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Local Lakes Basin Characteristics
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City of Tallahassee Stormwater Division
Characterization of Existing Drainage Basin Conditions
Tallahassee Leon County, Florida
May - 2004
The following information was compiled from an analysis of the information available from the Tallahassee Leon County GIS data and the City of Tallahassee, Stormwater Pollution Reduction Program (SPRP) problem area assessment.
Introduction:
Leon County totals approximately 702.6 square miles in area and, is divided into 18 large watersheds or drainage areas known as Basins. Six of these drain to large waterbodies. These include Lake Talquin or the Ochlockonee Basin, Lake Miccosukee, Lake Iamonia, Lake Jackson, Lake Lafayette, and Lake Munson. The remaining 12 basins are primarily what are often termed "stream to sink" watersheds where the stream system drains to a depression and disappears underground through a sink or fissure in the bed rock. Three of the major lake basins (i.e., Lake Jackson, Lake Lafayette, and Lake Munson) as well as three stream to sink basins are impacted by the Urban Services Area (USA) of Tallahassee and Leon County. A portion of the Lake Iamonia Basin is also partially impacted. Included within the three major urbanized lake Basins are numerous smaller lakes and ponds some of which are equally well recognized and heavily used for recreation by the community. These include Lake Ella, Lake Hall at McClay Gardens, and Lake Bradford. A total of 66 named lakes and ponds lie within or border the USA area of the City along with numerous smaller water bodies. Their size varies from large (5500 acres) to small (1/2 acres or less).
Discussion of Tallahassee Leon County USA Impacted Basins:
Lake Munson Basin (40,256 acres):
Of the 6 basins impacted by runoff from the USA, the Lake Munson Basin has historically been found to have the highest pollutant loading and to be the most flood prone. In the past this lake received treated effluent from the City's sewage treatment plants plus runoff from the central business district of Tallahassee. Today the lake does not receive any treated effluent but it remains heavily impacted by runoff from the central business district, FSU, FAMU and the West Tennessee Street business corridor. The Lake Munson Basin is characterized by a moderate percentage of developed area (56%) and a relatively high percentage of existing stormwater treatment (17.3%). However, these statistics are somewhat deceiving. This basin includes the Lake Bradford and Cascade Lakes Chain whose drainage areas include large expanses of the national forest west of the airport. This circumstance serves to reduce the proportion of developed area for the basin as a whole. The Northwest Florida Water Management District (NWFWMD) Stormwater Management Plan, (1991) found the Central Drainage Ditch and St Augustine Branch sub-watershed areas to be among the most highly polluted in the City, as did the recent City SPRP. Four of eight local water bodies identified as impaired and in need of pollution control by EPA are located in the Lake Munson Basin. The high level of existing treatment is associated with recent construction of a regional stormwater facility near FSU and the Frenchtown stormwater facility by the City. Implementation of these controls helped reduce the pollutant load ranking of the Central Ditch watershed somewhat when compared to others in the basin when analyzed in the recent SPRP assessment results.
Lake Jackson Basin (27,235 acres):
 Lake Jackson in northwest Tallahassee is the areas most well known and heavily used recreational lake. Periodically (most recently in 1999) this lake drains through sinkholes. Due to its significant recreational value to the community, the region and state, the lake has been the focus of significant lake restoration and regional runoff treatment efforts. The Lake Jackson Stormwater Filter and Constructed Wetland Treatment system on the Megginnis Arm was one of the first stormwater retrofit facilities constructed in the state. However, stormwater remains a threat from the I-10 corridor, the North Monroe Street business area and residential subdivisions that surround all but the north side of the lake. In addition, septic tanks appear to represent a significant source of pollution along the western side of Lake Jackson. The Lake Jackson Basin is characterized by a relatively high percentage of developed area (69%) and a moderate percentage of existing stormwater treatment (14.7%). Much of the residential development that surrounds the southeast and western side of the lake as well as that in the Megginnis Creek watershed was constructed prior to state regulations that require attenuation and treatment. One of eight local water bodies identified as impaired and in need of pollution reduction by EPA is located in the west Lake Jackson Basin. The water management district study and the City Stormwater Pollution Reduction Program (SPRP) results rate the Megginnis Arm Branch watershed as the basin's highest priority for implementation of stormwater controls. Several capital projects have been completed with more on-going or planned to help address both pollution and flood control in this high priority area of the basin. Examples include the City's John Knox Stormwater Facility; the Boone Blvd. Stormwater Facility; the Abbiegail Drive Stormwater Facility; as well as, the Tupelo Terrace Erosion Control and Ditch Enclosure Project.
Lake Lafayette Basin (53,842 acres):
Lake Lafayette in eastern Tallahassee is partly characterized as freshwater marsh and partly as open water. The lake has been divided into three segments by a series of manmade dikes. The basin includes Upper Lake Lafayette that receives runoff from the east side of the City. Piney-Z Lake located in the center of the chain is managed by the City Parks Department and the Florida Fish and Wildlife Commission as a fishery. Lower Lafayette and Alford Arm represent the western most and main body of the lake and associated wetland system. This portion of the basin receives runoff from the rapidly expanding Northeast quadrant of the USA.
The Lake Lafayette Basin is characterized by a moderately high percentage of developed area (61%). However, the Upper Lafayette sub-basin percentage is higher; in the 70% range. Two of eight local water bodies identified as impaired and in need of immediate pollution reduction by EPA and DEP are located in the Lake Lafayette Basin. Additional areas within the Lower Lake/Alford Arm Sub-basin area may be similarly designated within the next 5 years, as more water quality data is gathered. The NWFWMD Stormwater Management Plan (1991) and the City's SPRP results rate the Park Avenue Tributary that discharges to Upper Lake Lafayette as the highest priority for implementation of stormwater controls within this basin. Existing stormwater treatment is 18% within the Lafayette Basin. This is the highest of the six urban basins within the USA. This reflects the fact that the east and northeast areas of Tallahassee contain a greater percentage of newer development having stormwater treatment and flood attenuation facilities. Also, several recent stormwater treatment capital projects associated with the Blair Stone Road Project as well as the McCord Park/Laguna Pond improvements and the expansion of Weems Pond have helped to increase the existing level of stormwater treatment; particularly in the Upper Lake sub-basin which is the area most impacted by the USA area within the City. These facilities provide treatment for the new development they were associated with, plus added treatment for untreated areas within their respective watershed areas.
Fred George Sink Basin (2,710 acres):
The Fred George Sink Basin in northwestern Tallahassee is an area characterized as freshwater swamp and a stream to sink watershed. The streams and the ephemeral wetlands surrounding them remain in a natural condition in this area of the USA. The basin includes the Lake Jackson Trading Post commercial area along North Monroe Street. The Fred George Basin is characterized by a high percentage of developed area, in the 70% range. However, due largely to special development regulations that have been in effect in this basin for some time, the natural condition of the stream water quality remains good. However, flooding has been reported during extreme events. The NWFWMD Stormwater Management Plan (1991) and the City's SPRP results rate the severity of pollution loading in this basin as low to moderate. The existing level of stormwater treatment (14%) is moderate. This statistic, however, is somewhat misleading since the facilities located within this basin provide more retention of runoff per unit area than in many other areas of the USA.
Airport Vicinity Basin (3,334 acres):
The Airport Basin in southwest Tallahassee is characterized as a closed basin where runoff primarily drains to solution depressions some of which form small un-named lakes or ponds. Runoff is minimal due to the sandy nature of the soil in this area of the City. Statistics for this basin are very misleading. The developed area (46%) is primarily associated with the Tallahassee Regional Airport complex. The impervious area is predominantly run-way and is surrounded by large expanses of open space that would more closely resemble undeveloped areas within the City of Tallahassee than the typical urban developed area. The percentage of stormwater treatment facilities in this watershed is extremely low (1%). FAA regulations discourage the creation of ponds that attract birds due to potential safety hazards. Treatment ponds that serve the terminal complex are actually located in the Lake Bradford watershed area. Since runoff from the Airport Basin would be rare, this basin was not viewed as a stormwater threat to Lake Munson or other major lakes in the region. No local water bodies have been identified as impaired within the basin by either EPA or DEP.
Woodville Recharge Basin (42,520 acres):
The Woodville Recharge Basin in located in the sand hill region on the southeast side of Tallahassee. The basin is a karst plain with numerous small lakes and ponds that have formed in collapsed sinkholes and solution depressions. Until recently Campbell Pond and its associated chain of other smaller solution lakes and wetlands near the "Four Points" neighborhoods represented the primary water bodies experiencing both flooding and water quality effects associated with urban development in this area. The City monitors the quality of Campbell pond. Results show that water quality is good indicating that this lake is unimpaired despite the surrounding development. Further to the east in the basin, the Southwood development has begun to increase the percentage of developed area within this basin. However, the percent developed area still remains the lowest of all basins in the USA at 23%. The level of existing treated developed area in the basin is also low at 5%. The majority of existing treatment is associated with facilities constructed for the Southwood development. Runoff is minimal in the area below the hills of Tallahassee due to the sandy nature of the soil in this area. All of the watersheds and catchments that comprise this basin are closed and do not contribute runoff directly to other lakes beyond its boundary. Therefore, these watersheds would not be viewed as a threat to Lake Munson or other major lakes in the region. No local water bodies have been identified as impaired within the basin by either EPA or DEP. However, due to the karst nature of the area, down gradient groundwater impacts associated with increasing development activity may be possible. Both Leon County and the City of Tallahassee have ongoing studies designed to evaluate this issue as well as the potential effect of the City spray field located in the north central portion of the basin.
Discussion of Basins Not Directly Impacted by Tallahassee Leon County USA:
Outlying Drainage Basins (316731 acres):
None of the remaining 12 basins within Leon County are directly impacted by the City of Tallahassee. However isolated water quality and flooding problems exist in these basins that may be related to outlying development and excess runoff from the Tallahassee hills during periods of very heavy rains. These problems are primarily in southern areas of the County. Water quality concerns in the outlying basins include failing septic tanks, sediment from dirt roads, and runoff from fertilizers and herbicides.
The most well known urban development related problem area in the outlying basins is in the Lake Iamonia watershed and is associated with the Killearn Lakes development. The Lake Iamonia watershed is dominated by vacant, low-density and conservation lands (Tall Timbers Research Station. Except for limited commercial uses at the intersection of Bannerman and Thomasville Roads (NW quadrant of Bradfordville), the Killearn Lakes subdivisions are the primary source of non-point pollution as the properties are served by either septic tanks and drain fields or the Talquin wastewater facility that depends on a spray field for further nutrient uptake before running off to Lester Cove on the south shore of the lake. The lake exhibits oligo-mesotrophic status (median TSI of 46) with conditions degrading toward the west end, in part because of frequent overflows from the Ocklochonee River. While water quality is considered good, aquatic plants have proliferated because of the lake's shallowness (average depth less than five feet), because of stage control via damming of the sink, and because of significant residential non-point loading.
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