St. Johns River Water Management District St. Johns River Water Management District St. Johns River Water Management District St. Johns River Water Management District St. Johns River Water Management District St. Johns River Water Management District
St. Johns River Water Management District - www.sjrwmd.com

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Online tools, GIS, data

20020381 (Lake Griffin)

Site Photograph

Basin characterization

1,834.767 km²

Location: latitude:28°51’48.089”, longitude 81°50’59.211”, GPS datum—WGS-1984 Station 20020381 is located in the center of Lake Griffin offshore of Treasure Island.

Point sources: Mid Florida Lakes and Leesburg/Canal Street wastewater treatment facilities are within a five-mile radius and within the drainage basin of this water quality site.

Lake Griffin is a large lake covering approximately 9,400 acres located in Lake County in central Florida. It is one of the seven lake in the Harris Chain of Lakes, which stretches from Lake Apopka in the south to Lake Griffin in the northwest.

Site Photograph

There is heavy commercial development along the southern shore with plenty of private residences intermingled along the shorelines. The Lake Griffin State Park is located in the southwestern portion of the lake and can be accessed by boat. Wetlands and the Emeralda Marsh Conservation Area dominate the northeastern shore. Wildlife and waterfowl are abundant in the area and can be seen year-round. The lake is a popular fishing and boating destination. Haynes Creek flows into Lake Griffin in the northeastern part of the lake and the Ocklawaha River starts her journey to the St. Johns River at the north end of the lake.

There is a very nice public boat ramp in a county park on the southern shore of the lake. The park even contains an old steam locomotive for train enthusiasts.

The city of Leesburg is located at the south end of the lake and there is a major intersection of several state highways in the area.

Site and Watershed Locator Map

Quick links

All of the maps and charts shown below were created using a customized GIS data summary tool, with the watershed generated by Arc Hydro for this monitoring station. More information about Arc Hydro can be found by going to the Technical background page. From that page, a description of the customized GIS data summary tool can be accessed.

Spatial data summaries

Download spatial data summaries Excel Icon

2000 population density

Population data is collected by the Census Bureau every 10 years and is used to show the distribution of population in a number of ways. Population density has a direct impact on land use, which effects water quality in areas around or near water bodies. This map displays the 2000 population density per square kilometer within this surface water catchment. The legend shows the area for each class in square kilometers and the percentage of area in descending order. More complete metadata can be found by clicking on the metadata link for the 2000 population density.

Watershed Population Density

General land use 2000

Land use, which is usually derived from aerial photography by photo interpreters, shows the distribution of land and how it is used. Land use affects the water quality of water bodies through water runoff within a surface water catchment. This map displays the distribution of eight categories of general land use within this surface water catchment. The legend shows the area for each category in square kilometers and the percentage of area in descending order. More complete metadata can be found by clicking on the metadata link for general land use 2000.

Watershed General Land Use

Geology

The geology of the state of Florida was delineated by the Florida Geological Survey. Water quality is impacted by the underlying geology of streams and lakes. This map displays the underlying geological formations within this surface water catchment. The legend shows the area for each type of formation in square kilometers and the percentage of area in descending order. More complete metadata can be found by clicking on the metadata link for geology.

Watershed Geology

Physiographic divisions

Physiography describes the earth’s exterior physical features. These are divided into general groups and then subgroups containing features such as uplands, hills, ridges, plains, valleys, karst, etc. Water quality is affected through water runoff by physiography. This map displays the more detailed physiographic subdistricts within this surface water catchment. The legend shows the area for each subdistrict in square kilometers and the percentage of area in descending order. More complete metadata can be found by clicking on the metadata link for physiographic divisions.

Watershed Physiographic Divisions

2004 rainfall

Rainfall data comes from radar imaging as well as rainfall gauge surveys. Rainfall affects water quality through runoff within the surface water drainage basins. This map displays the total daily rainfall in inches for each pixel for 2004 within each surface water catchment. The legend shows the area for each rainfall range in square kilometers and the percentage of area in descending order. More complete metadata can be found by clicking on the metadata link for 2004 rainfall.

Watershed Rainfall

St. Johns River Water Management District and other public lands

The St. Johns River Water Management District (SJRWMD) purchases lands that are in environmentally sensitive areas to protect the water resources on, beneath or adjoining the property. Water quality is affected in water bodies adjacent to these protected lands. This map displays the lands owned, jointly owned, being considered for purchase, or lands through which SJRWMD has an easement. The legend shows the area of these lands in acres and the percentage of area in descending order. More complete metadata can be found by clicking on the metadata link for SJRWMD and public lands.

Watershed Public Lands

Soils drainage

Soils drainage characteristics can also impact surface water runoff, a source of nonpoint pollution for adjacent water bodies, which effects water quality. This map displays water bodies and soil drainage characteristics. The legend shows the area of these soils in square kilometers and the percentage of area in descending order. More complete metadata can be found by clicking on the metadata link for soils drainage.

Watershed Soils Drainage

5-foot elevation — DEM

Land elevation influences rainfall runoff, which effects the surface water quality, as water moves through the landscape to the rivers, streams, and lakes. This map with accompanying legend displays the maximum (MAX), minimum (MIN), range, standard deviation (STD) and mean of 5-foot elevations within the surface water drainage area (watershed). More complete metadata can be found by clicking on the metadata link for 5-foot elevation-DEM (Digital Elevation Model).

Watershed 5-Foot Elevation

Recharge 1995

In some areas of SJRWMD, the Floridan aquifer is at or near land surface and is vulnerable to pollutants that threaten our drinking water supply. It is especially important to preserve surface water quality in these areas. This map displays recharge to the Floridan aquifer in inches per year (in/yr) within this surface water drainage catchment. Discharge, where the potentiometric surface is greater than the land surface elevation, is also shown. The area for each class is shown in square kilometers and the percentage of area in descending order. More complete metadata can be found by clicking on the metadata link for recharge 1995.

Watershed Recharge

Arc Hydro model

The map below contains selected features from the St. Johns River Water Management District (SJRWMD) Arc Hydro geodatabase. The introduction of the SJRWMD Arc Hydro geodatabase made the creation of these fact pages possible, by providing improved geographic information system (GIS) data that has been combined into a GIS network. This hydrologically based network does for water resources what the commonly used mapping websites (such as MapBlast, MapQuest and GoogleMaps) have done for travel planning, except that instead of interstates, highways and roads, this hydrologic network shows streams, rivers, lakes and wetlands. Similar to transportation mapping sites, information about water resources has been related, or linked, to the GIS network and can be easily accessed. The legend to the right of the map includes the Arc Hydro network, Arc Hydro Polygon Feature Classes and HydroPoints. The features included in the Arc Hydro Network exist to establish relationships based on surface water flow. The lines (HydroEdges) may represent streams or rivers, which are commonly displayed as lines on maps. The lines may also represent, in a “shorthand” way, the concept of surface water flow through a lake or a wetland, which are not routinely displayed as lines. The features in the Arc Hydro Polygon Feature Classes and HydroPoints represent some of the water resources information that has been linked to the Arc Hydro GIS network. HDS in the map legend below refers to the District’s Water Resource Information program and NWIS refers to the National Water Information System, which is part of the United States Geological Survey (USGS). See Technical Background for a more detailed explanation of the SJRWMD Arc Hydro technology and its features.

Arc Hydro Model Graphic

Clicking on the Methodology link will direct you to information about how water quality samples were collected, analyzed, and summarized for this fact page. View the most recent Water Quality Status and Trends Report.

Water quality

Download water quality data

Lake Griffin is located in western Lake County and is the northern-most lake in the Harris Chain of Lakes. It is sampled off Treasure Island, by boat. The lake is about 2.5 meters deep at the sample site and has a typical range of water temperatures. Major ion concentrations result in moderately hard water. The median dissolved oxygen value is typical for a lake in the District. The lake has good buffering capacity and an alkaline pH. Secchi depth, total nitrogen, and chlorophyll concentrations all indicate a hypereutrophic rating, under Forsberg–Ryding criteria, while lower total phosphorus concentrations indicate eutrophic conditions. When compared to other lakes, total organic carbon is at typical concentrations, while total suspended solids, turbidity, and coliforms are elevated. The lake has poor water quality, according to the trophic state index.

Analytes Data Yrs N Data Min Q1 Median Q3 Max Range
Water temperature (°C) 14 211 11.83 18.64 24.00 28.49 31.41 mid
Secchi disc transparency (meters) 14 208 0.10 0.30 0.35 0.45 2.00 mid-lo
Color (platinum-cobalt units) 14 205 5.00 20.00 20.00 30.00 150.00 mid-lo
Specific conductance (µhmhos/cm @ 25° C) 14 207 3.11 306.00 330.23 348.77 420.25 mid
Sample collection depth (meters) 14 209 0.35 0.53 0.53 0.53 1.00 high
Dissolved oxygen analysis by probe (mg/L) 14 207 4.53 7.31 8.57 9.38 12.28 mid
pH (standard units) 14 207 7.44 8.40 8.65 8.89 9.66 mid-hi
Total alkalinity (mg/L as CaCO3) 14 204 78.58 100.18 112.53 123.51 148.81 high
Total nonfiltrable residue (mg/L) 14 203 3.50 16.00 23.00 30.00 63.00 mid-hi
Total nitrogen (mg/L as N) 14 205 1.23 2.50 2.96 3.71 6.67 mid-hi
Total phosphorus (mg/L as P) 14 204 0.02 0.05 0.06 0.08 0.17 mid-lo
Total organic carbon (mg/L as C) 14 203 15.89 20.10 22.66 27.07 47.29 mid
tsi 14 199 46.61 69.90 76.36 81.81 99.71 mid-hi
Total calcium (mg/L as Ca) 14 203 22.20 36.34 39.55 41.80 81.89 mid-hi
Total magnesium (mg/L as Mg) 14 203 5.66 9.15 9.73 10.50 18.63 mid
Total sodium (mg/L as Na) 14 203 10.90 13.02 14.28 15.50 20.21 mid-lo
Total potassium (mg/L as K) 14 203 0.44 6.15 6.70 7.20 13.50 mid-hi
Total chloride (mg/L) 14 206 19.00 24.48 27.17 30.68 44.00 mid-lo
Total sulfate (mg/L as SO4) 14 204 0.55 11.49 13.00 14.96 22.40 mid-lo
fecal coliform (MF M-FC broth 44.5° C) 4 11 2.00 2.00 8.00 20.00 40.00 mid-hi
Trichromatic uncorrected chlorophyll-a (µg/L) 14 207 7.05 52.05 88.29 138.10 461.14 mid-hi
Hardness (mg/L Ca+Mg) 14 203 101.00 129.26 137.22 146.20 281.20 mid
Total filtrable residue (mg/L dried at 180° C) 14 192 148.00 205.50 224.50 241.00 330.00 mid
Lab turbidity (NTU) 14 205 2.30 11.10 15.90 22.40 58.00 mid-hi
Sample site depth (meters) 14 210 0.70 2.35 2.50 2.60 4.80 mid-hi

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