St. Johns River Water Management District

Watershed Facts

Integrating environmental science and computer mapping technology


27010579 (Tomoka River)

Site PhotographBasin Characterization

190.203 km²

Location: latitude 29°13’01.485”, longitude 81°06’34.695”, GPS datum—WGS-1984 Station 27010579 is located on the Tomoka River at the 11th-Sreet Bridge.

Point Sources: Daytona Beach Westside Regional wastewater treatment facility is within a five-mile radius and within the drainage basin of this water quality site.

Site PhotographThe Tomoka River is located in Volusia County in east-central Florida. The sampling site is located on LPGA Boulevard where it crosses the river. The Tomoka River forms in wetlands approximately 5 miles south of the sampling site and runs to the northeast to the Tomoka Flats and the Halifax River.

The local area around the site is partially developed by commercial interests. On the west bank is a golf course and automobile dealerships occupy property nearby to the east. To the north, the Tomoka River has more natural surroundings and less development. As the Tomoka River heads toward the Halifax River, it becomes wider and deeper. It offers scenic vistas of “old Florida” and is a great area for boating and fishing.

 

 

 

 

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 clicking on the tab “About Arc Hydro,” which includes a link to SWQM Arc Hydro Development. From that page, a description of the customized GIS data summary tool can be accessed.

Spatial Data Summaries

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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


SJRWMD 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 square kilometers 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 Web sites (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 refers to the District’s Hydrologic Data Services 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 tab will direct you to information about how water quality samples were collected, analyzed, and summarized for this fact page. To access the most recent SJRWMD Surface Water Quality Status and Trends report, click here.

Water Quality

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The Tomoka River is sampled at the 11th Street bridge in eastern Volusia County. The site is sampled monthly, under contract with FDEP. The stream is about 0.7 meters deep at the sample site and has a typical temperature range. Major ion concentrations are high enough to result in moderately hard water. The median dissolved oxygen value is just above the FDEP standard for Class 3 surface waters. The water is well-buffered and slightly acidic. Total suspended solids, turbidity, total nitrogen, total phosphorus, and chlorophyll concentrations are below levels typically found in streams. Total organic carbon, color, and coliforms are typically at lower concentrations in other streams, although Secchi depth and coliform counts are typical. The river has fair water quality at the sample site, according to the water quality index.

Analytes Data Yrs n Data Min Q1 Median Q3 Max Range
water temperature (degrees C) 10 88 7.30 17.40 21.55 25.30 27.20 mid
Secchi disc transparency (meters) 8 15 0.00 0.35 0.50 0.55 0.80 mid
color (platinum-cobalt units) 3 10 50.00 150.00 250.00 400.00 600.00 mid-hi
specific conductance field (uhmhos/cm@25°C) 10 94 67.00 153.00 243.50 368.00 496.00 mid-lo
sampling station depth (meters) 10 96 0.05 0.20 0.35 0.50 0.60 low
dissolved oxygen analysis by probe (mg/L) 10 95 1.04 4.30 5.14 6.51 9.73 mid
pH (standard units) 10 95 5.47 6.52 6.86 7.14 7.93 mid-lo
total alkalinity (mg/L as CaCO3) 10 95 8.70 40.00 76.00 133.00 180.00 mid
total nonfiltrable residue (mg/L) 10 92 1.00 4.00 4.00 5.00 38.00 mid-lo
total nitrogen (mg/L as N) 10 89 0.43 0.71 0.96 1.26 2.47 mid-lo
total phosphorus (mg/L as P) 10 88 0.01 0.04 0.04 0.05 0.10 low
total organic carbon (mg/L as C) 10 89 13.60 18.00 25.00 37.70 68.10 mid-hi
total calcium (mg/L as Ca) 10 95 7.69 20.00 33.50 50.80 70.50 mid
total magnesium (mg/L as Mg) 10 95 1.06 2.00 3.15 4.20 5.61 mid-lo
total sodium (mg/L as Na) 10 95 5.45 9.60 13.70 18.00 31.70 mid-lo
total potassium (mg/L as K) 10 94 0.47 0.90 1.20 1.60 3.10 low
total chloride (mg/L) 10 95 7.90 17.00 22.00 28.00 96.00 mid-lo
total sulfate (mg/L as SO4) 10 95 0.01 3.70 7.70 11.00 33.00 low
wqi 10 95 26.84 43.56 52.08 58.42 68.52 mid
fecal coliform (MF M-FC broth 44.5°C) 10 82 20.00 82.00 150.00 220.00 2000.00 mid-hi
trichromatic uncorrected chlorophyll-a (ug/L) 4 20 0.00 0.30 1.79 5.46 11.00 mid-lo
total filtrable residue (mg/L dried at 180°C) 10 89 101.00 152.00 181.00 236.00 354.00 mid-lo
lab turbidity (NTU) 3 10 -0.10 2.50 2.70 4.00 20.00 mid-lo
sample site depth (meters) 10 96 0.10 0.40 0.70 1.00 2.00 mid-lo
hardness (mg/L Ca+Mg) 10 95 23.79 57.76 95.68 143.73 195.05 mid-lo

 


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