5.0  Futch Creek

            During 1995 and 1996 two channels were dredged in the mouth of Futch Creek (Fig. 5.1) to improve circulation and hopefully reduce fecal coliform bacterial concentrations.  There was a statistically significant increase in salinity in the creek in the months following dredging, significantly lower fecal coliform counts, and the lower creek was reopened to shellfishing (Mallin et al. 2000c).   During 2003-2004, there were no incidences of creek stations having turbidity levels exceeding the state standard of 25 NTU (Table 5.1).  Low dissolved oxygen, was a periodic problem at middle and upper creek stations in 2003-2004 (Appendix B).  Salinity levels were somewhat lower in 2003-2004 than during the previous year (Table 5.1; Mallin et al. 2004); this may have been a result of more rainfall prior to this year's samples relative to last year's collections.

Table 5.1.  Physical parameters at Futch Creek sampling stations, August 2003 - July 2004.  Data given as mean (SD) / range.
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Station                        Salinity (ppt)        Turbidity (NTU)       Dissolved oxygen (mg/L)
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FC-4                           33.2 (2.3)                   6 (7)                            7.6 (2.0)
                                    27.3-35.6                   0-25                            4.8-11.1 

FC-6                           32.2 (2.7)                   4 (3)                            7.8 (2.1)
                                    24.4-34.3                   0-9                              4.7-11.3 

FC-8                           29.3 (4.8)                   7 (4)                            7.4 (2.5)
                                    18.5-32.6                   1-13                            4.0-11.6 

FC-13                         25.8 (2.7)                   10 (7)                          7.2 (2.6)
                                    20.8-28.8                   2-25                            2.9-11.9 

FC-17                         16.5 (6.5)                   10 (7)                          6.8 (2.8)
                                    5.4-24.4                      3-25                            2.3-12.2 

FOY                            25.3 (5.5)                   7 (4)                            6.9 (2.6)
                                    11.4-31.0                   1-12                            4.0-12.2
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            Nutrient concentrations in Futch Creek remained generally low, although showing an increase in nitrate over the previous year in the upper stations FC-13 and FC-17 (Table 5.2).  One source of nitrate has been identified as groundwater inputs entering the marsh in springs existing in the area stretching from upstream of FC-17 downstream to FC-13 (Mallin et al. 1998b).  The creek was free from algal blooms during our sampling visits (Table 5.2), even in the upper stations. 

Table 5.2.  Nutrient and chlorophyll a data from Futch Creek, August 2003-July 2004.  Data as mean (SD) / range, nutrients in mg/L, chlorophyll a as mg/L.
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Station            Nitrate                        Ammonium                Orthophosphate        Chlorophyll a
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FC-4               0.009 (0.004)             0.016 (0.006)             0.007 (0.003)            1.4 (0.9)
                        0.005-0.020               0.008-0.025               0.004-0.016               0.3-2.9 

FC-6               0.012 (0.005)             0.016 (0.011)             0.008 (0.003)            1.4 (1.0)
                        0.004-0.020               0.008-0.035               0.004-0.016               0.3-3.3 

FC-8               0.025 (0.011)             NA                               0.010 (0.004)            1.6 (1.1)
                        0.008-0.048                                                   0.006-0.023               0.3-3.9 

FC-13             0.062 (0.029)             NA                              0.011 (0.005)             3.0 (2.9)
                        0.027-0.115                                                   0.006-0.023               0.5-10.1 

FC-17             0.111 (0.064)             0.026 (0.016)            0.014 (0.008)             2.4 (1.6)
                        0.035-0.274               0.008-0.052               0.008-0.036               0.6-4.8 

FOY                0.044 (0.029)             0.023 (0.010)             0.009 (0.005)             2.3 (1.8)
                        0.003-0.092               0.008-0.043               0.002-0.020               0.6-5.4
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            As reportedly previously (Mallin et al. 2000c) the dredging experiment proved to be successful and the lower portion of the creek was reopened to shellfishing.  During 2003-2004 the lower creek through FC-8 maintained excellent microbiological water quality for shellfishing (Table 5.3), and the mid-creek areas had good microbiological water quality as well.  The uppermost stations continued to have fecal coliform bacterial concentrations below those of the pre-dredging period; however, there was a notable deterioration in microbiological water quality at the upper stations compared with the previous year (Fig. 5.2).  All stations still had geometric mean fecal coliform counts that were well within safe limits for human contact waters (Appendix B).

Table 5.3.   Futch Creek fecal coliform bacteria data, including percent of samples exceeding 43 CFU per 100 mL, August 2003 - July 2004.
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Station                                         FC-4     FC-6     FC-8     FC-13     FC-17     FOY    
Geomean (CFU/100 mL)             2           3           8           19            77           24         
% > 43 /100ml                               0           10         10         20            70           50       
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