Report of the
Bradfordville Citizen Storm Water Study Group
to the
Leon County Board of County Commissioners

October 14, 1997

Study Group Members:

Robert E. Deyle, chair
William T. Cooper
William S. Jordan
Charles L. Mesing
Rhett A. Miller
Joseph Travis
Timothy B. Waddle
Table of Contents

Focus and Procedures1

Interpretation of Charge from the Board1

Procedures of the Study Group2

Recommended Substantive Focus of the Study3

Ground Water Impacts3

Environmentally Sensitive Areas4

Recommended Geographic Focus of the Study4

Findings Concerning the Issues to be Addressed in the Study5

Principles of How Lakes Work 6

Findings Regarding the Environmental Quality of Lakes in the Study Basins7

Findings Regarding Potential Flooding Problems9

Findings Regarding Applicable Standards10

Recommendations12

Recommended Short-Term County Initiatives12

Recommended Objectives of the Study13

Phase One13

Phase Two14

References Consulted15

Members of the Study Group17 Focus and Procedures

Interpretation of Charge from the Board

In the absence of a formal charge from the Board of County Commissioners, the Study Group relied on the advice and counsel of staff of the Department of Growth and Environmental Management (GEM) to define the Study Group's responsibilities. We took our direction principally from Section 4.b. of the Bradfordville Center Publix Site Mediation Agreement dated 8 April, 1994, and Objectives 8.1 and 8.2 and Policies 8.1.2 and 8.2.1 of the County Comprehensive Plan which we understand served in part as antecedents to the Publix Mediation Agreement. As part of our efforts to interpret the mediation agreement, we also conferred with the executive officers of the homeowners associations who were parties to the agreement: Mr. Harry Reed of the Killearn Lakes Homeowners Association and Mr. Larry Block of the Lake Carolyn Homeowners Association. County staff that were party to the agreement were not available to us.

Pertinent sections of these references include the following:

Section 4.b. of the Bradfordville Center Publix Site Mediation Agreement: Preconstruction, County will . . . direct staff to expedite a staff study of the Bradfordville area, including, but not limited to, the Gilbert Pond, Killearn Lakes, and Lake McBride watersheds, with recommendations for appropriate amendments to approved land uses and/or the County EMA to prevent unacceptable cumulative impacts from future development to the existing lakes; pending the staff study, staff, with Homeowners input will recommend whether the County Commission should adopt a temporary limitation on commercial or industrial development (to be later defined and to not affect this Publix agreement) and review procedures to protect the Bradfordville community from adverse storm water impacts until the amendments are in place.

Objective 8.1 of the County Comprehensive Plan: Develop and implement a comprehensive storm water management plan for the Bradfordville area by December, 1995, to eliminate the potential for damage and harm from flooding as a result of urbanization.

Policy 8.1.2: As an interim standard prior to the completion of the comprehensive storm water management plan, no development activity in the Bradfordville area shall be permitted to increase the frequency, duration or extent of flooding off-site.

Objective 8.2 of the County Comprehensive Plan: In addition to storm water quantity and flooding concerns, the comprehensive storm water management plan for the Bradfordville area will also address the protection and enhancement of natural surface water bodies.

Policy 8.2.1: As an interim standard prior to the completion of the storm water management plan, land development activities in the Bradfordville area shall serve to maintain or improve the water quality in all affected watersheds.

(1)To recommend the geographic and substantive scope for a study to be conducted by a qualified consultant that will provide the Board of County Commissioners with (a) a factual base for understanding the probable impacts of future development on flooding and the environmental quality of the water bodies of the Bradfordville area and (b) recommendations for policy and regulatory initiatives that would serve to prevent unacceptable cumulative impacts from storm water discharges.

Procedures of the Study Group

Following appointments by the Board of County Commissioners, the Study Group first convened on May 28, 1997. The Study Group elected a chairperson from among its members to facilitate the meetings. GEM staff provided administrative support for recording minutes and providing notice of meetings. Technical support was provided by GEM, the County Department of Public Works, and the Tallahassee-Leon County Planning Department. Storm water experts were also consulted from various agencies and organizations including Florida State University, the University of Florida, Georgia Institute of Technology, Camp, Dresser, and McKee, the Florida Department of Environmental Protection, the U.S. Geological Survey, the Northwest, Southwest, and St. Johns Water Management Districts, and the Atlanta Regional Commission.

The Study Group generally met at two week intervals. Three subcommittees were formed to develop the details of the substantive scope of work for the storm water study:

Storm Water Conveyance: William Jordan
Rhett Miller
Timothy Waddle (chair)

Water/Sediment Quality: William Cooper (chair)
Robert Deyle

Biological Resources: Charles Mesing (chair)
Joseph Travis

Recommended Substantive Focus of the Study

The Study Group recommends that the focus of the Bradfordville storm water study be directed at two principal issues:

(1)the effects of storm water quality on the environmental quality of the lakes within the study basins, and

(2)the potential for future development to create or exacerbate flooding problems within the study basins.

During our conversations with representatives of the homeowner associations that were parties to the Publix Mediation Agreement and other residents of the Bradfordville area two other issues were raised: (1) the potential impacts of storm water discharges on ground water quality and (2) the effects of development on "environmentally sensitive areas." While these are issues that merit attention by the Board of County Commissioners, we believe that they are not as urgent as those concerning flooding or the environmental quality of lakes within the study basins. In this section we briefly discuss these secondary issues. The remainder of the report details our specific findings and recommendations concerning the two principal issues which we believe should be the focus of the Bradfordville storm water study.

Ground Water Impacts

Our limited review of available information on the ground water resources of Leon County (Davis, 1995; Benoit and others, 1992), and discussions with scientists knowledgeable about the ground water resources of the county (Davis, 1997; Pratt, 1997), indicate that changes that might occur in the quality of water or sediments of the lakes within the study basins from development within the foreseeable future are unlikely to have significant impacts on the ground water aquifers that provide potable water to residents of the county. It does not appear that any of the lakes in the study basins has a direct hydrologic connection to the Floridan Aquifer which is the principal source of potable water supply in Tallahassee and Leon County. Lake McBride, and possibly one or more of the smaller lakes, may have a direct hydrologic connection with the so-called "Intermediate Aquifer System" which does provide some recharge to the Floridan Aquifer (Benoit and others, 1992; Davis, 1997). However, the Intermediate Aquifer System is a discontinuous array of "sporadically permeable beds" within a series of low-permeability sediments that generally serve to confine the underlying Floridan Aquifer. Any dissolved storm water pollutants, such as nitrates or heavy metals, that might pose a concern to ground water quality, are unlikely to be transported in sufficient quantities from the lakes into these aquifers so as to pose a significant threat.

Of possibly greater concern is the potential for localized contamination of the Intermediate Aquifer by pathogens or nitrates from improperly sited or malfunctioning subsurface wastewater disposal systems, such as septic tank and leach field systems. Where such systems are inundated by high ground water or surface flooding, such contaminants could pose a threat to nearby shallow wells. The Study Group is not aware of the extent to which this may be an actual problem or what measures, if any, the county may be taking to address this potential concern.

Environmentally Sensitive Areas

Harry Reed, who represented the Killearn Lakes Homeowners Association during negotiations which led to the Publix Mediation Agreement, raised the issue of "environmentally sensitive areas" when he met with the Study Group. This is a term from Objective 8.3 of the County Comprehensive Plan that applies to a broader array of natural resources than the lakes of the study basins: "The County will adopt policies by December, 1994, to protect environmentally sensitive areas from incompatible development." The Study Group believes that the substantive scope of the study encompassed by its charge should be limited to the cumulative effects of storm water discharges from development. Within this context, we believe it is appropriate to limit the focus on environmentally sensitive areas in the storm water study to the plant and animal communities that comprise the ecosystems of the lakes within the study basins.

Recommended Geographic Focus of the Study

Figure 1 defines the recommended geographic boundaries of the area to be encompassed by the Bradfordville storm water study. The area consists of five study basins each with one or more lakes that should be included in the storm water study.

Study Basin 1 is located north of Bannerman Road and west of Thomasville Road. This basin includes the southern-most parts of the Killearn Lakes Subdivision, the Arrow Head Lake catchment, the westerly portion of the Publix site, the AAA high school site, the wetland immediately north of the high school site, and the low area/pond to the north of the wetland on the Horseshoe Plantation. Specific lakes to be analyzed include Arrow Head Lake and the Horseshoe Plantation lake.

Study Basin 2 includes the catchment area immediately north of Bradfordville Road that lies east of Publix and the catchments of the following lakes: Lake Anna, Lake Carolyn, Lake Warner, and Gilbert Pond.

Study Basin 3 includes those catchments to the south of Bradfordville Road for a distance of approximately 1.5 miles that lie to the east and west of Velda Dairy Road. These encompass the following lakes: Lake Jeff, Rabbit Pond (Lake Jamie), Lake Mary Ann, Lake Charles, Lake Bess, Lake Faye, and Lake Tom John.

Study Basin 4 includes the entire catchment of Lake McBride which encompasses the area south and west of the intersection of Bannerman Road and Thomasville Road plus an area east of Thomasville Road that drains west through a culvert under Thomasville Road.

Study Basin 5 includes the catchments of the major lakes within the Killearn Lakes Subdivision: Pine Hill Lake, Lake Petty Gulf, Lake Diane, Blue Heron Lake, and Lake Monkey Business.

Study basins 1 through 4 encompass areas likely to be affected by commercial development that may be permitted under the current Mixed Use A zoning of land in the Bradfordville community area centered around the intersections of Thomasville Road with Bradfordville Road and Bannerman Road. The boundaries of study basin 1 have been defined to also encompass the area likely to be directly affected by storm water generated from the proposed AAA high school and possible future commercial development of the Middlebrook property. Study basin 5 is included in the study area principally because of the language of the Publix Mediation Agreement and concerns expressed by Harry Reed of the Killearn Lakes Homeowners Association with potential impacts of planned commercial and residential development on land that drains into Lake Petty Gulf. Study basin 5 will not receive storm water discharges that originate from commercial development in the Bradfordville community area as defined above.

Study basins 1 and 5 are part of the Lake Iamonia drainage basin. Study basins 2, 3, and 4 are part of the Lake Lafayette drainage basin. The downstream extent of the boundaries drawn for each study basin were defined to include the water body likely to serve as the principal attenuator of storm water discharge rates and/or as the principal or furthest downstream sink for suspended sediments and associated nutrients and other pollutants that might be transported through other smaller water bodies in the basin.

The Study Group recognizes that the impacts of storm water generated within the study basins may extend to water bodies beyond these boundaries. The analyses performed for the Bradfordville storm water study should include projections of storm water volumes, rates, stages, and quality that can be used as inputs to subsequent analyses that may be done for other portions of the drainage basins of which the study basins are a part.

Findings Concerning the Issues to be Addressed in the Study

The Study Group reviewed the scope of the studies that already have been conducted of the environmental quality of lakes and the hydrology and conveyance systems for storm water in the study basins. We did not conduct a thorough review of the content of the available studies; that is a task to be included in the Scope of Work for the storm water study. We also reviewed the state and county regulations that govern storm water discharges to surface water bodies. Here we summarize our findings about the data that are available for assessing the potential impacts of changes in the quality or quantity of storm water discharged to private property and the lakes in the study basins and the deductions that can be made from our limited review of the available studies. We also present findings concerning relevant standards.

Principles of How Lakes Work

Before summarizing the Study Group's findings concerning the potential environmental quality impacts of storm water from future development, we believe it would be helpful to provide a brief summary of the key principles that govern what happens when land use changes alter the quality of storm water entering a lake.

1.Lakes serve to varying degrees as "sinks" where suspended sediments, nutrients (nitrogen, phosphorus, and carbon), oxygen-demanding substances (biochemical oxygen demand or "BOD" and chemical oxygen demand or "COD"), and pollutants (metals and toxic organics) accumulate.

2.As nutrients accumulate, they eventually reach levels that cause changes in the plants and animals that live in a lake. Resulting increases in algae or in rooted or floating aquatic plants can radically alter the habitat of aquatic organisms, fish, and the animals that feed on them, such as wading birds. Such changes also can affect the recreational and aesthetic values of a lake.

3.This is a natural process known as eutrophication that occurs over hundreds or thousands of years as a lake changes from a deep, clear, nearly sterile body of water with relatively little biological activity (an oligotrophic lake) to a shallow, turbid system with extensive growths of algae and aquatic plants (a eutrophic lake). The point at which a lake is in this process is referred to as its trophic state.

4.Under natural conditions, a lake can assimilate a certain quantity of nutrient inputs on an annual basis without significant changes to its ecosystem or its trophic state. However, the eutrophication process can be greatly accelerated by human-caused increases in the loadings of nutrients that flow into a lake.

5.When the levels of nutrients that are present in a lake are already high (that is the lake is already eutrophic or nearly so), relatively small changes in the loadings of nutrients entering a lake can cause dramatic changes, such as the rapid expansion of populations of algae (an algae bloom) or aquatic plants such as duck weed, alligator weed, or Hydrilla. Such changes can alter the habitat of a lake directly. Significant expansions of algae or aquatic plant populations may also result in significant declines in dissolved oxygen which may cause fish kills or other, more long lasting changes in the lake's ecosystem.

6.When pollutants associated with storm water runoff from urbanized areas, such as metals (copper, chromium, lead, zinc, etc.) or organic chemicals such as polycyclic aromatic hydrocarbons (PAHs), accumulate in aquatic ecosystems they can cause diseases among fish and other aquatic organisms and can eventually lead to the loss of some species. Elevated levels of such pollutants in fish may also make them unsafe for human consumption.

Findings Regarding the Environmental Quality of Lakes in the Study Basins

The following summarizes what the Study Group has been able to conclude from the information currently available about the environmental quality of the lakes within the study basins. Our findings are based on information provided to us by staff of the Tallahassee-Leon County Planning Department, principals at the Center for Aquatic Research and Resource Management at Florida State University, which has conducted a number of studies of lakes under contract with the county, and Study Group member Charles Mesing who has worked with local homeowner associations to collect water quality data on some of the lakes.

1.The lakes within the study basins vary in their origins and uses. Some lakes in the area are natural lakes that have not experienced significant changes in land use within their watersheds or resultant changes in the quality of water entering them. Others were created to enhance residential property value, and some have been intentionally devoted to the purpose of managing residential storm water.

2.The available data are insufficient for estimating the additional storm water loadings that the lakes in the study basins can assimilate without causing significant changes to their environmental quality.

The data available on the quality of the water, sediments, and biological resources of the lakes in the study basins vary. However, there have been no ecological studies of any of the lakes which describe the structure, function, and dynamics of their ecosystems. Thus nothing is known about the interactions among the water, the sediments, and the plants and animals that inhabit these ecosystems other than what can be inferred from other lakes in the region which have been more thoroughly studied.

To our knowledge, no data are available for the quality of the water, sediments, or biological resources for ten of the lakes in the study basins: (1) Lake Anna, (2) Lake Warner, (3) Lake Jeff, (4) Rabbit Pond (Lake Jamie), (5) Lake Mary Ann, (6) Lake Charles, (7) Lake Bess, (8) Lake Faye, (9) Lake Tom John, and (10) the lake on the Horseshoe Plantation property. There is, therefore, no factual basis for estimating how long it will be before the environmental quality of these lakes is significantly affected by the storm water that is currently discharged to them or how they will be affected by additional storm water discharges.

Very limited water quality data (Secchi disk depth, chlorophyll a, total nitrogen, and total phosphorus), provided by the Lake Watch Program, are available for seven of the lakes in the study basins: (1) Arrow Head Lake, (2) Pine Hill Lake, (3) Lake Petty Gulf, (4) Lake Diane, (5) Blue Heron Lake, (6) Lake Monkey Business, and (7) Lake Carolyn. To our knowledge there are no sediment quality or biological data for these lakes with the possible exception of some fish studies that may have been done for Lake Carolyn by the Florida Game and Freshwater Fish Commission (Block, 1997). These data are not sufficient to estimate the additional storm water loadings that these lakes can assimilate without causing significant changes to their environmental quality.

More detailed water quality data are available for Gilbert Pond, from studies conducted by the City of Tallahassee, and for Lake McBride, from studies conducted by the Center for Aquatic Research and Resource Management (CARRMA). However, there are no biological data for Lake McBride and no sediment quality data for either of these lakes. It is not possible, therefore, to estimate the additional storm water loadings that these lakes can assimilate without causing significant changes to their environmental quality.

4.Most of the small lakes in the study basins are likely to be highly sensitive to increased loadings of suspended sediments, nutrients, or oxygen-demanding substances from additional storm water discharges. Water quality trend data for two lakes in the Bradfordville area suggest that small water bodies are highly sensitive to storm water discharges from commercial and residential development. For example, Lake Watch data for Lake Arrow Head, which receives storm water discharges from commercial and residential properties in Bradfordville, including one of the Publix storm water facilities, reveal more than a 100 percent increase in total phosphorus and chlorophyll a levels over the past three years (Mesing, 1997). Water clarity has also declined from 5 feet (1986-88) to approximately 2 feet in 1997. These water quality changes indicate a change from oligotrophic to eutrophic conditions with in a very brief period of time. A study by the Center for Aquatic Research and Resource Management (1997) documents the recent severe degradation of a small natural water body, "No-Name Pond" in the Lake McBride drainage system, associated with storm water discharges from a construction site. These cases signal the need for caution - significant increases in storm water loadings to the smaller lakes in the study basins could cause rapid and dramatic changes in environmental quality.

5.Available information for Lake McBride indicates that it also may be quite sensitive to increased storm water loadings. Recent studies (Livingston 1989; 1995) have documented very low levels of dissolved oxygen near the bottom of Lake McBride during the day and throughout the lake at night that may be at least partly the result of plant and algae growth in the lake. However, the available information is insufficient to explain the causes of the low dissolved oxygen levels or to define the trophic state of the lake. The low dissolved oxygen levels do indicate, however, that despite its greater size Lake McBride may be quite sensitive to increased loadings of suspended sediments, nutrients, or oxygen-demanding substances from storm water discharges.

6.No information is available on metals or organic pollutants, but caution is warranted. No data are available on the levels of metals or organic pollutants that are present in or being discharged to any of the lakes in the study basin. Studies conducted in areas of Lake Jackson that have been affected by storm water discharges indicate a possible correlation between concentrations of organic chemicals and metals associated with storm water and the occurrence of fish disease (Livingston and Swanson, 1993).

Findings Regarding Potential Flooding Problems

The County Department of Public Works provided the Study Group with information about existing and proposed studies of storm water hydrology and conveyance systems within the study basins. Existing studies we reviewed include the following:

City of Tallahassee and Leon County Stormwater Management Plan (1993) - This study, completed by the Northwest Florida Water Management District, includes the entire watersheds of Lake Lafayette, Lake Jackson, Lake Munson, and Fred George Sink. The Lake Lafayette Watershed includes study basins 2, 3, and 4. The Lake Iamonia watershed was not included in this study.

Leon County Stormwater Management Master Plan (1992) - This study, completed by Camp, Dresser and McKee, addressed 18 major basins in Leon County outside the area included in the 1993 Tallahassee and Leon County Stormwater Management Plan. The Lake Iamonia watershed was included in this study thus encompassing study basins 1 and 5.

Killearn Chain of Lakes Flooding Evaluation and Abatement Study (1993) - This study, also completed by Camp, Dresser and McKee, re-examined the Alford Arm portion of the Lake Lafayette watershed to identify and evaluate existing flooding and the potential for future flooding of the Killearn Chain of Lakes. This study encompassed study basins 2, 3, and 4.

Killearn Acres Flood Mitigation Study - This is a follow up to the 1993 Killearn Chain of Lakes study that is intended to assist the county in identifying solutions to reported problems within the Killearn Acres Subdivision.

Bannerman Road/Bradfordville Road Realignment - The purpose of this study is to assist the county in identifying flood reduction benefits that can be achieved from the proposed storm water management facility proposed for the realignment of Bradfordville and Bannerman Roads. This will encompass study basins 2 and 3.

1.Considerable analysis of storm water discharge volumes and conveyance has been completed or is in progress for study basins 1, 2, 3, and 5.

2.Conveyance modeling has not been completed for Basin 4 (Lake McBride) but may be undertaken in conjunction with a proposed regional facility for managing storm water from a segment of the proposed widening of Thomasville Road and several proposed commercial developments at or near the intersections of Thomasville Road with Bannerman Road and Bradfordville Road.

3.The focus of the previous studies was downstream of the Bradfordville area. Therefore this previous work may have to be analyzed, extended, and re-presented to address the more localized concerns with potential flooding within the study basins.

4.Some extension of previous conveyance modeling may be required to provide consistent analyses for comparable future development scenarios.


Findings Regarding Applicable Standards

Standards are needed in five aspects of determining how best to minimize the cumulative adverse impacts of storm water on private property and the environment.

1.Standards for the quality of lakes, their sediments, and their biological resources are needed as a reference point for defining what constitute the "unacceptable cumulative impacts" referenced in Section 4.b. of the Publix Mediation Agreement.

2.Similar reference points are needed for defining "unacceptable" flooding conditions.

3.Standards may be needed for defining acceptable loadings of suspended sediments, nutrients, oxygen-demanding substances, and other substances in permitted storm water discharges.

4.Standards may be needed for defining appropriate "best management practices" (BMPs) for storm water treatment or rate control, for example, specifying wet detention of the first 1.5 inches of runoff.

5.Standards also may be needed for defining appropriate development standards, for example specifying the maximum allowable percent of impervious surface area or the use of source controls such as porous pavement, drainage swales, vegetated buffers, and infiltration basins.

Our findings regarding current state and local standards that might apply in these circumstances are summarized here.

1.Adherence to state numerical standards for surface water quality does not guarantee protection of the environmental quality of lakes in the study basins. Applicable numerical state water quality standards for Class III water bodies are insufficient to characterize the relevant attributes of lakes. In particular, there are no numerical standards for nutrients. In the absence of adequate understanding of the physical, chemical, and biological functions of these lakes, there is no guarantee that adherence to these water quality standards would prevent significant changes in their environmental quality within the near future.

2.It is not possible at this time to estimate how effective any specific "best management practices" (BMPs) for storm water are likely to be in preventing or delaying the degradation of the lakes in the study basins. Storm water management standards are typically based on requirements for the installation of BMPs rather than on enforceable discharge standards such as maximum daily loads. This is partly because storm water treatment systems are engineered natural systems with substantial variation in performance (Debo and Reese, 1995). Variation in performance is a function not only of design, but also of the type of land use from which the storm water is generated, and the manner in which the facility is operated and maintained. A few studies have been conducted of the performance of operating storm water management facilities elsewhere in Florida (Kehoe, 1993; Kehoe et al., 1994; Harper, 1995; Nepshinsky et al., 1995), but no such studies have been conducted in watersheds comparable to those in the study basins (Cox, 1997; Macmillan, 1997). The BMP removal efficiencies used in Leon County's federal NPDES storm water permit (Camp, Dresser and McKee, 1996) are based on studies done outside Leon County.

3.BMPs for protecting water quality during construction are the weakest link in the storm water management system. State and county standards are broad and imprecise thus depending very greatly on the ability of regulatory officials to stipulate and enforce the application of specific BMPs suitable to individual development activities. Construction BMPs fail frequently because of inadequate vigilance and maintenance by permit holders (Cox, 1997; Macmillan, 1997). They require intense monitoring and enforcement. Furthermore, they may be readily overwhelmed by relatively high-frequency storm events.

Recommendations

Recommended Short-Term County Initiatives

Given the rapid rate at which land use changes are occurring in the Bradfordville area and the uncertainty as to whether existing standards and best management practices can be relied upon to provide adequate protection of the lakes in the study basins, the Study Group recommends that the Board of County Commissioners take initiatives immediately that minimize the potential for significant water quality impacts during the construction of new development and from finished developments that may be initiated before completion of the storm water study. We believe these initiatives are consistent with the language of Section 4.b. of the Publix Mediation Agreement and the intent of policies 8.1.2 and 8.2.1 of the County Comprehensive Plan.

1.The Board of County Commissioners should adopt a policy of strict enforcement of county regulations governing control of erosion and sedimentation during construction and should provide adequate staff and supporting resources to the Department of Growth and Environmental Management to assure frequent inspections of construction sites that have significant potential for impacting vulnerable surface water bodies throughout the county.

The committee emphasizes that adequate control of storm water during construction is essential. Given the evident sensitivity of the lakes in the study basins to increases in sediment and nutrient loadings, the impacts of inadequately controlled construction runoff may be sufficient to seriously degrade a lake. The potential impact on Lake McBride of the proposed widening of Thomasville Road and related commercial development is a specific area of concern in this regard.

We recommend that the Commission require the use of best management practices (BMPs) and/or source controls that limit loadings per acre of suspended sediments, nutrients, and oxygen-demanding substances to levels that are equivalent to the loadings per acre that would occur if the storm water from residential development at a density of one unit per acre were subjected to wet detention treatment of the runoff form the first 3 inches of rainfall, with the detention treatment volume available again within 72 hours of the storm event, and no more than one-half of the treatment volume discharged within the first 60 hours.

The committee must stress, however, that without the knowledge to be gained from the proposed study, there is no guarantee that any particular BMP will provide adequate protection for any of the individual lakes in the study area.

1.The Board of County Commissioners should avoid making significant changes that intensify allowable land uses within the study basins during the course of the storm water study so as to avoid undermining the validity of the study before it is completed.

Recommended Objectives of the Study

The Study Group recommends that the Bradfordville storm water study be conducted in two phases. The first phase would principally focus on water quality concerns because this is where there is the greatest need for new information. The first phase would also include a review and assessment of the existing information on storm water hydrology and conveyances. The second phase would involve filling in the gaps identified by that assessment.

Therefore, we recommend the following specific objectives for the two-phased storm water study. The more detailed Proposed Scope of Work, which is attached, lays out the specific tasks that we recommend be included in a request for proposals (RFP) for the study.

Phase One

The county should define the principal objectives of the first phase of the storm water study as follows. Estimated duration is six to twelve months. See attached Proposed Scope of Work for details.

1.To classify the lakes in the study basins according to origin, principal uses, and important physical attributes likely to influence vulnerability to storm water discharges.

2.To characterize the current environmental quality and the trophic state of each of the lakes in the study basins based on existing data.

3.To collect additional data as necessary to characterize the trophic states of each of the lakes in the study basins under typical, seasonal, worst-case conditions.

4.To identify the one lake in each study basin that is most vulnerable to degradation of environmental quality as a result of urban storm water discharges. These "designated" lakes are to be the focus of the storm water quality impact analyses that follow. If two or more of these lakes are sufficiently similar, the sample of designated lakes may be reduced to no fewer than three.

5.To estimate the probable water quality treatment performance of storm water quality best management practices, designed to meet current county design and performance standards, when operated and maintained under typical (rather than ideal) practices.

6.To estimate current average annual loadings of suspended solids, nutrients, and oxygen demanding substances from point and non-point sources to each designated lake.

7.To estimate the annual loadings of suspended sediments, nutrients, and oxygen-demanding substances that each designated lake can assimilate without changes in water quality that exceed the mesotrophic ranges for Secchi disk transparency, total nitrogen, total phosphorus, and chlorophyll a.

8.To estimate future loadings to each designated lake for alternative future land use scenarios based on the probable water quality treatment performance of storm water management facilities designed to meet existing county design and performance standards.

9.To estimate the cumulative impact of projected loadings on the water quality of the designated lakes.

10.To assess the effectiveness of alternative changes to current county development standards and/or permissible land uses, including the interim standards recommended by the Study Group, that could be initiated by the county to reduce the cumulative water quality impacts of storm water discharges from future development to acceptable levels.

11.To review, summarize, and evaluate the existing analyses of storm water hydrology and conveyance for all study basins.

12.To describe and estimate the costs of any additional analyses that are needed to predict the potential for increases in the frequency, duration, stage, or extent of flooding within the study basins as a result of storm water discharges from new development.

Phase Two

The county should define the principal objectives of the second phase of the storm water study as follows. Estimated duration is six months. See attached Proposed Scope of Work for details.

1.To conduct the supplemental analyses of storm water hydrology and/or conveyance identified under Phase One, Objective 12 as necessary to fully characterize the potential flooding impacts of new development within the study basins under alternative future land use scenarios.

2.To assess the effectiveness of alternative changes to current county development standards, permissible land uses, and/or storm water conveyance structures that could be initiated by the county to reduce the cumulative flooding impacts of storm water discharges from future development to acceptable levels.

References Consulted

Bagit, Alan. 1997. St. Johns Water Management District. Palatka, FL. Personal communication. September 17.

Benoit, Andrew T., Jay L. Johnson, Luann Rains, Eric F. Songer, and Paul O'Rourke. 1992. Characterization of Karst Development in Leon County, Florida, for the Delineation of Wellhead Protection Areas. Water Resources Special Report 92-B. Havana, FL: Northwest Florida Water Management District.

Block, Larry. 1997. Lake Carolyn Homeowners' Association. Tallahassee, FL. Personal communication. June 24.

Camp, Dresser and McKee. 1992. Leon County Storm Water Management Master Plan. Tallahassee, FL: Leon County Department of Public Works.

Camp, Dresser and McKee. 1993. Killearn Chain of Lakes Flooding Evaluation and Abatement Study. Tallahassee, FL: Leon County Department of Public Works.

Camp, Dresser and McKee. 1996. Environmental Protection Agency NPDES MS4 Permit Application Part 2 Submitted by Leon County and the Florida Department of Transportation. Volume 1. Tallahassee, FL: Leon County Department of Public Works.

Canfield, D. E., Jr., S. B. Linda, and L. M. Hodgson. 1985. Chlorophyll-Biomass-Nutrient Relationships for Natural Assemblages of Florida Phytoplankton. Water Resources Bulletin 21: 381-391.

Canfield, Daniel E. and M.V. Hoyer. 1992. Aquatic Macrophytes and Their Relationship to the Limnology of Florida Lakes. Tallahassee, FL: Bureau of Aquatic Plant Management, Florida Department of Environmental Protection.

Center for Aquatic Research and Resource Management (CARRMA). 1997. Effects of Urban Development on the Lake McBride Drainage System - Millstone Creek/No-Name Pond - Upper Lafayette Basin. Tallahassee, FL: The Center, Florida State University.

Cook, Skip. 1997. Camp, Dresser and McKee. Tallahassee, FL. Personal communication. October 7.

Cox, John. 1997. Florida Department of Environmental Protection. Tallahassee, FL. Personal communication. September 8.

Davis, Hal. 1995. Hydrogeologic Investigation and Simulation of Ground-Water Flow in the Upper Floridan Aquifer of North-Central Florida and Southwestern Georgia and Delineation of Contributing Areas for Selected City of Tallahassee, Florida, Water-Supply Wells. Water Resources Investigations Report 95-4296. Tallahassee, FL: U.S. Geological Survey.

Davis, Hal. 1997. United States Geological Survey. Tallahassee, FL. Personal communication. September 15.

Debo, Thomas N. and Andrew J. Reese. 1995. Municipal Storm Water Management. Boca Raton, FL: Lewis Publishers.

Debo, Thomas N. 1997. Georgia Institute of Technology. Atlanta, GA. Personal communication. September 15.

Forsberg, Curt and Sven Olof Ryding. 1980. "Eutrophication Parameters and Trophic State Indices in 30 Swedish Waste-Receiving Lakes." Arch. Hydrobiol. 89: 189-207.

Harper, Harvey. 1995. "Pollutant Removal Efficiencies for Typical Stormwater Management Systems in Florida." In Proceedings of the 4th Biennial Stormwater Research Conference. October 18-20. pp. 6-19. Brooksville, FL: Southwest Florida Water Management District.

Kandell, Stephen. 1997. Atlanta Regional Commission. Atlanta, GA. Personal communication. September 12.

Kehoe, Mark J. 1993. Water-Quality Survey of Twenty-Four Stormwater Wet-Detention Ponds (Final Report). Brooksville, FL: Southwest Florida Water Management District.

Kehoe, Mark J., Craig W. Dye, and Betty T. Rushton. 1994. A Survey of the Water-Quality of Wetlands-Treatment Stormwater Ponds (Final Report). Brooksville, FL: Southwest Florida Water Management District

Kratzer, C. R., and Brezonik, P. L. 1981. "A Carlson-Type Trophic State Index for Nitrogen in Florida Lakes." Water Resources Bulletin 17: 713-715.

Livingston, Robert J. 1989. "Lake McBride Report." Tallahassee, FL: Environmental Planning and Analysis, Inc.

Livingston, Robert J. 1995. "The Ecology of the Lakes of Leon County: Lake McBride." Tallahassee, FL: Center for Aquatic Research and Resource Management, Florida State University.

Livingston, Robert J. and Helge Swanson. 1993. "Project Overview: The Ecology of the Lakes of Leon County, Florida." Tallahassee, FL: Center for Aquatic Research and Resource Management, Florida State University.

Macmillan, Tyler. 1997. Northwest Florida Water Management District. 1997. Havana, FL. Personal communication. September 15.

Nepshinsky, Janis, C. Dewey, P. Victor, and R. Brown. "Water Quality Assessment of Permitted Stormwater Management Systems." Paper presented at the 4th Biennial Stormwater Research Conference, October 18-20, Clearwater, FL. Palatka, FL: St. Johns Water Management District.

Northwest Florida Water Management District. 1993. City of Tallahassee and Leon County Storm Water Management Plan. Havana, FL: The District.

Pratt, Thomas. 1997. Northwest Florida Water Management District. Havana, FL. Personal communication. September 15.

Rushton, Betty. 1997. Southwest Florida Water Management District. Brooksville, FL. Personal communication. September 17.

William T. Cooper has been a member of the analytical division of the Department of Chemistry at Florida State University for 16 years. He is currently an associate professor of chemistry, adjunct professor of oceanography, and director of the University Center Terrestrial Waters Institute. He received a B.S. in chemistry from the University of Tennessee and a Ph.D. in analytical chemistry from Indiana University, Bloomington. Dr. Cooper has served as a visiting scientist and consultant for the Waste Isolation Branch of the Earth Sciences Division, Oak Ridge (TN) National Laboratory, as well as an Air Force Summer Faculty Research Fellow at the Environics Laboratory, Tyndall AFB (FL). His research includes the biogeochemistry of organic compounds in aquatic sediments, characterization of the chemical composition of soil and sedimentary organic matter by nuclear magnetic resonance spectroscopy, biodegradation of toxics by microorganisms, and two-dimensional separation methods for analyzing complex environmental and biological samples. In addition, he has had extensive experience in both field sampling and laboratory analysis of trace organic contaminants in water and sediments..

Robert E. Deyle is an associate professor in the Department of Urban and Regional Planning at Florida State University where he has taught in the department's environmental planning specialization since 1991. Prior to joining the FSU faculty he served on the faculty of the Department of Civil Engineering and Environmental Science and as a research fellow with the Science and Public Policy Program at the University of Oklahoma. He holds a bachelor's degree in biology (Dartmouth College), a master's in environmental management (Duke University), and a Ph.D. in environmental science (State University of New York at Syracuse). His research includes water resources management, coastal hazards planning, and planning theory. Prior to his employment in academia he worked for 6 years as an environmental planner in Syracuse and upstate New York, primarily in the area of water resources planning and management.

William S. Jordan is a professional engineer registered in Florida and three other states. He has over 22 years of experience in geotechnical and hydrogeological studies, including 14 years in north Florida. Mr. Jordan received a bachelor of science degree in civil engineering from Northeastern University, Boston, Massachusetts, in 1974 and a master of science degree in civil engineering from Massachusetts Institute of technology, Cambridge, Massachusetts, in 1980.

Charles L. Mesing is a biological administrator for the Florida Game and Fresh Water Fish Commission. He is a graduate of Florida State University with a degree in biology and conducts research projects for the Division of Fisheries Research Bureau. Areas of research include environmental impacts to riverine habitats, water resource management, fish population dynamics, genetics, and habitat restoration. He is a consultant for private lake management and Lake Watch Coordinator for Killearn Lakes Plantation Homeowners.

Rhett A. Miller is a semi-retired civil engineer who served for 20 years as director of the Tallahassee Department of Public Works. He attended North Carolina State University and the University of Florida from which he earned a bachelor's degree in civil engineering. He worked in the offshore oil fields of Louisiana and in the construction and land development industry in Florida in addition to his 30 years of employment with the City of Tallahassee. He currently serves as a consultant to the City of Tallahassee coordinating construction at Kleman Plaza.

Joseph Travis is Robert O. Lawton Distinguished Professor of Biological Science at FSU and a former chair of the department. He is an ecologist and evolutionary biologist who has worked in aquatic and marine systems for 20 years. He received his B.A. from the University of Pennsylvania and his Ph.D. from Duke University. He has served as a program advisor for the National Science Foundation's Program in Population Biology (1986-1989) and as a member of the editorial boards of Oecologia (1990-1992), The American Naturalist (1991-1995), and the Journal of Evolutionary Biology (1988-1991). Travis has been a council member of the Ecological Society of America (1983-1989) and the Society for the Study of Evolution (1987-1990), a member of the Board of Governors of the American Society of Ichthyologists and
Herpetologists (1991-1995), and Vice-President of the American Society of Naturalists (1993-1994).

Timothy B. Waddle is a principal with Jim Stidham & Associates, Inc., a consulting engineering firm that provides hydrology, geology, civil and environmental engineering services. He holds a bachelor's degree in civil engineering and is a registered professional engineer in the states of Florida and Georgia and a registered land surveyor in Georgia. Mr. Waddle works as a design engineer for water distribution and sanitary sewer collection systems, water supply and storage, waste treatment and disposal, commercial and residential site planning, development and permitting, and storm water conveyance and management. He has over 20 years of experience in civil engineering and surveying.

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