Salinity Management Project Santa Ana Region Gerard Thibeault Executive Officer January 26, 2007

State of California Water Quality Control Regions North Coast 2. San Francisco Bay 3. Central Coast 4. Los Angeles 5. Central Valley 6. Lahontan 7. Colorado River 8. Santa Ana 9. San Diego

Need for Updated Salt Management Plan Discharger Concerns –TDS Limitations –Objectives – 1972 Rushed, under funded Not based on good science No good data on assimilative capacity If 1972 objectives invalid –Potential for enormous unnecessary expenditures of public funds

Genesis of Salt Management Plan Dischargers and water agencies appealed to Regional Board for complete review of salt management plan Regional Board agreed to evaluate objectives –Two-edged sword

Develop procedures to calculate groundwater quality objectives –1972 Basin Plan Objectives: Significantly under-funded effort TDS: About 200 wells; Two years of data Nitrate objectives not scientifically calculated –TIN/TDS Study: TDS/Nitrate: About 1,800 wells; 20 years of data Nitrate and TDS objectives rigorously calculated

Santa Ana Basin Salt Management Plan N/TDS Task Force – 7 years, water supply agencies (upper and lower basins), wastewater dischargers, USGS, Watermaster Funded by Task Force members –Approx. $3.5 million

Basin Plan Amendment Bottom Line 90 page staff report 99 page basin plan amendment Numerous public workshops and hearings Complete assessment and adoption of new objectives and boundaries throughout Region Adopted by Reg Bd, State Bd, and OAL WITHOUT dissent or opposition

N/TDS Task Force All factions within the basin represented –Upper Basin v. Orange County –Water Supply Agencies v. WW dischargers Consensus-building process Establish ground rules Strict conformance with existing laws and federal and state policies

N/TDS Task Force Complete scientific review of historic and current ambient water quality 20-Year running averages All wells in region with 3 or more data points and quality control Thousands of data points Developed nitrogen, TDS and water level maps for every 2 years since 1950 for entire region

N/TDS Task Force Hydrogeotechnical review of all groundwater basin boundaries All boundaries digitized Mass-weighted analysis of historic and current ambient groundwater quality

N/TDS Task Force Re-created objectives using year running average and evaluated current ambient quality, also with 20-year average Strong scientific basis in conformance with laws and policies Established antidegradation objectives (St. Bd. Res ) Compared current ambient quality to objectives to determine whether assimilative capacity exists

Develop Queries to Extract Data QA/QC Checks Develop TDS and NO 3 -N time histories Appropriate statistical tests for normality and outliers »Shapiro-Wilk test Standard methods tests »Anion-cation balance »Measured TDS vs. calculated TDS »Measured EC and ion sums »TDS to EC ratios Reject data if any test failed

Develop WQ Point Statistics at Each Well Each well must have at least three data points in separate years during the analysis period. TDS and Nitrate-nitrogen Computed statistics account for variability resulting from: sampling error analytical error hydrological/climatic events non-homogeneous hydrogeologic properties

Develop procedures to calculate groundwater quality objectives Develop volume-weighted management zone estimates of TDS and nitrate concentrations Concentration MZ = Mass MZ / GW Volume MZ historical ambient conditions (1954 – 1973) –Objective setting period current ambient conditions (1978 – 1997) –Measure of compliance

Compute Ambient Water Quality for Management Zones Create 400x400m grid across all MZs Populate each grid cell with: Water quality (TDS and Nitrate) Groundwater elevations Specific yield Bottom of the aquifer Aquifer geometry (layering) where appropriate

Compute Ambient Water Quality for Management Zones Create 3-D GIS layers of: Water quality (TDS and Nitrate) Groundwater elevations Specific yield Bottom of the aquifer Aquifer geometry (layering) where appropriate 3 rd dimension is value of layer

View Sample Map

Assimilative Capacity If assimilative capacity exists, then may discharge at quality in excess of objectives, if supported by antidegradation analysis (maximum benefit & support beneficial uses) –This reduces or exhausts assimilative capacity If no assimilative capacity, may not discharge at quality above objectives (Rancho Caballero decision)

Implications of the TIN/TDS Study Management Zones that lack assimilative capacity must have TDS and N0 3 discharge concentrations limited to a level at or below the proposed objectives. Effects: Planned recycled water recharge projects Potentially direct recycled water re-use Surface discharge in reaches that have GWR beneficial uses

Max Ben Objectives Less stringent objectives would allow lowering of water quality, so must satisfy state’s antidegradation policy – Resolution –1. Demonstrate that beneficial uses will continue to be protected –2. Water quality consistent with maximum benefit to the people of the state will be maintained

What are the Causes of TDS and N Degradation in the Chino Basin? Returns from use from agriculture and urban water users Recharge

Max Ben Demonstration Chino Basin Example –Integrated water supply plan Recycled water Enhanced stormwater capture Two (later, three) desalters Recharge excess low-TDS SPW Hydraulic Isolation Extensive monitoring proposal Water softener elimination program

Chino Basin Max Ben Max benefit to people of state –Extraction and treatment of salt- contaminated groundwater –Protect downstream users from rising poor-quality groundwater –Less reliance on SPW for growth –Integrated water supply planning – Optimum Basin Management Program

Status of Basin Plan Amendment Approved by: RWQCB – January 2004 SWRCB – September 2004 OAL – December 2004 No negative comments through adoption process

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