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
JUL-SEP 2026	1,591 ug/l	474.8 ug/l	1,641 ug/l	0.43 mg/l	7	7
APR-JUN 2026	901 ug/l	176.5 ug/l	962 ug/l	0.51 mg/l	9	13
JAN-MAR 2026	1,799 ug/l	811.8 ug/l	3,708 ug/l	0.54 mg/l	11	15
OCT-DEC 2025	1,870 ug/l	685.0 ug/l	799 ug/l	0.47 mg/l	13	18
JUL-SEP 2025	1,507 ug/l	243.0 ug/l	1,511 ug/l	1.04 mg/l	8	10
APR-JUN 2025	1,173 ug/l	433.0 ug/l	838 ug/l	0.69 mg/l	8	11
JAN-MAR 2025	1,841 ug/l	491.4 ug/l	799 ug/l	0.61 mg/l	13	17
OCT-DEC 2024	2,698 ug/l	616.0 ug/l	861 ug/l	0.6 mg/l	14	19
JUL-SEP 2024	1,246 ug/l	186.2 ug/l	1,498 ug/l	1.19 mg/l	15	20
APR-JUN 2024	1,402 ug/l		972 ug/l	0.67 mg/l	12	16
JAN-MAR 2024	1,479 ug/l		827 ug/l	0.5 mg/l	13	17
Five Year Seasonal Graph	Graph	Graph	Graph	Graph
Five Year Graph of All Samples	Graph	Graph	Graph	Graph

Source(s): Quarterly Routine Water Monitoring, EPC Monthly Routine Water Monitoring, Hillsborough County Lake Assessments, EPC Water Quality Data, LAKEWATCH Volunteer Water Quality Monitoring, FDEP Historic Data from Legacy STORET, Polk County Parks & Natural Resources Division, FDEP Watershed Monitoring Section, IMC Agrico (Florida), SWFWMD Water Quality Sampling Data, FDEP Southwest Regional Operations Center, Stream Waterwatch Water Quality Data, Volunteer , FDEP Watershed Monitoring Section, Environmental Protection Commission of Hillsborough County, Polk County Natural Resources Division, Southwest Florida Water Management District, FDEP - Southwest Regional Operations Center

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
JUL-SEP 2026	1,241 ug/l	10.0 ug/l	506 ug/l		2	2
APR-JUN 2026	1,193 ug/l	10.0 ug/l	447 ug/l		2	2
JAN-MAR 2026	1,245 ug/l	10.0 ug/l	333 ug/l		2	2
OCT-DEC 2025	1,225 ug/l	24.5 ug/l	378 ug/l		2	2
JUL-SEP 2025	1,285 ug/l	15.0 ug/l	522 ug/l		2	2
APR-JUN 2025	1,325 ug/l	10.0 ug/l	378 ug/l		2	2
JAN-MAR 2025	1,248 ug/l	10.0 ug/l	335 ug/l		2	2
OCT-DEC 2024	1,175 ug/l	10.0 ug/l	377 ug/l		2	2
JUL-SEP 2024	1,494 ug/l	13.5 ug/l	488 ug/l		3	3
APR-JUN 2024	1,580 ug/l		207 ug/l		3	6
JAN-MAR 2024	1,629 ug/l		267 ug/l		3	3
Five Year Seasonal Graph	Graph	Graph	Graph
Five Year Graph of All Samples	Graph	Graph	Graph

Source(s): LAKEWATCH Volunteer Water Quality Monitoring, Polk County Parks & Natural Resources Division, FDEP Watershed Monitoring Section, SWFWMD Water Quality Sampling Data, FDEP Southwest Regional Operations Center, SWFWMD Water Quality Monitoring Program Data, Florida LAKEWATCH, Polk County Natural Resources Division, FDEP - Southwest Regional Operations Center, FDEP - Watershed Assessment Section

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

River	Flows Whole River Range	Flows Data by Segment	Levels Whole River Range	Levels Data By Segment
Alafia River - North Prong	In the past 30 days Average river flow is faster 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
Alafia River - South Prong	In the past 30 days Average river flow is faster 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
Thirtymile Creek	In the past 30 days NO DATA Recent river flow data is unavailable.	No data table or graph available	In the past 30 days Average water levels are higher than they have been historically.	Levels Data Table and Graph

Source(s): Not Available

Source(s): Not Available