Seminole County Water Atlas

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Lake Howell

Howell, Lake


located within Howell Creek Watershed


Explore general as well as scientific information about the movement, chemistry and biology of area surface water environments.

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Water Quality sampling site
Hydrology sampling site
Closest Rainfall site
Rainfall sampling site
Multi-type sampling site
Other sampling site

Overall Trophic State Index

"Trophic" means "relating to nutrition." The Trophic State Index (TSI) takes into account chlorophyll, nitrogen, and phosphorus, which are nutrients required by plant life. The Florida Department of Environmental Protection (FDEP) uses this information to determine a rating for the waterbody. Learn more about the Trophic State Index »

Latest Value Limiting Nutrient Historic Range Additional Information
51 (Good)
3/12/2020 1:50:00 PM
Source: Seminole County Water Quality Data
BALANCED 36 (Good) - 87 (Poor)
9/14/1982 - 3/12/2020
502 samples
Water Quality Trophic State Index Trophic State Classification
GOOD0 - 59Oligotrophic through Mid-Eutrophic
FAIR60 - 69Mid-Eutrophic through Eutrophic
POOR70 - 100Hypereutrophic
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    Nutrient Chemistry

    Although present in all surface waters, nutrients are among the leading causes of degradation of Florida water resources. Learn more about nutrient chemistry »

    Parameter Latest Value Historic Range Additional Information
    Total Nitrogen (TN) 751.0 ug/l
    3/12/2020 1:50:00 PM
    Source: Seminole County Water Quality Data
    115.0 - 28,181.0 ug/L
    9/13/1966 - 3/12/2020
    616 samples
    Total Phosphorus (TP) 36.0 ug/L
    3/12/2020 1:50:00 PM
    Source: Seminole County Water Quality Data
    16.0 - 7,700.0 ug/L
    5/11/1972 - 3/12/2020
    616 samples
    Chlorophyll a,
    uncorrected for
    pheophytin help icon
    14.0 ug/L
    Source: LAKEWATCH Volunteer Water Quality Monitoring
    3.0 - 481.6 ug/L
    9/14/1982 - 2/14/2018
    14,956 samples
    Chlorophyll a,
    corrected for
    pheophytin help icon
    13.0 ug/L
    3/12/2020 1:50:00 PM
    Source: Seminole County Water Quality Data
    3.2 - 164.0 ug/L
    3/15/1983 - 3/12/2020
    74 samples

      Water Clarity

      Water clarity or turbidity measures the degree to which light is blocked because the water is cloudy or contains suspended particles, such as algae. Water clarity is one indicator of a waterbody's ability to sustain plants and wildlife. Learn more about water clarity »

      Parameter Latest Value Historic Range Additional Information
      Secchi Depth 3.0 ft
      Source: Seminole County Water Quality Data
      0.0 ft - 10.0 ft
      1/25/1982 - 3/12/2020
      775 samples
      Turbidity 2.4 NTU
      3/12/2020 1:50:00 PM
      Source: Seminole County Water Quality Data
      0.0 NTU - 199.8 NTU
      1/25/1982 - 3/12/2020
      13,964 samples
      Light Attenuation NO DATA NO DATA NO DATA


        The currently used bacterial indicators for recreational waters include total coliform, fecal coliform and enterococcus. Indicator organisms themselves are not necessarily pathogenic but their presence "indicates" or suggests recent contamination by human sewage or other waste which may result in human illness. Sources of contamination include storm water runoff, sewage overflows and feces from wild and domestic animals. Learn more about bacteria »

        Parameter Latest Value Historic Range Additional Information
        Fecal Coliform 3 CFU/100ml
        Source: Seminole County Water Quality Data
        0 - 120,000 CFU/100ml
        6/1/1972 - 2/27/2014
        126 samples
        Total Coliform 20 CFU/100ml
        Source: FDEP Historic Data from Legacy STORET
        0 - 8,600,000 CFU/100ml
        9/13/1966 - 10/23/1996
        110 samples
        Enterococcus NO DATA NO DATA NO DATA
        E. coli NO DATA NO DATA NO DATA

          Dissolved Oxygen

          Dissolved Oxygen (DO) is one of the most important indicators of water quality. It is essential for the survival of fish and other aquatic organisms. Learn more about dissolved oxygen »

          Parameter Latest Value Historic Range Additional Information
          Dissolved Oxygen 10.7 mg/l
          Source: Seminole County Water Quality Data
          0.0 - 18.0 mg/l
          9/13/1966 - 3/12/2020
          14,821 samples

            Impaired Waters

            The Impaired Waters Data is the most recent available data from FDEP, but it may not reflect the current FDEP impaired list. These data are updated when and as soon as they are made available from FDEP.

            This waterbody is impaired according to the State of Florida's Impaired Waters Rule (IWR) Chapter 62-303 F.A.C. that governs the Total Maximum Daily Loads (TMDL) Program or according to the U.S. Environmental Protection Agency (EPA). Identification of Impaired Surface Waters (IWR) is a new scientific approach for guiding Florida Department of Environmental Protection process for identifying and prioritizing impaired surface waters in Florida. The rule evaluates whether waters meet their designated uses for a particular analyte, which include aquatic life use support, primary contact and recreation use support, fish and shellfish consumption use support, and drinking water use support. All water resources in this county are designated as Class III waters. Class III waters are considered recreational use waters, which means that the water should be fishable and swimmable. Class II waters are for shellfish propagation and harvesting. Class I waters are considered potable (drinkable) water supplies. As part of the terms of a court order related to the 1998 303(d) list of impaired waters, some waters are listed as impaired by EPA but not listed by the State of Florida. Learn more about impaired waters »


            This waterbody has been associated with the following WBIDs deemed impaired by the Florida Department of Environmental Protection:

            WBID Basin Impairment(s)

            Source(s): Florida Department of Environmental Protection



            Advanced Data Features


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