table 7 summarizes the spatial extent and landscape proporti on for the general landscape classes in 1970. The data for the entire study area, wit hout the exclusion are also listed in Table 7. To ensure a consistent study area throughout the period of analysis, all results are based on the study area with the appropriate areas excluded from the data. The general landscape map gene rated for the 1970 Group is located in Figure 10. Figure 11 represents proportiona l landscape composition for the 1970 Group.
Table 7. 1970 Landscape Composition. 1970 All Available Data With Appropriate Area Excluded Land Use Class Area (square km) % of stud y area Area (square km) % of study area Mining 55.35 15.48 53.91 15.07 Water 122.15 34.15 115.12 32.19 Urban 2.69 0.75 2.60 0.73 Agriculture 67.47 18.86 65.65 18.35 Undisturbed / Other 110.00 30.76 105.88 29.60 Exclusion / No Data --14.50 4.05 Total 357.6 100 357.6 99.99 Figure 9. 1970 General Landscape Composition Map. Anthropogenic activities accounted for 34.15% of the study area in 1970. Agriculture, covering 65.65 sq km, account ed for the largest area of anthropogenic activity. Agriculture occurred throughout the basin, but was concentrated largely in the western portion of the basin. The size of th e agricultural patches of land varied, with the
largest patch covering 10.22 sq km. With a spatial extent of 53.91 sq km, phosphate mining activity accounted for a large portion of the anthropogenic activ ity. A majority of the phosphate mining activity occurred in the ea stern portion of the basin. A large cluster of mining activity, covering 25.25 sq km, wa s present on the southeast border of the basin. Phosphate mining activity was minimal in the western portion of the basin, with the largest patch covering 4.55 sq km. C overing only 2.60 sq km, urban activity occurred primarily in one cluster in the east central por tion of the basin. This urban area was the mining town of Bradley Junction. Figure 10. 1970 Landscape Proportion. A majority of the study area (61.79 %) wa s covered by natural landscape classes. The dominant natural landscape class was wa ter, covering 115.12 sq km of the study area. Covering 105.88 sq km, undisturbed / othe r lands occurred throughout the basin.
Together, these landscape classes formed a network of natural lands that extends throughout the basin. Composition: 2004 Group Table 8 summarizes the spatial extent and landscape proporti on for the general landscape classes in 2004. The data for the entire study area, without the exclusion, are also listed in Table 8. Again, to ensure a consistent study area throughout the period of analysis, all results are based on the study area with the appropriate areas excluded from the data. The general landscape map gene rated for the 2004 Group is located in Figure 12. Figure 13 represents proportiona l landscape composition for the 2004 Group. Table 8. 2004 Landscape Composition. 2004 All Data With Appropriate Area Excluded Land Use Class Area (square km) % of stud y area Area (square km) % of study area Mining 255.31 71.38 245.06 68.51 Water 39.12 10.94 37.32 10.43 Urban 1.52 0.42 1.52 0.42 Agriculture 47.58 13.30 46.99 13.14 Undisturbed / Other 14.15 3.96 12.30 3.44 Exclusion / No data --14.50 4.05 Total 357.6 100 357.6 99.99 Anthropogenic activities accounted for 82.08 % of the study area in 2004. Phosphate mining was the major land use, covering 245.06 sq km. Spatially dominating the basin, phosphate mining activity occurred throughout. Some agricultural activity was present, covering 46.99 sq km. Agricultural land use primarily occurred in large clusters in the west-southwest portion of the study area and in the northwest portion of the study area, near the basin outlet. Urban usage c overed 1.52 sq km of the basin. Encapsulated by mining activity, the urban area of Bradley Junc tion is present. Small patches of urban
areas also occurred adjacent to agriculture activity in the northwestern portion of the study area. Figure 11. 2004 General Landscape Map. Natural land use accounted for 13.87 % of the study area. Natural lands occurred relatively infrequently and were found primarily in the western portion of the basin. Covering 37.32 sq km, water accounted for a majo rity of the natural land in the basin. Water features occurred primarily along majo r streams segments and were frequently surrounded by anthropogenic activ ity, of which phosphate mining is the major factor. Undisturbed / other lands cover for 12.30 sq km and occur in small patches, mostly in the western portion of the basin. Some of these patches occur amidst vast expanses of phosphate mining activity; thes e patches exhibited no obvious signs of mining activity,
were not mined in either of the historic data sets, and were heavily vegetated. There is a possibility that these lands were mined and reclaimed, but lack of evidence led these lands to be classified as other / undisturbed. Figure 12, 2004 Landscape Proportion. Surface Hydrology A focus of this analysis was to unde rstand surface hydrology of the study area in 1940, 1970, and 2004. The landscape class ( 200) of surface hydrology is subdivided into four major categories: streams (210), wetlands (220), lakes (230), and karst depressions (240) (Table 4).
Surface Hydrology: 1940 Group The map of surface hydrology generated for the 1940 Group is located in Figure 14. In 1940, water features covered 42.57% of the landscape. Table 9 summarizes the spatial extent and proportion of study area for each water feature class. Figure 13. 1940 Surface Hydrology Map. Table 9. 1940 Surface Hydrology. 1940 Water Feature total # area (sq km) % of study area Wetlands -148.08 41.40 Ponds/lakes 147 3.02 0.85 Karst Depressions 76 1.16 0.32 Total -152.26 42.57
The study area was dominated by hydrologi cal features in 1940. Wetlands are present throughout as well as ponds, lakes, and karst depressions. A total of 147 lakes / ponds were mapped, covering 3.02 sq km. Lakes / ponds had an average size of 0.02 sq km. The minimum and maximum size of these features was 0.0012 sq km and 0.1717 sq km, respectively. These ponds and lakes were concentrated in the eastern portion of the basin, but were found throughout. A majority of these features are ci rcular in shape and are likely karstic in origin. A total of 76 karst depressions are present were 1940, covering 1.16 sq km. Mean size of karst depressions is 0.015 sq km. The minimum and maximum size of these features was 0.0011 sq km and 0.1105 sq km, resp ectively. Many of these features likely function as intermittent lakes. The features were found mostly in the eastern portion of the basin. Covering 148.08 sq km, wetlands dominated the surface hydrology in the study area in 1940. A network of wetlands covered the basin. Hookers Prairie, a major wetland system that serves as the headwaters of the South Prong Alafia River, was present in the south-southeast portion of the basin. In the western portion of the basin, wetlands occurred largely along the floodplai n of streams. Modifications from agriculture, such as drainage channels adjacen t to agricultural activit y, were present in some of the wetlands. Channelized flow occurred mostly in th e western portion of the basin. Total stream length in 1940 was 166.09 km and drainage density is 0.464. The streams flowed through sometimes wide areas of wooded and non-wooded wetlands. Many streams
flowed as poorly defined channels, originati ng in wetlands. Vegetation islands occurred in many streams. Surface Hydrology: 1970 Group In 1970, water features cover 32.19 % of th e landscape. Table a0 summarizes the spatial extent and proportion of study area for each water feature class. The data for water features in the entire study area, without the exclusion is also listed in Table 10. All results are based on the study area with the appropriate ar eas excluded from the data. The surface hydrology map generated for the 1970 Group is located in Figure 15. Table 10. 1970 Surface Hydrology. 1970 All Available Data With Appropriate Area Excluded Land Use Class Total # Area km 2 % of study area Total # Area km 2 % of study area Wetlands -117.98 33.70 -113.96 31.83 Ponds/lakes 25 0.18 0.05 24 0.17 0.05 Karst Depressions 56 1.63 0.45 54 0.99 0.28 Total -119.79 34.15 -115.12 32.15 Surface hydrological features were pres ent throughout the study area in 1970. Ponds/Lakes and karst features were presen t throughout the study area, but were largely concentrated in the eastern portion of the basin. Karst depressions covered 0.99 sq km and ponds and lakes cover 0.17 sq km of the ba sin. A total of 56 karst depressions were present. The mean size for karst depressi ons is 0.0106 sq km, with a maximum size of 0.165 sq km and a minimum size of 0.001 sq km. A total of 25 lakes / ponds were present. The mean size of lakes and ponds was 0.007 sq km, with a maximum size of 0.072 sq km and a minimum size of 0.001 sq km A majority of the lakes and ponds were circular in nature.
Figure 14. 1970 Surface Hydrology Map. Covering 113.96 sq km, wetlands spatia lly dominated the surface hydrology of the study area in 1970. Various networks of wetland systems were found throughout the study area. Some of these wetland systems have straight edges, characteristic of anthropogenic modification. Hookers Prairie wa s present in a reduced size in the southsoutheast area of the basin. In the western portion of the basin, wetlands were located primarily at the headwaters and fringes of streams. Channelized flow occurred primarily w ithin the western porti on of the basin. Total stream length in 1970 was 162.33 km. Nu merous tributaries flowed into the main stream. Drainage density in 1970 was 0.454. The streams meandered through areas of
wooded and non-wooded wetlands. Vegetation is lands were present along much of the main stream. Surface Hydrology: 2004 Group The map of surface hydrology generated fo r 2004 is located in Figure 16. In 2004, water features cover 10.94% of the lands cape. Table 11 summarizes the spatial extent and proportion of study ar ea covered for each water fe ature class. The data for water features in the entire study area, without the exclusion, is also listed in Table 11. Table 11. 2004 Surface Hydrology. 2004 All Data With Appropriate Area Excluded Land Use Class Total # Area km 2 % of study area Total # Area km 2 % of study area Wetlands -38.6 10.82 -36.92 10.32 Ponds/lakes 23 0.43 0.12 22 0.41 0.11 Karst Depressions 0 0 0 0 0 0 Total -39.12 10.94 -37.33 10.43 Surface hydrological features are confined to the western portion of the basin. The entire eastern portion of the basin is void of natural surface hydrology. Lakes and ponds are present in close proximity to ch annelized flow and amongst agricultural activity in the western portion of the basin. A total of 22 lakes / ponds are present, covering 0.41 sq km. Mean size of ponds / lakes is 0.034 sq km. The maximum and minimum size of ponds / lakes is .092 sq km and 0.0001 sq km, respectively. Most of these features do not exhibit natural form. No karst depressions were mapped in 2004. Above average rainfall from 2002-2004 may ha ve led to the filling of any karst depressions present, and the s ubsequent classification of thes e features as lakes / ponds in this analysis.
Figure 15. 2004 Surface Hydrology Map. Wetlands are present along streams in th e western portion of the basin. Although dominating the surface hydrology of 2004, wetlands cover only 36.92 sq km. Nearly all of these wetlands are bordered by anthropogeni c activity. Hookers Pr airie, historically the headwaters for the main cha nnel, is no longer present. Channelized flow is present in the eastern portion of the basin. Total stream length in 2004 is 118.85 km. Many of th e streams are fragmented by anthropogenic activity. Drainage density is 0.332. The main channel flows through thin areas of wooded and non-wooded wetlands as well as th rough mining activity. Ne ar the outlet of the basin, where agriculture is the dominant land use, the stream flows through a wide area of wetlands.
Phosphate Mining Another focus of this thesis was to u nderstand phosphate mining activity in the study area in 1940, 1970, and 2004. The ge neral landscape class of (100) phosphate mining activity was subdivided into nine major categories: mining facilities (110), gypsum stacks (120), active / open pits (130), clay settling areas (140), old clay settling areas (150), sand tailings / spoil piles (160) mining lakes (170), disturbed mined land (180), and reclaimed mined land (190) (Table 3). Phosphate Mining: 1940 Group The map of phosphate mining in 1940 is located in Figure 17. In 1940, phosphate mining activity accounted for 3.23% of the study area. Table 12 summarizes the spatial extent and proportion of study area covered by each mining feature. Table 12. 1940 Phosphate Mining. 1940 Mining Feature area (sq km) % of study area Facilities 0.58 0.16 Gyp Stacks 0 0 Open & Active Pits 0.63 0.18 Clay Settling Area 1.44 0.40 Old Clay Settling Area 0 0 Tailings & Spoil Piles 2.02 0.56 Mining Lake 0.94 0.26 Disturbed Mined Land 5.93 1.66 Reclaimed Land 0 0 Total 11.55 3.23 A majority of the mining land in 1940 is classified under the broad category of disturbed mined land, covering 5. 93 sq km. This is likely the result of two factors: reclamation was not yet mandatory and the be nefaction capabilities of the industry were limited. Although some of the mining activ ity that was present in 1940 is obviously
Figure 16. 1940 Phosphate Mining Map. historic, the mined land is filled with sharp feat ures. The industrys capability to separate the phosphate ore from the matrix was not effi cient in 1940, resulting in larger amounts of the matrix discarded as waste. Phosphate mining activity was limited to two small clusters in the eastern portion of the basin in 1940. These clusters we re located along the southern border and northeastern border of the study area. One of the areas excluded due to poor quality photos traverses mining activity. The cluster in the northeast was a mix of features resulting from prior mining activity. There was also a processing facility in this group of mining features. This is likely a benefaction plant (chemical processing had not yet begun) Numerous flooded
pits were present here as well as two clay se ttling areas, some tailings and spoil piles, and disturbed mined land. Active and recent mining activity was present in the cluster located along the southern border of the western portion of the basin. There wa s a series of active pits and the associated spoil piles. There was also a group of mining facili ties present along with clay settling areas and disturbe d mined land in this cluster. Some mining features are absent from the study ar ea in 1940. There are no gypsum stacks, old clay settling areas, or re claimed mined land. Gypsum stacks are not present because the chemical production of pho sphoric acid had not yet begun in 1940. The absence of old clay settling areas and re claimed land can likely be attributed to the relatively early stage of mining in the area. Phosphate Mining: 1970 Group Table 13 summarizes the spatial extent and landscape proportion in for each mining feature class in 1970. The data for th e entire study area, wit hout the exclusion are also listed in Table 13. A ll results are based on the study ar ea with the appropriate areas excluded from the data. The map of phospha te mining features generated for the 1970 Group is located in Figure 18. Phosphate mining covered 53.91 sq km in 1970, accounting for 15.07% of the basin. Both active mining and relic mining features were present in 1970. A majority of the phosphate mining activity was located in th e eastern portion of the basin. Mining activity in the wester n portion of the study area was lim ited to a large area of active mining pits, a gypsum stack, and a small mix of disturbed mined land and mining lakes. All mining features used in this analysis were found in the east ern portion of the basin.
Table 13. 1970 Phosphate Mining. 1970 All Data With Appropriate Area Excluded Land Use Class Area km 2 % of study area Area km 2 % of study area Facilities 2.91 0.81 2.87 0.80 Gyp Stacks 8.70 2.43 8.70 2.43 Open & Active Pits 14.94 4.18 14.66 4.10 Clay Settling Area 4.16 1.16 4.16 1.16 Old Clay Settling Area 2.24 0.63 2.24 0.63 Tailings & Spoil Piles 1.38 0.39 1.38 0.39 Mining Lake 2.42 0.68 2.37 0.66 Disturbed Mined Land 17.53 4.90 16.48 4.61 Reclaimed Land 1.07 0.30 1.05 0.29 Total 55.35 15.48 53.91 15.07 Figure 17. 1970 Phosphate Mining Map. Mining activity was spatially dominated by disturbed mined land and active pits, covering 16.48 sq km and 14.66 sq km, respectively. There are a number of mining facilities; this category is likely comprised of both benefaction and chemical processing
facilities. There were four gypsum stacks pr esent, ranging in size from 2.72 sq km to 0.19 sq km, covering 2.43% of the basin. C overing 6.40 sq km, three clay settling areas, one old and two new, were present. There were some small mining lakes, many in the rectilinear shapes of old pits, located amongs t disturbed mined land and adjacent to active mining activity. There was a small portion of agricultura l activity taking place on land that was mined in the past. Reclaimed land covered 1.05 sq km in 1970. This reclaimed land is located along the northern border of the study ar ea in the eastern portion of the county. Phosphate Mining: 2004 Group Table 14 summarizes the spatial extent and landscape proportion in for each mining feature class in 2004. The data for th e entire study area, wit hout the exclusion is also listed in Table 1r. All results are ba sed on the study area with the appropriate areas excluded from the data. The map of phospha te mining features generated for the 2004 Group is located in Figure 19. Table 14. 2004 Phosphate Mining. 2004 All Data With Appropriate Area Excluded Land Use Class Area km 2 % of study area Area km 2 % of study area Facilities 0.59 0.16 0.59 0.16 Gyp Stacks 6.80 1.90 6.81 1.90 Open & Active Pits 1.65 0.46 1.65 0.46 Clay Settling Area 11.00 3.07 11.00 3.08 Old Clay Settling Area 32.56 9.10 31.98 8.94 Tailings & Spoil Piles 5.18 1.45 5.18 1.45 Mining Lake 35.76 9.99 33.63 9.40 Disturbed Mined Land 154.28 43.13 146.73 41.03 Reclaimed Land 7.47 2.09 7.47 2.09 Total 255.31 71.38 245.05 68.51 Phosphate mining dominates the study area in 2004. The entire eastern portion of the basin is covered by mining activity that al so extends into the western portion of the
basin. A network of features associated with phosphate mining activity blankets the study area. Little active mining is present in the study area. Nearly all of the mining features present are relic in nature and / or associated with phosphate processing. Figure 18. 2004 Phosphate Mining Map. Most numerous are mining lakes, many of which exhibit the rectilinear form of old phosphate mining pits. Old and new clay settling areas cover 31.98 sq km and 11.00 sq km, respectively, and account for 11.02% of the study area. Sand tailings and spoil piles, covering 5.18 sq km, likely repres ent a temporary landform due to their contemporary use in reclamation practices. Three gypsum stacks are present, ranging in size from 1.95 sq km to 3.15 sq km, and account for 1.90% of the study area.
Reclaimed land covers 7.47 sq km and accounts for 2.09% of the basin. Lands that have been reclaimed and officially rele ased by FDEP occur in a large cluster on the eastern border of the basin. Covering 4.14 sq km, this land has been reclaimed to mimic natural systems such as wetlands. Two other areas were considered reclaimed in this analysis because of their conversion to other land uses. Urban activ ity, covering 1.99 sq km, occurs in a previously mined land in the northeastern portion of the basin. Agricultural activity, covering 1.32 sq km, o ccurs on previously mined land in one area adjacent to the main stream of the basin. Disturbed mined land dominates phosphate mining activity as well as all features used in this analysis in 2 004. Occurring throughout the study area, disturbed mined land covers 146.73 sq km and accounts for 43.03% of the basin. Phosphate extraction is nearly exhausted in the basin in 2004, and recl amation of mined land is required. Most of the land included in the disturbed mined land ca tegory in this analysis was classified as under reclamation by FDEP. It is possible that some areas classified in this analysis as disturbed mined land may have already been re claimed but not officially released by the FDEP. Landscape Change The second objective of this research is to understand landscape change in the study area between 1940, 1970, and 2004. Consistent with land use and land cover change throughout the state, the study area has undergone ex tensive landscape modification from the early 20 th century to the present. The unique physical and social context of the study area has le d to a particular mode of landscape alteration found only in this region of the state.
Composition Landscape evolution in the study area from 1940 2004 is characterized by an increase in lands dominated by anthropogenic ac tivity, and a loss of natural lands. Table 15 summarizes the total change in the lands cape, based on general landscape class, between the periods of 1940 -1970 and 1970 2004 as well as net change from 1940 2004. The data for the entire study area, without the exclusion is also listed in Table 15. Figure 20 is a graphical repr esentation of the general landscape changes from 1940 1970, 1970 2004, and overall from 1940 2004. All results are base d on the study area with the appropriate areas excluded from the data. Figures 21 25 represent the area covered by each land use category in 1940, 1970, and 2004. Table 15. General Landscape Change. General Landscape Change (sq km) All Data With Appropriate Area Excluded Land Use Class 1940-1970 1970-2004 1940-2004 1940-1970 1970-2004 1940-2004 Mining +43.80 +199.96 +243.76 +42.36 +191.15 +233.51 Water -30.10 -83.03 -113.13 -37.13 -77.81 -114.94 Urban +2.52 -1.18 +1.34 +2.42 -1.08 +1.34 Agriculture +40.24 -19.89 +20.35 +38.42 -18.66 +19.76 Undisturbed / Other -41.96 -95.86 -137.81 -46.08 -93.58 -139.66 From 1940 to 1970, landscape change is driv en by anthropogenic usage. All three anthropogenic land uses increase and the two natural landscape clas ses decrease. The largest increase in land use from 1940 to 1970 occurs with phosphate mining. Accounting for just 3.23% of the study area in 1940, mining land increases by 42.36 sq km, resulting in the coverage of 15.07% of the basin in 1970. The increase in agricultural lands from 1940 to 1970 is 38.42 sq km, resulti ng in the coverage of 18.86% of the study area.
Figure 19. General Landscape Change. Natural lands declined from 1940 1970, but account for a majority of the basin in both 1940 and 1970. The largest loss in natural land from 1940 to 1970 occurs in the undisturbed / other category. Covering 42.49% percent of th e basin in 1940, undisturbed / other lands decrease by 46.08 sq km, resulting in the cove rage of 29.06% of the study area. A large decline (-37.13 sq km) in th e area covered by natural water features also occurred from 1940 to 1970. The only land use category to gain in area from 1970 to 2004 is phosphate mining activity. Covering 15.07% of the study area in 1970, the area covered by phosphate mining activity increases by 191.15 sq km, resul ting in the coverage of 68.51% of the study area in 2004. The loss of natural lands from anthropogenic activity is depicted in Figure 26. All other land use categories experience a decline in this period. Agricultural
Figure 20. Mining 1940, 1970, & 2004
Figure 21. Water 1940, 1970, & 2004.
Figure 22. Urban 1940, 1970, & 2004.
Figure 23. Agriculture 1940, 1970, & 2004.
Figure 24. Undisturbed / Other 1940, 1970, & 2004.
Figure 25. Natural Lands Lost to Anthropogenic Activity 1970 2004 & 1940 2004.
lands decrease by 18.66 sq km from 1970 2004. A minimal land use throughout the study period, urban lands decrease by 1.08 sq km, resulting in the coverage of 0.42% of the study area in 2004. A majority of spatia l loss from 1970 to 2004 occurs in the natural lands category, with the largest decrease occurring in the undisturbed / other category. The areas covered by both water and undisturbed / other lands shrink dramatically from 1970 2004, with a loss of 77.81 sq km and 93.58 sq km, respectively. A Difference Between Proportions Two Sample Z-test was used to investigate the significance of the change in the proporti on of the study area covered by anthropogenic activity from 1940 1970 and 1970 2004, as well as overall change from 1940 2004. In order to maintain a consistent study area for the change comparisons, this test was conducted only on the study area with the appropriate exclusions. The following hypothesis was developed based on the land use maps and associated data generated for each time period studied: 1) The propor tion of the study area covered by anthropogenic activity significantly increases through time. The results of this statistical analysis are outlined in Table 16. For each time period ex amined, z critical falls in the rejection region at the .01 significance level. Therefore, there is enough evidence to support the alternative hypothese s that there is a significant increase in the proportion of anthropogenic lands from 1940 1970, 1970 2004, and overall from 1940 2004. Table 16. Results of Difference Between 2 Proportions Tests, Anthropogenic Activity. Anthro p1 p2 Claim Null Critical z-values ( = .01) z-score 1940 vs. 1970 p1
Figure 26. Natural Lands Lost to Phosphate Mining 1970 2004 & 1940 2004.
Phosphate mining activity experiences the largest sp atial increase from 1940 1970 and 1970-2004 as well as from 1940 2004. Natural land lost to phosphate mining activity is depicted in Figure 27. To fu rther investigate the role of phosphate mining activity in land use change, the Difference Between Proporti ons Two Sample Z-test was applied to the proportion of the study area covered by phosphate mining activity from 1940 1970 and 1970 2004, as well as overall change from 1940 2004. Again, in order to maintain a consistent study area fo r the change comparisons, this test was conducted only on the study area with the appropriate exclusions. The following hypothesis was developed based on the land use maps and associated data generated for each time period studied: 1) The proportion of the study area covered by phosphate mining significantly in creases through time. The re sults of this statistical analysis is outlined in Table 17. For each time period examined, z critical falls in the rejection region at the .01 si gnificance level. Therefore, there is enough evidence to support the alternative h ypotheses that there is a significan t increase in the proportion of phosphate mining from 1940 1970, 1970 2004, and overall from 1940 2004. A comparison of Figures 26 and 27 illustrate s the dominant role that phosphate mining played in the loss of natural lands throughout the study period. Table 17. Results of Difference Between 2 Pr oportions Test, Phosphate Mining Activity. Mining p1 p2 Claim Null Critical z-values ( = .01) z-score 1940 vs. 1970 p1
lands occurred as dispersed patches throughout the basin in the 1940 Group and are pushed to the extreme western portion of the basin by 2004 (F igure 24). A comparison of Figure 24 and Figure 21 illustrates phosphate minings influence on the geography of agriculture in the basin. The same patte rn emerges through time regarding the location and extent of the surface hydrologic features (Figure 22) undisturbed / other lands (Figure 25), and urban lands (Figure 23). Net change from 1940 to 2004 was: mining: + 233.51 sq km water: -114.94 sq km urban: +1.34 sq km agriculture: +19.76 sq km undisturbed / other: -139.66 sq km. In 1940, a network of natural lands covers the basin. In 2004, the natural lands are replaced with phosphate mining activity and some agriculture. Fi gures 28 30 provide an example of landscape evolution from 1940 1970 2004. This is an area of the main channel that experienced relativel y little change in comparison to other parts of the basin. An evolution in the surrounding area is evident.
Figure 27. 1940 Landscape Evolution Example.
Figure 28. 1970 Landscape Evolution Example.
Figure 29. 2004 Landscape Evolution Example.
Surface Hydrology The third objective of this research is to explore changes to surface hydrology from 1940 1970, 1970 2004, and overall from 1940 2004. Throughout the study period, natural surface hydrologic features dec lined. This trend is consistent with the overall decline in natural lands observe d throughout the study period. Figure 31 illustrates the extent and specific features of surface hydrology present in 1940, 1970, and 2004. Change to surface hydrology in the study area from 1940 2004 is characterized by a decrease in the number of features and their spatial extent. Table 18 summarizes the changes to the c overage in surface hydr ological features between the periods of 1940 -1970 and 1970 2004 as well as net change from 1940 2004. The data for the entire study area, without the exclusion is also listed in Table 18. Total stream length and drainage density for 1940, 1970, and 2004 is listed in Table 19. All results are based on the study area with the appropriate ar eas excluded from the data. Table 18. Changes to Surface Hydrology. Change in Surface Hydrology (sq km) All Data With Appropriate Area Excluded Hydrological Feature 1940-1970 1970-2004 1940-2004 1940-1970 1970-2004 1940-2004 Wetlands -27.73 -81.34 -109.07 -34.12 -76.75 -110.87 Lakes / Ponds -2.84 -0.06 -2.90 -2.85 -0.06 -2.91 Karst 0.47 -1.63 -1.16 -0.16 -0.99 -1.16 Total -30.10 -83.03 -113.13 -37.13 -77.81 -114.94 Table 19. Length of Streams & Drainage Density, 1940, 1970, & 2004. Streams and Drainage Density (km) All Data With Appropriate Area Excluded 1940 1970 2004 1940 1970 2004 Total Stream Length 166.09 168.04 123.85 166.09 162.33 118.85 Drainage Density 0.464 0.470 0.346 0.464 0.454 0.332
Figure 30. Surface Hydrology 1940, 1970, & 2004.
From 1940 1970, the total area covered by natural surface hydrological features declines by 37.13 sq km. A majority of the change does not include the direct alteration of defined drainage. Total stream length declines by 3.76 km and drainage density is reduced from 0.464 to 0.454. Some wetlands that remain in 1970 show signs of anthropogenic modification such as the cons truction of canals through wetland areas. Phosphate mining encroaches on Hookers Prai rie from the west, replacing areas of the wetland system with phosphate mining activity Additionally, many of the areas of Hookers Prairie that remain in 1970 show signs of modification. The area covered by surface hydrological features declines by 77.81 sq km from 1970 2004, nearly double the decline that occu rs from 1940 1970. These changes occur throughout the basin, affecting streams, wetlands, lakes / ponds, and karst depressions. The entire eastern portion of the basin is void of natural surface hydrologic features in 2004. The length of streams declines by 43.48 km and drainage density declines from 0.454 to 0.332. Many streams are lost to anthropogenic activity, most notably phosphate mining. Many streams that remain in 2004 are fragme nted. Figures 32 34 provide an example of landscape change and the fragmentation of surface hydrological features. Wetlands decline by 76.75 sq km. Together, lakes/ponds and karst depressions experience a 3.01 sq km decrease in spatial extent. This change may be best understood together due to the unique hydrologic landscape of Florida and the seasonal and annual fluctuations of water levels. The area covered by wetla nds declines by 34.12 sq km.
An important change occurs in the nature of the lakes/ponds in this time period. Most of the lakes in 1970 exhibit natu ral form, including characteristics such undisturbed and/or circular s horelines. In 2004, many of the lakes that remain are encapsulated by anthropogenic activities and ex hibit unnatural form such as straight shorelines. Nearly all of th e wetlands that remain in 2004 are present as narrow strips adjacent to remaining streams. Hookers Prairie is no longer present in 2004, replaced by phosphate mining activity. Figures 32 34 show the evolution of a portion of Hookers Prairie throughout the study period. A small tract (1.10 sq km ) of undisturbed land remains amongst mining activity in what was historically Hookers Prairie. However, this tract of land exhibits no verifiable signs of water and was classified as undisturbed / other. Much of the area that was once Hookers Prairie appears to be reclai med. However, this mining complex is listed as under reclamation by FDEP, result ing in the classification of this area as disturbed mined land. Overall, from 1940 2004, there is a major decrease in the number and extent of natural surface hydrological f eatures. Covering 152.26 sq km in 1940, the extent of natural water features declines by 114.94 sq km, resulting in the coverage of just 37.33 sq km of the basin in 2004. In 1940, the landscap e is covered by a networ k of natural lands, of which surface hydrological features account for approximately half. The 1940 network of natural lands is replaced in 2004 by a network of anthropogenic land uses, of which phosphate mining is the dominant landscape class.
Figure 31. 1940 Hooker's Prairi e Landscape Change Example.
Figure 32. 1970 Hooker's Prairi e Landscape Change Example.
Figure 33. 2004 Hooker's Prairi e Landscape Change Example.
The changes observed in surface hydrology are consistent with the overall decline in natural lands and increase in anthropogenic lands in the basin. Figure 35 illustrates spatial loss of natural surface hydrologic featur es to anthropogenic activity from 1970 2004 and overall from 1940 2004. It is impor tant to note that phosphate mining activity is the only landscape class that experiences an increase in the period of 1970 2004. Figure 36 illustrates spatial loss of natural surface hydrol ogic features to phosphate mining activity from 1970 2004 and overall from 1940 2004.
Figure 34. Surface Hydrology Lost to Anthropogenic Activity 1940 2004 & 1970 2004.
Figure 35. Surface Hydrology Lost to Phosphate Mining 1940 2004 & 1970 2004.
. CHAPTER 5: CONCLUSION Conclusions The results of this study have provided new information regarding the spatial and temporal dynamics of landscape alteration in the South Prong Alaf ia River Drainage Basin. The detailed mapping of lands cape characteristics on the 1940 Group and 1970 Group historic aerial photos and 2004 aer ial photos was a useful exercise in understanding landscape change in the South Prong Alafia River Drainage Basin. The approach utilized in this an alysis has provided a general understanding of the effects of phosphate extraction and processing on the loca l landscape, and particularly on the South Prong Alafia River basin Landscape change in the study period is characterized by a loss of natural lands and an increase in anthropogenic lands. The proportion of th e study area covered by anthropogenic activity significantly increased, at a confidence level of .01, from 1940 1970, 1970 2004, and overall from 1940 2004. This trend is first apparent from 1940 1970, where the area covered by water featur es and undisturbed / other lands declines by a total of 83.21 sq km. The loss of these features was replaced by an increase in phosphate mining activity (42.36 sq km), agriculture (38.42 sq km), and urban lands (2.42 sq km). Despite the spat ial loss of water and undisturbe d / other lands, a network of natural lands continues to span the basin in 1970. Natural lands account for 61.79% of the basin in 1970.
The loss of natural lands to anthropogenic activity increases tremendously from 1970 2004. The total decline in the area cove red by natural lands is -171.39 sq km. The area covered by agriculture and urban usages decline as well, with a change of -18.66 sq km and -1.08 sq km, respectively. The increase in anthropogenic activity is attributed entirely to phosphate mining activity, with a change of +191.15 sq km. Natural lands account for 13.87% of the basin in 2004. Overall from 1940 2004, the landscape of the basin is transf ormed from an area dominated by natural lands to an area do minated by anthropogeni c activity, of which phosphate mining is the primary land use. The natural lands that remain in 2004 are confined to the western portion of the ba sin and are fragmented by anthropogenic land uses. An important aspect of the loss of natu ral lands throughout the study period is the dramatic alteration of surface hydrological features. From 1940 1970, the number of and area covered by wetlands, lake / ponds, a nd karst depressions decline. The area covered by hydrological features declined by 37. 13 sq km in this time period. Defined drainage is also impacted, with the loss of 3.76 km of streams and a decline in drainage density from 0.464 to 0.454. From 1970 2004, the number of features and area covered by wetlands, lakes / ponds, and karst depressions dramatically declined. The area covered by hydrological features decreased by 77.81 sq km. Wetlands are confined to thin areas surrounding the remaining streams. Most lakes that are present in 2004 occur in areas of agricultural activity and do not exhibit natu ral form. Total stream le ngth declined by 43.48 km and drainage density declines from 0.454 to 0.332. Many streams were lost to phosphate
mining activity. Hookers Prairi e, the headwaters of the ma in stream, was replaced by phosphate mining activity. The nature of the surface hydrology in th e basin was radically altered from 1940 2004. Accounting for 42.57% of the basin in 1940, water features cover just 10.43% of the basin in 2004. A number of st reams were lost, with a total decline in str eam length of 47.24 km. Many streams that remained in 2004 are fragmented by anthropogenic activity. Hydrological featur es in 2004 are surrounded by anthropogenic activity. The entire eastern portion of the basin is void of natural surface hydrological features. The primary force in landscape alte ration throughout the study period is phosphate mining activity. The proportion of the study area covered by phosphate mining activity significantly in creased, at a confidence level of .01, from 1940 1970, 1970 2004, and overall from 1940 2004. The largest increase in land area observed from 1940 1970 is in phosphate mining activity. The only increase in land area observed from 1970 2004 is in phosphate mini ng activity. Many natural features were lost to phosphate mining, including wetland s, ponds / lakes, karst depressions, and undisturbed / other lands. Perhaps most striki ng is the erasure of Hookers Prairie, a critical source of flow for the South Prong Alafia River. Additionally, phosphate mining activity replaced agricultural areas and sm all areas of the mining town of Bradley Junction. Phosphate mining activity dominate s the study area in 2004, forming a network of mining-induced anthropogenic landforms throughout the basin. Limitations It should be mentioned that there were some limitations associated with this research. Landscapes are not static and lack clearly defined boundaries. Thus, it is
inherently difficult to draw boundaries around a natural landscape. To best account for this limitation, landscape class delineation was guided by a review of the literature regarding the physical and human geography of the basin, the utiliz ation of available spatial data, and regular data quality monitoring. The ma nual methods used in this analysis provided the capability to ma ke educated judgments regarding landscape composition when necessary. The historic aerial photosets presented an additional limitation. Aerial photos are most accurate in the center of the image; this was considered when layering the georeferenced photos. Some spatial accuracy ca n be lost in the various stages of data management and with aging of the photos. Additionally, the aerial photos used to assemble the 1940 and 1970 Groups were taken in different, but near years. Although the difference in years is not ideal, these phot osets provided the only way to capture landscape characteristics for the entire basin for the period of interest. The results and conclusions of this thes is provide a genera l understanding of landscape composition and change in the South Prong Alafia River drainage basin. Details regarding the conseque nces of these changes can be obtained only through more detailed modeling. There is, however, a well-established body of literature regarding 1) the effects of phosphate mining on the natural la ndscape of Florida and 2) the effects of land use change on the behavior of the drainage basin system. The results of this thesis are briefly explored below th rough the context of this literature.
Implications The natural landscape of the South Prong Alafia River drainage basin has been radically altered by anthr opogenic activity, particular ly phosphate excavation, benefaction, and processing. These activities have been especially robust over the last 35 years. The implications associated with the landscape modification documented in this research transverse a variety of scales. Fr om the hydrological and ecological effects of the erasure of a single karst lake to the im portance of the Alafia River as a source of freshwater to the residents of Tampa Bay, th e consequences associat ed with the alteration of the South Prong Alafia River drai nage basin are many. At least 68.5% of the basin has been directly modified by phosphate mining activity. The consequences of these alterations potentiall y extend throughout the system, beyond the directly modified areas. The er asure of vast areas of undisturbed land, wetlands, streams, lakes, ponds, and karst de pressions indicates th at hydrological and ecological functions within the basin ha ve been altered and likely degraded. Additionally, the replacement of these natural lands with phosphate mining and agricultural activity further indicates that hydrological and ecologi cal functioning within the basin have been corrupt. The common practice of reclaiming the land to beneficial uses does not necessarily restore hydrologic and ecologic functioning. The quality of reclamation practices in the basin should be critically considered and closely monitored to ensure an optimal recovery to the basin system. The nature of phosphate extraction, bene faction, and processing results in the transformation of a many physical paramete rs that influence f unctioning within the
drainage basin system. The removal of nativ e land cover, alteration of soil stratigraphy and composition, modification of topography an d natural drainage pa tterns, alteration and destruction of critical flow sources, and water consumption associated with phosphate mining activity inevitably alters hydrologic behavior. The dominant and long-lasting influence of the phosphate activity in the South Prong Basin may indicate that the hydrologic system presen t prior to phos phate activity no longer exists. The nature of phosphate mining activities, the proportion of the basin affected, the rapid rate of landscape alterati on, and the fragmentation of the remaining natural landscape are evidence of a destr oyed system. The possi bility of future phosphatic waste clay storage in the basin has the potential to further modify the physiography and functions throughout the basin system. Many natural habitats have been destroye d and the remaining natural lands within the basin are fragmented as a result of phosphate mining activity. The erasure of and disturbance to natural lands a ssociated with the industry di srupts ecosystem functions and health. Mining discharges and accidental spil ls have impacted water and environmental quality throughout the basin system The possibility of spills remains. The extent of the basin that has been altered, a nd the rate at which these altera tions occurred, indicates that environmental health has been degrad ed by the industrys presence. The role of the South Prong Alafia River as one of the two main tributaries that form the Alafia River additionally denotes the significance of the modifications documented in this research. As a subsyste m of the Alafia River drainage basin, the landscape alteration in the Sout h Prong Alafia River basin likely damaged ecological and
hydrological functioning in the Al afia River basin and Tampa Bay. The Alafia River is important to the sustaina bility of the local popula tion and environment. The multitude and duration of the nega tive impacts of phosphate mining on the Alafia River should be a critical concern for local water and land management. The documented effects of phosphate mining within the Alafia River drainage basin should inform the public and private debate regard ing the phosphate industry and its impact on the local environment. Future Research As a system whose landscape has been severely modified but will not undergo any further phosphate excavation, the South Pr ong Alafia River drainage basin presents a unique research opportunity. Modeling of hydrologic and ecologic response to reclamation activities within the basin woul d be beneficial to future and current reclamation efforts, both within and beyond th e basin. The variet y of mining landforms and range in the age of these features pres ent an ideal landscape for a more detailed analysis of the effects of phosphate mining activity on the na tural environment. The extent of the landscape modification th at occurred in the basin indicates that the success of reclamation ac tivities should be closely mon itored. In particular, the success of the reclamation of Hookers Prai rie should be monitored for an extended period of time. The significance of this we tland system and its eventual destruction necessitates proper management and restoration. Raster-based analysis may be a useful tool in understand ing the spatial and temporal dynamics of landscape change in th e basin and regionally that have occurred more recently or in the future. This woul d be especially helpful in understanding the
increasingly dominant role of phosphate mini ng in the landscape pattern of the basin as well as the region. Additiona lly, this would be useful to monitor the efficiency of reclamation practices and the associated environmental responses. Additionally, an examination of basin landscape composition in the future would provide insight into the dynamics of landscape and environmental change postphosphate extraction.
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Appendix Figure A-1. 1940 Aerial photo of wetlands, lakes / ponds, and undisturbed / other. The circular form of the lakes / ponds is characteristic of many of these features in both 1940 and 1970. These are likely karstic in origin.
Appendix (Continued) A-2. 1940 Aerial photo of wetlands and stream, undisturbed / other, and small agricultural patches amongst wetlands. The placement and size of this agri cultural activity is characteristic of much of the agricultural activity in 1940.
Appendix (Continued) Figure A-3. Aerial photo of open phosphate pits in 1970. There is also a small group of processing facilities in the southwest corner of the photograph.
Appendix (Continued) Figure A-4. Aerial Photo of clay settling area in 1970.
Appendix (Continued) Figure A-5. 1970 Aerial photo of stream amongst wetlands. The densely vegetated nature of the floodplain, when undisturbed, is characteristic of this feature in 1940, 1970, and 2004.
Appendix (Continued) Figure A-6. 1970 Aerial photo of straight-edged wetlands, an indicator of anthropogenic modification. Also note the large patch of open pits and spoil piles in the west and small patch of agriculture in the east.
Appendix (Continued) Figure A-7. 2004 Aerial photo of gyp stack, mining lakes, tailings, and disturbed mined land. The rectilinear form of the mining lakes indicates that thes e are old phosphate pits, a characteristic of many mining lakes present throughout the study period. Gypsum stacks are easily identified due to their significant height and location near processing facilities.
Appendix (Continued) Figure A-8. 2004 Aerial photo of a clay settling area, mining lakes, and disturbed mined land. The disturbed mined land appears to be in the process of reclamation.
Appendix (Continued) Figure A-9. 2004 Aerial photo of a stream and wetlands fragmented by mining activity.
Appendix (Continued) Figure A-10. 2004 Aerial photo of agriculture, a pond, and a small patch of undisturbed / other land in the eastern portion of the photograph. The unnatural form of the pond is characteristic of many of these features in 2004.
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Koenig, Kimberly Sarah.
Landscape change in the South Prong Alafia River drainage basin
h [electronic resource] /
by Kimberly Sarah Koenig.
[Tampa, Fla.] :
b University of South Florida,
ABSTRACT: West-central Florida has supplied much of the national and global demand for phosphate for over 100 years. The two main tributaries of the Alafia River, the North and South Prongs, have been extensively modified by the strip mining, benefaction, and chemical processing activities associated with the phosphate mining industry. Using aerial photos, an analysis of landscape change in the South Prong Alafia River drainage basin (357.4 km2) between 1940, 1970, and 2004 was conducted. A modified Florida Land Use, Land Cover, and Forms Classification System code (FLUCCS) was used to classify and measure change through the study period. Change in the study area is characterized by a dramatic decline in the area covered by natural lands and an increase in the area covered by anthropogenic activity. Increasing 43.8 km2 from 1940 -- 1970 and 199.96 km2 from 1970 -- 2004, phosphate mining activity is the primary force of landscape alteration in the study area. The historic headwaters of the main stream, Hooker's Prairie, is completely replaced by mining-induced landforms in 2004. Net change in landscape composition from 1940 -- 2004 is 1) phosphate mining (+243.76 km2), 2) surface hydrology (-113.13 km2), 3) urban (+2.42 km2), agriculture (+19.76 km2), and undisturbed / other (-139.66 km2). The results of this study indicate that the regional environment and hydrology have been heavily impacted by phosphate mining activity. The critical management of the industry's environmental impacts and reclamation practices is essential for the current and future health of the local environment and its inhabitants.
Thesis (M.A.)--University of South Florida, 2006.
Includes bibliographical references.
Text (Electronic thesis) in PDF format.
System requirements: World Wide Web browser and PDF reader.
Mode of access: World Wide Web.
Title from PDF of title page.
Document formatted into pages; contains  pages.
Advisor: Robert Brinkmann, Ph.D.
t USF Electronic Theses and Dissertations.