Sherwood, E.T. 2010. 2009 Tampa Bay Water Quality Assessment. Tampa Bay Estuary Program Technical Report #02-10. TBEP, St. Petersburg, FL. 1

For additional Info Visit:

www.tbeptech.org

Original Reference:

Janicki, A., D. Wade, & R.J. Pribble.

2000. Developing & Establishing a

Process to Track the Status of

Chlorophyll-a Concentrations and

Light Attenuation to Support

Seagrass Restoration Goals in Tampa

Bay. Tampa Bay Estuary Program

Technical Report # 04-00.

Historic Results:

Year to year algae abundance (measured as chlorophyll-a

concentrations) and visible light penetration through the

water column (depth of secchi disk visibility) have been

identified as critical water quality indicators in Tampa Bay.

Tracking the attainment of bay segment specific targets for

these indicators provides the framework from which bay

management actions are developed & initiated. TBEP

management actions adopted in response to the annuallyassessed decision support results are as follows:

2009 Decision Matrix Results

Figure 3: Map depicting individual station

chlorophyll-a exceedences in Tampa Bay.

A Tampa Bay Estuary Program Initiative to Maintain and Restore the Bays Seagrass Resources

Background

Light availability to seagrass is the guiding paradigm for

TBEPs Nitrogen Management Strategy. Because excessive

nitrogen loads to the bay generally lead to increased algae

blooms (higher chlorophyll-a levels) (Figure 1) and reduce

light penetration to seagrass, an evaluation method was

developed to assess whether load reduction strategies are

achieving desired water quality results (i.e. reduced

chlorophyll-a concentrations and increased water clarity).

Decision Support Approach

Table 1. Observed water quality indicators & management

outcomes for 2009. *Small & **large magnitude exceedence.

Bay

Segment

Chlorophyll-a

(ug/L)

Effective Light

Penetration (m-1) Management Re2009 Target 2009 Target sponse

OTB 12.1** 8.5 0.81 0.83 Yellow

HB 14.6* 13.2 1.10 1.58 Yellow

MTB 6.5 7.4 0.65 0.83 Green

LTB 4.4 4.6 0.56 0.63 Green

Green

“Stay the course;” partners continue with planned projects to

implement the CCMP. Data summary and reporting via the

Baywide Environmental Monitoring Report and annual

assessment and progress reports.

Yellow

TAC and Management Board on caution alert; review

monitoring data and loading estimates; attempt to identify

causes of target exceedences; TAC report to Management

Board on findings and recommended responses needed.

Red

TAC, Management and Policy Boards on alert; review and

report by TAC to Management Board on recommended

types of responses. Management and Policy Boards take

appropriate actions to get the program back on track.

Continuing water quality

monitoring support

provided by the EPCHC.

Consulting support

provided by Janicki

Environmental, Inc.

A decline in water quality was observed in 2009 for Old

Tampa Bay (OTB) and Hillsborough Bay (HB). A large

magnitude exceedence of the chlorophyll-a threshold in

OTB and a small magnitude exceedence in HB were

observed (Fig. 2). Site-specific exceedences of the TBEP

bay segment chlorophyll-a targets were prevalent in OTB

and HB (Fig. 3). A persistent algae bloom occurred from

May-August during 2009 in the upper bay segments, and

observed summer monthly chlorophyll-a averages far

exceeded normal historical levels (Fig. 4, page 2). In

response, an assessment & action plan will be developed

starting in the Fall 2010.

Figure 2: Historic chlorophyll-a annual averages for the four bay segments. Old

Tampa Bay and Hillsborough Bays 2009 exceedences are highlighted in yellow.

Figure 1: Guiding paradigm for Tampa Bay seagrass restoration through the management of nitrogen loads.

Total N Chlorophyll Light

Load -a Attenuation

Seagrass Growth Seagrass Light

& Reproduction Requirements

2009 Tampa Bay Water Quality Assessment

Year Old TB Hills.

Bay

Middle

TB

Lower

TB

1975 Red Red Red Green

1976 Red Red Red Yellow

1977 Red Red Red Red

1978 Red Red Red Yellow

1979 Red Red Red Red

1980 Red Red Red Red

1981 Red Red Red Red

1982 Red Red Red Red

1983 Red Yellow Red Red

1984 Red Green Red Yellow

1985 Red Red Red Yellow

1986 Red Yellow Red Green

1987 Red Yellow Red Green

1988 Yellow Green Yellow Green

1989 Red Yellow Red Yellow

1990 Red Green Red Yellow

1991 Green Yellow Yellow Yellow

1992 Yellow Green Yellow Yellow

1993 Yellow Green Yellow Yellow

1994 Yellow Yellow Red Red

1995 Red Yellow Red Yellow

1996 Yellow Green Yellow Green

1997 Yellow Green Red Yellow

1998 Red Red Red Red

1999 Yellow Green Yellow Yellow

2000 Green Green Yellow Yellow

2001 Yellow Green Yellow Yellow

2002 Yellow Green Green Green

2003 Red Yellow Green Yellow

2004 Red Green Green Yellow

2005 Green Green Yellow Yellow

2006 Green Green Green Green

2007 Green Green Green Green

2008 Yellow Green Green Yellow

2009 Yellow Yellow Green Green
Sherwood, E.T. 2010. 2009 Tampa Bay Water Quality Assessment. Tampa Bay Estuary Program Technical Report #02-10. TBEP, St. Petersburg, FL. 2

2009 Chl-a Monthly Variation Compared to 1974-2008

Attaining FDEP Reasonable Assurance & EPA TMDLs

Progress Towards Meeting Regulatory Goals

FDEP Targets Met:

Year Old TB Hills.

Bay

Mid.

TB

Low.

TB

1975 No No No Yes

1976 No No No Yes

1977 No No No No

1978 No No No Yes

1979 No No No No

1980 No No No No

1981 No No No No

1982 No No No No

1983 No No No No

1984 Yes Yes No Yes

1985 No No No Yes

1986 No No Yes Yes

1987 No Yes No Yes

1988 Yes Yes Yes Yes

1989 No Yes Yes Yes

1990 No Yes Yes Yes

1991 Yes Yes Yes Yes

1992 Yes Yes Yes Yes

1993 Yes Yes Yes Yes

1994 No No No No

1995 No No No Yes

1996 Yes Yes Yes Yes

1997 Yes Yes Yes Yes

1998 No No No No

1999 Yes Yes Yes Yes

2000 Yes Yes Yes Yes

2001 Yes Yes Yes Yes

2002 Yes Yes Yes Yes

2003 No Yes Yes Yes

2004 No Yes Yes Yes

2005 Yes Yes Yes No

2006 Yes Yes Yes Yes

2007 Yes Yes Yes Yes

2008 Yes Yes Yes Yes

2009 No Yes Yes Yes

An initiative of the Tampa Bay Nitrogen Management Consortium (NMC)

Figure 5: Historic seagrass acreage estimates for Tampa Bay from

1950-2008 (Source: SWFWMD).

Based upon the yellow cautionary management response for some of the bay segments in 2009, chlorophyll-a

concentrations were evaluated within the bay (Fig. 3) and monthly during 2009 (Fig. 4) to discern where and

when target exceedences occurred, respectively. Observed 2009 monthly averages were generally within the

range of historic levels except during the summer months in 2009 (Fig. 4, circled in yellow).

Figure 4: 2009 monthly chlorophyll-a bay segment averages (red dots) compared to monthly distributions from 1974-2008 (blue box

plots). Boxes encompass the 25th and 75th percentiles, while whiskers bound the interquartile range. Blue dots represent outliers.

Starting in December 2007, public and private participants in the Tampa Bay Nitrogen Management Consortium (NMC)

proactively committed to develop an equitable process to allocate nitrogen loads among all sources discharging to the

bay in order to support continued attainment of bay management targets (Table 1 & Fig. 5), FDEPs 2002 Reasonable

Assurance determination and chlorophyll-a targets (matrix to the left), and the EPAs 1998 total maximum daily load

(TMDL) limits. The Consortium includes representatives of every major government in the Tampa Bay watershed, as

well as key industries such as utilities, fertilizer manufacturers, commercial agriculture and regulatory agencies.

In Sept. 2009, the Consortium participants finalized and approved their technical process, and proposed TN allocations

to 189 point and nonpoint sources within the Tampa Bay watershed. The proposed nitrogen load limits developed from

the NMC agreement have been endorsed by more than 40 area government and private industry representatives and

defines how much nitrogen can enter Tampa Bay through stormwater, air pollution, treated wastewater, and industrial

discharges through 2012. The limits will maintain nitrogen loadings to the bay at existing levelsand consequently require any future additional nitrogen inputs to be offset through added pollution controls. For example, communities that

hold permits to discharge more treated wastewater than they currently are must hold the line on existing discharge

levels  unless they can prove they have lowered nitrogen pollution elsewhere in their communities. Participating private

sector partners must meet the same restrictions.

In December 2009, FDEP provided its concurrence with the technical basis and allocations developed by the Consortium. This accomplishment has been recognized by local media (Tampa Tribune editorial Sept. 24, 2009) and regulators:

Tampa Bays cooperative and proactive approach to watershed management continues to serve as a successful model

for communities throughout our region and nation  Jim Giattina, Director of the Water Protection Division for the

U.S. Environmental Protection Agencys Region 4 office in Atlanta.