15

Chapter 2: Drainage Control Activities by Grassland Area Farmers

2G

R

A

S

S

L

A

N

D

B

Y

P

A

S

S

P

R

O

J

E

C

T

Drainage ControlActivities by

Grassland AreaFarmers

Joseph C. McGahan,Drainage Coordinator

Grassland Bypass Project Annual Report

16

IntroductionThe Grassland Area Farmers formed a regional

drainage entity in March 1996 under the umbrella of theSan Luis and Delta-Mendota Water Authority toimplement the Grassland Bypass Project. The Projectconsolidates subsurface drainage flows on a regional basisand utilizes a portion of the federal San Luis Drain toconvey the flows around the habitat areas (see Figure 1).Participants include the Broadview Water District,Charleston Drainage District, Firebaugh Canal WaterDistrict, Pacheco Water District, Panoche DrainageDistrict, Widren Water District and the Camp 13Drainage District (located in part of Central CaliforniaIrrigation District). This entity includes approximately97,000 gross acres of irrigated farmland on the westsideof the San Joaquin Valley, referred to as the GrasslandDrainage Area. The area is highly productive, producingan estimated $113 Million annually in agricultural cropmarket value, with an additional estimated $126 Milliongenerated for the local and regional economies, for a totalestimated economic value of $239 Million.

The Grassland Area Farmers have implementedseveral activities aimed at reducing discharge of subsur-face drainage waters to the San Joaquin River. Theseactivities have included the Grassland Bypass Project andthe San Joaquin River Water Quality ImprovementProject. They also include: formation of a regionaldrainage entity, newsletters and other communicationwith the farmers, a monitoring program, using StateRevolving Fund loans for improved irrigation systems,utilizing and installing drainage recycling systems to mixsubsurface drainage water with irrigation supplies understrict limits, tiered water pricing and tradable loadsprograms.

Grassland BypassProject

The Grassland Bypass Project is an innovativeprogram that was designed to improve water quality inthe channels used to deliver water to wetland areas. Priorto the Project, subsurface drainage water was conveyedthrough those channels in route to the San Joaquin Riverand limited their availability to deliver high-qualityhabitat supplies. The Project consolidates subsurfacedrainage flows on a regional basis and utilizes a portionof the federal San Luis Drain to convey the flows aroundthe habitat areas. Figure 2 shows the discharge from theGrassland Bypass Project for the initial 5 years includingWater Year (WY) 2001.

Negotiations between the San Luis & Delta-Mendota Water Authority and the U.S. Bureau ofReclamation to utilize a portion of the San Luis Drainfor the Project commenced in 1988. Stakeholdersincluded in the process were: U.S. EnvironmentalProtection Agency, U.S. Fish & Wildlife Service,California Department of Fish and Game, the CentralValley Regional Water Quality Control Board, Environ-mental Defense, Contra Costa County and Contra CostaWater District. In late 1995, environmental documenta-tion for the first five years was completed and the UseAgreement was signed. Discharge through the projectbegan in September 1996. In September 2001, the UseAgreement was extended for another 8 years and 3months (through December 2009). An EnvironmentalImpact Report/Environmental Impact Statement wascompleted and on September 7, 2001 the Central ValleyRegional Water Quality Control Board issued newWaste Discharge Requirements. Other items completedto support the continued use were a Biological Assess-ment/Biological Opinion, a selenium Total MaximumMonthly Load (TMML) report submitted by theRegional Board to EPA, and a continued monitoringprogram. The new Use Agreement contains continuedreductions in selenium discharge until ultimatelyTMML limits are achieved in 2005 for above normaland wet years and continued progress is made to meetwater quality objectives in 2010 for below normal, dryand critical years. The future load limits are shown onFigure 3.

The benefits of the Grassland Bypass Project arewell documented. In WY 2001, drainage volume hasbeen reduced 47%, selenium load has been reduced 56%,salt load has been reduced 28% and boron load has beenreduced 41%, all from pre-project conditions in WY1996. In WY 1996, prior to the Grassland BypassProject, the mean selenium concentration in Salt Sloughat Lander Avenue was 16 µS/cm. Since October 1996,the 2 µS/cm water quality objective for Salt Slough hasbeen met in all months except one. The only month inwhich objectives were not met was February 1998 whenuncontrollable flood flows were mixed with subsurfacedrainage water and could not be contained within theGrassland Bypass Project (that month the seleniumconcentration in Salt Slough was 4 µS/cm). In WY 1996the mean selenium concentration at Camp 13 Ditch was55.9 parts per billion (µS/cm). In WY 1997, the first yearof operation of the Grassland Bypass Project, the meanselenium concentration at Camp 13 Ditch was 2.6 µS/cm. This value was slightly above the wetland seleniumobjective of 2 µS/cm. In April, 1998, specific actions

17

Chapter 2: Drainage Control Activities by Grassland Area Farmers

Figure 1. Grassland Drainage Area Location Map

Grassland Bypass Project Annual Report

18

0

200

400

600

800

1000

1200

1400

1600

1800

OCT JAN APR JULY OCT JAN APR JULY OCT JAN APR JULY OCT JAN APR JULY OCT JAN APR JUL

SE

LE

NIU

M L

bs

0

200

400

600

800

1000

1200

1400

1600

1800

Lbs OF SELENIUM TARGET

1997 1998 1999 2000 2001

0

2000

4000

6000

8000

10000

12000

14000

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

Water Year

Se D

isch

arg

e (

lbs)

Wet TMML

(3,087 lbs)

Dry TMML (1,001 lbs)

Begin New

Use Agreement

Actual Discharge

from Drainage

AreaLoad Limits

Begin Grassland

Bypass Project

Gradually increasing Slope to Critical,

Dry, or Below Normal TMML

Figure 2. Discharge from the Grassland Bypass Project

October 1996 through September 2001

Figure 3. Grassland Drainage Area

Selenium Discharge and Targets

19

Chapter 2: Drainage Control Activities by Grassland Area Farmers

Figure 4

Grassland Bypass Project Annual Report

20

were taken to eliminate any possible subsurface drainagedischarges from the Grassland Drainage Area into theCamp 13 Slough and other discharge points. Since thattime there have been no discharges from the GrasslandDrainage Area into wetland channels.

San Joaquin RiverWater QualityImprovement Project

Funds provided from Proposition 13 allowed forthe purchase and improvement of 4,000 acres of landwithin the Grassland Drainage Area as part of the SanJoaquin River Water Quality Improvement Project(SJRIP) for the purpose of drain water disposal. The firstphase of the SJRIP was implemented in the winter ofWY 2001 with the planting of salt tolerant crops andconstruction of distribution facilities. 1,821 acres wereirrigated with drainage water or blended water. Thisresulted in a displacement of 1,025 pounds of selenium,14,500 tons of salt and 62,000 pounds of boron, whichwere prevented from discharging to the GrasslandBypass Project and to the San Joaquin River. Thelocation of the SJRIP Project is shown in Figure 1 andthe cropping details for WY 2001 are shown in Figure 4.The SJRIP project is the key for the Grassland DrainageArea as a whole to meet future selenium load limits. Thisproject will ultimately allow for planting and irrigation ofthe entire 4,000 acres with drainage water. Future phases

call for acquisition of additional acreage, installation ofsubsurface drainage systems and implementation oftreatment and salt disposal components.

A component of this future phase is being imple-mented with Proposition 13 funds. Subsurface drains arebeing installed in 550 acres within the SJRIP area.Irrigation systems are being improved to distributedrainage water to the land and crops are being planted toutilize the subsurface drainage water. This project iscalled the Grassland Integrated Drainage ManagementProject.

Other ActivitiesThe Grassland Area Farmers and member districts

are continuing advances into drainage management anddisposal with the cooperation of federal and stateagencies. Research is being undertaken in algal bacteriaselenium treatment, reverse osmosis treatment, flowthrough selenium removal and individual district reuseprojects. Continued funding is being sought for theseactivities. An estimate has been made of the componentsof subsurface drainage within the GDA. This informa-tion is shown in Figure 5.

Future regulations may include salt and borondischarge limits to the San Joaquin River. The GrasslandArea Farmers are active participants in this process aswell other regulatory efforts such as the dissolved oxygenissue in the San Joaquin River.

2,500

4,400

5,800

Conservation

River

Discharge

Reuse & Treatment • Recycling

• Use on salt tolerant crops

• Displacement

• Pilot Treatment

• Improved irrigation

applications

• Tiered water pricing

• Tailwater controls

• Tradable Loads

lbs Selenium

lbs Selenium

WY 2001

1,200± lbs

w/ 4000 acres of

SJRWQIP Fully

Planted

lbs Selenium

Figure 5. Historic Drainage Water (lbs selenium)

57,000 AF 12,700 lbs Se 240,000 Tons Salt