Figure 2. (upper) The cumulative flow excess or deficiency – how much each water year’s flow (measured in inches of runoff at Foster Park) varied from

-60

-50

-40

-30

-20

-10

0

10

20

30

1930 1940 1950 1960 1970 1980 1990 2000

cum

ula

tive

dep

artu

re fr

om

th

e m

ean

(i

nch

es)

0

10

20

30

40

50

60

"big

yea

r" r

ain

fall

(in

ches

)

big years Ventura-flow

-50

50

150

250

350

1930 1940 1950 1960 1970 1980 1990 2000

vari

atio

n f

rom

med

ian

an

nu

al f

low

(c

fs)

median annual flow = 18.5 cfs

Figure 2. (upper) The cumulative flow excess or deficiency – how much each water year’s flow (measured in inches of runoff at Foster Park) varied from the 4.98 inch overall average. The plot shows the same pattern of rising and falling trends, heavily influenced by big years, as rainfall. Big years, in this chart, represent Ojai rainfall above 31.5 inches. (lower) Median annual flow on the Ventura (at Foster Park) is 18.5 cfs, i.e., half the years on the chart had average flows less than this, the other half were greater. The distribution is skewed – “above the median” years tend to be really big. While not a “big year,” slightly above-average rainfall in 2006 reinforced increased groundwater inflows from 2005 giving appreciably enhanced flows (annual average = 72 cfs) this past summer.

0

2

4

6

8

10

12

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

mo

nth

ly r

ain

fall

(in

ches

)

0

2

4

6

8

10

12

average

2001

2002

2003

2004

2005

2006

0

5

10

15

20

25

30

35

40

2001 2002 2003 2004 2005 2006

an

nu

al r

ain

fall

(in

ch

es

)O

ct. t

o S

ept.

Figure 4. Monthly (upper panel) and yearly (lower panel, for Oct. to Sept. water years) rainfall for 2006 and previous years of the ChannelKeeper Ventura Stream-team survey (Ventura COOP station, 049285-6, http://www.calclim.dri.edu/ccda/scacoop.html). The heavy line in the lower panel represents the average annual Ventura rainfall of 14 inches. While rainfall in 2006 rainfall was not as remarkable as that of 2005, it was an above average year (17.8 inches) with an extremely wet spring; April rainfall was 4.6 inches, the second wettest in since 1874) and far above the median of 0.55 inches (half of Ventura’s April’s have been wetter than this, half drier).

Figure 5. In the upper panel, annual rainfall (in Ventura) is plotted for the severe El Niño year of 1998 and every year since, along with average June, July, August and September flows at Foster Park in cfs for each year (shown on the right-hand axis); the median rainfall and monthly flows are included for comparison. Rainfall is again plotted in the lower panel, but the right-hand scale now shows the ratio between average May through September flow and rainfall, i.e., the ratio between average dry-season flow and rainfall. The bold lines show the trend towards less flow per inch of rain as we get further from a large El Niño; it required two years of above average rainfall (2000 and 2001) to partially recover from low rainfall in 1999. River flow in 2004 is as low as it was in 2000, is spite of having approximately 5-times the rainfall. In contrast, 2006 shows an increase in the ratio, more runoff than expected, the result of a wet spring and two good years in a row enhancing groundwater supplies.

0

10

20

30

40

1998 1999 2000 2001 2002 2003 2004 2005 2006 median

ann

ual

rai

nfa

ll (

inch

es)

0

20

40

60

mo

nth

ly f

low

(cf

s)

rainfall

Jun

Jul

Aug

Sep

158

0

10

20

30

40

1998 1999 2000 2001 2002 2003 2004 2005 2006

ann

ual

rai

nfa

ll (

inch

es)

0

1

2

3

4

dry

-sea

son

flo

w :

rai

nfa

ll r

atio

(cfs

/in

ch)

rainfall ratio

Figure 6. Monthly conductivities for the Ventura sampling locations during the 2006 water year are shown with along with the average monthly conductivity during 2001 through 2005; error bars indicate the monthly standard deviation in µS/cm.

0

500

1000

1500

2000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR01

0

500

1000

1500

2000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR02

0

500

1000

1500

2000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR03

0

500

1000

1500


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR06

0

500

1000

1500

2000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR07

0

1000

2000

3000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR08

0

2000

4000

6000

8000


con

du

ctiv

ity

(µS

/cm

)mean

2006VR04

0

2000

4000

6000

8000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR05

Figure 6 cont. Monthly conductivies for the Ventura sampling locations during the 2006 water year are shown with along with the average monthly conductivity during 2001 through 2005; error bars indicate the monthly standard deviation in µS/cm.

0

500

1000

1500

2000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR09

0

500

1000

1500

2000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR10

0

500

1000

1500


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR13

0

500

1000

1500


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR14

0

500

1000

1500


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR15

0

500

1000

1500

2000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR11

0

500

1000

1500

2000


con

du

ctiv

ity

(µS

/cm

)

mean

2006VR12

Figure 7. Median conductivities during the 2006 water year are contrasted with median conductivity for the pervious five years (2001-2005). The “error bars” indicate twice the standard error of the median, i.e., the 2006 median would be expected to lie within these error bars and anything outside the limits could indicate a significant change (only 1 out of every 20 years would be expected to naturally fall outside of ± 2 standard errors). Note that 2006 conductivity at locations with year-round water is generally below these limits. The horizontal line represents a generally accepted upper conductivity limit of 1600 µS/cm for drinking water.

0

1,000

2,000

3,000

4,000

VR01 VR02 VR03 VR04 VR05 VR06 VR07 VR08 VR09 VR10 VR11 VR12 VR13 VR14 VR15

con

du

ctiv

ity

(µS

/cm

)20

01-2

005,

200

6 m

edia

ns

700

900

1100

1300

1500

VR06 VR07 VR10 VR14 VR15

stan

dar

d c

on

du

ctiv

ity

(µS

/cm

)w

ate

r y

ea

r m

ed

ian

s

2001 20022003 20042005 2006

Figure 8. Changes in annual median conductivity for Ventura River sampling sites with relatively natural, year-round flows: 2001 through 2006. There had been a consistent increase in conductivity over the initial four years of sampling: the percent increase from 2001 through 2004 at VR06 through VR15 was 12, 23, 19, 25 and 19 %, respectively. However, in 2005 conductivity abruptly decreased by 20 % throughout the Ventura system. In 2006 conductivity generally increased at upper elevation sites (VR14 & 15) and decreased at the lower (VR06 & 07).

0

5

10

15

20

25

30


tem

per

atu

re (

°C)

mean

2006VR01

0

5

10

15

20

25


tem

per

atu

re (

°C)

mean

2006VR02

0

5

10

15

20

25


tem

per

atu

re (

°C)

mean

2006VR03

0

5

10

15

20

25

30


tem

per

atu

re (

°C)

mean

2006VR04

0

10

20

30

40


tem

per

atu

re (

°C)

mean

2006VR05

0

5

10

15

20

25


tem

per

atu

re (

°C)

mean

2006VR06

0

5

10

15

20

25


tem

per

atu

re (

°C)

mean

2006VR07

0

5

10

15

20

25

30


tem

per

atu

re (

°C)

mean

2006VR08

Figure 9. Monthly water temperatures for the Ventura sampling locations during the 2006 water year are shown with along with the average monthly temperature from 2001 through 2005; error bars indicate the monthly standard deviation in °C.

0

5

10

15

20

25


tem

pe

ratu

re (

°C)

mean

2006VR09

0

5

10

15

20

25


tem

pe

ratu

re (

°C)

mean

2006VR10

0

5

10

15

20

25

30


tem

pe

ratu

re (

°C)

mean

2006VR11

0

5

10

15

20

25


tem

pe

ratu

re (

°C)

mean

2006VR12

0

5

10

15

20

25

30


tem

pe

ratu

re (

°C)

mean

2006VR13

0

5

10

15

20

25


tem

pe

ratu

re (

°C)

mean

2006VR14

0

5

10

15

20

25

30


tem

pe

ratu

re (

°C)

mean

2006VR15

Figure 9 cont. Monthly water temperatures for the Ventura sampling locations during the 2006 water year are shown with along with the average monthly temperature from 2001 through 2005; error bars indicate the monthly standard deviation in °C.

0

3

6

9

12

15

18


dis

so

lve

d o

xy

ge

n (

mg

/L)

mean

2006VR01

0

3

6

9

12

15

18


dis

so

lve

d o

xy

ge

n (

mg

/L)

mean

2006VR02

0

3

6

9

12

15

18


dis

so

lve

d o

xy

ge

n (

mg

/L)

mean

2006VR030

3

6

9

12

15

18


dis

so

lve

d o

xy

ge

n (

mg

/L)

mean

2006VR04

0

3

6

9

12

15

18


dis

so

lve

d o

xy

ge

n (

mg

/L)

mean

2006VR05

0

3

6

9

12

15

18


dis

so

lve

d o

xy

ge

n (

mg

/L)

mean

2006VR06

0

3

6

9

12

15

18


dis

so

lve

d o

xy

ge

n (

mg

/L)

mean

2006VR07

0

3

6

9

12

15

18


dis

so

lve

d o

xy

ge

n (

mg

/L)

mean

2006VR08

Figure 10. Monthly dissolved oxygen concentrations for the Ventura sampling locations during the 2006 water year are shown with along with the average monthly dissolved oxygen from 2001 through 2005; error bars indicate the monthly standard deviation in mg/L.

Figure 10 cont. Monthly dissolved oxygen concentrations for the Ventura sampling locations during the 2006 water year are shown with along with the average monthly dissolved oxygen from 2001 through 2005; error bars indicate the monthly standard deviation in mg/L.

0

3

6

9

12

15


dis

solv

ed o

xyg

en (

mg

/L)

mean

2006VR09

0

3

6

9

12

15


dis

solv

ed o

xyg

en (

mg

/L)

mean

2006VR10

0

3

6

9

12

15


dis

solv

ed o

xyg

en (

mg

/L)

mean

2006VR11

0

3

6

9

12

15


dis

solv

ed o

xyg

en (

mg

/L)

mean

2006VR12

0

3

6

9

12

15


dis

solv

ed o

xyg

en (

mg

/L)

mean

2006VR13

0

3

6

9

12

15


dis

solv

ed o

xyg

en (

mg

/L)

mean

2006VR14

0

3

6

9

12

15

18


dis

solv

ed o

xyg

en (

mg

/L)

mean

2006VR15

Figure 11. (upper panel) Average dissolved oxygen concentrations for the Ventura sampling locations during the 2006 water year are contrasted with mean dissolved oxygen from 2001 through 2005; error bars indicate the maximum and minimum concentrations for each average. The 3 horizontal lines mark important DO milestones; above 8 mg/L represents near ideal conditions; at 6 hypoxia begins and fish start to feel stress (but no lasting harm is done in the short term); and below 4 lies severe damage and death. (lower panel) Average 2006 stream temperature contrasted with mean temperature from 2001 through 2005; error bars again indicate maximum and minimum temperatures. The lines represent temperature milestones: above 24 °C leads to death; below 16 °C indicates good dry season conditions; and below 11 °C is excellent for spawning and incubation. Extreme values become critical at locations with measurements below (for DO) or above (for temperature) the red line

0

5

10

15

20


dis

solv

ed o

xyg

en (

mg

/L)

mean (2001-2005)2006

0

5

10

15

20

25

30

35


stre

am t

emp

erat

ure

(°C

)

mean (2001-2005)2006

0

50

100

150

200


dis

solv

ed o

xyg

en (

% s

at)

mean

2006VR01

0

50

100

150

200


dis

solv

ed o

xyg

en (

% s

at)

mean

2006VR02

0

50

100

150

200


dis

solv

ed o

xyg

en (

% s

at)

mean

2006VR03

0

50

100

150

200


dis

solv

ed o

xyg

en (

% s

at)

mean

2006VR04

0

50

100

150

200


dis

solv

ed o

xyg

en (

% s

at)

mean

2006VR05

0

50

100

150

200


dis

solv

ed o

xyg

en (

% s

at)

mean

2006VR06

0

50

100

150

200


dis

solv

ed o

xyg

en (

% s

at)

mean

2006VR07

0

50

100

150

200


dis

solv

ed o

xyg

en (

% s

at)

mean

2006VR08

Figure 12. Monthly dissolved oxygen concentrations in percent saturation for the Ventura sampling locations during the 2006 water year are shown with along with the average saturation from 2001 through 2005; error bars indicate the monthly standard deviation.

Figure 12 cont. Monthly dissolved oxygen concentrations in percent saturation for the Ventura sampling locations during the 2006 water year are shown with along with the average saturation from 2001 through 2005; error bars indicate the monthly standard deviation.

0

50

100

150

200


dis

so

lved

ox

yge

n (

% s

at)

mean

2006VR09

0

50

100

150

200


dis

so

lved

ox

yge

n (

% s

at)

mean

2006VR10

0

50

100

150

200


dis

so

lved

ox

yge

n (

% s

at)

mean

2006VR11

0

50

100

150

200


dis

so

lved

ox

yge

n (

% s

at)

mean

2006VR12

0

50

100

150

200


dis

so

lved

ox

yge

n (

% s

at)

mean

2006VR13

0

50

100

150

200


dis

so

lved

ox

yge

n (

% s

at)

mean

2006VR14

0

50

100

150

200


dis

so

lved

ox

yge

n (

% s

at)

mean

2006VR15

0

50

100

150

200

VR01VR02

VR03VR04

VR05VR06

VR07VR08

VR09VR10

VR11VR12

VR13VR14

VR15

dis

so

lved

ox

yge

n (

% s

at)

mean (2001-2005)2006

Figure 14. Average dissolved oxygen (in percent saturation) during the 2006 water year is contrasted with average values from 2001 through 2005. Concentrations above 120 % saturation (red line) usually indicate problems with algal growth: over saturation during daylight followed by depleted concentrations at night. The error bars indicate the maximum and minimum percent saturation at each site.

Figure 15. Geomean turbidity during the 2006 water year is contrasted with the geomean of all measurements from 2001 through 2006: error bars indicate the 95 % confidence interval for the geomean. Two of the horizontal lines mark typical Public Health drinking water quality benchmarks: a maximum turbidity of 5 NTU and no more than 5 % of monthly samples with greater than 0.5 NTU. The red line indicates the EPA’s proposed ecological limit for maximum (non-storm) turbidity in streams of this region: 1.9 NTU.

0.01

0.1

1

10

100

VR01VR02

VR03VR04

VR05VR06

VR07VR08

VR09VR10

VR11VR12

VR13VR14

VR15

turb

idit

y (

NT

U)

20

01

-20

05

, 20

06

ge

om

ea

ns

geomean (2001-2005)2006

7

8

9


pH

mean

2006

VR01

7

8

9


pH

mean

2006

VR02

7

8

9


pH

mean

2006VR037

8

9


pH

mean

2006VR04

6

7

8

9


pH

mean

2006VR05

7

8

9


pH

mean

2006

VR06

7

8

9


pH

mean

2006

VR07

7

8

9


pH

mean

2006

VR08

Figure 16. Monthly pH values for the Ventura sampling locations during the 2006 water year are shown with along with the average pH from 2001 through 2005 (pH of the average H ion concentration); error bars indicate the maximum and minimum values from 2001-2005.

7

8

9


pH

mean

2006

VR09

7

8

9


pH

mean

2006VR10

7

8

9


pH

mean

2006VR11

6

7

8

9


pH

mean

2006

VR12

7

8

9


pH

mean

2006VR13

7

8

9


pH

mean

2006VR14

7

8

9


pH

mean

2006VR15

Figure 16 cont. Monthly pH values for the Ventura sampling locations during the 2006 water year are shown with along with the average pH from 2001 through 2005 (pH of the average H ion concentration); error bars indicate the maximum and minimum values from 2001-2005.

7

8

9

OctNov Dec Ja

nFeb M

ar AprM

ay Jun Ju

lAug Sep

pH

0

40

80

120

160

200

% s

atu

rati

on

mean

2006

% sat

VR01

7

8

9

OctNov Dec Ja

nFeb M

ar AprM

ay Jun Ju

lAug Sep

pH

0

40

80

120

160

200

% s

atu

rati

on

mean

2006

% sat

VR02

7

8

9

OctNov Dec Ja

nFeb M

ar AprM

ay Jun Ju

lAug Sep

pH

0

40

80

120

160

200

% s

atu

rati

on

mean

2006

% sat

VR07

7

8

9

OctNov Dec Ja

nFeb M

ar AprM

ay Jun Ju

lAug Sep

pH

0

40

80

120

160

% s

atu

rati

on

mean

2006

% sat

VR08

7

8

9

OctNov Dec Ja

nFeb M

ar AprM

ay Jun Ju

lAug Sep

pH

0

40

80

120

160

% s

atu

rati

on

mean

2006

% sat

VR09

7

8

9

OctNov Dec Ja

nFeb M

ar AprM

ay Jun Ju

lAug Sep

pH

0

40

80

120

160

% s

atu

rati

on

mean

2006

% sat

VR10

7

8

9

OctNov Dec Ja

nFeb M

ar AprM

ay Jun Ju

lAug Sep

pH

0

40

80

120

160

% s

atu

rati

on

mean

2006

% sat

VR13

7

8

9

OctNov Dec Ja

nFeb M

ar AprM

ay Jun Ju

lAug Sep

pH

0

40

80

120

160

% s

atu

rati

on

mean

2006

% sat

VR15

Figure 17. Monthly 2006 % DO saturation values for selected Ventura sampling locations are plotted along with pH data from Figure 16. Since Ventura waters are highly buffered there should be a reasonable correspondence between pH and % saturation – since both increase with daylight photosynthesis. And there generally is, at the lower river sites and elsewhere during the first part of the year. However, at many locations, particularly towards the end of the year, the relationship breaks down.

Figure 18. Average pH during the 2006 water year is contrasted with average values from 2001 through 2005: the “error bars” indicate the highest and lowest values measured for each time period at the sampling locations. The horizontal line represents the Los Angles Regional Water Quality Control Board’s upper pH limit of 8.5 (from the Ventura basin plan). Average pH was computed from the mean hydrogen ion concentration. Concentrations above 120 % saturation (red line) usually indicate problems with algal growth: over saturation during daylight followed by depleted concentrations at night. The error bars indicate the maximum and minimum percent saturation at each site. A pH above 8.5 is usually associated with excessive algal growth.

6.5

7.0

7.5

8.0

8.5

9.0

9.5

VR01VR02

VR03VR04

VR05VR06

VR07VR08

VR09VR10

VR11VR12

VR13VR14

VR15

pH

mean (2001-2005)2006

Figure 19. Monthly nitrate concentrations for the Ventura sampling locations during the 2006 water year are shown with along with average monthly nitrate from 2001 through 2005; error bars indicate the monthly standard deviation in mg/L.

0

1

2

3

4


nit

rate

(m

g/L

)

mean

2006

VR01

0

1

2

3

4


nit

rate

(m

g/L

)

mean

2006

VR02

0

2

4

6


nit

rate

(m

g/L

)

mean

2006

VR03

0

1

2

3


nit

rate

(m

g/L

)

mean

2006

VR06

0

2

4

6


nit

rate

(m

g/L

)

mean

2006

VR07

0

1

2

3


nit

rate

(m

g/L

)

mean

2006

VR08

0

1

2

3

4


nit

rate

(m

g/L

)

mean

2006

VR04

0

2

4

6


nit

rate

(m

g/L

)

mean

2006

VR05

Figure 19 cont. Monthly nitrate concentrations for the Ventura sampling locations during the 2006 water year are shown with along with average monthly nitrate from 2001 through 2005; error bars indicate the monthlyh standard deviation in mg/L.

0

1

2

3

4


nit

rate

(m

g/L

)

mean

2006

VR09

0

2

4

6

8


nit

rate

(m

g/L

)

mean

2006

VR10

0.0

0.2

0.4

0.6


nit

rate

(m

g/L

)

mean

2006

VR13

0.0

0.1

0.2

0.3


nit

rate

(m

g/L

)

mean

2006

VR14

0.0

0.1

0.2

0.3


nit

rate

(m

g/L

)

mean

2006

VR15

0

1

2

3


nit

rate

(m

g/L

)

mean

2006

VR11

0

1

2

3


nit

rate

(m

g/L

)

mean

2006

VR12

Figure 20. Average nitrate concentrations for the Ventura sampling sites during the 2006 water year are contrasted with average concentrations over the pervious five years (2001 through 2005). The “error bars” indicate twice the standard error of the mean, i.e., the 2006 average would be expected to lie within these error bars, anything outside these limits could indicate a significant change. Note that most 2006 locations are generally within or below the error bars. The red horizontal line mark marks the EPA’s proposed limit for maximum nitrate in this region: 0.16 mg/L; the dashed line is the recommended limit for nitrogen (0.52 mg/L). In 2006, nitrate typically made up about 80 % of the total nitrogen in the Ventura system so most sites considerably exceed both the recommended nitrate and total nitrogen amounts. Only the higher elevation, relatively pristine, Matilija sampling points consistantly exhibit low nitrogen.

0.01

0.1

1

10

VR01VR02

VR03VR04

VR05VR06

VR07VR08

VR09VR10

VR11VR12

VR13VR14

VR15

nit

rate

(m

g/L

)2

00

1-2

00

5, 2

00

6 m

ea

ns

mean (2001-2005)2006

0.0

0.5

1.0

1.5


ph

os

ph

ate

(m

g/L

)

mean

2006

VR01

0.0

0.5

1.0

1.5


ph

osp

ha

te (

mg

/L)

mean

2006

VR02

0.0

0.5

1.0

1.5


ph

osp

ha

te (

mg

/L)

mean

2006

VR03

0.0

0.1

0.2

0.3


ph

osp

ha

te (

mg

/L)

mean

2006

VR06

0.0

0.2

0.4

0.6


ph

osp

ha

te (

mg

/L)

mean

2006

VR07

0.0

0.2

0.4

0.6


ph

osp

ha

te (

mg

/L)

mean

2006

VR08

0.0

0.1

0.2

0.3


ph

osp

ha

te (

mg

/L)

mean

2006

VR04

0.0

0.2

0.4

0.6


ph

osp

ha

te (

mg

/L)

mean

2006

VR05

Figure 21. Monthly phosphate concentrations for the Ventura sampling locations during the 2006 water year are shown with along with average monthly phosphate from 2001 through 2005; error bars indicate the monthly standard deviation in mg/L.

Figure 21 cont. Monthly phosphate concentrations for the Ventura sampling locations during the 2006 water year are shown with along with average monthly phosphate from 2001 through 2005; error bars indicate the monthly standard deviation in mg/L.

0.0

0.2

0.4

0.6


ph

osp

ha

te (

mg

/L)

mean

2006

VR09

0.0

0.1

0.2

0.3


ph

osp

ha

te (

mg

/L)

mean

2006

VR10

0.0

0.1

0.2

0.3


ph

osp

ha

te (

mg

/L)

mean

2006

VR13

0.0

0.1

0.2

0.3


ph

osp

ha

te (

mg

/L)

mean

2006

VR14

0.0

0.1

0.2

0.3


ph

osp

ha

te (

mg

/L)

mean

2006

VR15

0.0

0.1

0.2

0.3


ph

osp

ha

te (

mg

/L)

mean

2006

VR11

0.0

0.1

0.2

0.3


ph

osp

ha

te (

mg

/L)

mean

2006

VR12

0.001

0.01

0.1

1


ph

osp

hat

e (m

g/L

)20

01-2

005,

200

6 m

ean

s

mean (2001-2005)2006

Figure 22. Average phosphate concentrations for the Ventura sampling sites during the 2006 water year are contrasted with average concentrations over the pervious five years (2001 through 2005). The “error bars” indicate twice the standard error of the mean, i.e., the 2006 average would be expected to lie within these error bars, anything outside these limits could indicate a significant change. Note that almost all 2006 results are below the error bars indicating unusually low phosphate. The red horizontal line mark marks the EPA’s proposed limit for maximum phosphorus in this region: 0.030 mg/L.

0.0

0.5

1.0

1.5

2.0

Jan-

01

May

-01

Sep-0

1

Jan-

02

May

-02

Sep-0

2

Jan-

03

May

-03

Sep-0

3

Jan-

04

May

-04

Sep-0

4

Jan-

05

May

-05

Sep-0

5

Jan-

06

May

-06

Sep-0

6

ph

osp

hat

e (m

g/L

)VR01 VR02 VR03 VR06

0.0

0.1

0.2

0.3

0.4

0.5

Jan-

01

May

-01

Sep-0

1

Jan-

02

May

-02

Sep-0

2

Jan-

03

May

-03

Sep-0

3

Jan-

04

May

-04

Sep-0

4

Jan-

05

May

-05

Sep-0

5

Jan-

06

May

-06

Sep-0

6

ph

osp

hat

e (m

g/L

)

VR07 VR08

VR09 VR10

0.00

0.05

0.10

0.15

0.20

0.25

Jan-

01

May

-01

Sep-0

1

Jan-

02

May

-02

Sep-0

2

Jan-

03

May

-03

Sep-0

3

Jan-

04

May

-04

Sep-0

4

Jan-

05

May

-05

Sep-0

5

Jan-

06

May

-06

Sep-0

6

ph

osp

hat

e (m

g/L

)

VR13 VR14

VR15

Figure 23. Phosphate concentrations, Jan. 2001 to Aug. 2006: dashed vertical lines mark the start of each water-year. The horizontal line marks the EPA proposed target for maximum phosphorus in this region: 0.030 mg/L (Ecoregion III, sub-region 6). The graphs show phosphate which typically makes up around 90 % of the total phosphorus in the stream. Note that the graphs use different vertical scales.

Figure 24. Median nitrate to phosphate ratios for the Ventura sampling sites: 2001 through 2005 and 2006. Life requires both nitrogen and phosphorus, but in different amounts. Plankton, on which the oceanic food chain is based, use nitrogen and phosphorus in a ratio of 16 molecules of N to 1 of phosphorus; this is known as the “Redfield Ratio.” In creeks and rivers the ratio is closer to 30:1 and is indicated by the green horizontal bar in the figure (the nitrate to phosphate ratio is being used as an approximation of the nitrogen to phosphorus ratio; on average, nitrate is approximately 85 % of the total nitrogen and phosphate 90 % of the total phosphate in Ventura samples). The Matilija tributaries and Lion Canyon are severely “nitrogen limited,” meaning that while phosphorus is plentiful, nitrogen is often exhausted. VR10, below Ojai, is “phosphorus limited”; more than sufficient nitrogen but phosphorus is typically in short supply. All other locations move across the boundary depending on time of year: typically being phosphorus limited during winter and spring, nitrogen limited in summer and fall. The error bars indicate the quartile points, i.e., 50 % of the monthly N/P ratios for that location lie within the band represented by the error bar. In 2006, N/P ratios noticeably increased above long-term mean values, mainly as a result of lower than usual phosphate concentrations (see Figure 18).

0.1

1

10

100

1000

VR01VR02

VR03VR04

VR05VR06

VR07VR08

VR09VR10

VR11VR12

VR13VR14

VR15

mo

lar

N/P

rat

io2

00

1-2

00

5, 2

00

6 m

ed

ian

s

Figure 25. Average dry-season (June through September) nitrate to phosphate ratios for 2004, 2005 and 2006. The green horizontal bar marks the approximate 20:1 to 30:1 zone where both nitrients are in balance. The letter “I” indicates sites were phosphate concentrations fell below dectection limits (< 0.3 µM) and the N:P ratio was indeterminate. In 2005, increased nitrate concentrations and heavy algal growth following a wet winter produced a substantial increase in N:P ratio at all locations except VR08 (Lion Canyon). Wet years flush out the nitrogen accumulated in higher-elevation chaparrel during dry spells, increasing nitrate concentrations in both storm runoff and groundwater seepage. And increased algal growth, which follows a wet winter due to greater availability of nitrogen, sunlight and favorable habitat, disproportionally reduces river phosphate concentrations. 2006 is an example of the gradual return to the conditions seen in 2001-2004: growing season N:P ratios are still high because of heavy algal growth, but have decreased from the level seen in 2006 as nitrate becomes less pleantiful and growing aquatic vegetation reduces available algal habitat.

0.01

0.1

1

10

100

1000

10000

VR01VR02

VR03VR06

VR07VR08

VR09VR10

VR13VR14

VR15

nit

rate

/ph

osp

hat

e ra

tio

200420052006

II

Figure 26. 2006 geomean enterococci (upper panel) and E. Coli (lower panel) concentrations compared with geomeans from 200-2005 (error bars represent the 95 % confidence interval for the long-term geomeans). Solid horizontal lines mark the EPA’s recommended freshwater beach Public Health limits for maximum enterococcus (61 MPN/100 ml) and E. Coli (235 MPN/100 ml).

0

100

200

300

VR01VR02

VR03VR04

VR05VR06

VR07VR08

VR09VR10

VR11VR12

VR13VR14

VR15

en

tero

co

cc

i (M

PN

/10

0 m

l)20

01-2

005

, 20

06 g

eom

ean

s Geomean (2001-2005)2006

431

0

100

200

300

400

500

VR01VR02

VR03VR04

VR05VR06

VR07VR08

VR09VR10

VR11VR12

VR13VR14

VR15

E. C

oli

(M

PN

/100

ml)

2001

-200

5, 2

006

geo

me

ans

Geomean (2001-2005)2006

1252

Figure 27. (upper panel) 2006 geomean concentrations for total coliform compared with 2001-2005 geomeans (error bars represent the 95 % confidence interval for the long-term geomeans). The California limit for total coliform is 10,000 MPN/100 ml. (lower panel) 2006 and 2001-2006 fecal to total coliform ratios: the California limit for total coliform decreases to 1000 MPN/100 ml if the fecal coliform/total coliform ratio exceeds 0.1 (blue horizontal line).

0

1000

2000

3000

4000

5000

6000

VR01VR02

VR03VR04

VR05VR06

VR07VR08

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VR11VR12

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tota

l co

lifo

rm (

MP

N/1

00 m

l)20

01-2

005,

200

6 g

eom

ean

s

Geomean (2001-2005)

2006

0.0

0.1

0.2

0.3

0.4

VR01VR02

VR03VR04

VR05VR06

VR07VR08

VR09VR10

VR11VR12

VR13VR14

VR15

feca

l co

lifo

rm/t

ota

l co

lifo

rm r

atio

FC/TC (2001-2005)

2006

Figure 28. (upper panel) The average 2006 fecal to total coliform ratio with E. coli and enterococci concentrations (as geomeans). Dashed horizontal lines mark the EPA’s recommended freshwater beach Public Health limits for maximum enterococcus (61 MPN/100 ml) and E. Coli (235 MPN/100 ml). The California limit for total coliform (10,000 MPN/100 ml) decreases to 1000 (indicating a pollution problem) if the fecal coliform/total coliform ratio exceeds 0.1 (solid line). (lower panel) Total coliform, E. coli and enterococci geomean concentrations: 2006.

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0.1

0.2

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0.4

VR01VR02

VR03VR04

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feca

l to

to

tal c

oli

form

rat

io

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400

500

E. c

oli

or

ente

roco

cci (

MP

N/1

00 m

l)

FC/TC ratioE. coli geomeanenterococci geomean

1252

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tota

l co

lifo

rm (

MP

N/1

00 m

l)

0

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E. c

oli

or

ente

roco

cci (

MP

N/1

00 m

l)

TC geomeanE. coli geomeanenterococci geomean

1252

Documents

Figure 2. (upper) The cumulative flow excess or deficiency – how much each water year’s flow (measured in inches of runoff at Foster Park) varied from