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 2016	931 ug/l		87 ug/l	0.09 mg/l	1	2
OCT-DEC 2015	1,310 ug/l		55 ug/l	0.02 mg/l	2	2
JUL-SEP 2015	1,404 ug/l		52 ug/l		1	1
APR-JUN 2015	1,704 ug/l		76 ug/l	0 mg/l	5	21
JAN-MAR 2015			42 ug/l		4	21
OCT-DEC 2014	1,523 ug/l		45 ug/l	0.01 mg/l	6	22
JUL-SEP 2014	2,215 ug/l		60 ug/l	0.02 mg/l	5	13
APR-JUN 2014	1,896 ug/l		67 ug/l	0.02 mg/l	8	21
JAN-MAR 2014	1,744 ug/l		59 ug/l	0.04 mg/l	9	23
Five Year Seasonal Graph	Graph		Graph	Graph
Five Year Graph of All Samples	Graph		Graph	Graph

Source(s): FDEP Historic Data from Legacy STORET, FDEP Central District Water Quality Data, Florida Fish and Wildlife Conservation Commission Water Quality Data, FDEP Ambient Monitoring Sampling Data, SFWMD Water Quality Sampling Data, USGS National Water Information System

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
APR-JUN 2016	1,363 ug/l		51 ug/l	0.01 mg/l	5	8
JAN-MAR 2016	1,060 ug/l		39 ug/l	0.01 mg/l	5	5
OCT-DEC 2015	1,262 ug/l		37 ug/l	0.01 mg/l	5	5
JUL-SEP 2015	1,394 ug/l		33 ug/l	0.01 mg/l	7	7
APR-JUN 2015	1,298 ug/l		44 ug/l	0.01 mg/l	8	13
JAN-MAR 2015	1,121 ug/l		31 ug/l	0 mg/l	8	9
OCT-DEC 2014	1,234 ug/l		32 ug/l	0.01 mg/l	9	12
JUL-SEP 2014	1,334 ug/l		40 ug/l	0.01 mg/l	8	10
APR-JUN 2014	1,402 ug/l		63 ug/l	0.01 mg/l	7	10
JAN-MAR 2014	1,486 ug/l		44 ug/l	0.01 mg/l	7	9
Five Year Seasonal Graph	Graph		Graph	Graph
Five Year Graph of All Samples	Graph		Graph	Graph

Source(s): LAKEWATCH Volunteer Water Quality Monitoring, FDEP Historic Data from Legacy STORET, Polk County Parks & Natural Resources Division, Florida Fish and Wildlife Conservation Commission Water Quality Data, FDEP Ambient Monitoring Sampling Data, SFWMD Water Quality Sampling Data, SWFWMD Water Quality Sampling Data (STORET), FDEP Southwest District Sampling Data, FDEP, Water Quality Standards and Special Projects (Florida), SWFWMD Water Quality Monitoring Program Data, USGS National Water Information System

River	Flows Whole River Range	Flows Data by Segment	Levels Whole River Range	Levels Data By Segment
NO DATA

Source(s): Southwest Florida Water Management District, Southwest Florida Water Management District, USGS National Water Information System

Source(s): Not Available