St. Johns River Watershed

Southwest Florida Water Management District calculates the Aquifer Resource Indicator (ARI) for their three groundwater regions each month. The ARI was created to provide the public with a gauge of groundwater levels in their area, so they can develop an understanding of the severity and cycles of drought and recovery. The three regions include: North (Citrus, Hernando, Lake, Levy, Marion and Sumter counties), Central (Hillsborough, Pasco, Pinellas, and Polk counties), and South (Charlotte, DeSoto, Hardee, Highlands, Manatee, and Sarasota counties). Learn More about the Aquifer Resource Indicator >>

To determine the ARI for a region, each well is compared weekly to its respective low-normal value and the difference is calculated. The weekly differences are reduced to a monthly value for all monitoring wells within a region, and the resulting ARI value represents how far water levels in the aquifer must rise or fall to reach their respective low-normal values.

Source: SWFWMD Hydrologic Data Section Data
Click here to view a period of record graph for the central, north, and south groundwater regions

The following data are summarized as seasonal average values for lake and river sampling locations located within the watershed. While these data are useful to serve as a general picture of watershed health, these data must be viewed with caution because these samples have been taken from ecologically different water resources.

Rivers:

Samples from most rivers located in this watershed are averaged as part of these data summaries.

Season	Total Nitrogen	Nitrate (NO3)	Total Phosphorus	Orthophosphate	Number of Sample Stations	Number of Samples
JAN-MAR 2013	1,490 ug/l		53 ug/l		1	1
OCT-DEC 2012	1,554 ug/l		70 ug/l		3	8
JUL-SEP 2012	1,313 ug/l		69 ug/l		2	4
APR-JUN 2012	931 ug/l		64 ug/l		3	8
JAN-MAR 2012	1,455 ug/l		85 ug/l		3	7
OCT-DEC 2011	1,548 ug/l		93 ug/l		3	8
JUL-SEP 2011	1,309 ug/l		72 ug/l		6	17
APR-JUN 2011	1,149 ug/l		84 ug/l		16	27
JAN-MAR 2011	993 ug/l		75 ug/l		16	29
Five Year Seasonal Graph	Graph		Graph
Five Year Graph of All Samples	Graph		Graph

Source(s): Lake County Surface Water Quality, FDEP Historic Data from Legacy STORET, FFWCC Legacy Storet Data, Seminole County Legacy Storet Data, Volusia County Water Quality Data, SJRWMD Water Quality Data, FDEP Central District Water Quality Data, Florida Fish and Wildlife Conservation Commission Water Quality Data, FDEP Ambient Monitoring Sampling Data, St. Johns River Water Management District, Volusia County Sampling Data, FDEP, Water Quality Standards and Special Projects (Florida), USGS National Water Information System, Watershed Action Volunteer Water Quality Data

Lakes:

Samples from most lakes located in this watershed are averaged as part of these data summaries.

Season	Total Nitrogen	Nitrate (NO3)	Total Phosphorus	Orthophosphate	Number of Sample Stations	Number of Samples
OCT-DEC 2012	398 ug/l		8 ug/l		1	2
JUL-SEP 2012	410 ug/l		10 ug/l		4	7
APR-JUN 2012	305 ug/l		8 ug/l		2	2
JAN-MAR 2012	462 ug/l		8 ug/l		4	4
OCT-DEC 2011	405 ug/l		9 ug/l		6	7
JUL-SEP 2011	396 ug/l		7 ug/l		4	11
APR-JUN 2011	408 ug/l		10 ug/l		4	6
JAN-MAR 2011	331 ug/l		5 ug/l		6	6
Five Year Seasonal Graph	Graph		Graph
Five Year Graph of All Samples	Graph		Graph

Source(s): Lake County Surface Water Quality, LAKEWATCH Supplemental Water Quality Sampling, LAKEWATCH Volunteer Water Quality Monitoring, FDEP Historic Data from Legacy STORET, SJRWMD Water Quality Data, FDEP Central District Water Quality Data, FDEP Ambient Monitoring Sampling Data, FDEP, Water Quality Standards and Special Projects (Florida), Watershed Action Volunteer Water Quality Data

• Water Quality Sampling Locations - View a map showing the point locations of water quality monitoring stations which collect data being presented on the Water Atlas.

River	Flows Whole River Range	Flows Data by Segment	Levels Whole River Range	Levels Data By Segment
Blackwater Creek	In the past 30 days Average river flow is slower than it has been historically.	Flows Data Table and Graph	In the past 30 days Average water levels are lower than they have been historically.	Levels Data Table and Graph
St. Johns River	In the past 30 days Average river flow is slower than it has been historically.	Flows Data Table and Graph	In the past 30 days Average water levels are lower than they have been historically.	Levels Data Table and Graph
Wekiva River	In the past 30 days Average river flow is slower than it has been historically.	Flows Data Table and Graph	In the past 30 days Average water levels are higher than they have been historically.	Levels Data Table and Graph

Source(s): LAKEWATCH, Orange County, Orange County, St. Johns River Water Management District, Southwest Florida Water Management District, USGS National Water Information System

Source(s): Not Available