CHAPTER 2
ENVIRONMENT
TABLE OF CONTENTS

INTRODUCTION.......... 2-3

• EARTH..........2-4
• AIR..........2-11
• WATER..........2-12
  

COASTAL ZONE MANAGEMENT..........2-16

• COASTAL PLANNING AREA INVENTORY AND ANALYSIS..........2-16
• BARRIER ISLAND SYSTEM..........2-16
• ESTUARIES..........2-26
• WATER-DEPENDENT/WATER-RELATED USES..........2-39
• COASTAL HAZARDS AND MITIGATION PLANNING..........2-45
  
  

NATIVE HABITATS..........2-60

ENDANGERED SPECIES AND CRITICAL HABITAT..........2-61

HABITAT INVENTORY AND ANALYSIS..........2-65

PLANNING OPTIONS AND TECHNIQUES..........2-90

PRINCIPLES FOR EVALUATING DEVELOPMENT PROPOSALS IN NATIVE HABITATS..........2-97

ENVIRONMENT PLAN..........2-107

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Earth

General Geology

The subsurface geology and subsurface features of Sarasota County are directly related to historic sea level fluctuations. The geologic formations that underlie Sarasota County developed as the result of physical, chemical, and biological processes. These processes included near-shore deposition of sediment, precipitation of chemicals directly from seawater, and accumulation of the skeletal remains of marine organisms. These geologic formations range in age from the Oligocene epoch (38 to 22.5 million years ago) to the Holocene epoch (10,000 years ago to present).

Surface and near-surface sediments consist of quartz sand, consolidated and unconsolidated shell beds, clays, limestone, and dolomite. Stratified layers of relatively pure limestones and phosphatic clays (clays rich in phosphate, salts of phosphoric acid) developed gradually in Sarasota County. Quartz sands that eroded from exposed higher land were also deposited. These near-surface sediments, which occur within approximately 1,500 feet of ground elevation, were of major importance to settlement because of their capacity to store and/or contain potable water. In addition to supplying water, the marine sediments provide phosphate and other mineral resources.

Mineral Resource Development

Nearly the entire area east and north of I-75 in the County contains sand and gravel deposits and there are several commercial sand and gravel mining operations in Sarasota County. Known phosphate deposits in Sarasota County are relatively small and phosphate mining has focused on the extensive deposits in Polk County. One phosphate mine within the Myakka River watershed in eastern Manatee County is currently active. Plans for a mining operation in the Manatee County part of the Big Slough watershed have not yet been finalized.

These existing and future operations may adversely impact not only Sarasota County's environment, but its tourist/retirement economy as well. However, State mining regulations including provisions for reclamation, were strengthened in 1985. As a result, the impacts of phosphate mining have been reduced although dangers to the environment remain. Local governments may mitigate the risks of phosphate mining by enacting ordinances more stringent than the State's regulations, by ensuring that the conditions that led to permitting are upheld, and by incorporating state of the art advances into the permitting requirements.

In 1982, the County adopted an ordinance that limits mining activities to areas designated as Rural on the "Future Land Use Map". However, mining activities are prohibited within designated areas of special environmental significance and/or sensitivity. The watersheds of Cow Pen Slough, the Myakka River, and the Braden River are designated areas of special environmental significance.

Surface Features

Sarasota County is physiographically defined by a series of marine scarps and terraces that developed during the Pleistocene epoch. These terraces, combined with the underlying marine sediments, are responsible for Sarasota County's topography, which ranges in elevation from mean sea level along

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the coast and the lower Myakka River to a height of 95 feet in the northeast corner of the County near Verna.

The County's generally flat topography is characterized by isolated swamps and marshes, which connect into sloughs and meandering streams. Depressions in the landscape seasonally fill with water and form intermittent ponds. Series of ponds often link together during heavy rains to create shallow and slow-moving waterways, while streams may form when flow, volume, and velocity increase. This topography results in a very slow rate of stormwater runoff. For a more detailed discussion on drainage, refer to the section in the Public Facilities Chapter.

The County lies within three physiographic provinces: the Gulf Coastal Lowlands, the Desoto Plain, and the Barrier Island Chain. (See Figure 2-1 for these Generalized Physiographic Provinces). The majority of the County is in the Gulf Coastal Lowlands province, which ranges in elevation from sea level to approximately 40 feet. The Myakka River is the principal feature of the Gulf Coastal Lowlands. The Myakka, along with its tributaries, is the County's largest drainage system and flows into Charlotte Harbor to the south. Several small creeks, which empty into the County's bays and estuaries, drain the coastal portion of the County. Soils in the Gulf Coastal Lowlands are generally unconsolidated sands that increase in clay content with depth. Organic soils are found underlying wetland areas.

A small part of the northeastern County lies within the Desoto Plain province. Elevations in this province range from 40 to 75 feet. Soils in the Desoto Plain are somewhat poorly drained with shallow sediments overlying organic hardpans, which are layers of strongly cemented material.

Shell is excavated in certain parts of the County to be used for construction projects such as roadways. These commercial earthmoving enterprises provide a valuable service, and positive economic benefit to the community. Earthmoving operations such as shell excavation may cause adverse impacts to watersheds, drainage patterns, native habitats, air and water quality, land use compatibility and roads, and may create erosion and sedimentation problems. The County's Earthmoving Ordinance (No. 81-060, as amended) contains provisions for protecting the integrity of the environment and meeting the social and economic needs of Sarasota County residents. Mining of other materials is regulated in accordance with Sarasota County Ordinance No. 82-111.

The Barrier Island Chain province is a dynamic system of barrier islands, inlets, and lagoons, which consists of marine and estuarine terrace deposits that were laid down at the same time as receding water created Tampa Bay and Charlotte Harbor. River valleys were eroded during the periods of receding seas and vast quantities of sediments were transported offshore. The riverine sediments, combined with shells and other materials, gradually washed landward to form the Barrier Islands. The bay waters shaped by these dynamic features include Sarasota Bay, Little Sarasota Bay, Dona/Roberts Bays, and Lemon Bay. Elevations on the Barrier Islands are generally less than 15 feet.

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Figure 2-1: Physiographic Pronvinces and Topographic Contours in Sarasota County

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Changes in barrier island shorelines are the direct result of the energy associated with winds, waves, currents, and tides. The action of wind and waves can create a flow of water with sand in suspension parallel to the shoreline. This parallel flow is referred to as littoral drift. An active beach area has a cycle of erosion and accretion caused by wave action and littoral drift. These dynamics and trends of the Barrier Island system in Sarasota County are discussed in the Coastal Zone Management section of this Chapter.

Soils

Soil characteristics are determined by climate, composition of parent materials, topography, biological activity, and the duration of soil development. Sarasota's warm, humid climate causes rapid chemical and biological reactions within the soil, which eventually deplete soil fertility. Because the ground rarely freezes these reactions continue year-round, which results in continual depletion of soil fertility. Further losses occur due to abundant seasonal rains, which cause leaching (downward movement of soluble materials by a percolating liquid). Together this depletion of soil nutrients that are essential to plant growth and the overall reduction of soil fertility, have limited the development and distribution of intensive agriculture. The low soil fertility requires improvements for farming and large acreage of land to support livestock.

There are no widespread soil erosion problems in Sarasota County. Due to the relatively flat terrain, soils are generally stable. Under normal volumes of precipitation, the slow-moving rivers of Sarasota County create few erosional changes. Erosion does occur, though, when the rate of runoff is increased by improper or poorly designed drainage modifications that carry away topsoils. Soil erosion is also a problem during the construction activities of development. Topsoils, which are end products of thousands of years of natural buildup, are important to vegetation. Once carried off, not only are they lost to the vegetation, but they often create siltation and sedimentation problems in the receiving estuaries. To mitigate soil erosion problems created during agricultural and urban development activities, the County Natural Resources Department encourages developers to follow the Natural Resources Conservation Service and the Florida Department of Transportation's Best Management Practices.

Many soils have characteristics that limit their ability to be developed in their natural state. While poor drainage is perhaps the major limitation, others include wetness (amount of water in the soil at various times of the year), effective depth (to water and plant nutrients), depth to rock, shrink and swell behavior (changes in soil volume due to the amount of moisture), presumptive bearing value (ability of soil to sustain dead weight), and corrosion.

As a result of these limitations, major soil modifications (such as draining or excavating) are frequently necessary before areas can be developed. The modifications necessary to overcome these natural limitations may destroy valuable soil and vegetation. In addition, such modifications often destroy the valuable habitats that have evolved in response to the natural characteristics of the soil. An example of this would be the destruction of wetland vegetation when naturally wet soils are subjected to improperly designed artificial drainage.

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Due to the fact that well-drained soils have little surface runoff and allow fairly easy water movement, they may serve as important recharge areas for ground-water systems. With the limited extent of these soils in Sarasota County and the degree to which they have experienced urban development, undisturbed habitats associated with these soils are rare.

Riverine soils and coastal soils also serve valuable environmental functions. Riverine soils are important for water-table recharge, flood control (by storing excess water), filtration of stormwater runoff, as transition areas along riverbanks, and for the support of hammock and freshwater marsh vegetation. Coastal soils, in turn, are important stabilizers of shorelines, act to filter runoff, and support coastal strand vegetation, including mangroves and salt marshes.

Table 2-1 identifies the characteristics for five broad soil categories: Coastal Islands, Hammocks, Flatwoods, Depressions and Sloughs, and Floodplains. Figure 2-2, which is adopted as part of the Future Land Use Map Series, identifies general soil associations, including floodplain associated soils and mineral resources in Sarasota County. Due to the generalized scale, the soils map is not suitable for specific planning purposes. Refer to the detailed soil map in the United States Department of Agriculture Soil Conservation Service publication, "Soil Survey, Sarasota County, Florida," for a detailed description of soil types.

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Figure 2-2: General Soil Associations Mineral Resources in Sarasota County

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Air

Air Quality

Sarasota County Natural Resources Department has been monitoring air quality since 1978.

Four air-quality parameters have been measured at a variety of monitoring sites. Ozone, carbon monoxide, particulate matter, and sulfur dioxide are monitored on a continuous basis for twenty-four hours a day, seven days a week. Particulate matter, is also monitored by another method every sixth day for twenty-four hours. The new monitoring plan for ambient air was approved by the Board of County Commissioners in January 1987. In general, monitoring sites are chosen based on known or suspected sites of maximum pollutant concentration and/or population exposure. Presently, monitoring sites are located at Brookside Middle School, the U.S. 41 Bypass in Venice, Bee Ridge Park, the Sarasota County Courthouse, the City of Sarasota's reverse osmosis plant, South Lido Park, and Goff Communications in Venice. The County has plans to operate a nitrogen oxide (NO_x) monitor that will record NO_x emissions 24 hours a day, seven days a week at the Brookside Middle School site.

The air quality in the County is considered good and has not exceeded the Environmental Protection Agency's (EPA) and Florida Department of Environmental Protection's (FDEP) established standards to date. In the future, meeting these standards may be more difficult due to ozone pollution associated with the increasing number of automobiles in Sarasota County. The impact, extent, and form of future growth should be considered to determine what effect it would have on local air quality. Land use patterns and transportation systems should be compatible with the desired level of air quality. The Air Quality Section of the Pollution Control Division reviews permit applications in Sarasota County and has representation on the Sarasota/Manatee Metropolitan Planning Organization's Congestion Management System Task Force.

The provisions of air quality were initially addressed in County Ordinance No. 72-37, which was repealed by County Ordinance No. 85-37. Ordinance No. 85-63 was adopted to achieve compatibility between the air pollution control regulation of the State and County. County Ordinance No. 94-038, which was adopted April 12, 1994 for the control and regulation of air and noise pollution, repealed Ordinance Nos. 85-37 and 85-63. The intent of this Ordinance was to achieve compliance with the current requirements of the local air program approved by the FDEP. Sarasota County's Local Air Pollution Control Program complies with the Florida Air and Water Pollution Control Act, Chapter 403 Florida Statutes.

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Water

Water is one of Sarasota County's most important natural resources. It is found throughout the natural environment in a variety of "interconnections". These interconnections are collectively called the hydrologic cycle, and include regional precipitation patterns, ground-water resources and surface-water systems as their components.

There are four freshwater-bearing aquifers in Sarasota County: the surficial aquifer; two intermediate aquifers (Tamiami-upper Hawthorn and Lower Hawthorn-upper Tampa); and the Floridan aquifer. Most of the County's consumptive water use is derived from these aquifers. These ground-water resources are extremely valuable to Sarasota County residents and must be protected. For a more detailed discussion on the County's ground-water resources, refer to the Potable Water section in the Public Facilities Chapter.

Surface Water Systems

Surface water is collected by streams and lakes, numerous sloughs, ponds, and swampy areas. Rainfall accounts for the majority of surface water in the County. However, due to the flat terrain typical in Sarasota County, there is little gravitational impetus for streamflow and not all of the rainfall is retained as part of the surface-water system. According to the Southwest Florida Water Management District (SWFWMD), only 30-35 percent of the rainfall contributes to that system through surface-water runoff. The balance is lost to evapotranspiration (65-70 percent) with a small amount (5 percent) recharged into the ground-water system.

The Myakka River, the largest natural drainage system in Sarasota County, drains approximately 540 square miles. Several creeks and shallow sloughs, including Phillippi and Howard Creeks, and Cow Pen, Deer Prairie, and Big Sloughs, drain the County's lowlands. The Upper and Lower Myakka Lakes are the County's two largest bodies of freshwater. Together the two lakes cover approximately 1,380 acres.

Floodplains

Floodplain development has several negative consequences. Urban development increases runoff by enhancing the velocity of flow from impervious surfaces. The runoff decreases estuarine salinity and increases the amount of pollutants that drain into the County's bays and estuaries. Also, increased flooding can result from fill placed within the floodplain.

There are four major floodplains in the County: Phillippi Creek; Cow Pen Slough; the Myakka River; and Big Slough (also known as the Myakkahatchee Creek). While some development has occurred within each of these floodplains, the Phillippi Creek floodplain is the most urbanized. Since much of the County's settlement occurs in the coastal lowlands, where the majority of population is located within the 100-year floodplain, many residential and agricultural areas have experienced flooding.

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Excess volumes of water that enter the County's meandering channels and wide floodplains create flooding due to low elevations and flat terrain. The Storm and Surface Water Management section of the Public Facilities Chapter discusses the regulatory aspects of development in the floodplain and contains a generalized map of the flood hazard areas in Sarasota County (see Figure 4-10: Areas of Special Flood Hazard). Policies related to development in floodplains and flood-prone areas are located in the Future Land Use Plan.

Stream modification, such as straight box-cut channelization, could generate negative impacts downstream and should be monitored. In 1962, severe flooding of the County's urban and agricultural areas spurred a series of structural modifications to drainage systems (for example Phillippi Creek, Cow Pen Slough, and Big Slough). These natural meandering streams were replaced with straight, box-cut channels. During periods of intense and prolonged rainfall, stormwater rapidly drains through the channelized streams into the County's bays and estuaries. This rapid runoff increases sediment loading, pollution, and freshwater influx into the bays, and can result in severe damage to the estuarine waters. Nutrients, pesticides, solid wastes, bacteria, heavy metals, and petroleum products have been found in stormwater runoff.

Channelization also reduces the capacity for natural water storage by placing greater stress on existing drainage systems and increasing the potential for downstream flooding. In the natural drainage system, when a heavy rainfall generates large volumes of runoff, excess surface water is stored in the floodplain and is gradually drained by the natural wetland waterways. Development can also produce flooding in areas not normally flood prone. When fill and/or impermeable surfaces are placed within the floodplain, flooding occurs because natural stormwater retention areas have been displaced. The "Freshwater Wetlands" section of the Environment Chapter discusses management guidelines for buffering wetlands. Vegetation buffers along the shore and adjacent to wetlands are at least partially intended to protect the natural function of floodplains and flood-prone areas.

Water Consumption

The Potable Water section of the Public Facilities Chapter analyzes the current and projected domestic water consumption in the County. This section, which uses the best available data from SWFWMD, considers the general trends and projections for agricultural water consumption. Ground water supplies most of the County's needs for agricultural, industrial, and domestic uses. Table 2-2 indicates that the average water use estimates for agriculture between 1990 and 2020 generally ranges from 25 million gallons per day (mgd) and 39 mgd.

In 1986, field crops constituted approximately 88 percent of the agricultural water consumption in Sarasota County. Included in these are turf and ornamental, truck farming (primarily celery and tomatoes), corn, and melons. The balance of the agricultural water demand came from citrus groves and pasture lands. The vast majority of agricultural acreage in the County is pasture, which has been slightly decreasing along with its associated water usage.

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The acreage of citrus has increased along with increases in water demand. Turf and ornamental farming, which basically serves the local market, has become the largest single agricultural water consumer in the County and continues to increase in acreage.

Industrial water use in the unincorporated County is roughly 100,000 gallons per day according to SWFWMD.

The ongoing water conservation planning efforts in Sarasota County are discussed in the Potable Water and Storm and Surface Water Management sections of the Public Facilities Chapter.

Surface-Water Quality

Several waterbodies in Sarasota County have been designated Outstanding Florida Waters (OFWs). The Outstanding Florida Water designation was developed to provide additional protection to special waters recognized for their ecological and recreational significance. OFWs in the County include Sarasota Bay, Little Sarasota Bay, Lemon Bay, and the Myakka River. The exceptions within these waters include two areas of degradation at the mouth of Whitaker Bayou and Phillippi Creek. Sarasota Bay, Little Sarasota Bay, and Lemon Bay were designated OFWs in February 1987. In 1988, the OFW designation for the Myakka River was extended to cover its entire length within the County. This designation provides these waterbodies with the highest degree of protection under the FDEP permitting policy. In general, direct discharges into an OFW cannot lower ambient water quality in the year prior to designation, while direct discharges cannot significantly degrade the OFW. These provisions are predicated on the antidegradation concept that degradation should not occur except after full consideration of the consequences and then only to the extent necessitated by desirable economic and social development. Designation as an Aquatic Preserve by the FDEP provides additional water-quality protection to Lemon Bay.

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According to the Florida DEP surface water classifications, surface waters in the County are designated as follows: Class I, potable water supply; Class II, shellfish propagation or harvesting; and Class III, recreation, propagation and maintenance of a healthy, well-balanced population of fish and wildlife. The Class I waters include Big Slough Canal to US 41, the Myakka River south to I-75, and the Upper and Lower Myakka Lakes. Class II waters include the western half of Sarasota Bay in the County, Lemon Bay from Forked Creek south to the County line, and a portion of the Myakka River between US 41 and the south County line. The remaining surface waters in Sarasota County are Class III surface waters. The Myakka River in Sarasota County has also been designated a State Wild and Scenic River.

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Coastal Zone Management

Coastal Planning Area Inventory and Analysis

The County's coastal resources are essential to the tourism and retirement focus of the local economy. Any adverse effects upon the resources could have a detrimental impact on the area's economic base.

Sarasota County has been designated by the State as a coastal area; technically the entire County could be included in the inventory and analysis of the coastal area. However, in order to more completely address the dynamic interrelationships between human endeavors and natural processes in coastal areas, it was determined that a narrower definition of the immediate coastal planning area was needed. For the purposes of this inventory and analysis section, the Coastal Planning Area will be defined as the area that encompasses the Barrier Islands, bayfront mainland, Gulf and bay waters, and all other areas affected by tidal waters including mangrove swamps and tidal marsh habitats. Generally, the Coastal Planning Area is defined as the area west of US 41 and SR 776, but it also includes all areas below and including the five + foot NGVD contour line supporting salt tolerant vegetation within the tidal reaches of the coastal creeks and the Myakka River.

The designated coastal planning area of Sarasota County contains a mixture of developed land uses and natural habitat coverages as outlined in Sections 1 and 2 of Appendix I: Future Land Use. These uses and features are illustrated on the Existing Land Use Map and Land Cover Map. In 1988 there were approximately 4,544 acres of seagrass beds, 131 acres of oyster bars, 845 acres of mangroves, 45 acres of tidal marsh, and 13,988 acres of open water. In addition to the 5,565 acres of estuarine and marine habitats, there were approximately 2,045 acres of uplands including coastal hammock, freshwater wetlands, pine prairie and scrub which remain in the coastal area. Both estuarine and coastal habitats support numerous wildlife species including endangered, threatened, and species of special concern. Figure 2-3 shows the general area of living marine resources in Sarasota County. Appendix B, Section 3 contains a listing of artificial reefs along with an illustration identifying their location.

Barrier Island System

Sarasota County has 35 miles of Gulf beach shoreline. Approximately 31 of these miles stretch along several Barrier Islands, including the southern portion of Longboat Key and the northern portion of Manasota Key. The other 4 miles, from Tarpon Center Drive in the City of Venice south to Red Lake, are part of the mainland. The County's barrier islands, in addition to those within the Town of Longboat Key and the City of Sarasota, will likely reach maximum development capacity during the 1990's at which time minimal additional growth is expected.

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Figure 2-3: Coastal Area Marine Resources

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Three active tidal passes provide access for boaters and marine species between Gulf and bay waters in the County. New Pass separates south Longboat Key from Lido Key which is separated from north Siesta Key by Big Sarasota Pass. Venice Inlet separates south Casey Key from Manasota Key.

Beaches and Dunes

Sarasota County beaches are generally narrow, although the public beaches on Longboat Key, Lido Key and Venice have been widened by artificial beach nourishment. As a recreational amenity, the beaches are vital to the County's economic base. Recreational and visual access to the beaches and waters of the Gulf of Mexico are major factors in attracting tourists and residents to Sarasota County.

The interrelationships of the various local economic sectors are addressed in the Economy Chapter, specifically the importance of the coastal area to the economic base.

The County's sandy beaches also protect upland property against flooding and storm damage and contribute to wildlife habitat. The gently sloping form of a natural beach dissipates wave energy; the vegetated areas behind the high energy beach act as an additional buffer and a repository for drifting sands. Numerous species, including the endangered loggerhead sea turtle, several threatened wading bird species, and the snowy plover, use the sandy beaches and dunes for nesting and feeding.

Natural beaches are dynamic systems that erode and accrete in response to wave action, wind, currents, periodic storms and sea level rise. The amount and location of erosion is a result of:

• the size and direction of the waves;
• the amount and type of sand;
• the shape of the beach; and
• the rate of sea level rise.

This complexity makes shoreline changes difficult to predict. Yet the dynamics of an active beach and man's response to these forces potentially impact development along the entire coast.

The visible sandy shore is only a small part of the total beach system; in reality, the beach is a large and dynamic system most of which is underwater. The offshore portion is the zone of active sand movement. The degree of sand movement is related to the size and direction of the waves striking the beach and the steepness of the underwater section of the beach and the characteristics of the sediments. What happens on the part of the beach we see depends in large measure upon processes that go on in the offshore portion that we cannot see.

Often, when private structures and public infrastructure are threatened by erosion, shorelines are stabilized. County Ordinance No. 79-03, as amended, has served to restrict development including shoreline hardening seaward of the Gulf Beach Setback Line (GBSL) and the Barrier Island Pass 20-Year Hazard Line. A 1995 study of beach conditions in Sarasota County indicates that approximately 36% (12.5 miles) of the Gulf beach shoreline in Sarasota County was stabilized with either seawalls, revetment, or groins (see Table 2-3). Since the time of the 1983 shoreline inventory, the length of hardened shoreline has decreased a total of 0.7 mile. The factors that attributed to this decrease

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include beach nourishment projects, removal of derelict shoreline structures, and beach accretion. Specific conditions of State permits required the removal of certain shoreline structures prior to commencing the construction of beach nourishment projects (e.g. the Longboat Key project in 1993). Some existing shoreline structures have been buried by new sand added to the beach and discounted by County staff that prepared the 1995 survey because these structures were no longer visible. In addition, Casey Key experienced an apparent decrease in the amount of shoreline hardening, which may be attributed to a recent ephemeral accretionary shoreline trend, and to the establishment of a vegetated dune system, especially along sections of north Casey Key.

Structural alterations to the Gulf shoreline interfere with normal coastal processes and can potentially accentuate shoreline erosion. Seawalls, revetments, groins, and jetties can interrupt the littoral movement of sands and cause erosion on adjacent properties. Seawalls interfere with the formation of sandbars and cause the beach profile to steepen. Groins and jetties inhibit littoral drift and cause sand to accumulate on beaches updrift of the structure. In both cases, erosion occurs on the downdrift beaches. When erosion threatens their property, downdrift property owners often respond to increased erosion rates by hardening the shoreline.

Shoreline stabilization has several negative effects, not the least of which is the loss of valuable public beach. Man-made structures built too close to the waterfront interfere with natural coastal processes; shoreline stabilization can cause erosion on downdrift properties and, thus, further shoreline hardening. In many cases, the beach in front of seawalls and revetments has disappeared or is

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disappearing. Structural shoreline stabilization is detrimental to the shoreline, to the community, and to the-long-range best interests of the development itself.

Although erosion has been caused by many human activities and natural events, recent studies predict a sea level that is 6 inches greater than present by the year 2020, and approximately 14 inches above present by the year 2065.

If we assume that no new sediment is supplied to the barrier systems, a 2 inch rise should result in a shoreline retreat of 60-150 feet. The actual amount of retreat depends on the gradient of the coastal plain, with rapid retreat on flat coastal plains and slower retreat on steeper coastal plains. Considering that most shoreline structures have less than 100 feet of sand between their foundations and the water's edge, the significance of these predictions for the future cannot be overlooked in the present. Several areas of public policy and planning must acknowledge an increasing rate of sea level rise.

Inlets

Tidal inlets, or passes, can be classified within the extremes of "tide-dominated" or "wave-dominated". Tide-dominated inlets have a large tidal prism (total volume of water that flows into the bay with each cycle of the tide) in relation to the longshore transport ( sediment transported by currents that moves along the shore). Wave-dominated inlets have a small tidal prism in relation to the longshore transport. A continuum of various relationships exist between these two types and are known as "mixed-energy" inlets.

Big Sarasota Pass is classified as a mixed-energy, offset pass. This type of pass is characterized by one shoreline being distinctly offset from the other. This particular configuration is the result of the onshore migration of swash bars. The swash bars often form discernible upland sand ridges as the downdrift side of the pass continues to accrete by the addition of more offshore bars. The migration of these bars is driven by wave refraction around the ebb tidal shoal.

The migration of tidal passes can also negatively impact adjacent shorelines. For example, by 1953, the main channel of Big Sarasota Pass migrated to the south enough to cause the south bank of the pass, Sarasota Point on Siesta Key, to erode 1,000 feet. At present, most of this section of the shoreline is artificially stabilized. In 1987, the former Florida Department of Natural Resources (FDNR) considered but rejected Sarasota County's proposal that Sarasota Point receive federal and state funds for beach nourishment.

New Pass is classified as being a mixed-energy, straight pass. This type of pass is often characterized by an arcuate (arc-shaped) ebb tidal delta and migrating swash bars downdrift of the pass.

Midnight Pass closed in 1983 during an attempt to divert the northerly migration of the pass which was threatening houses situated along the south end of Siesta Key. The Pass was a mixed-energy pass that evolved into a wave- dominated pass. A combination of dredging and filling projects from

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1920 to 1983 reduced tidal flow through the pass resulting in a change in its stability. The reduced flow allowed sediment to accumulate into the inlet. The pass became increasingly unstable and, in 1983, the pass migrated north, threatening private property on the south end of Siesta Key. As stated previously, the pass was artificially closed in November, 1983. Several attempts to reopen the pass have proven inadequate and have failed. Permit applications for reopening Midnight Pass were submitted to the appropriate state and federal agencies and denied.

The closure of Midnight Pass has resulted in a slow reduction of tidal flushing in the immediate area of the former inlet. One of the effects of the reduction in tidal flow and mixing has been a metamorphosis in the character of Little Sarasota Bay from a more saline environment to a more brackish water environment. The metamorphosis has been accompanied by corresponding changes in the floral and faunal communities.

The closure of Midnight Pass also led to changes in the adjacent beach shorelines. The shoreline north of Midnight Pass has eroded and some accretion has occurred along north Casey Key.

Venice Inlet was stabilized by jetties in 1937-1938. Since installation of the jetties, the area downdrift of the inlet has experience moderate to severe erosion. In 1987, Congress authorized a beach nourishment project for the downdrift area because of erosion caused by the Venice jetties. A subsequent nourishment project on Venice Beach was completed in 1996.

Erosion and Accretion Trends

The shoreline dynamics along Sarasota County's Gulf Coast have contributed to a mixture of erosion and accretion. In some locations, these forces have balanced over time. Other locations, such as areas adjacent to unprotected inlets, are especially prone to significant changes in shoreline morphology. Of prime importance in the study of shoreline dynamics is the identification of the areas that have exhibited an overall erosion trend.

County Ordinance No. 79-03, as amended, furthers the restrictions on development seaward of the Gulf Beach Setback Line (GBSL) and includes regulations which control development along the passes in the County. The objective of the ordinance is to protect the unincorporated coastal areas which are directly exposed to the Gulf or the barrier island passes from erosion and flooding through the establishment of a Gulf Beach Setback Line and a Barrier Island Pass 20 Year Hazard Line.

The following discussion identifies observed erosion and accretion trends. This discussion is based on information gathered from the Florida Department of Environmental Protection (FDEP), Sarasota County Beach Restoration Management Plan and from the County's emergency permits.

LONGBOAT KEY

All of Longboat Key is incorporated within the Town of Longboat Key. Longboat Key is situated in both Sarasota and Manatee Counties. In Sarasota County, Longboat Key is intensively developed

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on the Gulfside, with bayside residential finger canals along the southern portion. While the northern area of Longboat Key has accreted, the central and southern sections have significantly eroded.

Historically, the southern portion of the Key, the portion within Sarasota County, has eroded at twice the rate of the central part. Since 1964, when the Army Corps of Engineers (ACOE) first dredged New Pass, portions of the southern part of the Key have eroded at a rate of approximately five feet per year. FDEP identified a 6.5 mile section of southern Longboat Key (3 miles in Sarasota County) as a potential beach nourishment project. The Longboat Key project, however, failed to gain the state's support due to lack of adequate public beach access. Subsequently the Town of Longboat Key implemented a special taxing district to raise funds to nourish the entire shoreline of the key and in 1994, a nourishment project was completed.

LIDO KEY

Lido Key is located in the City of Sarasota. The key was formed in the 1920's, when the open water between several small mangrove islands was filled with spoil from the New Pass dredging project. Lido Key has substantial residential development on the bay. Commercial development has taken place at St. Armand's Circle and along the Gulf south of the circle.

Between 1939 and 1953, approximately 750 feet of shoreline accreted on North Lido Key; and over 200 feet accreted on the southern end of the Key. During the same time period, the central section eroded approximately 200 feet. North Lido Key remained stable until 1966, two years after New Pass was dredged by the ACOE. Between May 1982 and April 1983, approximately 200 feet of erosion occurred on North Lido. In 1985, the COE redredged the pass in an attempt to reduce the trend. Later, in 1986, a seawall was constructed by residents of Lido Shores along the south side of the pass which resulted in some loss of public beach.

SIESTA KEY

The majority of Siesta Key is in the unincorporated portion of Sarasota County. It is the most densely developed barrier island in the County, and has commercial, residential, and tourist development on both bay and gulf shores. There are two large public beaches and several beach access points on the island.

Like all dynamic barrier islands, Siesta Key has experienced erosion. As mentioned in the Tidal Inlets section, Sarasota Point has been subject to severe erosion. In the past, tropical storms and hurricanes have heavily impacted the area. Portions of Beach Road on Siesta Key washed out during the 1982 "No-Name Storm" and again in 1986. Subsequent to the 1986 storm, a section of Beach Road west of Ocean Boulevard was left as one lane.

From 1883 to 1967, the area immediately north of Siesta Key Public Beach accreted approximately 600 feet; the shoreline along Point of Rocks, naturally revetted by coquina rocks, has remained relatively stable. Historically, the south end of Siesta Key fluctuated as much as 1,500 feet north and

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south in response to the migration of Midnight Pass. Since Midnight Pass was closed in 1983, and south Siesta Key was connected to North Casey Key, the Gulf shoreline has straightened with some erosion occurring north of the former pass.

CASEY KEY

Casey Key is long and narrow with low density residential development. There are a few small motels near the southern end of the key. Between 1883 and 1953, the shoreline at the north end of Casey Key receded approximately 274 feet. This erosional trend continued until 1974 when Midnight Pass began to migrate northward.

FDEP identified but rejected a 2.65 mile section on north Casey Key as a potential beach nourishment project. All but the southern 1,200 feet of this section are artificially stabilized. Portions of Casey Key Road along this 2.65 mile section, two sections north of Blackburn Point Road and one south of Blackburn Point, have repeatedly washed out during storms. All three portions of the road require regular maintenance; even after minor rain storms, the County places fill on these portions of Casey Key Road. These road sections are maintained for public health and safety. In the event of a major storm, Blackburn Point Road is the only exit for the north Casey Key residents. South Casey Key residents can leave the key from both Blackburn Point Road and Albee Road. The beaches on south Casey Key, immediately north of Venice Inlet, have benefitted from the North Jetty which acts as a barrier to drifting sands.

VENICE

North of Red Lake in Venice, the beaches are part of the mainland. High rise condominiums and hotels have been constructed along the Tarpon Center Drive and Esplanade portion of the shoreline. From 1883 to 1953, Venice's coastal shoreline retreated approximately 175 feet, although the shoreline along a rock outcrop in the central portion remained relatively stable.

Venice beach erosion is particularly severe just south of the inlet. Coastal erosion in the Tarpon Center Drive and Esplanade area is attributed to the Venice Inlet jetties which act as a barrier to the net southward littoral drift. In the past, spoil from periodic Intracoastal Waterway dredging was placed along the beaches south of the inlet to mitigate erosion.

FDEP identified and supported a beach nourishment project along a 3.3 mile section south of the Venice jetties and north of Caspersen Beach. The majority of the developed portions of this section, which consist of multi-family and mixed residential structures, are artificially hardened with either seawalls or revetments. Widening the beach protects these developments and extends the area of public beach access. The project also provides some protection to the City of Venice wastewater treatment plant which benefits from the placement of beach fill.

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MANASOTA KEY

Technically, Manasota Key is a peninsula which begins just south of Red Lake. The key is narrow with residential development on both gulf and bay sides.

Manasota Key is split between Sarasota and Charlotte Counties. The following discussion will refer only to that portion in Sarasota County. Between 1883 and 1939, gains and losses from erosion and accretion were fairly well balanced. From 1939 to 1953, however, erosion predominated. South of Manasota Key Beach Road, general erosion and storm damage have impacted shore protection structures and undermined private residences.

A portion of Manasota Key Road along the County-owned Blind Pass Park washed out during both the "No-Name" Storms in June 1982 and March 1992 and Hurricane Elena in 1985. While road washout presents a major problem in terms of the financial expense, a road washout at this point is not a significant threat to public health and safety. Residents north of Blind Pass Park can leave the island from Manasota Beach Road. Residents south of the park can exit through Charlotte County.

Analysis

Protection of the County's remaining natural beaches and dunes is essential to public beach access and wildlife. There are several ways to protect these resources in the face of current erosion patterns: 1) landward relocation of structures which allows the beach to migrate and erode naturally; 2) structural or passive restoration of the beaches and dunes; 3) a combination of the first two methods; or 4) purchase of lands by government for recreation, resource protection and to prevent costly government-financed reconstruction following storm events. Whichever form it takes, protection of the County's beaches will be expensive.

Depending on the cause and severity of erosion, a variety of mitigation measures might be pursued. Threatened structures can be relocated, shoreline protection structures removed, and the beach/dune system revegetated. Another alternative is to directly nourish the beach with compatible sediments. Such nourishment is not a permanent solution and must be performed periodically. Shoreline stabilization with hardened structures such as a vertical seawall or revetment should only be attempted as a last resort.

In the previous section, roads subject to repeated storm damage were identified at five areas in unincorporated Sarasota County: one segment of Beach Road west of Ocean Boulevard; three segments on Casey Key Road, two north and one south of Blackburn Point Road; and one segment of Manasota Key Road at Blind Pass Beach. The potential for relocating the road segments on Siesta and Casey Keys is limited due to existing residential development. In both cases, alternative action has been taken to reduce the public cost of rebuilding the damaged road segments. The segment of Beach Road has officially been reduced to one lane for northbound traffic only. Presently, the County maintains the road surface, but has no plans to reconstruct the road base. In 1988, north Casey Key

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residents agreed to a special taxing district to provide needed improvements including shore protection structures.

In 1993, the County approved the relocation of Manasota Key Road at Blind Pass. As noted in the "Blind Pass Beach General Development Plan", Manasota Beach Road at Blind Pass Beach, "is in direct conflict with the processes of the beach ecosystem." A new road alignment through the County-owned property will have to work in concert with the natural features of the area: habitat; soils; and hydrology. The plan calls for turning Manasota Key Road landward towards the bay at the site's north and south boundaries. The potential for relocating roads in areas with existing residential development is best addressed as part of a hurricane mitigation/post-disaster planning strategy discussed later in this Chapter.

Structural beach/dune restoration includes the construction of jetties, breakwaters, and piers designed to dampen wave energy so that sands transported by littoral currents are dropped in the erosion area. Such structural changes to the shoreline require site specific engineering and are not necessarily the best solution. In many cases, structural attempts to solve problems of beach erosion merely displace the problem to downdrift properties.

Non-structural or "flexible" beach/dune restoration programs include dune revegetation and beach nourishment. Dune revegetation can be accomplished through natural revegetation or replanting. While there are a number of groins and jetties in Sarasota County, the County's current management guidelines discourage shoreline stabilization techniques that interrupt natural beach processes. Non-structural approaches to beach/dune restoration are preferred.

The County's Parks and Recreation and Natural Resources Departments encourage dune protection and restoration. In County-owned beachfront parks, the Parks and Recreation Department implements a dune restoration and protection program that includes revegetation and dune protection with beach walkovers and sand fences. It is important that this program be maintained and that adequate funds to complete planned projects be allocated.

The Parks and Recreation Department's restoration program is not the County's only effort to protect and restore valuable dune systems. Ordinance 79-03, as amended, includes a beach cleaning and grooming permit requirement. In order to groom a beach front, property owners must obtain a permit from the County's Natural Resources Department. The Department has determined the historic dune vegetation line Beach grooming should be prohibited in this dune area. If dune vegetation has been destroyed, property owners should be required to revegetate the dune either through passive revegetation or replanting efforts. In many cases, structures have been built upon the historic dune area. To re-establish the dune, relocation of private structures and public infrastructure might be pursued. Beach nourishment and dune creation is another potential solution.

Beach nourishment is another alternative measure to protect the County's beaches and dunes. In September 1987, FDNR sent a proposed Beach Restoration Management Plan for Sarasota County

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to the County's Natural Resources Department. This plan identified six specific areas in Sarasota County that have experienced severe coastal erosion. Of these six areas, State funding for beach nourishment has been approved in only one case: the Gulf shoreline south of the Venice Inlet.

The remaining areas did not meet State criteria for funding. The State recommended that the County consider alternative methods to mitigate the erosion problem at Sarasota Point Beach, South Siesta Key Beach, and Casey Key Beach.

Estuaries

An estuarine ecosystem includes the coastal water basin, the adjacent shorelands and water flowing into the estuary. The estuary is a zone of transition between freshwater and saltwater systems and an important nursery for numerous marine animals. Historically, estuaries have fostered many important commercial and recreational activities such as ports, marinas, and commercial and recreational fisheries. Balancing the diverse environmental, economic, and social interests in estuarine areas is essential to coastal management.

Bay and creek shorelines are important transitional areas between uplands and bay waters; they buffer estuaries from upland development and are the location of important tidal wetlands. Development activities in the bays and creeks (dredging and filling), along the shorelines (artificial stabilization), and in the uplands (sewage effluent and stormwater runoff) can negatively impact these resources. The challenge of coastal management involves addressing the interrelationships of the complex estuarine ecosystem so that development, including the development of recreational facilities, is consistent with bay protection.

The quality of water in the estuaries is a growing concern as development pressures increase. Because these waters naturally receive large amounts of organic matter, the biological competition for available oxygen to assimilate these nutrients often leads to depletion of dissolved oxygen. The introduction of urban and agriculture runoff, sewage effluent, and septic tank seepage, aggravates the competition for oxygen.

The Comprehensive Conservation and Management Plan, developed through the Sarasota Bay National Estuary Program (NEP), was adopted by the NEP Policy Committee in 1995 and provides the following update to conditions in the Bay environment.

In general, water quality in the northern and central portions of Sarasota Bay is improving, although similar improvements have not been detected in the southern Bay. Sediment quality is degraded in tributaries Baywide, but the main Bay is relatively free of contaminants. A principal pollutant affecting water quality is an overabundance of nitrogen which harms the Bay by increasing algae growth. Excessive algae reduce light penetration to submerged seagrasses and, through biological and chemical processes, deplete oxygen from the water.

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Nitrogen loading into Sarasota Bay has tripled since intensive development began. Human-induced sources of nitrogen are wastewater (including small and large wastewater treatment plants), groundwater (from septic systems and small treatment plants) and stormwater (including fertilizers from lawn care and agriculture).

Healthy wetlands, including both freshwater and intertidal habitats, are important to the vitality of Sarasota Bay because they provide food and shelter for marine life. Wetlands also filter pollutants and help regulate the flow of freshwater into the Bay, and intertidal habitats. Salt marshes and mangroves help protect shorelines from erosion. Since 1950, the area of intertidal wetlands in the Bay watershed has declined 39 percent. Since 1975, freshwater wetlands (as a whole) have declined 16 percent, while non-forested wetlands have declined 35 percent.

The health of Sarasota Bay's fisheries is generally dependent on the quality of Bay waters, wetlands and seagrasses. As with water quality, wetlands and seagrass acreage has generally declined in the Bay. Nitrogen pollution is damaging the habitat value of many remaining seagrass meadows. Seagrasses have declined approximately 30 percent Baywide, except in localized areas where water quality has improved in recent years. Seagrass recovery in Sarasota Bay is directly linked with restoring water quality, particularly by reducing nitrogen loadings to the Bay.

Since most of the natural factors affecting fish populations, such as water quality, seagrasses, intertidal wetlands and low-salinity areas, have been degraded over time, declines in Bay fisheries come as no surprise. The limited data available suggest that Sarasota Bay's fish populations have remained relatively stable since 1978. However, seatrout landings are down 50 percent as compared to earlier decades, although seven times more recreational anglers currently use the Bay than in the 1950s. Improving water quality and habitats is expected to result in greater numbers and diversity of fish in the Bay.

Increased recreational use of Sarasota Bay has resulted in conflicts between user groups, such as anglers vs. skiers or boaters vs. swimmers, in certain geographic areas. Management plans targeted to areas of recreational conflict, if developed in cooperation with government agencies and Bay users, would enhance the recreational experience provided by Sarasota Bay. This enhancement in turn would promote stewardship of the Bay, contribute even more to the local economy and protect Bay resources.

Drainage Basins

Sarasota County contains a portion of three regional drainage basins as identified by the FDEP in their 1994 Technical Report on Water Quality Assessment. A fourth, Charlotte Harbor Basin, receives drainage from the Myakka River and estuarine influences from Lemon Bay. Included in these general basins are inland and bay waters which extend from Tampa Bay to Charlotte Harbor. These basins, including the Manatee River Basin, the Sarasota Bays Basin, the Myakka River Basin, and the Charlotte Harbor Basin, are shown on Figure 2-4.

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Figure 2-4: Regional Drainage Basins

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The overall water quality in the three basins (as identified in the 1994 FDEP Water Quality Assessment Report) is considered fair to good. In the Sarasota Bays Basin, however, Whitaker Bayou is considered to be in poor condition. The water quality in each basin will be dealt with individually in order to identify any problem areas based upon the results from the FDEP Report and other regional and local studies. Further analysis within the section will focus on the sources of pollution within the bays and streams of Sarasota County.

MANATEE RIVER BASIN

The portion of the Manatee River Basin that is contained within Sarasota County is the southern extreme of the Braden River Watershed. Cooper Creek, which is one of the primary tributaries of the Braden River and Evers Reservoir (the City of Bradenton's potable water supply), has its headwaters in Sarasota County. Cooper Creek originates in Long Swamp and is ditched from I-75 until it reaches Manatee County. Existing land use designations under the 1989 Apoxsee are Urban for the Sarasota County portion of the watershed. This updated Plan contains Major Employment Center (MEC) designated acreage on the southwest and southeast quadrants of the I-75/University Parkway interchange. Areas adjacent to these quadrants are designated Urban and Rural, respectively. According to the FDEP Technical Report and Tampa Bay Regional Planning Council's study in 1986, the current water quality of the Braden River is generally good and consistent with its designated uses. However, the widespread nutrient and coliform loading from agricultural runoff in the watershed poses a major threat. Future land use development, particularly in the University Parkway/I-75 area of the County, will require specific recognition of this area's sensitivity and the potential negative impacts of stormwater runoff on surface and groundwater quality in this watershed.

CHARLOTTE HARBOR BASIN

According to the Charlotte Harbor Management Plan, the Charlotte Harbor area is a series of distinct, but related bays and estuaries including Lemon Bay, Charlotte Harbor, Pine Island Sound, Matlacha Pass, San Carlos Bay and Estero Bay. Together they form the largest estuarine system in the state.

Since Sarasota County is a member of the tri-county Charlotte Harbor Resource and Management Committee, which approved the Management Plan for the Harbor in 1981, pertinent environmental considerations in the plan have been incorporated into the updated Chapters of Apoxsee. The goal, objectives, and programs of the Management Plan have been listed in Appendix B, Section 1.

Sarasota County also is represented on the Policy and Management Committees of the Charlotte Harbor National Estuary Program (NEP). Lemon Bay will be included in the Charlotte Harbor Comprehensive Conservation and Management Plan that will be prepared by the Charlotte Harbor NEP.

Water quality in the estuary is generally good. The greatest direct threats to the waters of the Harbor area are inadequately treated and improperly disposed domestic wastes, in addition to the accidental

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release of phosphate sludge. As the population of the area rapidly increases, the need for effective waste treatment increases correspondingly. Increases in non-point and point source pollution problems are likely in the future as additional acreage are converted from agricultural to urban land uses. This will result in the need for a coordinated stormwater management plan in order to maintain and improve estuarine water quality.

MYAKKA RIVER BASIN

The Myakka River system is an extremely valuable resource for the County because of its natural beauty, recreational significance, vegetation and wildlife habitat area, and natural purification system for surface water and groundwater. The Myakka River is roughly 54 miles long and drains 540 square miles before entering Charlotte Harbor. The River's headwaters are located to the northeast in the nearby swamps of Manatee and Hardee Counties. The City of North Port is located adjacent to the River on the east, while the City of Sarasota is situated just west of the drainage basin. Ranching and agriculture are the major land uses in this relatively undeveloped basin. According to the FDEP, the majority of the basin has good water quality which supports productive freshwater and estuarine habitats. Approximately 20 miles of the southern reaches of the River are influenced by tidal flows, as evidenced by the abundance of mangrove swamps and islands. The Myakka River Basin contains the only Class I surface waters designated in the County.

Big Slough, a major tributary of the Myakka River which is also designated a Class I surface water, is currently being utilized as a source of potable water by the City of North Port. Nutrient loading from nearby agricultural operations into the Big Slough, in addition to increased urban development in the area of North Port, have contributed to higher volumes of stormwater runoff and have impacted water quality.

DEP considers the Myakka River and Lower Myakka Lake to be in generally good condition while the Upper Myakka Lake is considered to be in poor condition. Dense hydrilla and hyacinth growth in the upper lake area has caused depressed levels of dissolved oxygen (DO).

SARASOTA BAYS BASIN

There are nine embayments in the Sarasota Bays Basin: Sarasota Bay, Roberts Bay, Little Sarasota Bay, Dryman Bay, Blackburn Bay, Lyons Bay, Dona Bay, Roberts Bay (South), and Lemon Bay. Small creeks enter these estuaries and form independent sub-basins. Rapid urban development in the North County area has increased stormwater runoff from non-point sources of pollution which has lowered the DO levels within a number of these sub-basins. According to the FDEP, the water quality of surface drainage from the adjacent coastal basins is considered fair, although in some cases it is poor. Agricultural drainage within the basin occurs primarily from citrus groves located west of I-75, and from rangelands situated at the headwaters of Phillippi Creek and Cow Pen Slough. The Dona/Roberts Bay estuarine area has received sediment loading from the upland Cow Pen Slough watershed which has caused a reduction in freshwater and estuarine plants and fish.

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The assessment report has indicated that the majority of bay waters and creeks in this basin are in fair to good condition with the exception of Whitaker Bayou which is in poor condition. Table 2-4 identifies point source discharges in the basin.

Bayfront Development Trends

There are six bay groupings in Sarasota County: Sarasota Bay; Roberts Bay; Little Sarasota Bay; Dryman/Blackburn Bays; Lyons, Dona, and Roberts Bay; and Lemon Bay (See Figure 2-5). For the purposes of the following discussion, Dryman/Blackburn and Lyons/Dona/Roberts Bays will be grouped together.

Bayfront development in Sarasota County is predominantly residential which varies according to the following densities established for the existing land use cover map: low (less than 2 dwelling units per acre), moderate (2-5 dwelling units per acre), and high densities ( greater than 5 dwelling units per acre) occur around the bays on both the barrier islands and the mainland. The majority of this development occurred between 1948 and 1978, although Sarasota Bay had already experienced significant development prior to 1948.

According to a February, 1988 update of the County bay shoreline survey, bayfront development has involved considerable shoreline and bay modification. By 1978, approximately 60 miles of bay shoreline were added through dredge and fill projects. Since 1985, shoreline hardening projects have been discouraged through local and State policies and regulated through State and County agencies. Over the past decade, only a few shoreline hardening projects have been approved by the County which were necessary to protect the integrity of existing residential structures. The decrease in the rate of shoreline creation is primarily due to the effectiveness of County and state regulations governing dredge and fill activities. As of 1988, 53 percent of the County's bay shorelines were

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Figure 2-5: Designated Bay Groupings in Sarasota County

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artificially stabilized with bulkheads (vertical seawalls and retaining walls) or revetment (rip-rap). While the amount of stabilized shoreline increased 5 percent between 1978 and 1987, the overall rate of shoreline stabilization has decreased since 1978.

In 1948, 86 percent or 125.7 miles of the County's bay shoreline was in a natural state, either as beach (38.5 miles) or vegetated with mangroves (87.2 miles). By 1978, the amount of beach had decreased to 33.8 miles and mangrove shorelines to 73.5 miles. Since then, mangrove shorelines have increased approximately 4 miles while an additional 9 miles of beach has been lost. Another representatively small, but important shoreline type is the marshgrass shoreline. This shoreline type has steadily decreased since 1948 with the most significant reduction from 7 miles to 4.2 miles between 1978 and 1987.

The Sarasota County portion of Sarasota Bay has medium to moderate density residential development on both the mainland and the barrier islands. There are very few parcels of undeveloped land and property in native habitat is rare. Approximately 67 percent or 43.4 miles of Sarasota Bay's shoreline was artificially stabilized in 1987 which represents a 9 percent increase from 1978. This same time period indicates a 5 mile reduction in beach (from 13.2 to 8.2) as well as relatively stable mileage of mangrove shoreline.

Roberts Bay has medium to moderate density residential development on the barrier island side and medium density residential development on the mainland. Moderate density development is also located on both sides of Phillippi Creek. Very few properties along the bay remain in native habitat. In 1987, there was 48 percent or roughly 20 miles of bay shoreline that was artificially stabilized which represents a 4 percent increase from 1978. Despite the high degree of development which has taken place during this time period, 44 percent or 18 miles of shoreline remains as mangrove vegetation with another 3.8 miles as beach.

Little Sarasota Bay has low to medium density residential development on both the barrier island and the mainland shoreline. Moderate density development is situated along the bay adjacent to the Turtle Beach area. By 1987, an estimated 45 percent or 13.4 miles of Little Sarasota Bay was mangrove shoreline while approximately 42 percent or 12.6 miles has been stabilized. The extent of primary beach shoreline decreased from 5.7 miles to 4.4 miles during this period.

The Dryman, Blackburn, Lyons, Dona, and Roberts Bay grouping includes bayfront lands which extend from the Laurel area on the north to Venice on the south. Dryman and Blackburn Bays have medium residential density along both barrier island and mainland shorelines. Low to medium residential density occurs along the shorelines of Lyons, Dona, and Roberts Bays, while moderate density development is located along the Gulf side from Venice Inlet south to Venice Avenue. After Sarasota Bay, this bay grouping has the greatest amount of shoreline stabilization at 60 percent or 26 miles. The amount of beach decreased by 1.7 miles between 1978 and 1987 while native shoreline vegetation increased by roughly 2 miles for a total of 16.2 miles.

Lemon Bay is the least developed bay in Sarasota County. The majority of development along the bay's shoreline is low density residential development with some medium density development in the

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Englewood area. Several large parcels remain in a variety of native habitats: coastal hammock on the barrier islands and coastal hammock, pine flatwoods, and scrub habitats on the mainland. Beach shorelines have decreased. An estimated 45 percent or 14.5 miles of the bay has a mangrove shoreline.

Substantial reductions in native shoreline occurred along the County's bays from 1948 to 1978, and indications over the past ten years show a continuing trend, however at a much slower rate. Increased shoreline hardening and the subsequent loss of native vegetation has resulted in increased turbidity affecting seagrass production and limiting recreational access and use.

In 1989, the Sarasota Bay National Estuary Program (NEP) was established. Sarasota County Government along with other local governments and state agencies are represented on the Management and Policy Committees as well as other technical advisory committees. The Comprehensive Conservation and Management Plan was adopted in 1995. The issues addressed in this plan include wastewater, stormwater, wetlands, fisheries, recreation and overall bay management within the study area. NEP is now overseeing implementation of the action strategies identified in this plan.

This plan could provide strategies for habitat preservation and restoration bay-wide including the creation of a funding mechanism for the restoration and/or acquisition of wetland and upland habitats; the integration of stormwater management and wetland management/restoration programs; and the adoption of specific goals for habitat restoration. Information regarding the historic and predicted sea level rise and projected shoreline changes should also be considered in the development of a Bay-wide Management Plan and in the adoption of management guidelines. Issues concerning public access to the County's bays and waterways will be discussed in the Water-Dependent/Water-Related Uses section of this Chapter.

Point and Non-Point Sources of Pollution

The key contributors to the degradation of bay water quality include stormwater runoff, sewage effluent, shoreline stabilization and dredging.

Sarasota County Environmental Services Laboratory monitored ambient water quality in County bays and streams from 1978 until 1992. In 1992, the County's Environmental Services Laboratory was closed. Since January 1995, ambient water quality in bays and the Myakka River has been monitored by a private contractor. The sampling methodology recommended by the Sarasota Bay National Estuary Program, is designed to track the progress in improving estuarine health by implementation of the Program's Comprehensive Conservation and Management Plan and the Myakka River Wild and Scenic Management Plan.

Five randomly chosen stations are monitored monthly in each of 10 subregions. Subregions include Lemon Bay, Blackburn Bay, Little Sarasota Bay, Roberts Bay, east lower Sarasota Bay, west lower Sarasota Bay, and the Myakka River, north and south of