Turbidity measurements in Alameda Creek and selected tributaries: August through December

2007

Alicia N. Gilbreath and Lester J. McKee

San Francisco Estuary Institute

Turbidity measurement

Sadar, Hach Co., 2005

Turbidity WQ objective

“Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses.

Increases from normal background light penetration or turbidity relatable to waste discharge shall not be greater than 10 percent in areas where natural turbidity is greater than 50 NTU.”

- San Francisco Regional Water Quality Control Board (SFRWQCB) Basin Plan (2007), Turbidity water quality objective (3.3.19)

Thresholds used in analysis

10 NTU > 50% exposure time 25 NTU > 20% exposure time

and

50 NTU > 10% exposure time

Klein and Trush (in prep), in McBain and Trush, 2007

Aug Sep Oct Nov Dec

Dis

char

ge

(CF

S)

0

100

200

300

400

Results

Ala Ck @ Ardenwood

Ala Ck @ Alvarado

Ala Ck @ Decoto

Ala Ck @ Mission

Ala Ck @ Stonybrook Ck

Ala Ck @ frmr Sunol Dam

Ala Ck @ Sunol Temple

Ala Ck @ 680

Ala Ck @ Welch Ck

ADLL @ Paloma Bridge

ADLL @ Verona

ADLL @ Bernal

ADV @ Valley

ADV @ Bernal

Alamo Canal @ 580

Mocho @ Hopyard

Tsjra @ W. Las Positas

Mocho @ Santa Rita

Line G-3 @ Mocho

Mocho above Line G-3

Mocho @ El Charro

ALP @ El Charro

ALP @ Livermore

ALP @ First St.

ALT @ Redwood

Turbidity (NTU)

0

10

0

20

0

30

0

40

0

80

0

Alameda Ck @ Ardenwood

Alameda Ck @ Alvarado

Alameda Ck @ Decoto

Alameda Ck @ Mission

Alameda Ck @ Stonybrook Ck

Alameda Ck @ frmr Sunol Dam

Alameda Ck @ Sunol Temple

Alameda Ck @ 680

Alameda Ck @ Welch Ck

Arroyo De La Laguna @ Paloma

Arroyo De La Laguna @ Verona

Arroyo De La Laguna @ Bernal

Arroyo Del Valle @ Valley

Arroyo Del Valle @ Bernal

Alamo Canal @ 580

Arroyo Mocho @ Hopyard

Tassajara Ck @ W. Las Positas

Arroyo Mocho @ Santa Rita

Line G-3 @ Arroyo Mocho

Arroyo Mocho above Line G-3

Arroyo Mocho @ El Charro

Arroyo Las Positas @ El Charro

Arroyo Las Positas @ Livermore

Arroyo Las Positas @ First

Altamont Ck near Bristlecone

Turbidity (NTU)

0 10

20

30

40

50

60

Ala Ck @ Ardenwood

Ala Ck @ Alvarado

Ala Ck @ Decoto

Ala Ck @ Mission

Ala Ck @ Stonybrook Ck

Ala Ck @ frmr Sunol Dam

Ala Ck @ Sunol Temple

Ala Ck @ 680

Ala Ck @ Welch Ck

ADLL @ Paloma Bridge

ADLL @ Verona

ADLL @ Bernal

ADV @ Valley

ADV @ Bernal

Alamo Canal @ 580

Mocho @ Hopyard

Tsjra @ W. Las Positas

Mocho @ Santa Rita

Line G-3 @ Mocho

Mocho above Line G-3

Mocho @ El Charro

ALP @ El Charro

ALP @ Livermore

ALP @ First St.

ALT @ Redwood

Turbidity (NTU)

0

10

0

20

0

30

0

40

0

80

0

Alameda Ck @ Ardenwood

Alameda Ck @ Alvarado

Alameda Ck @ Decoto

Alameda Ck @ Mission

Alameda Ck @ Stonybrook Ck

Alameda Ck @ frmr Sunol Dam

Alameda Ck @ Sunol Temple

Alameda Ck @ 680

Alameda Ck @ Welch Ck

Arroyo De La Laguna @ Paloma

Arroyo De La Laguna @ Verona

Arroyo De La Laguna @ Bernal

Arroyo Del Valle @ Valley

Arroyo Del Valle @ Bernal

Alamo Canal @ 580

Arroyo Mocho @ Hopyard

Tassajara Ck @ W. Las Positas

Arroyo Mocho @ Santa Rita

Line G-3 @ Arroyo Mocho

Arroyo Mocho above Line G-3

Arroyo Mocho @ El Charro

Arroyo Las Positas @ El Charro

Arroyo Las Positas @ Livermore

Arroyo Las Positas @ First

Altamont Ck near Bristlecone

Turbidity (NTU)

0 10

20

30

40

50

60

USGS Gage Arroyo De La Laguna at Verona

09/

10/0

7

09/

24/0

7

10/

08/0

7

10/

22/0

7

11/

05/0

7

11/

19/0

7

12/

03/0

7

Tu

rbid

ity (

FN

U)

0

50

100

150250

300

Dis

cha

rge

(C

FS

)

0

50

100

150250

300Turbidity (USGS)Turbidity (SFEI)Discharge

Results compared

to thresholds

  Percentage of Sampling Events:  

  ≥ 10 NTU ≥ 25 NTU ≥ 50 NTU Count (n)

Alameda Ck @ Ardenwood 100% 95% 63% 19

Alameda Ck @ Alvarado 39% 0% 0% 18

Alameda Ck @ Decoto 11% 0% 0% 9

Alameda Ck @ Mission 33% 8% 8% 12

Alameda Ck @ Stonybrook Ck 10% 0% 0% 10

Alameda Ck @ frmr Sunol Dam 8% 8% 8% 12

Alameda Ck @ Sunol Temple 20% 0% 0% 5

Alameda Ck @ 680 0% 0% 0% 3

Alameda Ck @ Welch Ck 0% 0% 0% 8

Arroyo De La Laguna @ Paloma 53% 5% 5% 19

Arroyo De La Laguna @ Verona 89% 5% 5% 19

Arroyo De La Laguna @ Bernal 84% 5% 5% 19

Arroyo Del Valle @ Valley 5% 0% 0% 19

Arroyo Del Valle @ Bernal 0% 0% 0% 3

Alamo Canal @ 580 41% 6% 6% 17

Arroyo Mocho @ Hopyard 100% 95% 53% 19

Tassajara Ck @ W. Las Positas 94% 71% 24% 17

Arroyo Mocho @ Santa Rita 100% 71% 29% 17

Line G-3 @ Arroyo Mocho 92% 69% 31% 13

Arroyo Mocho above Line G-3 77% 15% 8% 13

Arroyo Mocho @ El Charro 50% 50% 50% 2

Arroyo Las Positas @ El Charro 21% 5% 5% 19

Arroyo Las Positas @ Livermore 0% 0% 0% 3

Arroyo Las Positas @ First 20% 10% 0% 10

Altamont Ck @ Bristlecone 67% 33% 0% 6

Recommendations

1) Conduct a bioenergetics study in areas where turbidity may impact the fish.

2) Investigate sources and management options for inputs into Arroyo Mocho.