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. TBEPmanagement 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 Main t a i n a n d R e s t o r e t h e B a y  s S e a g r a s s R e s o u r c e s 

# Background Light availability to seagrass is the guiding paradigm for T B E P  s N i t r o g e n M a n a g e m e n t S t r a t e g y . B e c a u s e e x c e s s i v e 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. BaySegment Chlorophyll-a

(ug/L) Effective Light

Penetration (m -1 ) Management Response 2009 Target 2009 Target

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 T a m p a B a y a n d H i l l s b o r o u g h B a y  s 2 0 0 9 e x ceedences 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 GreenSherwood, 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 man a g e m e n t t a r g e t s ( T a b l e 1 & F i g . 5 ) , F D E P  s 2 0 0 2 R e a s o n a b l e Assurance determination and chlorophyll-a targets (matrix to t h e l e f t ) , a n d t h e E P A  s 1 9 9 8 t o t a l m a x i m u m d a i l y l o a d (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 d i s c h a r g e s t h r o u g h 2 0 1 2

. T h e l i m i t s w i l l m a i n t a i n n i t r o g e n l o a d i n g s t o t h e b a y a t e x i s t i n g l e v e l s  a n d c o n s e q u e n t l y r e quire any future additional nitrogen inputs to be offset through added pollution controls. For example, communities that h o l d p e r m i t s t o d i s c h a r g e m o r e t r e a t e d w a s t e w a t e r t h a n t h e y c u r r e n t l y a r e m u s t  h o l d t h e l i n e  o n e x i s t i n g d i s c h a r g e l e v e l s  u n l e s s t h e y c a n p r o v e t h e y h a v e l o w e r e d n i t r o g e n p o l l u t i o n e l s e w h e r e i n t h e i r c o m m u n i t i e s . P a r t i c i p a t i n g p r i v a t e 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:

 T a m p a B a y  s c o o p e r a t i v e a n d p r o a c t i v e a p p r o a c h t o w a t e r s hed management continues to serve as a successful model f o r c o m m u n i t i e s t h r o u g h o u t o u r r e g i o n a n d n a t i o n 

 J i m G i a t tina, Director of the Water Protection Division for the U

. S

. E n v i r o n m e n t a l P r o t e c t i o n A g e n c y  s R e g i o n 4 o f f i c e i n A t l a n t a .