Table 6.  Concentrations of nutrients in samples collected at the urban indicator site, Salado Creek (lower station) at San Antonio

[ft3/s, cubic feet per second; mg/L, milligrams per liter; <, less than: MDL, method detection limit]
Date Dis-
charge
(ft3/s)		 Nitrogen,
ammonia,
dis-
solved
(mg/L)		 Nitrogen,
nitrite,
dis-
solved
(mg/L)		 Nitrogen,
ammonia
plus
organic,
dissolved
(mg/L)		 Nitrogen,
ammonia
plus
organic,
total
(mg/L)		 Nitrogen,
nitrite
plus
nitrate,
dissolved
(mg/L)		 Phos-
phorus,
total
(mg/L)		 Phos-
phorus,
dis-
solved
(mg/L)		 Phos-
phorus,
ortho-
phosphate,
dissolved
(mg/L)
04-22-96

4

0.11  

 0.01  

0.3  

0.5  

0.31

0.1

0.04

0.03
05-21-96

1

.15  

   .02  

.3  

.6  

  .3

  .2

  .07

.08
06-27-96

9

.1    

  .05  

.4  

.7  

  .6

  .15

  .07

.06
07-29-96

1

.12  

 <.010

.4  

.7  

  .2

  .12

  .03

.04
09-03-96

2

.05  

   .02  

.3  

.4  

  .39

  .07

  .04

.06
10-15-96

3

.07  

   .02  

.2  

.3  

  .2

  .05

  .04

.04
11-06-96

2

.03  

   .01  

<.20

.2  

  .09

  .03

  .04

.03
12-05-96

11

.03  

   .01  

<.20

.3  

  .38

  .08

  .06

.04
01-23-97

4

<.015

   .03  

<.2   

.4  

  .25

  .06

  .02

<.010
02-07-97

4

.02  

   .01  

.3   

.4  

  .16

  .04

<.010

<.010
02-20-97

24

<.015

   .03  

.3  

.4  

  .5

  .04

  .01

.02
03-06-97

6

.08  

   .02  

.3  

.4  

  .57

  .08

  .07

.06
03-20-97

11

.07  

   .03  

.3  

.3  

  .5

  .12

  .11

.04
04-09-97

12

.087

   .037

.37

.51 

  .713

  .102

  .065

.075
04-16-97

7

.036

   .022

.27

.37 

  .638

  .071

  .057

.067
04-23-97

6

.052

 <.010

.23

.3   

  .427

  .081

  .077

.052
04-26-97

834

.123

   .023

.35

1.7  

  .506

  .528

  .096

.099
05-02-97

21

.047

   .021

.3  

.23

  .825

  .085

  .069

.073
05-07-97

17

.04  

   .02   

<.20

.32

  .685

  .055

  .038

.07
05-14-97

23

.056

   .032

.24

.38

  .367

  .092

  .065

.064
05-22-97

21

.047

   .019

.34

.48

  .559

  .15

  .109

.084
05-27-97

15

.055

   .021

.37

.4  

  .551

  .121

  .109

.084
06-02-97

10

.02  

   .01   

.26

.3  

  .413

  .126

  .065

.078
06-17-97

24

.029

   .015

.26

.42

  .517

  .111

  .073

.071
07-03-97

68

<.015

    .011

.35

.24

  .602

  .025

  .016

.027
07-14-97

31

<.015

 <.010

<.20

<.20

  .975

  .013

<.010

.027
07-22-97

27

.026

 <.010

.27

.29

  .862

  .047

 .031

.031
07-29-97

21

<.015

 <.010

<.20

<.20

  .742

  .019

  .042

.026
08-06-97

5

.023

   .011

<.20

<.20

  .604

<.010

<.010

.016
08-12-97

6

.03  

 <.010

<.20

.34

  .339

  .016

  .03

.029
08-21-97

12

<.015

 .01 

<.20

<.20

  .548

  .057

  .029

.025
08-27-97

13

.015

 <.010

<.20

<.20

  .56   

  .028

  .021

.022
09-03-97

12

.018

 <.010

<.20

<.20

  .433

  .016

  .025

.016
09-09-97

10

<.015

 <.010

<.20

.21

  .651

  .016

  .015

.024
09-17-97

15

<.015

 <.010

.23

<.20

  .836

  .022

  .023

.03  
09-25-97

25

.017

 <.010

<.20

.28

  .784

  .093

  .027

.037
10-22-97

21

<.015

 <.010

<.20

<.20

1.16

  .034

  .027

.027
Change in MDL for nitrogen, ammonia, dissolved; nitrogen, ammonia plus organic, dissolved; and nitrogen, ammonia plus organic, total for the following analyses; see table 4
10-28-97

22

<.020

 <.010

<.10

.13

1.12

  .035

  .01

.023
11-06-97

18

<.020

 .039

<.10

  .1  

1.14

  .021

<.010

.016
11-19-97

26

.362

 <.010

.14

.16

1.11

  .054

  .029

.042
12-10-97

21

<.020

 <.010

<.10

<.10

  .904

  .031

<.010

.018
12-17-97

14

<.020

   .034

<.10

.14

  .834

  .066

  .061

.038
12-20-97

1,230

<.020

   .021

.26

1.4

  .629

  .456

  .085

.072
01-06-98

1,180

<.020

 <.010

.26

.44

  .565

  .114

  .041

.064
01-12-98

25

<.020

 <.010

.17

.25

1.05

  .079

  .058

.053
01-22-98

22

<.020

   .015

<.10

.13

1.1    

  .032

  .01

.028
01-31-98

1,190

.036

   .011

.35

1.4   

  .726

  .371

  .057

.052
02-19-98

18

<.020

 <.010

.22

.33

  .406

  .059

  .035

.039
02-21-98

1,210

.052

 <.010

.27

1.4   

  .443

  .436

  .075

.069
03-16-98

1,070

.036

   .056

.36

2     

  .459

  .545

  .079

.083
03-23-98

31

.04   

 <.010

.19

.31

  .517

  .04

  .023

.027
04-27-98

10

.033

 <.010

.26

.26

<.050

  .038

  .026

<.010

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