Jun 10, 2008 - 1600 Ken Thompson Parkway. Sarasota, FL 34236. Cynthia ..... Prairie Slough and for 2001-2006 for Big Slough. The gages are upstream of ...
Estimation of coastal nutrient loads from flow and water quality monitoring data for EcoHAB:Karenia Nutrient Dynamics
Submitted by:
L.K. Dixon Senior Scientist Mote Marine Laboratory 1600 Ken Thompson Parkway Sarasota, FL 34236
Submitted to:
Cynthia Reil, Ph.D. Florida Fish and Wildlife Conservation Commission Fish and Wildlife Research Institute 100 Eight Street South East St. Petersburg, Florida 33701-3093
Draft Mote Marine Laboratory Technical Report # 1278 June 10, 2008
Table of Contents List of Tables ...... ..... .... .. .. ... ............ ............. .. ......... ............................ ..... ....... ......... ............ ... ....... ii List of Figures ......................................... ..... .................... .................... .... .... ........... .... ............ ....... ii
Introduction ...................................................................... .. ................ ................. ..................... .. .. . 1 Methods ....... ......... ....... .... ............ ..... .... ................... ........ ................. ............................. ..... ..... ...... . 1 Flows ........................ ................................................ .......... ............... ......................................... . 1 Water quality concentrations ......................................... .......... .......... ..... ... ...... ...... ..................... 2 Coastal Tampa Bay ..... .... ...... ......... ................................ .... ............... ..... ..... ..... .. .... ..................... 2 Sarasota Bay and Venice Inlet ........... ................................ .... ....... .... .......... .......... ...................... 4 Tampa Bay ...................................... .............. ..... .......... ...... .... .......... ......................................... .. 4 Charlotte Harbor .......... .... .... ... .... ......... ......... ...... ... ........................ ............................. ..... .......... 6 Caloosahatchee River ......... ........ .. ...... ... ............................ ........ ............. .... .. ... .... ................. ..... . 7 Results ...... ..... ...... .................. ...... ......... ............................................... .......... .............. ... .......... ...... 9 Acknowledgements ........... .. ........................ ..... ................. .......... .............. ......... ...... .. .. ....... .... .. .. 13 Literature Cited ........................ .. ...... ....... .. .. ....................................... .............. .... .... ... ............. .. 13
List of Tables
Table 1.
Summary of estimated flows from the four estuarine regions, 2000-2007 ............... 11
Table 2.
Summaries of estimated loads from the four estuarine regions, 2000-2007. Note variation in Chlorophyll analytical technique between regions .......... ............. 12
List of Figures
Figure l.
Pinellas County Environmental Management ambient water quality segments illustrating the spatial extent of Segment W -l. Source: Levy et al. 2007 .............. 14
Figure 2.
Time series of observed and interpolated salinity data from St. Joseph's Sound, Pinellas County, and the mouth of Tampa Bay ....................................................... 15
Figure 3.
Time series of observed and interpolated Total N data from St. Joseph's Sound, Pinellas County, and the mouth of Tampa Bay ................................ ....................... 16
Figure 4.
Daily flow estimates to Coastal Tampa Bay and to Tampa Bay proper indicating generally similar climatic influences ................. ...................................................... 17
Figure 5.
Environmental Protection Commission Hillsborough County ambient monitoring stations. Source: http://www.epchc.org/surface_water_maps.htm ......................... 18
Figure 6.
Average annual loads for 2000-2007 for the four regional watersheds ................... 19
Figure 7.
Average annual loads for 2000-2007. Chlorophyll is in units of 106 grams ........... 20
ii
Introduction
For the EcoHAB:Karenia project, both a hydrodynamic and an ecological model are to be linked to simulate the physical and biogeochemical conditions present during the development of a bloom or blooms of Karenia brevis. The study and models are sited in the estuaries and coastal shelf region of southwest Florida. Data to support these modeling efforts were to include freshwater inflows as well as estimates of nutrient loads to the coastal environment (prepared as a product of freshwater inflows and observed nutrient concentrations). The estimation period was selected to be 2000-2007, to allow for model stabilization in advance of the 2001 bloom which will be simulated under the project. This report summarizes the approach and results of the preparation of estimates. Methods
The premise for the task was that daily loads of nutrients to the coastal environment could be estimated from daily freshwater inflows multiplied by the nutrient concentrations measured at the mouths of the major estuaries. Only a portion of the watersheds are gauged, however, leading to an incomplete water budget of freshwater flows. In addition, there are substantial impacts from both freshwater withdrawals for consumption and from point source discharges. Some information also exists on groundwater inflows but this parameter is generally less well constrained. Flows To estimate ungaged flows, the flows (and the areas) from the various gauged stations were summed, and the flows increased in direct proportion to the area ratio of gauged area:total area. For example, if a gage represents 75% of the watershed, then daily flows should be increased by 110.75 or a factor of 1.33 to estimate both gauged and ungaged flows. The inherent assumption is that the yield of unit volume of water per unit area of watershed is comparable between the gauged and the ungaged portions. To reflect any gradients in soils or climatology, the extrapolated yields were computed from gauged data within the same major estuarine basin. The assumption of similar yields, however, is only valid where the watershed is not affected by withdrawals for consumptive use or known groundwater contributions. Point source discharges also represent an additional input of freshwater which should be incorporated if substantive. Watersheds with altered yields were separated from the remainder of the watershed and flows from that portion of the watershed were either obtained from gauged measurements below the withdrawal, or the yields were computed as if unaltered and known withdrawals were then used to reduce the total inflows. Estimates of point source discharges were available for Tampa Bay and included in the total inflows.
Flow data were generally obtained from either U.S.G.S. (h!tp://waterdata.usgs.gov/nwis/dv/?referred _module=sw), or from the South Florida Water Management District DB HYDRO website (https://my.sfwmd.gov/portal/page? pageid=2235.4688582& dad=portal& schema=PORTAL). Within each watershed, data from the most downstream stations with gauged discharge were assembled. Missing data, if only one or two days were missing, were replaced with the flow on the day(s) prior. Larger periods of missing data were replaced via regression of the existing data on a nearby site if it appeared to have a roughly linear relationship. These regressions are included in the
various spreadsheets and data generated from them were maintained in a separate column labeled 'synthetic' data. For a given watershed or region, the various stations are also tabulated with location information and drainage area represented at the gage. The individual gauged flow data were compiled and flow data were summed for 2000 through 2007. Where stations did not have essentially continuous data for 2000-2007, they were not included in the sum of either flow or drainage area. Total flows were also converted from cubic feet per second to cubic meters per second. A 'Notes' sheet of each regional workbook details workbook-specific comments pertaining to the data. Daily flows were then extrapolated based on the watershed areas and alterations described above, and summed for the entire watershed. The final daily mean flow value for a given watershed was presented as the total freshwater leaving the mouth of the various estuaries. Estimates were prepared for coastal Tampa Bay flowing directly to the Gulf, for Tampa Bay, Charlotte Harbor and the Caloosahatchee River. The estimated freshwater flows neglected the subtleties of tidal variation, time of travel from gage to estuary mouth, evaporation within the estuary, rainfall falling directly to open water, and differing land use (resulting in differing impervious surface and total runoff) between the coastal and upper portions of a watershed. Nevertheless, the flow values obtained represented a good approximation of the daily variation in flows that should be expected on a seasonal and interannual basis and represents a logical first step for incorporation into linked hydrological and ecological modeling efforts. Water quality concentrations To transform flow to nutrient loads, volumes of freshwater must be multiplied by a concentration value. One or more stations at the mouths of the major estuaries were selected. The rational for selecting stations at the mouths of the estuary were that the complexities of in-stream and in estuary transformations and losses could be avoided. The loads computed differ from most prepared to date in that they represent loads to the coastal region and not loads to the head of the estuary.
Data transformations included conversion of all data reported as less than detection limits to a value of 0.0. Data with quality assurance qualifiers of"]" (inaccurate values) were not used. As water quality data were generally only available monthly, concentration data were linearly interpolated between successive measurements in order to provide "daily" water quality values. Interpolated water quality data, until the fmal load computation, were maintained as negative values to distinguish between observations and interpolated values. Again sub-diurnal variations in water quality produced by tidal exchange and sub-monthly variations due to short term weather or climatic events were ignored in favor of obtaining a seasonally and annually representative nutrient loads which could be used as a modeling forcing function. Interpolated time-series of salinity, turbidity, chlorophyll parameters, nitrogen and phosphorus species, and silica were prepared. Loading estimates were limited to inorganic and total nitrogen and phosphorus species, silica, and chlorophyll. Coastal Tampa Bay The coastal Tampa Bay watershed, including the Anclote and Pithlachascotee Rivers, is a relatively small region which drains to the Gulf of Mexico. Gages used to determine watershed
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yields included Saint Joe Creek near Pinellas Park (U.S.G.S. station 230895) , Curlew Creek at County Rd. 1 near Ozona (2309425), Anclote River near Elfers (2310000), Hollin Creek near Tarpon Springs (2310147), and Pithlachascotee River near New Port Richey (2310300) for a total of 686.1 km2 (265.0 sq.mi.) gauged area. Missing data from the Hollin Creek gage were replaced via a regression on Anclote River near Elfers data (n=9538, r2=0.665). The region as a whole is in excess of 933.9 km2 (360.6 sq.mi., SWFWMD, 2002). The mean annual gauged flows exceed 85 X 106 m 3, for a watershed yield of 0.124 X 106 m 3km-!yr-! (4.9 inches yr-!). The yield is low in the region, relative to other portions of the study area, due the exposed and nearsurface karst geology and the low elevations of the surficial water table which increase infiltration and reduce runoff. Total estimated annual flows for the watershed are slightly over 116 X 106 m 3 . The water quality data used to estimate coastal loads were primarily drawn from the ambient monitoring program of the Environmental Management Department of Pinellas County. The program samples approximately every six weeks for in situ physical parameters (temperature, salinity, pH, dissolved oxygen, depth, and Secchi depths) and chemical parameters of chlorophyll (a, b, c), total Kjeldahl nitrogen, ammonia-nitrogen, nitrate-nitrite-nitrogen, total phosphorus, and dissolved orthophosphorus, total suspended solids, transmissivity, total and fecal coliform, and turbidity. Silica values were not available. Sample collection has occurred at four randomized stations within St. Joseph's Sound (Segment W-I) since January 2003. Prior to 2003, there was a station located at the mouth of the Anclote River (just slightly north of Segment W -1). This station, however, was undoubtedly heavily influenced by direct discharge from the Anclote River and biased by tidal phase sampled, and was not considered to be a reasonable water quality record to compute loadings to coastal waters outside ofSt. Joseph's Sound. Without a mid-Sound comparable record for 2000-2002, the existing data from the mouth of Tampa Bay, 2003-2007, were compared with the St. Joseph's Sound data of the same period in hopes of developing a regression that could be used to synthesis St. Joseph's Sound data for 2000-2002. As sampling usually occurred on different days, interpolated data from one system were compared with actual observations in the other system. Climatology between the two regions, as represented by calculated total flows (Figure 2), appeared similar. For water quality, St. Joseph's Sound data were generally lower in salinity, turbidity, chlorophyll, and total phosphorus and were higher in total N and occasionally nitrate-nitrite than the mouth of Tampa Bay. Regressions between the two data sets were not significant, however, and a comparison of time series of salinity (Figure 3) and total nitrogen (Figure 4) indicate that differing loadings may have affected the two regions. Some portion of the variation may be attributed to the randomized sampling design of Pinellas County compared to the fixed station location of the data at the mouth of Tampa Bay. Estimated annual loads from the coastal Tampa Bay region were estimated at nearly 20% of the calculated loads for Tampa Bay during the 2003-2007 period. In order to provide estimates of loads for the entire period of interest (2000-2007), monthly mean water quality data from 20032007 were applied to the middle of the months of the missing years and interpolations conducted
3
as described above. These data are highlighted in the final spreadsheet of concentrations and loading results and their use can be minimized for model calibration and verification. For coastal Tampa Bay, average annual loads were calculated as 4.4 X 106 moles (123 metric tons) of nitrogen and 0.09 X 106 moles (3 metric tons) of phosphorus per year. Less than 1% of the phosphorus is present as the orthophosphate form, although much of the data were less than detection limits and therefore set to 0.0 values. Only 2% of the total nitrogen is in the inorganic form of ammonia or nitrate-nitrite-nitrogen; again with most data less than detection limits. Using total quantities and assuming that all of the total quantity will eventually be available for phytoplankton uptake, the quantities indicate an overall phosphorus limitation for phytoplankton based on Redfield ratios (TN:TP = 45:1). For immediate growth, ratios indicate an even stronger phosphorus limitation (IN:IP = 134: 1). Sarasota Bay and Venice Inlet Sarasota Bay is a relatively small watershed located between Tampa Bay and Charlotte Harbor with a number of inlets between bay and coastal waters. Despite a long standing and comprehensive monitoring plan in these lagoonal waters, the tidal variation of the stations near the inlets was deemed to be unacceptable for the purpose of load computation. Sampling near the inlet on a falling tide, for example, would result in a falsely high nutrient load for the intervening month, sampling on an incoming tide resulting in a falsely low nutrient load. The loads to the coastal waters from these inlets are undoubtedly pulsed on a sub-diurnal frequency as well as on a seasonal basis, but the sampling was not designed to capture the short term variation, and loadings calculated from these data could seriously misrepresent coastal loads. While the same general effects are present in the data for Tampa Bay and St. Joseph's Sound, the temporal variation of Sarasota Bay data was greater. Accordingly flows from the ungaged watershed area of Sarasota Bay, (including that down to coastal Venice, but not including Dona and Robert's Bays, Cow Pen Slough, and Shakett Creek) were computed using watershed yields derived from Tampa Bay data, and these flows were summed with the remainder of flows from Tampa Bay before load computation.
Similarly, the water quality data from the Venice Inlet region displayed similar high variation associated with tides. The area is noted for the interface between highly colored freshwaters and coastal water with high salinity and mineral turbidity, often forming bi-Iayered systems. Accordingly, flows from Dona and Robert's Bays and Cow Pen Slough, and the Lemon Bay region were allocated to Charlotte Harbor for load computation using the water quality data from Boca Grande. If desired, the resulting loads from Tampa Bays and Charlotte Harbor, can be repartitioned back to these coastal inlets, but should continue to use the Tampa Bay and Charlotte Harbor water quality concentrations for load estimation. Tampa Bay Gages in the Tampa Bay watershed with adequate periods of record and a mlll1mum of withdrawals or anthropogenic alterations were used to develop watershed yields and to estimate un~aged flows. USGS gages used included Alafia River at Lithia (2301500), Archie Creek at 78 t St. near Tampa (2301738), Delaney Creek Popoff Canal near Tampa (2301745), Sulfur Springs at Sulfur Springs (2306000), Sweetwater Creek near Tampa (2306647), Alligator Creek below U.S. Hwy 19 at Clearwater (2307671), and Allen Creek near Largo (2307731). Although representing a much larger gauged area than the Alafia River at Lithia, the Alafia River near
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Gibsonton was not used due to large blocks of negative data. A regression with Alligator Creek (n=2545, r2=0.686) was used to replace some missing blocks of Allen Creek data. The gauged area totaled 938.3 km2 (362 sq.mi.) and deliberately excluded the Hillsborough River near Tampa (2304500) and the Tampa Bypass Canal (Structure S-160), both of which are subject to withdrawals. The total of gauged and ungaged area of this portion of the Tampa Bay watershed was reportedly 2679.3 km2 (1034.5 sq.mi; Zarbock et aI., 1994). 1- The mean annual gauged flows were 329 X 106 m 3, for a watershed yield of 0.35 X 106 m km- I y(1 (13.8 inches yr- I). Total estimated annual flows for this portion of the watershed are slightly over 939 X 106 m3 . For the Hillsborough River and the Tampa ByPass Canal, annual flows were 180 X 106 m 3 for a watershed yield of 0.11 X 106 m3 km- I yr- I (4.2 inches yr- I). Due to differing yields, the southwestern portion of the Tampa Bay watershed and the northern portion of the Sarasota Bay watershed were treated separately. Flows from the Little Manatee River near Wimauma (2300500), Manatee River near Myakka Head (2299950), Walker Creek near Sarasota (2299861), and Gamble Creek near Parrish (2300018) were summed for a 529.7 km2 (204.5 sq.mi.) gauged area. The gauged plus ungaged areas were 1425.8 km2 (550.5 sq.mi.) and again excluded those watershed with substantial consumptive use (Ward Lake outfall near Bradenton, 2300042; Lake Manatee at the Dam, Manatee County Utilities). The mean annual gauged flows were 219 X 106 m3, for a watershed yield of 0.41 X 106 m3 km- I yr-I (16.3 inches y(I). Total estimated annual flows for this portion of the watershed were slightly over 591 X 106 m 3 and from Lake Manatee and the Braden River were 210 X 106 m3 . In addition to withdrawals from the Tampa Bay region, point source discharge data, as monthly means, were also available from 1999-2003 (Poe et aI, 1995). These inflows, in large part concentrated in developed coastal regions, are not well captured by the watershed ratio method. Accordingly, point sources estimations available were added to the gauged and ungaged flow estimates. The literature values were available for 2000-2003, and the data were also regressed against the mean monthly flows of largest point source for Tampa Bay, to City of Tampa's Howard F. Curran Plant. The regression (n=48, r2=0.668) was then used to simulate the total point source flows to Tampa Bay from 2004-2007. New data will be available shortly and the regression values will be updated for subsequent years of this contract. Groundwater contributions to Tampa Bay have been previously estimated (Zarbock et aI., 1994) and consisted of the direct discharge to Tampa Bay, i.e. did not include that contributed to gauged portions of the watershed. Flows were based on Darcy's equation and employed groundwater levels in the various aquifers during 1978, 1982, 1985, and 1990. Wet and dry season estimates were 4.6 and 3.9 m3 sec-I, respectively, when contributions to Tampa Bay, Boca Ciega and Terra Ciea Bays and the Manatee River were summed. These groundwater estimates, however, were developed during a time when a number of groundwater levels were higher than recent years and so were not added to Tampa Bay flows. South of Tampa Bay, the region was generally considered to be a net recharge rather than discharge area (Wolanski, 1983) and so groundwater contributions were considered minimal. Combining all inputs and withdrawals to Tampa Bay, including the Sarasota Bay estimated flows and point sources, resulted in a mean annual input of 2,167 X 106 m3, a mean value of 68.65 m3sec- l , and an overall watershed yield of 0.34 m3 km- I yr- I (13.6 in yr-I). The flows attributed
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to be from Sarasota Bay were approximately 7% of the total estimated flows. An upper estimate of potential groundwater inflows was 134 X 106 m 3, or approximately 6% of total estimated flows. Tampa Bay water quality concentrations were obtained as a daily average of Hillsborough County Environmental Protection Commission (HCEPC) of stations 92, 93 , 94, 95, and 96 ( http://www.epchc.org/surfacewatermaps.htm ), the four most coastal stations below the Sunshine Skyway (Figure 5). Data are available from the early 1970's and recent parameter coverage includes sec chi depth, dissolved oxygen, salinity, pH, temperature, biochemical oxygen demand, turbidity, color, total suspended solids, chlorophylls a, b, and c, ammonia-nitrogen, nitrate-nitrite-nitrogen, total Kjeldahl nitrogen, orthophosphorus .and total phosphorus, dissolved silica, fecal coliform and enterococcus. Silica is the only parameter described as dissolved. Average annual loads for the entire Tampa Bay watershed were calculated as 63.6 X 106 moles (891 metric tons) of total nitrogen, 5.78 X 106 moles (179 metric tons) of total phosphorus and 12.7 X 106 moles (356 metric tons) of dissolved silica per year. Approximately 46% of the phosphorus is present as the orthophosphate form, while only 6% of the nitrogen is in the inorganic forms of ammonia or nitrate-nitrite-nitrogen. Using total quantities and assuming that all of the total quantity will eventually be available for phytoplankton uptake, the quantities indicate a slight nitrogen limitation for phytoplankton based on Redfield ratios (TN :TP = 11 :1). For immediate growth, however, inorganic quantities indicate strong nitrogen limitation of both phytoplankton in general (IN:IP = 1.3: 1), and diatoms in particular (IN:Si = 0.3 :1). Charlotte Harbor Gages used in the estimation of total Charlotte Harbor inflow were Peace River at Arcadia (2296750), Joshua Creek at Nocatee (2297100), Horse Creek near Arcadia (2297310), Shell Creek near Punta Gorda (2298202), and Myakka River near Sarasota (2298830). Deer Prairie Slough and Big Slough were not used as the available data were only through 2003 for Deer Prairie Slough and for 2001-2006 for Big Slough. The gages are upstream of significant consumptive uses in the basin. Other ungaged regions which were considered to flow into Charlotte Harbor were coastal Venice which included the discharges from Dona and Robert's Bays and Cow Pen Slough, and the discharges to Lemon Bay. Similar to the Sarasota Bay discharges, the water quality record of the Venice Inlet was deemed to be tidally influenced to the extent that interpolated daily water quality concentrations and loads would be unreliable. Accordingly loads associated with discharges from these basins were computed using the water quality data at the mouth of Charlotte Harbor. Lastly, one half of the watershed area of Pine Island was also added to the Charlotte Harbor ungaged totals, with the remaining half totaled with the ungaged watershed contributing to the Caloosahatchee discharges. The gauged area was 6006 km2 (2319 sq.mi.) or about 76% of the watershed. Watershed yields for Charlotte Harbor were computed from gages not subject to potable withdrawals and extrapolated to the entire watershed. Subsequently, records of consumptive use were removed from the total estimated flows using the daily withdrawal records of the City of Punta Gorda (from the Shell Creek Reservoir) and the Peace River Manasota Regional Water Supply Authority (from the Pease River). The mean annual gauged flows were 1,842 X 106 m3, for a watershed yield of 0.31 X 106 m3 km-1 yr- I (12.1 inches yr- I ). Total estimated annual flows for the entire watershed were slightly over 2,387 X 106 m 3.
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Water quality data were obtained from http://leegis.leegov.comlSurfaceWater/fordownloadi and included data both from the Lee County ambient monitoring program of fixed stations as well as from the Charlotte Harbor Estuary's program of randomized and gridded stations. Stations selected were Lee County's PI-08, and any of the Charlotte Harbor Estuary Program's stations west of 82.2005W and north of 26.7235. As two sampling programs were represented, sampling was often more frequent than monthly. Jointly the two programs sample temperature, salinity, pH, and dissolved oxygen, as well as the chemical parameters of biochemical oxygen demand, color, ammonia, nitrate, nitrite, and total Kjeldahl nitrogen, ortho- and total phosphorus, silicate, turbidity, chlorophyll corrected for pheophytin, and pheophytin. Total organic carbon and total suspended solids have also been included more recently, since mid-2002 for the CHNEP stations, since mid-2004 for the Lee County stations. Average annual loads for the Charlotte Harbor watershed were calculated as 97.5 X 106 moles (1,365 metric tons) of total nitrogen, 8.17 X 106 moles (253 metric tons) of total phosphorus and 95.6 X 106 moles (2,676 metric tons) of dissolved silica per year. Approximately 77% of the phosphorus is present as the orthophosphate form, while only 13% of the nitrogen is in the inorganic forms of ammonia or nitrate-nitrite-nitrogen. Using total quantities and assuming that all of the total quantity will eventually be available for phytoplankton uptake, the quantities indicate a slight nitrogen limitation for phytoplankton based on Redfield ratios (TN:TP = 12:1). For immediate growth, however, inorganic quantities indicate strong nitrogen limitation of phytoplankton in general (IN:IP = 2.0:1), and diatoms in particular (IN:Si = 0.1:1). Caloosahatchee River For the Caloosahatchee River, flow data were retrieved from http://my.sfwmd.gov/dbhydroplsql/ show dbkey info.main menu for a number of sites identified as being located at Lock S79, Franklin Lock near Olga. The sites were identified as DJ237 S79_S, J8190 S79_S, P1023 S79, TA254 S79_T, and 865 S79_T. The various gages represent a number of different installations with varying periods of record and degrees of overlap. A complete record for 1963 to present was assembled by judicious selection of the most complete record, supplemented as needed by other gages.
For the Caloosahatchee River, the controlled releases from S79 (Franklin Lock above Olga) have little daily relationship to rainfall and synthesizing flows from the lower portion of the watershed using the S79 values was not appropriate. Instead, the watershed areas of the lower Caloosahatchee River, Y2 of Pine Island, Telegraph Swamp, Orange River, and Estero Bay were used together with the daily flows, gauged area, and watershed yields of Charlotte Harbor to estimate daily ungaged flows. These estimated flows from the ungaged watershed were then summed with the S79 flows and the combined flows multiplied by the water quality concentrations measured at the mouth of San Carlos Bay. The ungaged area to which Charlotte Harbor yields were extrapolated was 1868 km2 (721 sq.mi.). The mean annual gauged flows from S79 were 1,899 X 106 m 3 . Total estimated annual flows for the entire region were slightly over 2,472 X 106 m3 . Water quality data were obtained from the monthly Lee County ambient monitoring program, described above, using stations PI-13, PI-14, and PI-O!' Average annual loads from the
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Caloosahatchee River were calculated as 134 X 106 moles (1,874 metric tons) of total nitrogen, 5.73 X 106 moles (178 metric tons) of total phosphorus and 182 X 106 moles (5,116 metric tons) of silica per year. Approximately 50% of the phosphorus is present as the orthophosphate form, while only 15% of the nitrogen is in the inorganic forms of ammonia or nitrate-nitrite-nitrogen. Using total quantities and assuming that all of the total quantity will eventually be available for phytoplankton uptake, the quantities indicate a phosphorus limitation for phytoplankton based on Redfield ratios (TN:TP = 23:1). For immediate growth, however, inorganic quantities indicate nitrogen limitation of both phytoplankton in general (IN:IP = 6.8: 1), and diatoms in particular (IN:Si = 0.1:1).
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Results A comparison of the flows and estimated annual loads from the four estuarine regions appear in Tables I and 2 and average annual loads appear in Figures 6 and 7. Flows from the three major estuaries were roughly comparable with only a small fraction contributed by the coastal Tampa Bay drainage. Loads of nitrogen, however, were dominated by that from the Caloosahatchee River system (44% of total), which had only approximately 30% of the total phosphorus loads. The largest phosphorus loads were from the Charlotte Harbor discharges (41 % of the regional totals), which was also highest in inorganic phosphorus. Other noteworthy differences between estuaries were that nitrate-nitrite loadings from Charlotte Harbor were three times greater than that from Tampa Bay and nitrate-nitrite loads from the Caloosahatchee River were three times greater than from Charlotte Harbor. Ammonia loadings were greatest from Charlotte Harbor. Silica loads from the Caloosahatchee River were double that from Charlotte Harbor. Daily values of interpolated salinity, turbidity, nutrient, and chlorophyll concentrations, and estimated nutrient and chlorophyll daily loadings from the four regions are provided as an electronic appendix. Files provided consist of flow and precipitation compilations, water quality data, and a compiled data set for use in modeling. Parent flow files are: 1. Flow ppt Data for Coastal Tampa Bay Watershed.xIs 2. Flow ppt Data for Tampa Bay Waershed.xls 3. Flow ppt data for Manatee Watershed. xis 4. Flow ppt Data for Charlotte Harbor.xls 5. Flow ppt Data for Caloosahatchee River.xls Each "Flow ppt. .. " file has a "Notes" worksheet with remarks on the data and a worksheet for each gage record. Discharge data are in cubic feet per second. Any regressions used to replace missing data are provided. Latitude and longitude of gauged stations and rainfall stations are provided as are drainage areas. Discharges are compiled on another worksheet ("Combined Discharge"), and rainfall data on another ("Combined Precipitation"). On the "Combined Discharge" sheet, the flows and watershed areas are summed and discharges converted to cubic meters per second. Water quality data files are: 1. PinellasCty_ w'L2003 _2007 .xls 2. Hills_Cty_WQ_1974_2007.xls 3. Lee_Cty_WQ_1996_2008.xls As each data were formatted slightly differently, these water quality files differ from one another but in general include a "Notes" page, the original data download, any transformations (mg L- 1 to uM), daily average results, and interpolated daily data. Lastly the file "Compiled Flows and Loads for SW Florida 080611 .xls" contains a complex worksheet of watershed areas with sources of data referenced. Some watersheds appear twice
9
and others are the result of a difference between a large area and a smaller gauged area. Care should be taken before altering this sheet. The regional worksheets contain the total gauged flows from the "Flow ppt. .. " files above, and the watershed ratio used to account for ungaged flows and to arrive at total flows from the entire estuary. Interpolated time series of concentration data are associated with the daily flow estimates as are the computed loads. Positive concentration values are the observed averages, while negative values are the linearly interpolated quantities. Summary statistics appear at the bottom of these worksheets and are reproduced in the Tables 1 and 2. Water budget elements unaccounted for in this analysis include evaporation from and rainfall to the open waters of each estuary. Estimates of groundwater are provided for Tampa Bay but, as they were developed during other years and groundwater conditions, were not included in totals.
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Summary of estimated flows from the four estuarine regions, 2000-2007.
Table 1.
Coastal Tampa Bay
Tampa Bay
Charlotte Harbor
Caloosahatchee River
116
2167
23 87
2472
3.68
68.65
75 .64
78 .33
Flows Annual lO6 m 3 3
Mean m sec-I Mean 106 m 3 da/
0.32
5.93
6.54
6.77
Watershed Yield, lO6 m km-I yea(1
0.12
0.34
0.31 *
NA
Watershed Yield, in y(1
4.89
13.57
12.07*
NA
Annual Rainfall (m)
1.15
1.32, 1.25
1.21
1.37
3
3
Groundwater m sec- I Wet Season
4.6
Dry Season
3.9
* Gaged portion only
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Table 2.
Summaries of estimated loads from the four estuarine regions, 2000-2007. Note variation in Chlorophyll analytical technique between regions.
Average Moles day"l Coastal Tampa Bay Tampa Bay
Chlorophyll a, corrected for phaeophytin (G/day)
Total N
Inorganic N
Ammonia-N
Nitratenitrite-N
Total P
Inorganic P
Silica
1579*
12,078
269
32
237
268
2
35,999*
174,286
10,063
6,677
3,418
15,843
7,461
34,813
NA
Charlotte Harbor
38,002
267,081
34,228
21,960
12,268
22,391
17,229
261,876
Caloosahatchee
48,353
366,460
53,372
16,776
36,599
15,699
7,834
500,545
4.41
0.10
0.01
0.09
0.10
0.00
NA
63.61
3.67
2.44
1.25
5.78
2.72
12.71
Average 106 Moles year- 1 Coastal Tampa Bay Tampa Bay Charlotte Harbor
97.48
12.49
8.02
4.48
8.17
6.29
95.58
Caloosahatchee
133 .76
19.48
6.12
13.36
5.73
2.86
182.70
123.43
1.38
0.16
1.21
3.03
0.02
NA
Average Metric Tons year- 1 Coastal Tampa Bay Tampa Bay
89l.04
51.45
34.14
17.47
179.27
84.43
355.79
Charlotte Harbor
1365.47
174.99
112.27
62.72
253.36
194.95
2676.37
Caloosahatchee
1873.55
272.73
85.77
187.12
177.64
88.65
5115 .57
* Total chlorophyll (a,b, and c) NA-Not available
12
Acknowledgements: Especially Lori Zaworski. Data obtained through the efforts of Natasha Dickrell, Mike Heyl, Roger Johansson, Kelli Hammer Levy, Ralph Montgomery, Ray Pribble, and Mark Simpson.
Literature Cited
Levy, K.H., M. Flock, S.M. Deitche, and C. Meyer. 2007. Ambient Monitoring Program Annual Report, 2003 - 2006. Pinellas County Department of Environmental Management, Watershed Management Division, Clearwater, FL Poe, A., K. Hackett, S. Janicki, R. Pribble, and A. Janicki. 2005. Estimates of Total Nitrogen, Total Phosphorus, Total Suspended Solids, and Biochemical Oxygen Demand Loadings to Tampa Bay, Florida: 1999-2003. Tampa Bay Estuary Program Technical Report 02-05, ST. Petersburg, FL. SWFWMD. 2002. Tampa Bay/ Anclote River Comprehensive Watershed Management Plan. SWFWMD, Tampa, FL.
Wolanski, R.M. (1983) Hydrogeology of the Sarasota-Port Charlotte Area, Florida. u.S. Dept. of the Interior, Geological Survey, Water-Resources Investigations Report 82-4089.48 pp. Tallahassee, FL. Zarbock, H., A. Janicki, D. Wade, and D. Heimbuch. 1994. Estimates of total nitrogen, total phosphorus, and total suspended solids loadings to Tampa Bay Florida. Tampa Bay National Estuary Program Technical Report, No. 04-94, St. Petersburg, FL.
13
PINELLAS COUNTY WATER QUALITY MONITORING PROGRAM OPEN WATER SEGMENTS
N
o I
A
1.5 I
I
3 I
I
6 Miles
I
Created by: C. Meyer. PCDEM Project: Amb_strata_KL.mxd cate : January 2007
Figure 1.
Pinellas County Environmental Management ambient water quality segments illustrating the spatial extent of Segment W-1. Source: Levy et al. 2007.
14
40 .--------------------------------------------------------, 38
--,
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30 - - St. Joseph's
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28
- - - Tampa Bay 26 +--------.--------,-------~-------.--------.--------.------~
07/03/02
05/19/03
04103104
02/17/05
01/03106
11119106
10105107
08/20108
Date
Figure 2.
Time series of observed and interpolated salinity data from St. Joseph's Sound, Pinellas County, and the mouth of Tampa Bay.
70 .--------------------------------------------------------. -
60
St. Joseph's
••• TampaBay
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07/03/02
05/19/03
04103104
02/17/05
01103 /06
11 /19/06
10/05/07
08/20/08
Date
Figure 3.
Time series of observed and interpolated Total N data from St. Joseph's Sound, Pinellas County, and the mouth of Tampa Bay.
16
60 ~--.-------------r----'rT---------'~---------------------'
1000 900
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