Summary

Total nitrogen load estimates to Tampa Bay for the 1970s and 2010s period by source:




Nitrogen inputs into Tampa Bay are a key limiting nutrient that can stimulate algal growth and negatively affect seagrass habitat. The long-term recovery of Tampa Bay is attributed to the successful nitrogen reduction efforts of the Tampa Bay Nitrogen Management Consortium. Nitrogen loads and sources are routinely estimated for Tampa Bay and reported to the Florida Department of Environmental Protection and US Environmental Protection Agency under a 5-year Reasonable Assurance Plan.

This dashboard provides a summary of nitrogen load estimates in various formats (all estimates from Janicki Environmental, Inc.). Load estimates are partitioned into one of five categories by source:

  • AD: atmospheric deposition
  • DPS: domestic point source
  • GWS: groundwater source
  • IPS: industrial point source
  • NPS: nonpoint source

Source estimates for total nitrogen are shown annually from 1985 to present, by month from 2017 to 2021 (previous Reasonable Assurance period, also including total phosphorus, total suspended solids, and BOD), and by month from 2004 to 2021 for select sources (DPS reuse, DPS end of pipe, IPS, NPS). The totals tab shows annual results for total nitrogen (TN), hydrologic load, and total nitrogen vs hydrologic load ratios. The load ratio plots show adopted numeric nutrient criteria for TN as horizontal lines that are applicable to each bay segment.

Estimates are also assigned to individual bay segments recognized in the Tampa Bay Reasonable Assurance Plan: Old Tampa Bay, Hillsborough Bay, Middle Tampa Bay, Lower Tampa Bay, and the Remainder of Lower Tampa Bay. The “Remainder of Lower Tampa Bay” includes the Manatee River, Terra Ceia Bay, and southern Boca Ciega Bay. Estimates for all segments are also provided as the sum of loads across the four major bay segments and the remainder of Lower Tampa Bay. Note that this does not include the northern portion of Boca Ciega Bay (i.e., (- N. BCB) in the tables and plots).

Annual load targets for total nitrogen (US tons/yr) by major bay segments are as follows (2009 RA Addendum, shown on relevant annual load plots):

  • Old Tampa Bay: 486 tons (US) / year
  • Hillsborough Bay: 1451 tons (US) / year
  • Middle Tampa Bay: 799 tons (US) / year
  • Lower Tampa Bay: 349 tons (US) / year
  • Remainder of Lower Tampa Bay: 629 tons (US) / year

Hydrologically-normalized load targets, as a ratio of total nitrogen to hydrologic load (nitrogen delivery ratios) for each bay segment, are also shown on relevant plots (2009 RA Addendum). These nitrogen delivery ratios have been adopted as the annual RA compliance assessment thresholds and/or estuarine numeric nutrient criteria for Tampa Bay and are as follows :

  • Old Tampa Bay: 1.08 tons/million cubic meters of water
  • Hillsborough Bay: 1.62 tons/million cubic meters of water
  • Middle Tampa Bay: 1.24 tons/million cubic meters of water
  • Lower Tampa Bay: 0.97 tons/million cubic meters of water
  • Remainder of Lower Tampa Bay: 1.59 tons/million cubic meters of water
  • Boca Ciega Bay South: 0.97 tons/million cubic meters of water
  • Terra Ceia Bay: 1.10 tons/million cubic meters of water
  • Manatee River Estuary: 1.80 tons/million cubic meters of water
  • Boca Ciega Bay North: 1.54 tons/million cubic meters of water

Major bay segments in Tampa Bay used to assign load estimates. The Remainder of Lower Tampa Bay includes the Manatee River, Terra Ceia Bay, and Boca Ciega Bay. Figure courtesy of Janicki Environmental, Inc.

Total nitrogen (annual, 1985 - 2021)





By source

Dotted line is annual bay segment target.

Table

Metadata

Data from the Download plot data button includes the following:

  • year: year of the estimate
  • bay_segment: the bay segment for the source/year estimate, one of Old Tampa Bay, Hillsborough Bay, Middle Tampa Bay, Lower Tampa Bay, Remainder of Lower Tampa Bay (Manatee River, Terra Ceia Bay, and Boca Ciega Bay South), and all segments as the sum of all (excluding Boca Ciega Bay North)
  • source: total nitrogen source as atmospheric deposition (AD), domestic point source (DPS), groundwater source (GWS), industrial point source (IPS), and non-point source (NPS)
  • tn_load: total nitrogen load in tons (US) / year

Total nitrogen, phosphorus, suspended solids, and BOD by source (monthly, 1995 - 2021)





Total nitrogen by source

Total nitrogen table

Total phosphorus by source

Total phosphorus table

Total suspended solids by source

Total suspended solids table

BOD by source

BOD table

Metadata

Data from the Download all plot data button includes monthly estimates by bay segment and source for total nitrogen, phosphorus, suspended solids, and BOD. Columns are as follows:

  • year: year of the estimate (1995 - 2021)
  • month: month of the estimate
  • bay_segment: the bay segment for the source/year estimate, one of Old Tampa Bay, Hillsborough Bay, Middle Tampa Bay, Lower Tampa Bay, Remainder of Lower Tampa Bay (Manatee River, Terra Ceia Bay, and Boca Ciega Bay South), and all segments as the sum of all (excluding Boca Ciega Bay North)
  • source: total nitrogen source as atmospheric deposition (AD), domestic point source (DPS), groundwater source (GWS), industrial point source (IPS), and non-point source (NPS)
  • tn_load: total nitrogen load in tons / month
  • tp_load: total phosphorus load in tons / month
  • tss_load: total suspended solids load in tons / month
  • bod_load: biological oxygen demand in tons / month

Data from the Download all entity data button includes the following:

  • year: year of the estimate (2017 - 2021)
  • month: month of the estimate
  • bayseg: bay segment where the load applies
  • entity: entity responsible for the load, e.g., a specific wastewater treatment plant
  • source: total nitrogen source as atmospheric deposition (AD), domestic point source (DPS), groundwater source (GWS), industrial point source (IPS), and non-point source (NPS)
  • tn_load: total nitrogen load in tons / month

Total hydrologic load (monthly, 1985 - 2021)





Plot

Table

Metadata

Data from the Download all plot data button includes the following:

  • year: year of the estimate
  • month: month of the estimate
  • bay_segment: the bay segment for the month estimate, one of Old Tampa Bay, Hillsborough Bay, Middle Tampa Bay, Lower Tampa Bay, Remainder of Lower Tampa Bay (Manatee River, Terra Ceia Bay, and Boca Ciega Bay South), and all segments as the sum of all (excluding Boca Ciega Bay North)
  • hy_load_106_m3_mo: hydrologic load as 10\(^6\) m\(^3\)/month

Total nitrogen select sources (monthly, 2004 - 2021)





By source

Table

NPS by land use

Metadata

Data from the Download plot data button includes the following:

  • year: year of the estimate
  • month: month of the estimate
  • bay_segment: the bay segment for the source/year estimate, one of Old Tampa Bay, Hillsborough Bay, Middle Tampa Bay, Lower Tampa Bay, Remainder of Lower Tampa Bay (Manatee River, Terra Ceia Bay, and Boca Ciega Bay South), and all segments as the sum of all (excluding Boca Ciega Bay North)
  • source: total nitrogen source as domestic point source reuse (DPS - reuse), domestic point source end of pipe (DPS - end of pipe), industrial point source (IPS), and non-point source (NPS)
  • tn_load: total nitrogen load in tons / month

Data from the Download entity data button includes the following:

  • year: year of the estimate
  • month: month of the estimate
  • bayseg: bay segment where the load applies
  • entity: entity responsible for the load, e.g., a specific wastewater treatment plant
  • source: total nitrogen source as atmospheric deposition (AD), domestic point source (DPS), groundwater source (GWS), industrial point source (IPS), and non-point source (NPS)
  • tn_load: total nitrogen load in tons / month

Data from the Download NPS by land use button includes the following:

  • year: year of the estimate
  • month: month of the estimate
  • bay_segment: the bay segment for the source/year estimate, one of Old Tampa Bay, Hillsborough Bay, Middle Tampa Bay, Lower Tampa Bay, Remainder of Lower Tampa Bay (Manatee River, Terra Ceia Bay, and Boca Ciega Bay South), and all segments as the sum of all (excluding Boca Ciega Bay North)
  • land use: land use type associated with the load
  • source: total nitrogen source as non-point source (NPS)
  • tn_load: total nitrogen load in tons / month

Totals





Total Nitrogen

Dotted line is annual bay segment target.

Total Phosphorus

Dotted line is annual bay segment target.

Hydrology

Dotted line is annual bay segment target.

Total Nitrogen vs Hydrology

Dotted line is annual bay segment target.

Total Phosphorus vs Hydrology

Dotted line is annual bay segment target.

Table

Metadata

Data from the Download plot data button includes the following:

  • year: year of the estimate
  • bay_segment: the bay segment for the source/year estimate, one of Old Tampa Bay, Hillsborough Bay, Middle Tampa Bay, Lower Tampa Bay, Remainder of Lower Tampa Bay (Manatee River, Terra Ceia Bay, and Boca Ciega Bay South), and all segments as the sum of all (excluding Boca Ciega Bay North)
  • tn_load: total nitrogen load in tons (US) / year
  • tp_load: total phosphorus load in tons (US) / year
  • hy_load: hydrologic load in million cubic meters / year
  • tnhy: ratio between total nitrogen and hydrologic loads
  • tphy: ratio between total phosphorus and hydrologic loads