Water Quality Contour Mapping

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Water Quality Changes Over Space and Time

In an open body of water such as a bay, water quality may vary considerably in its different regions, and its water quality will also change continually from month to month, season to season, year to year. Tidal influence, land use in the watershed, inflow from tributaries, seasonal temperature changes, and rainfall are the most important factors driving these differences. A Water Quality Contour Map (WQCM) shows the spatial distribution of water quality for a defined period in time. By creating contour maps for multiple different periods, it is possible to detect both spatial and temporal patterns in water quality, and to see trends over time. Learn more »

Click on a parameter name and select a year from the list of report years available to discover spatial and temporal variations in water quality. Clicking on a PDF thumbnail will open the full report for viewing and download. Alternatively, click the "View Image Slideshow" button to view an interactive slideshow of the generated raster images.

Available Parameters (Select One)

Contour Maps

Select a report to open and view/download the corresponding PDF file. Alternatively, you can open an image slideshow of the contour rasters used in these reports.

Agency Summary

Data collected by the following agencies were used in preparation of these reports.

Agency Period of Record
(Month, Year)		 Station Count
(Approximate)		 Sample Count
(Approximate)
Shellfish Environmental Assessment Data January 1979 — June 2003 15,490 48,900
FLORIDA DEPARTMENT OF HEALTH IN SARASOTA COUNTY BEACH RESULTS November 2017 — January 2021 1,180 9,400
LAKEWATCH Volunteer Water Quality Monitoring August 2001 — December 2018 800 2,100
Briarwood Stormwater Treatment Facility July 2020 — April 2024 920 900
Sarasota County Coastal Creeks February 1998 — March 2025 205,540 325,300
Sarasota County Environmental Services Department Sampling Data March 2004 — April 2007 410 220,200
Sarasota County Environmental Services Department Sampling Data February 1998 — May 2025 247,060 433,100
SWFWMD Hydrologic Data Section Data October 2024 — July 2025 90 1,300
USGS National Water Information System October 1939 — July 2025 20,200 110,900
FDEP Charlotte Harbor Aquatic/Buffer Preserves Sampling Data November 1996 — April 2025 23,300 27,200
Charlotte County June 2022 — May 2024 14,250 16,200
Florida Healthy Beaches Program and Data (Bacterial Counts) July 2000 — March 2025 7,600 69,700
FDEP South District Sampling Data September 2003 — April 2025 11,050 18,300
FDEP Watershed Monitoring Section October 1998 — January 2025 10,790 16,800
Florida LAKEWATCH December 2018 — October 2024 5,620 6,600
Manatee County Environmental Management Sampling Data January 1995 — October 2024 39,940 77,000
Mosaic Fertilizer, LLC January 2018 — January 2024 530 600
City of North Port September 2004 — December 2024 10,320 12,600
Sanibel-Captiva Conservation Foundation October 2022 — March 2023 40 0
Enviro-Audit September 2017 — April 2025 320 300
SWFWMD Water Quality Sampling Data August 1997 — December 2024 38,870 76,200
FDEP Southwest Regional Operations Center April 2013 — February 2025 2,430 5,300
FDEP Watershed Assessment Section December 2012 — August 2019 180 200
Peace River Manasota Regional Water Supply Authority (FL) August 1996 — December 2024 27,900 181,900