Results of Back Bay Nutrient Ron Southwick Virginia ...
Transcript of Results of Back Bay Nutrient Ron Southwick Virginia ...
Results of Back Bay NutrientSampling, April 1986 - March 1987
by
Ron SouthwickDistrict Fish Biologist
and
Mitchell D. NormanSupervising Fish Biologist
Virginia Department of Game and Inland Fisheries
December, 1987
INTRODUCTION
To determine nutrient levels in Back Bay, water samples were
collected monthly from April, 1986 through March, 1987. Surface
water samples were collected at six stations (Figure 1) and sent
to the Virginia Consolidated Laboratory for analyses. Parameters
monitored by the State Lab were suspended solids (total, volatile
and fixed), ammonia, nitrite, nitrate, total Kjeldalh nitrogen
and phosphorus (total and ortho). Other parameters which were
monitored in the field at the time of the collection were
salinity, conductivity, water temperature, Secchi disc
transparency, pH and turbidity. These results were reported by
Norman and Southwick (1987).
Overall, the nutrient levels in Back Bay were not
excessively high. Only suspended solids and total Kjeldalh
nitrogen surpassed or violated the EPA reference levels. Levels
for the basic nutrients (nitrate and phosphate) were well below
the EPA reference levels. Furthermore, the 1986 Virginia Water
Quality Assessment (S.W.C.B., 1986) reported the water quality in
Back Bay to be "good". Nutrient levels in Back Bay have changed
little since the early 1970's. Water samples collected by the
State Water Control Board from 1972 to 1975 showed that Total
Kjeldalh nitrogen and pH were the only parameters which violated
the EPA reference levels. However, levels for suspended solids
were not determined during that survey.
RESULTS
Sol.j.ds Uota]̂ y.°l§til§ and F
Total suspended solids include 1) "Fixed" matter which is
inorganic colloidal clay and coarse suspensions of soil
particles, and 2>"Vo1 atile" matter which is made up of living and
dead organic matter.
Total suspended solids in Back Bay were very high during the
study period. The mean 1evel/station ranged from 57.3 mg/1 (Sta.
22) to 94.8 mg/1 (Sta. 5 and 20). Suspended solids were highest
from January through March when the level routinely exceeded 10O
mg/1 and frequently exceeded 2OO mg/1 (Figures 9-14). Values as
high as 294 mg/1 were detected (March, Sta. 20). The high level
of suspended solids during the Winter months was due to strong
wind induced wave action which kept the sediment in suspension.
The EPA reference level for suspended solids is SO mg/1
(Table 7). By comparison, the mean level of suspended
solids/station in Back Bay exceeded the EPA reference level at
two stations (# 5 and 2O) (Figure 2). Individual station
readings for suspended solids were generally below the EPA
reference level from April through December. However, during the
January—March period the individual- readings for suspended solids
exceeded the EPA reference level considerably - sometimes by a
factor of three.
The cause for this high level of suspended solids
(turbidity) in Back Bay is two fold; 1) an abundance of inorganic
material in suspension and 2) an abundant phytoplankton
population (unpublished report, H.G. Marshall, 1987). Both of
these factors keep water clarity poor year around. Average
Secchi disc transparencies ranged from less than 5 inches to a
maximum of only 1*+ inches during the same period.
Volatile suspended solids ranged from a mean of 25.8 mg/1
(Sta. 22) to 3̂ .6 mg/1 (Sta. 20). The value for volatile
suspended solids was highest in February at each station except
#22 (Figures 15-20).
Fixed suspended solids ranged from a mean of 31.5 mg/1 (Sta.
22) to 60.3 mg/1 at (Sta. 20). Monthly values were consistently
higher during March (Figures 21-26).
Nitrate as Nitrogen
Nitrite does not appear to be a problem in Back Bay. Mean
nitrite level for each station ranged from 0.01 to 0.03 mg/1.
Many of the individual station readings were below the minimum
detectable level (0.01 mg/1) and are indicated with a "K" in
Tables 1-6. The EPA reference level for nitrite in natural
waters in 0.9 mg/1. Therefore, the nitrite levels in Back Bay
are well below the EPA standards (Figure 3). Nitrite levels of
natural waters are generally very low (Wetzel, 1983). Generally
nitrite levels in Back Bay were lowest during the Spring and
highest during the Winter (Figures 27-32).
Nitrate as Nitrogen
Nitrate occurs in relatively small concentrations in
unpolluted waters (Reid, 1961). This nutrient is rapidly taken
up by plants (including phytoplankton). There is concern by some
that excessive nitrate from agricultural sources around Back Bay
is posing a problem in the bay. However, the data from this
survey indicate differently. Nitrate levels in Back Bay were
well below the EPA reference level of 0.9 mg/1 (Figure ̂ ).
Average nitrate readings/station ranged from 0.18 mg/1 (Sta. 5)
to 0.2^+ mg/1 (Sta. 20). Apparently the marsh vegetation and
phytoplankton in Back Bay utilize much of the nitrates entering
the system. This would account for the decrease in nitrate
levels from May through December, e.g. a period of increase
phytoplankton activity. Nitrates were very low (<0.05 mg/1) at
each station from May through January but increased appreciably
in February and March (Figures 33-38). This increase was
probably due to increased run-off from agricultural fields with
heavy rainfall during those months.
iQtal Kjel.da.lh Nitrogen HKN1
This form of nitrogen is present in soluable organic
compounds and as a constituent of living and dead particulate
organic matter. According to Boyd (1979), concentrations of
organic nitrogen are usually well below 1.0 mg/1 in unpolluted
natural waters. The EPA reference level for TKN is 0.9 mg/1
(Table 7). Average TKN/station in Back Bay ranged from 2.3 to
2.8 mg/1 with three of the six stations having the same high
value. Levels of TKN in Back Bay violated the reference level in
all of the samples (Figure 5). This is a substantial increase
from the results of the 1972-75 SWCB study when TKN levels
exceeded the EPA reference level in only 11. V/. of the samples.
These high values in Back Bay are indicative of the high level of
biological productivity from the marsh vegetation and the
abundant phytop lank ton in the bay. As a general rule, TKN was
relatively low in April; then increased progressively through the
Summer to peak in August or September; then declined through
January; and then increase again through March (Figures 39-^4-).
Ammonj_a as Nitrogen
Ammonia is an end product of the bacterial decomposition of
organic matter and an excretory product of aquatic animals. At
high levels, ammonia can be detrimental to aquatic life. The EPA
reference level for ammonia is 0.89 mg/1 (Table 7). The mean
ammonia 1evel/station in Back Bay ranged from O.3E mg/1 (Sta. 1^)
to 0.^1 mg/1 (Sta. 3) and was, therefore, well below the EPA
reference level (Figure 6). Ammonia was generally low April
through November, then increased progressively each month to peak
in January—February, and then "crashed" to low values again by
March (Figures ^5-50). High concentrations of ammonia occur
following phytoplankton die-offs (Boyd, et al . , 1975). This
could be an explanation for the increase in ammonia in Back Bay
from December through February.
Phosphorus is a key metabolic nutrient, and the supply of
this element often regulates the productivity of natural waters.
Concentrations of total phosphorus seldom exceed 1.0 mg/1 (Boyd,
1979). The EPA reference level for total phosphorus is 0.3 mg/1
(Table 7). The average level /stat ion for total phosphorus in
Back Bay ranged from 0.1S mg/1 (Sta. 22) to 0.15 mg/1 (Sta. 5 and
20) (Figure 7). At most stations, total phosphorus showed two
distinct peaks in a seasonal cycle (Figures 51-56). One peak was
in March-April; the other was in August.
Ortho phosphorus is the soluble and simplest form of
phosphorus found in natural waters, making it readily available
to plants. Concentrations of ortho phosphate are quite low and
usually no greater than 0.0005 to 0.02 mg/1 and seldom exceed O.I
mg/1 even in highly eutrophic waters (Boyd, 1979). The EPA
reference level for ortho phosphate is 0.1 mg/1 (Table 7).
Average values/station for ortho phosphorus in Back Bay ranged
from O.O4 to O.06 mg/1 (Figure 8). Although mean phosphorus
levels in Back Bay did not surpass the EPA reference level, some
sample values approached or equalled the reference level. At
most stations, ortho phosphorus was highest July through
September (Figures 57—62).
LITERATURE CITED
Boyd, C.E., E.E. Prather, and R. W. Parks. 1975. Sudden
mortality of a massive phytoplank ton bloom. Weed Sci. ,
23:61-67
Boyd, Claude E. 1979. Water quality in warm water fish
ponds. Auburn University, Agri. Exp. Sta., 359 pg.
Marshall, H. G. 1987. Back Bay Phytoplank ton Study.
Va-DJ-F-58 (in preparation).
Norman, M. D. and Ron Southwick, 1987. Back Bay: Report on
salinity are Water Clarity in 1986. Department of Game
and Inland Fisheries. 30 pp
Reid, George K. 1961. Ecology of Inland waters and
Estuaries, ed. Van Nostrand Reinhold Company, New York,
375 pp.
State Water Control Board. 1976. Water Quality Inventory
(305(b) Report). S.W.C.B. Info. Bull. 5E6. 361 pp.
Wetzel, Robert G. 1983. Limnology, ed. Saunders College
Publishing Philadelphia. 767 pp.
List of Tables
Table 1. Nutrient levels (mg/1) determined from water samples collected atStation 3, Back Bay from April, 1986 to March, 1987.
Table 2. Nutrient levels (mg/1) determined from water samples collected atStation 5, Back Bay from April, 1986 to March, 1987.
Table 3. Nutrient levels (mg/1) determined from water samples collected atStation 9, Back Bay from April, 1986 to March, 1987.
Table 4. Nutrient levels (mg/1) determined from water samples collected atStation 14, Back Bay from April, 1986 to March, 1987.
Table 5. Nutrient levels (mg/1) determined from water samples collected atStation 20, Back Bay from April, 1986 to March, 1987.
Table 6. Nutrient levels (mg//l)determined from water samples collected atStation 22, Back Bay from April, 1986 to March, 1987.
Table 7. Reference levels and source for selected water quality parameters.
List of Figures
Figure 1. Map of Back Bay, Virginia showing the location of stations fornutrient analysis.
Figure 2. Comparison of Total Suspended Solids (mg/1) in Back Bay (as meanof each station for period April, 1986 to March, 1987) wilhlEPA"Reference Level"
Figure 3. Comparison of Total Nitrite level (mg/1) in Back Bay (as meanof each station for period April, 1986 to March, 1987) with EPA"Reference Level".
Figure 4. Comparison of Total Nitrate (mg/1) in Back Bay (as mean of eachstation for period April, 1986 to March, 1987) with EPA "ReferenceLevel".
Figure 5. Comparison of Total Kjeldalh Nitrogen (mg/1) in Back Bay (asmean of each station for period April, 1986 to March, 1987) withEPA "Reference Level".
Figure 6. Comparison of Total Ammonia (mg/1) in Back Bay (as mean of eachstation for period April, 1986 to March, 1987) with EPA "ReferenceLevel".
Figure 7. Comparison of Total Phosphorus(mg/l) in Back Bay (as mean of eachstation for period April, 1986 to March, 1987) with EPA "ReferenceLevel".
Figure 8. Comparison of Total Ortho Phosphorus(mg/l) in Bck Bay (as mean ofeach station for period April, 1986 to March, 1987) with EPA"Reference Level".
Figure 9. Monthly level of Total Suspended Solids (mg/1) at Station 3, BackBay from April, 1986 to March, 1987.
Figure 10. Monthly level of Total Suspended Solids (mg/1) at Station 5, BackBay from April, 1986 to March, 1987.
Figure 11. Monthly level of Total Suspended Solids (mg/1) at Station 9, BackBay from April, 1986 to March, 1987.
Figure 12. Monthly level of Total Suspended Solids (mg/1) at Station 14, BackBay from April, 1986 to March, 1987.
Figure 13. Monthly level of Total Suspended Solids (mg/1) at Station 20, BackBay from April, 1986 to March, 1987.
Figure 14. Monthly level of Total Suspended Solids (mg/1) at Station 22, BackBay from April, 1986 to Marach, 1987.
Figure 15. Monthly level of Volatile Suspended Solids (mg/1) at Station 3,Back Bay from April, 1986 to March, 1987.
Figure 16. Monthly level of Volatile Suspended Solids (mg/1) at Station 5,Back Bay from April, 1986 to March, 1987.
Figure 17. Monthly level of Volatile Suspended Solids (mg/1) at Station 9,Back Bay from April, 1986 to March 1987.
Figure 18. Monthly level of Volatile Suspended Solids (mg/1) at Station 14,Back Bay from April, 1986 to March, 1987.
Figure 19. Monthly level of Volatile Suspended Solids (mg/1) at Station 20,Back Bay from April, 1986 to March, 1987.
Figure 20. Monthly level of Volatile Suspended Solids (mg/1) at Station 22,Back Bay from April, 1986 to March, 1987.
Figure 21. Monthly level of Fixed Suspended Solids (mg/1) at Station 3,Back Bay from April, 1986 to March, 1987.
Figure 22. Monthly level of Fixed Suspended Solids (mg/1) at Station 5,Back Bay from April, 1986 to March, 1987.
Figure 23. Monthly level of Fixed Suspended Solids (mg/1) at Station 9,Back Bay from April, 1986 to March, 1987.
Figure 24. Monthly level of Fixed Suspended Solids (mg/1) at Station 14,Back Bay from April, 1986 to March, 1987.
Figure 25. Monthly level of Fixed Suspended Solids (mg/1) at Station 20,Back Bay from April, 1986 to March, 1987.
Figure 26. Monthly level of Fixed Suspended Solids (mg/1) at Station 22,Back Bay from April, 1986 to March, 1987.
Figure 27. Monthly level of Nitrite as Nitrogen (mg/1) at Station 3, BackBay, from April, 1986 to March, 1987.
Figure 28. Monthly level of Nitrite as Nitrogen (mg/1) at Station 5, BackBay from April, 1986 to March, 1987.
Figure 29. Monthly level of Nitrite as Nitrogen (mg/1) at Station 9, BackBay from April, 1986 to March, 1987.
Figure 30. Monthly level of Nitrite as Nitrogen (mg/1) at Station 14, BackBay from April, 1986 to March, 1987.
Figure 31. Monthly level of Nitrite as Nitrogen (mg/1) at Station 20, BackBay from April, 1986 to March, 1987.
Figure 32. Monthly level of Nitrite as Nitrogen (mg/1) at Station 22, BackBay from April, 1986 to March, 1987.
10
Figure 33. Monthly level of Nitrate as Nitrogen (mg/1) at Station 3, BackBay from April, 1986 to March, 1987.
Figure 34. Monthly level of Nitrate as Nitrogen (mg/1) at Station 5, BackBay from April, 1986 to March, 1987.
Figure 35. Monthly level of Nitrate as Nitrogen (mg/1) at Station 9, BackBay from April, 1986 to March, 1987.
Figure 36. Monthly level of Nitrate as Nitrogen (mg/1) at Station 14, BackBay from April, 1986 to March, 1987.
Figure 37. Monthly level of Nitrate as Nitrogen (mg/1) at Station 20, BackBay from April, 1986 to March, 1987.
Figure 38. Monthly level of Nitrate as Nitrogen (mg/1) at Station 22, BackBay from April, 1986 to March, 1987.
'Figure 39. Monthly level of TKN (mg/1) at Station 3, Back Bay from April,1986 to March, 1987.
Figure 40. Monthly level of TKN (mg/1) at Station 5, Back Bay from April,1986 to March, 1987.
Figure 41. Monthly level of TKN (mg/1) at Station 9, Back Bay from April,1986, to March, 1987.
Figure 42. Monthly level of TKN (mg/1) at Station 14, Back Bay from April,1986 to March, 1987.
Figure 43. Monthly level of TKN (mg/1) at Station 20, Back Bay from April,1986 to March, 1987.
Figure 44. Monthly level of TKN (mg/1) at Station 22, Back Bay from April,1986 to March, 1987.
Figure 45. Monthly level of Ammonia as Nitrogen (mg/1) at Station 3, BackBay from April, 1986 to March, 1987.
Figure 46. Monthly level of Ammonia as Nitrogen (mg/1) at Station 5, BackBay from April, 1986 to March, 1987.
Figure 47. Monthly level of Ammonia as Nitrogen (mg/1) at Station 9, BackBay from April, 1986 to March, 1987.
Figure 48. Monthly level of Ammonia as Nitrogen (mg/1) at Station 14, BackBay from April, 1986 to March, 1987.
Figure 49. Monthly level of Ammonia as Nitrogen (mg/1) at Station 20, BackBay from April, 1986 to March, 1987.
Figure 50. Monthly level of Ammonia as Nitrogen (mg/1) at Station 22, BackBay from April, 1986 to March, 1987.
11
Figure 51. Monthly level of Total Phosphorus as P (mg/1) at Station 3, BackBay from April, 1986 to March, 1987.
Figure 52. Monthly level of Total Phosphorus as P (mg/1) at Station 5, BackBay from April, 1986 to March, 1987.
Figure 53. Monthly level of Total Phosphorus as P (mg/1) at Station 9, BackBay from April, 1986 to March, 1987.
Figure 54. Monthly level of Total Phosphorus as P (mg/1) at Station 14, BackBay from April, 1986 to March, 1987.
Figure 55. Monthly level of Total Phosphorus as P (mg/1) at Station 20, BackBay from April, 1986 to March, 1987.
Figure 56. Monthly level of Total Phosphorus as P (mg/1) at Station 22, BackBay from April, 1986 to March, 1987.
Figure 57. Monthly level of Ortho Phosphorus as P (mg/1) at Station 3, BackBay from April, 1986 to March, 1987.
Figure 58. Monthly level of Ortho Phosphorus as P (mg/1) at Station 5, BackBay from April, 1986 to March, 1987.
Figure 59. Monthly level of Ortho Phosphorus as P (mg/1) at Station 9, BackBay from April, 1986 to March, 1987.
Figure 60. Monthly level of Ortho Phosphorus as P (mg/1) at Station 14, BackBay from April, 1986 to March, 1987.
Figure 61. Monthly level of Ortho Phosphorus as P (mg/1) at Station 20, BackBay from April, 1986 to March, 1987.
Figure 62. Monthly level of Ortho Phosphorus as P (mg/1) at Station 22, BackBay from April, 1986 to March, 1987.
12
APRIL86
HAY
JLNE
JULY
AUE
SEPT
OCT
NQV
DEC
JAN67
FEE
HPR
MEANS
TOT. SOLIDSTC'.iig/i)
343E
3597
4135
4616
4613
4S39
4EO'
4561
4614
3924
£840
2659
4079.2
TQT.5GLID3VOL.!tg/l!
629
532
891
847
941
92s
841
32!
711
465
496
393
7E5.1
TOT, SOLIDSFI1U ing/I)
280?
3i65
34Z4
2769
3i77
3903
3968
40+0
3603
3259
2344
2266
3344.1
SUS.SOLID5TOT.(ifl/l!
15
37
60
46
4o
36
40
70
50
S3
31
188
63.1
SOS. SOL IDSvOL.,ifg'l)
i
17
24
30
28
30
31
34
E,
32
23
44
27.8
SUS.50LID3Fn...«g/l)
9
20
36
16
8
6
c
36
£6
56
58
144
35.3
HHMONIA NITRITE(•3/1 as N) (ag/1 as N)
0.1 O.tl
.iOK .01*:
.10K .OIK
.IOK .OIK
O.E 0.01
0.1 0.02
.IOK 0.02
0.1 t.OE
0.4 0.0!
C.S 0.04
C.9 0.02
0.7 0.03
0.41 0.02
NITRA'E(«g/l as N)
C.I 2
MY.
.05K
.05K
.W
,05K
.05K
.C5K
.05K
0,09
0.31
0.23
0.19
TOT. K. NIT(irg/1;
1.3
1.5
2.1
3
3.8
3.3
3.5
3.1
3
2.'
2.6
2.9
2.8
TOT.PHOS.(«g/l as P)
O.S
.IOK
0.1
0.1
0.2
0.:
0.1
0,1
0.1
0.1
0.1
0.2
0.13
ORTHO.PHDS.(«g/l as P)
0.05
0.02
0.02
0
o.oe
0.09
0
0
0.08
0
0.06
0
0.06
TOT.OR6.C.(cg/i)
15
17
20
22
54
22
24
24
21
18
IE
21
20
Table 1. Nutrient levels (mg/1) determined from water samples collected at Station 3, Back Bay from April, 1986 toMarch, 1987.
APRILS*
MY
ME
JULY
AU6
SEP-
OCT
NOV
DEC
JAN97
FEE
IMF.
MEANS
TOT. SOLIDSTQT.(«g>!)
336!
3543
42:E
4565
4039
4475
479E
v:E
43i!
3^i
«x
2452
3995
'DT. SOLIDSVQL.hg/1)
559
509
S74
306
Si;
90-
w71;
^i
494
435
3Ei
495.2
TOT. SOLIDSPH.(«5/I!
£802
3035
3413
373?
3!"4
S571
35*:
J95-
3iic
29£0
2027
EOit
3199.8
BUS. SOLIDS SUS. SOLIDSTQT.iag/!! VOL.!sg, ii
-3 i"
33 T
57 £;
34 3'
50 34
50 30
7" 34
7o 32
2: 14
!44 ,0
1S4 4)
26s 54
97. E 3;. 5
SUS, SOLIDSFIl. (*g/ii
2 4
la
31
20
1*
20
41
44
7
104
144
203
54.3
AMI* JO NITRITE•'Rg 1 as N) ''ng.'i as N)
O.i 0.0!
.i*C .C1K
,10K .OIK
0.1 0.0!
O.I 0.02
0,£ 0.02
0,1 0.03
O.i 0,03
0.5 0.01
O.S 0,0'
0,9 0,02
0.5 0.0;
0.34 0.02
NITRATE!sg/I 35 N;
0.1
• 05̂
.0-
'1C«'
.05-'
,05r
.05*
.G5K
0,05
0,14
0.35
0.24
0.1S
TOT. K. NIT.
1.3
1.7
2
3.1
3,4
3
3 . .-.
E.7
2.8
2,,
3.2
3,4
2.B
TCT.PHOS.
0.3
0.1
0.1
O.i
0.2
0.1
'j . I
0,1
0,1
0 1 1
0.2
V 1 U
0.15
ORTHD.PHOS.iiq/! as P;
0.04
0.03
C.OE
0
0
0
C
0
O.OT
o
o
0
0.04
TOT.OR5.C.Ug/li
15
IE
20
22
22
21
25
22
1?
19
16
23
20.2
Table 2. Nutrient levels (mg/1) determined from water samples collected at Station 5, Back Bay from April, 1986to March, 1987.
APRIL36
MF-Y
JiJNE
JULY
PUB
SEPT
OCT
NOV
DE:
JfiN'87
FES
HAF
HEANS
TOT. SOLIDSTOT.iig/i:-
3020
3406
i405
4405
2«5
345"
4634
4cC9
,*5
3335
1719
1974
3491.2
TOT. SOLIDSV3L.dg/l)
500
486
1065
784
507
703
391
"i-
715
640
304
30?
636.3
TOT .SOL IDSFlLiig/i!
2520
2930
3320
3621
1923
2755
3743
336t
3730
E745
1415
16o5
2652.3
SUS.SGLKSTOT. lag/ 1)
40
32
46
42
40
6E
63
10"
47
64
,4
206
69.3
SOS- SOLIDS SUS, SOLIDSVCL.!f.g/l) FIMag/i-
14 26
13 1?
14 34
2S !4
24 16
2E 40
27 41
44 60
£3 Ei
28 38
2d 52
36 17E
2t.6 44. "?
APHONIAisg/1 as N -
0.!
.10K
.IJK
0,1
3
0.1
0.5
C , 4
0 . 5
0.7
0.6
0.5
0.37
NITRITE(rg/i as N'i
0.01
.oi':
.OIK
0.01
0.01
•"< , OP
).03
0.04
0,02
0.04
O.Oc
0,05
0 . 03
NITRATEiffg/l as N!
0.1?
.05K
.05K
.05K
AC''. 5.-' J'-.
,05K
.05.:
,05K
0.05
0.16
0.46
0.26
0.22
TOT. K. NIT.(eg/i)
1.1
1.7
c
3.4
2.5
2.7
3.3
2,9
2.7
2.2
2,2
2.8
2.5
TQT.PHOS.(*g/i as F!
0.1
O.I
O.i
0.1
0.2
0.2
n _ 1
0.2
0.1
0.1
0.1
0,2
0.13
ORTHO.DHOS.iig/i as ?!
0 , 06
0.02
0.02
0
0,07
0.09
<:<
0
0.03
0
0.06
0
0.06
TOT. ORE. C.lug/I)
15
1?
2'"'
23
13
22
21
23
20
16
IE
23
19.3
Table 3. Nutrient levels (mg/1) determined from water samples collected at Station 9, Back Bay from April, 1986to March, 1987.
6PRILB6
IfiY
JUNE
JULY
AUt
SEPT
OCT
NtV
DEC
JANS:
FEE
HAR
HEAHS
TOT. SOLIDSTOT.ijig/I)
3384
35<C
4252
-51!
4556
44-4
4349
4S02
4641
44!t
2555
2775
4109.6
TOT. SCUDS TDT. SOLID:VOL. (dig/!! F!Usiq;i;
558 £95 s
474 3026
856 3396
937 36""-
958 3598
'76 369£
901 3945
830 396̂
''SS 3906
824 35̂ 2
561 2394
418 2357
744.7 336̂ .9
SUS.SQLiDSTC'T.(irg/l;
5t
41
66
38
A P
36
53
68
4-
62
133
240
75. E
SUS. SOLIDSVOL. (fig/1;
20
16
T":CC
2S
42
32
35
44
24
30
33
56
31.6
SuS. SOLIDS AMMONIAFIL !ffg/ r inq/l as M
3i O.i
25 ,iO<
4-'- O.i
10 0,1
20 0.2
6 0,1
:8 ).l
?4 0.;
20 0.2
32 0.7
100 1
192 0.7
43.5 0.32
NITRITEirg-i as Hi
0.0!
.OIK
0.0!
0.01
0.0;
i. AJ
0.02
0.02
0.01
0.03
0.33
O.C3
0.02
NITRATE!»g/l as N;
0,13
,05f;
0.05
.m
.05K
.05K
.PFik'
.05'.:
,05K
0.07
0,47
0.25
0.2
TO'. K. NIT.fug/1 /
1.1
1.8
2.1
£.9
3.3
3.4
3.7
2.8
3.7
2.4
3.5
3.5
2.3
TOT.PHGS. ORTHC.PHDS.i»C;;i as PJ (nig /I as P!
0.1 0.06
0.1 0.03
O.i O.OB
O.i 0
0.2 0.03
O.i 0.1
O.i 0
O.i 0
0.1 0.08
0.1 0
0.2 0
0.2 0
0.13 O.Ob
TOT. ORE. C!»g/l»
15
17
22
£1
21
2£
2t
24
21
17
16
25
20.4
Table 4. Nutrient levels (mg/1) determined from water samples collected at Station 14, Back Bay from April, 1986to March, 1987.
APRR96
HAY
JUNE
JULV
AU6
SEPT
OCT
NQV
DEC
JftNS7
FEB
HAR
MEANS
TOT. SOLIDSTDT.Iig/1)
?957
345!
420?
4469
458:
4800
.554
C.'iCIJv'.Jt
47j£
^525
E?33
E738
4131.4
TOT. SOLIDSyGL,f*g/i!
430
487
366
303
950
967
935
965
"78
"Bl
55'
414
74.8.1
TOT. SOL IDSFlUfg/i!
S4"
£964
3341
3666
3635
3633
3919
4.086
4180
3744
8381
2374
3383.3
3US. SOLIDSTOT. la g / i f
33
3E
58
4(
56
35
5E
156
50
100
£29
294
94. ,3
SUS. SOLIDSVOL, iffiq/n
11
16
E8
ES
,3
34
3,
5E
26
38
5E
54
34.6
SUS. SOLIDS AMQN'IA NITPITIFit.isg/1-' !»g;! as Ni !«q/l as N'
£E .10K .OIK
16 ,:OK ,01?:
30 ,10k 0.01
IE O.i 0.01
14 r...g 0.01
4 j,[ C , OE
18 0.1 O.OE
1'"'4 ••'''. ; <^.03
24 0,2 O.Oi
i£ 0.7 0.03
177 0,3 O.OE
E40 0.7 0.04
60.3 0.33 O.OE
NITRATE TOT, K. NIT.•UQ/1 as fif i5q;l)
0.13 0.9
.05t 1.6
. OSK E
.05K E. 9
,03K 3,3
.05?" 3.4
.05K 3.3
.m 3.1
..-. 2.-
0.05 E.5
0.45 3.9
C.3E 3.6
0,24 2.7
TOT.PHOS.(iig.'i as P)
5.1
0.1
0.1
C.I
0.2
0.1
0.1
O.E
O.i
O.E
i' » 0
O.E
0.15
ORTHG.PHOS.(ag/1 as P)
0.04
0.03
0.03
0
0.08
0.1
f;
V
0.07
0
0
0
0.04
TOT. ORB. C.(sg/1)
13
16
13
21
E4
£5
£3
E9
El
18
19
23
E0.8
Total 5. Nutrient levels (mg/1) determined from water samples collected at Station 20, Back Bay from April, 1986to March, 1987.
APRILS 5
W
JUNE
JOLY
AUB
SEPT
OCT
NOv1
DEC
JAN87
FEE
WAR
MEANS
TOT, SOL IDS7[T.(j!g/l!
3503
3529
WO
4534
480S
473S
5157
3343
5109
4̂ 76
£333
2579
425=, 3
TOT, SOLIDSVOL.!aq/ii
534
492
364
303
996
92?
56-
834
7*7
573
493
379
740.7
TOT.SGLI33Flung/!}
E'19
3037
3326
3733
3B12
3309
^44?*
4362
3S9S
23M
220)
3518.6
3US. SOLIDSTOT.isg/ 1)
34
u'
66
QC-j j
51
32
-:jr =
31
S3
134
92
37.3
3U3.50LID3i'0 . ! * 3 • i 'i
\B
:7
£2
25
42
3C
£H
f6
:?
30
;n
20
•ic r.C J . C
3yS;SCLlDS AMHOMA NITRI'E' I *. '' ng / i / (ag/1 a; K i :*g/. as Kl-
16 .1CK 0.01
24 ,;OK .OH
44 ,10K .01̂ '
10 0.1 O.Oi
9 0,2 O.Oi
£ 0.1 0,02
10 .10K 0,0!
£6 ,10' 0.01
i£ 0,4 0.0:
52 0.6 0.02
101 0.3 0.02
72 0.1 0.02
31.5 0.33 0.01
NITRATElit.;-! a; Ni
.05K
,05K
• 05<
,05K
.m
.m
.05"
,05K
/5K
C.Ofc
0.27
:' , u
0.21
TOT. K. NIT,(ig/ll
t « -J
1.5
1.9
2,9
3.2
E.B
2,4
I.3
2.,
£.3
2.6
1.8
2.3
TOT.'HCS. Qrtho.Fhos.(ic/l as Pi i'iq/1 as F!
0.2 0
I,'- it -i. 1 V V
0.1 0
.lOK
0.2 0
0.1 0
O.i 0
,SOK 0
''• . ! 0
0,1
0.! 0
0,1
c.je o
,04
.03
.02
0
,08
.09
.06
.-
.03
0
.04
0
.05
TOT. ORGAN 1C
15
16
£0
El
25
24
19
19
' -t
17
14
18
13.9
Table 6. Nutrient levels (mg/1) determined from water samples collected at Station 22, Back Bay from April, 1986to March, 1987.
PARAMETER
Orthophosphate (as P)
Total Phosphorus
Ammonia (as N)
Nitrite (as N)
Nitrate (as N)
Total Kjeldalh Nitrogen
REFERENCE LEVEL AND SOURCE
0.1 mg/1 -Nutrient*
0.3 mg/1 -Nutrient*
0.89 mg/1 -Aquatic Life **
0.9 mg/1 -Nutrient***
0.9 mg/1 -Nutrient***
0.9 mg/1 -Nutrient***
* Guidelines for Developing or Revising Water Quality Standards, EPA WaterPlanning Division, April 1973
** Criteria for Water Quality, EPA, 1973 (Section 304(a)(l) Guielines)***Biological Associated Problems in Freshwater Environments, FWPCA, 1966, pp 132-3
Source: Virginia State Water Control Board
Table 7. Reference levels and source for selected water quality parameters.
LITTLE ISLAND CITYRtCRtATION AREA
Figure 1. Map of Back Bay, Virginia showing the location of stations for nutrient analysis,
TOTA L. Si US!:;:' EN D ED SO LI DS (rn g /I)LI U —
H[| •-
71:1 -
on -
an ••••
40 •-
31.1 ••••
7 II ••••
1 ! ! ••••
1.1 ••••
.
T"
/ .r (.
..'•'' ..•'' /
..-' ,.-' /
''./,//
••"''/"/',
' /'' / .-•'
' .••'' / r
' ••'' r'' t~>'" ..>'' ...'"
.'' .*'' .'.*' .•' .•'
•' y ,••' ,•>''' '"'' .•'*'
.•'' .-' .•''
' ••'' ' ,••' ••''•' ,/ .i'1
•'"•••••'ii: •••"I" PA
—
.' «' ('
' ' ••' ' i-''' ,•
' ' ' . •• ' ' . ••• ' .
••'/'"/'',••' ,.••' ..'•'.,••' ..•'' _/' ,.
•' i../ .,••''/•'' .••'' ••'' ••''"•••''"•••''",•,-'" ,•'' /'
•'' .-*'' .•''
*' ,-••' i,-i' ,-
.'' .'*' .•'*
•'* .-'' •'''
•' .•'
•'' .•' i'*'
i1' i' i'*
!
ETA ili
•'"''.'••'""/"!•1 / ' .-•' .••'/•'' /"''.••"'• ' ' ' . • • ' ' ! • • • ' ! •'-•'' '•••'/
//:'/::•••"/"',••'"'!•
,••' ..'' .r
•''•••"/"'/•' y'
'' ,-''' '•'"' »'
• ' ' . •• ' ' ,-•'',-
•' ,.•'' .•*'y' t.-1 y*
i'* .'* .''.'' .'*'* /
,-' .-•'' .-'*'
/*' y*' y'
•' .-'' I1'*
l! T"--'-J
KTA lii
''1 J' ['"'
•'' •'' r'
'* .-'" .-•'
•' ' r'"
•'"•-'" "•••' ' .-
' •••' I*'"' r
•' /' ,-'* .
i'"'* •' •''*' .'' .•'
''".•''",.••''',..' ' •'*' ••'
.'"' .•'' .-*'
»'" i1' i*r'' t '" ' .''
I1' .'' .''
•' .•' .•'*'
'::: ;:| :"-
KTA 13
>;;/;;>;' ' V'': - ' ' " ' ••' ••' ."'
'''-•'""!-••'".'.••••' '/•' ' ',•' ',••' ,.-' .1*'
.••'"' .'•''' .-•1 .•'' .•''' i'"'* .•'"' .•
•*'' .•'"' »'*•'"'' .••''' r'1'
,•'' ' .'' .'*'
•''* .•''l t1'
«'' .**' )•'*
.-' .•" .''
•''./'' /•''..•,••' (.i*' ,..*'
•'- "| •'•'••••
Err.-1-. 1 4
r-7-7-7
'',••'".•••'''./'
y" ..•' .r
.•'' .'*' .•'*
,-••' ,.••'' iy1'
.•' .-•' ••**
"'',,•''" ,•-'"/•
'''/'''/'/
,•' y ,-•'
• '* ' • ' •'' .
r*' .'*"' r'
i'' -•'" r'-'' ,.-'' /' .
•P < r' .-1' .•
•** .*'" t''
•• ' .*''"' .'•''' •' ••"' r'/' ,.•' (.-''
..•' ,.-'' y'
.•' -•' .'*••' .•' .-•'
'' "'"1 '
BTA 3D—
-, — .....
''/'/'/
.*' .-1' i*
'.••'''/''','•.-* _.-*
i'- • " * r'•* ,-•'* -• ' .
1*"' •'"' ••*'.••"' r1"' .-''*
' •'' ••'*' «•'.' .•'*
..-'' ,.-•' .''
••' .-'' .-•'y* .' '
*i™.*ii-~i:-1--STA 33
" i
Figure 2. Comparison of Total Suspended "Solids (mg/1) in Back Bay (as mean ofeach station for period April, 1986 to March, 1987) with EPA "ReferenceLevel".
tTTE (rnq/! as
1:1.1:1
IICI
1:1.:;!
in -
STA li! E!TA 14 ST.- STA
rn:i.,:
I'"" I"'STA 3 STA
Figure 3. Comparison of Total Nitrite level (mg/1) in Back Bay (as mean of eachstation for period April, 1986 to March, 1987) with EPA "Reference level.
NfT'RATE iVnn/i as N)
I'1!1'i;
111:1 -•
"U.B -
n.ri
1:1.4
••"iEiFA STA 3 STA 5 KTA El STA 14 STA 2CI ffl'A 3'J
r~
Figure 4. Comparison of Total Nitrate (mg/1) in Back Bay (as mean of each stationfor period April, 1986 to March, 1987) with EPA "Reference Level".
I1'-*.!ITROGEN, Tot, K |eIclahi (mq/i)
'•I 1:1 ....•i. . !.!
l-'i
:;!.:;! ••••
3 ••••
1.1:1 •-
1.1:1 ••••
•( .if. ._.
•i.:,? -
•i ....
0.1:1 -
111:1 ••••
11-1
1:1.:;! -
...
•
i -
.•'•' .''•' .••'
/XX.'••' .'••' ••'•',-••' ,••'•' /•''
.'••' .•' .•'.'• ,..'• ,.••' t.
•''' ..'•'' .1'''
i1'' r'1 r1'1
EPA
V/'"/
r' i'' .-'
/'/[./'•• /' _..'•
•' r'
••''' _..-'' (..-''
•' ' .-' .-•'
,••'' .-'•' .•''''h .••''' ,•• :' .-•''•' ..' ••' ,-
'',/.,• '"'/
•'"/'' '••'"/
.,•'' ..•' ./'
,-•'' ,••'' /''/ .•' .-''
' r'" ' •'•'' ..•''' ..-'' .r' r1' r'"' 1 ""
STA ?.i
'• '•"'•'"" '
.•'' .-•' .-
' ,-'' ..'
"'".••'"'/
..•••'"..•••"/
•'" .•''
,'•• ..•'"'.. '
••'' ••',.'
••' ••'' ..'•
.'•'' .•''' .•,-•'
..'
..* .-• ..
•'' •'' ..''
'•' •'"' /..''' ••' .• '
,.'
.. ' .r1'-•' .**
1 '
STA S
,-' ,•'" _.''
'•"'.••'"/"'
' /''' .••'' .••''.-'•'' .••' .-•''
...••' ...-'' i..-1'
•-''. •-'/•••' | ••'' ./''
:'' •'"' .•'
• ..' ,.'•' ,.
• ' " • • "/•'"/
.••'
.•'
.•'•' .••' .•''
I1' .«'•' .''
• . * .•'''
'' I'''
'"1 '
EiTA F.I
' '- '". '•'"'/
.•••"/"/"'.
.-' .••' .'*'
,-•' .i** _,''
/ f.'' ,i'
,.'* ,•' t..'
..'' )(*' .1'
/••'',.•••"/"
••''./•"'.,•'"/
•• ' ' " •" ' ••• ' " , ' •.''* t'1' I-1'.•'' .••' .-'''
'' ,•'' ' ••'' I'"
''/'",'•'"'',-'"
••''',//'[..
••' ••'•' .I''''
' .••''' r'' ••''' ' .-'•' .'•' ' .1'..'' _.'*' _..''
,••' ,••' ,••'•' '"1
EiTA 1 4
--;.-••;: ;:r
.'" .'*' 1*.''' .-"' l''
>••;/;/.••' ••' /'
•' •'*' r*
r'' ' .'''*' -•*'''
!-"'. '•"''. ••'''.*"' .•'' I*'
.'*'' ..•'' <•""'/" ..''' /'
.'" .'' l'*
',••''',•••''','•'
••''.-•'','•''',••' ••'•' .''•'
I1' .•'•' .I1' ..-' ,-
..' ..' ,.'
••'• .•'•• .-•'"
I1' I1' I1'ISTA :;!o
"• "i1 *i'"".-•' .-•' .••"'
' .''"'' ,••'"' .'"'.••'* ••'
•••''' .-•'' .-•*
r' •'
.'' ..•" y'
•' .•*' .'.' t'' i*''..'''' X .- ''
•' ,-•'*' .-•' •••' .•'' .-' .-
-'"/'/'" .'"' t "** •'
,-•'' ..'"' ...'*' /' .•*' r
.•*• .''• .•'•,.•' ,-•* ,.'*
rSTA 23
1
Figure 5. Comparison of Total Kjeldalh Nitrogen (mg/1) in Back Bay (as mean ofeach station for period April, 1986 to March, 1987) with EPA "ReferenceLevel".
AMMONIA (mg/l as N)
...j
CI.KI
11.1:1
lie
a. 5
a. 4
a.3
112
U.I
n;iA R'FA i!i STA !:>
,>;....,!..„,::;„.,
E:TA 'n
Figure 6. Camaprison of Total Ammonia (mg/1) in Back Bay (as mean of each station for period April,1986 to Mbrch, 1987) with EPA "Reference Level".
TOTAL PI IOSPI IORUS frna/i")n.35 -•
D.25 -
[1.3
1:1.1 ••••
'" "~T iSTA 5
r-
STA H STA 14 STA 30 STA 22
Figure 7. Comparison of Total Phosphorus (mg/1) in Back Bay (as mean of eachstation for period April, 1986 to March, 1987) with EPA "ReferenceLevel".
IORU3, ORTI 10 I'V
I''!'
11 1 -
licit! ••••
11. DH -
n ni:i «..LI . U 1.1 "
u.ns -
n.i].ii
i:i.i:i;!i ••••
mi:;! -
11. H I -
i.i i
',/.,••''/
•' .•'' ' ,••''
I'** r '/"!""' '"'-
/'/"'/'
,-•'' ,-•'' /
,-•' .'' i.'i.-•' ..-''
'"'.••'",'•••'"
.•"'' .-'
' • • ' ' ' • • • ' , •'/"'/'.,•
i1' r' r*iEPA
'/'.•'"'/•' .-' .-'"'
-'•' ' •'"' ••''
I1'*' i'"' •'
/ .1'
'' r' •''
•'•''...'•'''..•••''',.
' ' ' '••'"'•••'' ', '•
'•••'"'•••'''/:•' ,.'' ..''
,-•' ,-•' ,-•'' '"1
STA ;ii
,-• ' _ , • * .'',.••' (..-' .. •
.'''' .•' .•'
, • • • ' ' , •••' '/ 'r" r' r'
'r'"1
STA !:i
i-'1' ,-••' .••''
,-•' ,-•' .''i1*' ,•"' .•*'•*' .•'
' ' ' . • • ' ' , • • • ' •••"'/"'/"./ ...-•'',•••'
. '' ..'' .. '
r' r' i -1
' 1
STA i;i
, ' .•'
'' ••'' .•'' .-
./' ..-• . ••'.'"' .- r*
,•' r.'' i t''
r ''
• • •" ' • • • '.'•"!.
! • • • • " ' /,•' t ' ,-
.1! i!..,....i!iSTA 1 4
,•' ,.-' .r*
•"/•"'...•''"',.•
.'' .-'' r.''* ,-•' .•'
.••'' ,•*'' .-•'*
.'•'' .-'' /'y//f///,
\~ •''•'* .•' •'"
r' r' i''' T
STA :;!i:t
....,....,,......,.,
•'"'/'(''** .-•' r'
.*'' l'*' .''.''' r'* »''
.'•"' .«• '" _ , - •
/''..••'"' ,'•-'''_..' ,'•' I1'
.•' ' .-•' ••''
.••' .•' .•'
.:'.'.'.....,>'.'. :'.!....1STA :r.;i
i
Figure 8. Comparison of Total Ortho Phosphorus (mg/1) in Back Bay (as mean of eachstation for period April, 1986 to March, 1987) with EPA "Reference Level",
STARTING DATE 86/4 /28 SAMPLE DATE
Figure 9. Monthly level of Total Suspended Solids (mg/1)at Station 3, Back Bay from April, 1986 to March, 1987.
TlH-
00c1-1fD 00530 RESIDUE TOT NFLT MG/L
40 •0 120 160
o3rt
ol-tl
Hort03
C/3Cw
O.fDCL
C/3O
D.cn
300
03rt
03rtH-O3
oo
ooo>
O
</>rnTJ
m
amo
200—t—
240
—4—
03n?r
a?•<l-h
O mCD
00
rtO
03"Inrr
•30
00
o
UJ3ato111a:
onv>oo
STARTING DATE 86/4 728SAMPLE DATE
Figure 11. Monthly level of Total Suspended Solids (mg/l) at Station 9,' Back Bay from April, 1986 to March, 1987.
1M?
ow
X(3
S
Z
»—O
UJr>oinUJa:
oninoo
NAY I JUN I JUL I AUG I SEP \T I MOV I DEC MAR I APR
STARTING DATE 86/4 /28SAMPLE DATE
Figure 12. Monthly level of Total Suspended Solids (mg/1) at Station 14, Back Bay from April, 1986 to March, 1987.
1987
Xo
UJr>a»-•toUJoc.
ofOinoo
STARTING DATE 86/4 728SAMPLE DATE
Figure 13. Monthly level of Total Suspended Solids (mg/1) at Station 20, Back Bay from April, 1986 to March, 1987.
E oo 4.
UJz>oV)UJ
oroinoo
I OCT I NOV I
1987
HAT I JUN I JUL I AUG I SEP DEC JAN I FEB MAR APR
STARTING DATE 86/4 /28SAMPLE DATE
Figure 14. Monthly level of Total Suspended Solids (mg/1) at Station 22, Back Bay from April, 1986 to March, 1987.
1987
* 4-n To
UJr>a
IDroinoo
STARTING DATE 86/4 728SAMPLE DATE
Figure 15. Monthly level of Volatile Suspended Solids (mg/1) at Station 3, Back Bay from April, 1986 to March, 1987.
1M7
X0
UJ30
COUJa:
10ninoo
STARTING DATE 86/4 728SAMPLE DATE
Figure 16. Monthly level of Volatile Suspended Solids (rag/1) at Station 5, Back Bay from April, 1986 to March, 1987,
O
o>
UJ=>Q
V)UlQC
r>inoo
1987
MAY JUN I JUL I AUG ISEP I OCT I NOV I DEC JAN i FEB I MAR I APR IMAY
STARTING DATE 86/4 /28SAHPLE DATE
Figure 17. Monthly level of Volatile Suspended Solids (mg/1) at Station 9, Back Bay from April, 1986 to March, 1987,
00C
00 00535 RESIDUE VOL NFLT MG/L
00
IMF
Xo
tu3Q
Ul1C
V>n10oo
STARTING DATE 86/4 /28SAMPLE DATE
Figur^ 19. Monthly level of Volatile Suspended Solids (mg/1) at Station 20, Back Bay from April, 1986 to March, 1987.
1987
o
Z
_lO
UJr>oCOUJcr
tof>tooo
STARTING DATE 86/4 /28SAMPLE DATE
Figure 20. Monthly level of Volatile Suspended Solids (mg/1) at Station 22, Back Bay from April, 1986 to March, 1987.
00cnCO
00540 RESIDUE FIX NFLT MG/L
o3
fD<CD
Xroa.
cw
T3fD3a.fDO-
Q.W
ao
ffl
CDrt0)rfH-O3
UJ
td03n
Cd01
o
140
oo
rtO
3
Otr
oo
S .
(9
ow
X••*u.
Ulr>o
UJac
8
o . .
utoo
Iff 7
STARTING DATE 86/4 /28SAMPLE DATE
Figure 22. Monthly level of Fixed Suspended Solids (mg/1) at Station 5, Back Bay from April, 1986 to March, 1987.
3
xu.
UJr>a»•*
V)(Ua:
oo
s
o . .
e ..
inoo
MAY JUN I JUL AUG I SEP OCT I NOV DEC MAR APR IhAYSAMPLE DATE
STARTING DATE 86/4 /28
Figure 23. Monthly level of Fixed Suspended Solids (mg/1) at Station 9, Back Bay from April, 1986 to March, 1987.
19S7
on
X
U-
LUOa»•«
V)UJa:
inoo
STARTING DATE 86/4 /28SAMPLE DATE
Figure 24. Monthly level of Fixed Suspended Solids (mg/1) at Station 14, Back Bay from April, 1986 to March, 1987.
N.O
X o•— MU.
UJ3a
UJac
oo
DEC JAN I FEB
STARTING DATE 86/4 /28SAMPLE DATE
Figure 25. Monthly level of Fixed Suspended Solids (mg/1) at Station 20, Back Bay from April, 1986 to March, 1987,
8.
o 2
o .
-I Ou_ *
X.
Uu
HI3O
wUl
V)oo
JAN FEB MAR APR MAY
\997
STARTING DATE 86/4 /28SAMPLE DATE
Figure 26. Monthly level of Fixed Suspended Solids (mg/1) at Station 22, Back Bay from April, 1986 to March, 1987.
STARTING DATE 86/4 /28SAMPLE DATE
1M7
O
O
Mr>
»—O
IMO
inu>oo
MAY JUN JUL AUG SEP OCT NOV DEC JAN I FEB I MAR APR MAY
STARTING DATE 86/4 /28SAMPLE DATE
Figure 28. Monthly level of Nitrite as Nitrogen (mg/1) at Station 5, Back Bay from April, 1986 to March, 1987.
r>O
o
•>f»
i<MO
V)
<0OO
MAY JUN I JUL I AUG I SEP i OCT I NOV I DEC JAN IFEB I MAR I APR JMAY
STARTING DATE 86/4 /28SAMPLE DATE
Figure 29. Monthly level of Nitrite as Nitrogen (rag/1) at Station 9, Back Bay from April, 1986 to March, 1987.
r>O
Ow
ICMO
to
OO
JAN MAR APR MAY
STARTING DATE 86/4 728SAMPLE DATE
Figure 30. Monthly level of Nitrite as Nitrogen (mg/1) at Station 14, Back Bay from April, 1986 to March, 1987.
r»O
v.O
<
»—O
zI<MO
«ntooO
MAY I JUN I JUL i AUG I SEP I OCT I NOV I DEC
1987
JAN I FEB I HAR I APR IflAY
STARTING DATE 86/4 728SAMPLE DATE
Figure 31. Monthly level of Nitrite as Nitrogen (mg/1) at Station 20, Back Bay fro April, 1986 to March, 1987,
r»O
x ;
o
CM . .
t—o
I<MO
in
oo
-fHAY I JUN I JUL I AUG I SEP j OCT j NOV I DEC JAN FEB I MAR I APR M A Y i
STARTING DATE 86/4 /28SAMPLE DAI£
Figure 32. Monthly level of Nitrite as Nitrogen (mg/1) at Station 22, Back Bay from April, 1986 to March, 1987.
f»o
Xo
8o
I—o
iroo
oCM<OOO
o6
oo
s
IM7
MAY JUN JUL I AUG SEP I OCT I NOV I DEC JAN i FEB I MAR I APR MAY
STARTING DATE 86/4 /28SAMPLE DATE
Figure 33. Monthly level of Nitrate as Nitrogen (mg/1) at Station 3, Back Bay from April, 1986 to March, 1987.
wr»
Xo
wo
t—O
o<M(0OO
wo
§
1M7
MAY JUN JUL AUG I SEP I OCT I NOV DE(L jJAH_LFEB MAR APR IMAY
STARTING DATE 86/4 /28SAMPLE DATE
Figure 34. Monthly level of Nitrate as Nitrogen (mg/1) at Station 5, Back Bay from April, 1986 to March 1987.
V.o
f»o
<»—o
8 5
<ooo 3
1987
MAY JUN | JUL I AUG 1 SEP I OCT I NOV I DEC JAN I FEB MAR APR MAY
STARTING DATE 86/4 728SAMPLE DATE
Figure 35. Monthly level of Nitrate as Nitrogen (mg/1) at Station 9, Back Bay from April, 1986 to March, 1987
XO *)
N
o
»-o
Ino
oCM<£>OO
K.O
A A
MAY JUN JUL I AUG I SEP OCT I NOV DEC JAN FEB I hAR I APR |MAY
STARTING DATE 86/4 /28SAMPLE DATE
Figure 36. Monthly level of Nitrate as Nitrogen (mg/1) at Station 14, Back Bay from April, 1986 to March, 1987.
V.o
8o
<»—o
Ino
oc\tooo
So
S
MAY I JUN JUL I AUG SEP OCT I NOV DEC
IM7
JAN I FEB I MAR APR MAY
STARTING DATE 86/4 728SAMPLE DATE
Figure 37. Monthly level of Nitrate as Nitrogen (mg/1) at Station 20, Back Bay from April, 1986 to March, 1987.
ofto
N
6
i—o
iroo
o<M<ooo
so
oo
MAY I JUN I JUL I AUG I SEP I OCT I NOV I DEC I JAN FEB MAR I APR MAYSAMPLE DATE
STARTING DATE 86/4 /28
Figure 38. Monthly level of Nitrite as Nitrogen (rag/1) at Station 22, Back Bay from April, 1986'to March, 1987.
1987
O
UJ
in<M<ooo
STARTING DATE 86/4 728SAMPLE DATE
Figure 39. Monthly level of TKN (mg/1) at Station 3, Back Bay from April, 1986 to march, 1987.
CD
UJ-5
inCM«ooo
STARTING DATE 86/4 /28SAMPLE DATE
Figure 40. Monthly level of TKN (mg/1) at Station 5, Back Bay from April, 1986 to March, 1987.
Xo
oFt
M
N
O•N
IU
in<M«ooo
HAY I JUN I JUL I AUG I SEP I OCT I NOV I DEC
1987
JAN j FEB I HAR I APR
STARTING DATE 86/4 728SAMPLE DATE
Figure 41. Monthly level of TKN (mg/1) at Station 9, Back Bay from April, 1986 to March, 1987.
1987
O
UJ
to01(OOO
JAN FEB MAR APR
STARTING DATE 86/4 /28SAMPLE DATE
Figure 42. Monthly level of TKN (mg/1) at Station 14, Back Bay from April, 1986 to March, 1987.
19«7
STARTING DATE 86/4 728SAMPLE DATE
Figure 43. Monthly level of TKN (mg/1) at Station 20, Back Bay from April, 1986 to March, 1987.
1987
J
O
UJ
inCslu>oo
STARTING DATE 86/4 /28SAMPLE DATE
Figure 44. Monthly level of TKN (mg/1) at Station 22, Back Bay from April, 1986 to March, 1987.
Xo
t—o
M
6
z onx.
N
O
U>OO
HAY I JUN [ JUL AUG | SEP I OCT I NOV I DEC JAN I FEB MAR I APR MAY
STARTING DATE 86/4 /28SAMPLE DATE
Figure 45. Monthly level of Ammonia as Nitrogen (mg/1) at Station 3, Back Bay from April, 1986 to March 1987.
1987
Xo
»—o
u>oo
MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY
STARTING DATE 86/4 728SAMPLE DATE
Figure 46. Monthly level of Ammonia as Nitrogen (mg/1) at Station 5, Back Bay from April, 1986 to March, 1987.
Xo
no
tn
<0OO o
o
MAY JUN I JUL I AUG I SEP I OCT I NOV I DEC JAN FEB I MAR I APR |MAY
STARTING DATE 86/4 728SAMPLE DATE
Figure 47. Monthly level of Ammonia as Nitrogen (mg/1) at Station 9, Back Bay from April, 1986 to March, 1987.
Xo
<I—o
no
•fro
<ooo
MAY JUN JUL I AUG I SEP I OCT I NOV DEC
1M7
JAN I FEB I MAR APR IMAY
STARTING DATE 86/4 728SAMPLE DATE
Figure 48. Monthly level of Ammonia as Nitrogen (rag/1) at Station 14, Back Bay^ from April, 1986 to March, 1987.
1987
STARTING DATE 86/4 /28SAMPLE DATE
Figure 49. Monthly level of Ammonia as Nitrogen (mg/1) at Station 20, Back Bay from April, 1986 to March, 1987.
Xo
Mo
»—O
Xzn
rto
<OOO
MAY JUN JUL I AUG I SEP I OCT I NOV DEC JAN I FEB MAR APR MAY
STARTING DATE 86/4 /28SAMPLE DATE
Figure 50. Monthly level of Ammonia as Nitrogen (mg/1) at Station 22, Back Bay from April, 1986 to March 1987.
N.C3
ICOOXCL
inu><ooo
oo
no
oo
MAY JUN I JUL I AUG | SEP I OCT I NOV I DEC JAN JFEB MAR I APR
STARTING DATE 86/4 728SAMPLE DATE
Figure 51. Monthly level of Total Phosphorus as P (mg/1) at Station 3, Back Bay from April, 86 to March, 1987.
o
Itoo
inu><ooo
1987
MAY I JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR I APR
STARTING DATE 86/4 /28SAMPLE DATE
Figure 52. Monthly level of Total Phosphorus as P (mg/1) at Station 5, Back Bay from April, 1986 to March, 1987.
oz:
i05OXQ_
in(D«0OO
(M
O
O
O
O•
O
no
1987
MAYL I JUN I JUL I AUG I SEP I OCT i NOV I DEC JAN I FEB MAR I APR
STARTING DATE 86/4 /28SAMPLE DATE
Figure 53. Monthly level of Total Phosphorus as P (mg/1) at Station 9, Back Bay from April, 1986 to March, 1987.
(9z:
oXQ_
V)<O<DOo
m
o
N
o
oo
o
r>o
s
198?
MAY | JUN I JUL I AU6 I SEP \T I NOV I DEC MAR IAPRSTARTING DATE 86/4 /28
SAMPLE DATE
Figure 54. Monthly level of Total Phosphorus as P (mg/1) at Station 14, Back Bay from April, 1986 to March, 1987.
XC9
ot—Io0.
in<ou>oo
W
O
oM
10
O
CM
O
O
o
oo
g
1987
HAY I JUN | JUL | AUG I SEP I OCT I NOV DEC JAN FEB MAR APR
STARTING DATE 86/4 /28SAMPLE DATE
Figure 55. Monthly level of Total Phosphorus as P (mg/1) at Station 20, Back Bay from April, 1986 to March, 1987.
o
ICOoXa.
10<ou>oo
r>o
s
1987
HAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR I APR
STARTING DATE 86/4 /28SAMPLE DATE
Figure 56. Monthly level of Total Phosphorus as P (mg/1) at Station 22, Back Bay from April, 1986 to March 1987.
I 917
O
OI
Vt
aiV)o
N.(Ooo §
JUL. i_ AUG
STARTING DATE 86/4 728SAMPLE DATE
Figure 57. Monthly level of Ortho Phosphorus as P (mg/1) at Station 3, Back Bay from April, 1986 to March, 1987.
1M7
xo
o»—a:o
V)
oiwoX.0_
N.U>OO g
STARTING DATE 86/4 /28SAMPLE DATE
Figure 58. Monthly level of Ortho Phosphorus as P (mg/1) at Station 5, Back Bay froitApril, 1986 to March, 1987.
1987
Xo
oX
OI
(AOzOL
(OOO
STARTING DATE 86/4 728SAMPLE DATE
Figure 59. Monthly level of Ortho Phosphorus as P (mg/1) at Station 9, Back Bay from April, 1986 to March, 1987.
0
oX
M
aiV)oT.a.
K.toOo
oo
o*o
Is.O
O
o
mo
o•o
oo
MO
1987
MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAT
STARTING DATE 86/4 /28SAMPLE DATE
Figure 60. Monthly level of Ortho Phosphorus as P (mg/1) at Station 14, Back Bay from April, 1986 to March, 1987.
I9i7
O
OIOX0-
N.<OOO
I O C T \ 1 C
S
STARTING DATE 86/4 728SAMPLE DATE
Figure 61. Monthly level of Ortho Phosphorus as P (mg/1) at Station 20, Back Bay from April, 1986 to March 1987.
H-00Ci-tCD
ON
O3rf3*
ro<fD
rt3"O
Oen
^3troi-!CCO
03en
00
COrt03rtH-O3
NJK3
W03n
i-hi-iO
•a
oo
03i-tnET
00671
0.00 0.01
PHOS-DIS ORTHO MG/L P
0.02 0.03 0.04 0.05 0.06 0.07 0.0*
00