SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 1

Issue 4bIssue 4bCompliance location at Contra Compliance location at Contra Costa Canal at Pumping Plant Costa Canal at Pumping Plant

#1#1

-- Proposed Solution - Proposed Solution -

Richard A. DentonWater Resources Manager

Contra Costa Water District

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 2

Location of Sources of Degradation

Pumping Plant #1

Local Drainage Source

Holland Tract EC meter

Contra Costa Canal

Local SeepageSource

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 3

Dec99_timeseries.m

07-Jan-2005 mm

Nov 21, 1999 Dec 5, 1999 Dec 19, 1999 Jan 2, 200050

100

150

200

250

300

Ch

lori

des

[m

g/l]

CCWD PP#1Delta Road BridgeHolland Tract250 Objective

Holland Tract

Chlorides (mg/L)

CCWD Reduced Pumping Helped with 250 Compliance in Nov. 1999

Pumping Plant #1

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 4

Dec04_timeseries.m

09-Jan-2005 mm

Nov 21, 2004 Dec 5, 2004 Dec 19, 2004 Jan 2, 200580

100

120

140

160

180

200

Ch

lori

des

[m

g/l]

CCWD PP#1Delta Road BridgeHolland Tract150 Objective

Holland TractChlorides

(mg/L)

Reduced CCWD Pumping Helped with 150 Compliance in Dec. 2004

Pumping Plant #1

150 mg/L

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 5

holland_lag_loop_quadrants.m

09-Jan-2005 mm

0 200 400 600 800 1000 1200 14000

50

100

150

200

250

300

EC at Holland Tract, [uS/cm]

Ch

lori

des

at

Pu

mp

ing

Pla

nt

#1 [

mg

/l]

CCWD Water Quality, 1978 - 2003

all pumping rates

All Data 1983-2003

All Pumping Rates

Pumping Plant #1

Chlorides (mg/L)

Historical data show degradation due to seepage and local drainage

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 6

holland_lag_loop_hi_lo_3day_avg.m

09-Jan-2005 mm

0 200 400 600 800 1000 1200 14000

50

100

150

200

250

300

EC at Holland Tract, [uS/cm]

Ch

lori

des

at

Pu

mp

ing

Pla

nt

#1 [

mg

/l]

CCWD Water Quality, 1978 - 2003

pumping more than 30 cfs at PP#1

940 uS/cm

560 uS/cm

Pumping

> 30 cfs

Pumping Plant #1

Chlorides (mg/L)

Pumping 30 cfs eliminates most effects

250 mg/L

150

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 7

holland_lag_loop_hi_lo_3day _avg.m

09-Jan-2005 mm

0 200 400 600 800 1000 1200 14000

50

100

150

200

250

300

EC at Holland Tract, [uS/cm]

Ch

lori

des

at

Pu

mp

ing

Pla

nt

#1 [

mg

/l]

CCWD Water Quality, 1978 - 2003

pumping more than 60 cfs at PP#1

940 uS/cm

560 uS/cm

Pumping Plant #1

Chlorides (mg/L)

Use cutoff between 30 cfs and 60 cfs

250 mg/L

150Pumping

> 60 cfs

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 8

holland_lag_loop_quadrants.m

09-Jan-2005 mm

0 200 400 600 800 1000 1200 14000

50

100

150

200

250

300

EC at Holland Tract, [uS/cm]

Ch

lori

des

at

Pu

mp

ing

Pla

nt

#1 [

mg

/l]

CCWD Water Quality, 1978 - 2003

pumping more than 60 cfs at PP#1

940 uS/cm

Compliance: Pumping Plant #1 chlorides less than 250 mg/L

Use Holland Tract to Determine Control

250

Out of ComplianceCompliance: Beyond SWP

and CVP Control

0.94 EC

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 9

Location of Sources of Degradation

Pumping Plant #1

Local Drainage Source

Holland Tract EC meter

Contra Costa Canal

Local SeepageSource

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 10

Proposed Modification: 250 M&I Objective

• If CCWD diverting more than 20 cubic feet per second (cfs) at Pumping Plant #1 (3-day running average) and 250 mg/L chloride objective not met, M&I chloride objective considered exceeded

• If CCWD diverting less than 20 cfs at Pumping Plant #1 (3-day average) and 250 mg/L chloride not met, then:

• Check Holland electrical conductivity (EC) from 3 days previously

• If Holland EC greater than 0.94 mS/cm, M&I objective considered exceeded

• If Holland EC equal to or less than 0.94 mS/cm, situation beyond control of DWR and USBR, and M&I objective not exceeded

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 11

Proposed Modification: 150 M&I Objective• Similarly, if CCWD diverting more than 20 cfs at PP#1 (3-day

average) and daily chloride at PP#1 is above 150 mg/L, day does not count toward 150 mg/L objective

• If CCWD diverting less than 20 cfs at PP#1 (3-day average) and chlorides above 150 mg/L chloride, then:

• Check Holland electrical conductivity (EC) from 3 days previously

• If Holland EC greater than 0.56 mS/cm, that day does not count toward 150 mg/L M&I objective

• If Holland EC is equal to or less than 0.56 mS/cm, situation is beyond control of DWR and USBR, and day counts toward meeting 150 mg/L objective

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 12

Summary of CCWD Comments

• Compliance location must remain at Pumping Plant #1 to ensure water diverted by CCWD is at or better than 150 mg/L and 250 mg/L M&I chloride objectives

• Two major projects are currently well underway to eliminate effect of the two primary sources of degradation in Rock Slough and unlined section of Contra Costa Canal

• If Pumping Plant #1 diversions less than 30-60 cfs (3-day average), M&I chloride objectives should not be considered exceeded at Pumping Plant #1 provided electrical conductivity at Holland Tract is at or better than specific EC targets

• 250 mg/L = 0.94 EC• 150 mg/L = 0.56 EC

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 13

SWRCB Public Workshop for Periodic ReviewJanuary 10-12, 2005 Slide 14

Even with Los Vaqueros, CCWD still uses Rock Slough for water quality and water supply