Orange County Water District

Salt and Nitrate Projections for Orange County Management Zone

Final Technical Memorandum

Prepared by Greg D. Woodside, P.G., C.Hg.

July 18, 2016 Table of Contents

SECTION 1 INTRODUCTION ...... 1-1 1.1 Background Discussion ...... 1-1 1.2 General Description of Orange County Management Zone ...... 1-3 1.3 Types and Sources of Data Used in the Model ...... 1-4 SECTION 2 BASIN HYDROGEOLOGY ...... 2-1 2.1 Description of Basin Hydrogeology...... 2-1 2.1.1 Forebay and Pressure Areas ...... 2-3 2.1.2 Groundwater Subbasins, Mesas, and Gaps ...... 2-5 2.1.3 Coastal Plain of Orange County: Areas outside OCWD Boundaries ..... 2-6 2.2 Determination of Total Basin Volume ...... 2-7 2.3 Water Budget ...... 2-8 2.3.1 Measured Recharge ...... 2-9 2.3.2 Unmeasured Recharge ...... 2-11 2.3.3 Groundwater Production ...... 2-13 2.3.4 Subsurface Outflow ...... 2-13 2.3.5 Evaporation ...... 2-14 2.4 Calculation of Change in Groundwater Storage ...... 2-14 2.5 Elevation Trends...... 2-18 2.6 Basin Model ...... 2-23 SECTION 3 MODELING APPROACH...... 3-1 3.1 Conceptual Model...... 3-1 3.2 Model Methodology ...... 3-2 3.3 Model Input ...... 3-3 3.4 Model Verification ...... 3-10 3.5 TDS Predictions Using the Model ...... 3-11 3.6 Sensitivity Analysis ...... 3-12 3.7 Nitrate Projection for Orange County Management Zone ...... 3-15 SECTION 4 SUMMARY AND CONCLUSION ...... 4-1 SECTION 5 REFERENCES ...... 5-1

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum i Table of Contents

List of Tables

Table 2-1: Estimated Basin Groundwater Storage by Hydrogeologic Unit ...... 2-8 Table 2-2: Example Annual Basin Water Budget ...... 2-9 Table 3-1: Summary of Inflows to Orange County Management Zone ...... 3-3 Table 3-2: Delivered Water Quality Summary ...... 3-4 Table 3-3: Recent TDS Concentrations at Monitoring Wells in Shallow Semi-Perched Interval ...... 3-5 Table 3-4: Summary of Subsurface Inflow Components ...... 3-8 Table 3-5: Summary of TDS Estimates for Model Cases ...... 3-13 Table 3-6: Comparison of Amount of Imported Water Recharge and Projected TDS Concentrations for Cases 1-4 ...... 3-14 Table 3-7: Summary of Inflows to OC Management Zone ...... 3-16 Table 3-8: Summary of Subsurface Inflow Components ...... 3-17

List of Figures

Figure 1-1: Boundaries of the Orange County Management Zone ...... 1-4 Figure 2-1: Coastal Plain of Orange County Groundwater Basin, Basin 8-1 ...... 2-1 Figure 2-2: Geologic Cross-Section, Orange County Groundwater Basin ...... 2-3 Figure 2-3: Orange County Groundwater Basin ...... 2-4 Figure 2-4: Basin 8-1 and OCWD Boundaries ...... 2-7 Figure 2-5: OCWD Recharge Facilities in Anaheim and Orange ...... 2-10 Figure 2-6: Seawater Intrusion Barriers ...... 2-11 Figure 2-7: Estimated Subsurface Recharge ...... 2-12 Figure 2-8: Distribution of Groundwater Production, Water Year 2012-14 ...... 2-13 Figure 2-9: Relationship between OCWD Basin Storage and ...... 2-14 Figure 2-10: Schematic Cross-Section of the Basin Showing Three Aquifer Layers .. 2-16 Figure 2-11: Groundwater Level Contour Map, June 2014 ...... 2-17 Figure 2-12: Groundwater Level Changes, June 2013-14 ...... 2-17

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum ii Table of Contents

Figure 2-13: Change in Groundwater Storage, WY 1974-75 to 2013-14...... 2-18 Figure 2-14: Principal Aquifer Groundwater Elevation Profiles, 1969 and 2013 ...... 2-19 Figure 2-15: Location of Long-Term Groundwater Elevation Hydrograph ...... 2-19 Figure 2-16: Water Level Hydrographs of Wells SA-21 and GG-16 in Pressure Area 2-20 Figure 2-17: Water Level Hydrographs of Well A-27 in Forebay ...... 2-21 Figure 2-18: Water Level Hydrographs of Wells SAR-1 and OCWD-CTG1 ...... 2-22 Figure 2-19: Basin Model Extent ...... 2-23 Figure 2-20: Basin Model Extent ...... 2-24 Figure 3-1: TDS Concentration in SAR at Below Prado Dam ...... 3-5 Figure 3-2: Estimation of Stormflow TDS ...... 3-6 Figure 3-3: Monitoring Well AM-50 TDS Concentration ...... 3-7 Figure 3-4: Location of Miraloma Basin and Monitoring Well AM-50 ...... 3-7 Figure 3-5: Subsurface Inflow into the Orange County Management Zone...... 3-9 Figure 3-6: Wells Used To Estimate Subsurface Inflow Concentrations ...... 3-10 Figure 3-7: Estimated TDS Concentration in Base Case for 30-year Period ...... 3-11 Figure 3-8: TDS Estimates for Model Cases ...... 3-14 Figure 3-9: Estimated Nitrate (as N) Concentration for 30-year Period ...... 3-18

Appendices

Appendix A – Amount and Quality of Imported Water Recharged, Orange County Management Zone Calendar Years 2012-2014

Appendix B – 2013-14 Delivered Water Quality Summary

Appendix C – Septic System Locations

Appendix D – TDS Projection Spreadsheets

Appendix E - Nitrate Projection Spreadsheets

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum iii Section 1 Introduction

SECTION 1 INTRODUCTION

1.1 Background Discussion

The purpose of this report is to present results of an evaluation of future total dissolved solids (TDS) and nitrate concentrations in the Orange County (OC) Management Zone. The evaluation consists of estimating future TDS and nitrate concentration based on estimated future inflow and outflow from the basin.

Management of salt and nitrate concentrations in groundwater is important to maintaining the long-term sustainable use of groundwater supplies. An important aspect of managing salt and nitrate concentrations in groundwater is managing the salt and nitrate concentrations of water used to recharge the groundwater basin. Removing poor-quality groundwater is another component of successful management. The evaluation of future salt and nitrate concentrations is important to the Orange County Water District (OCWD). OCWD was established by the State of California in 1933 to manage the Orange County Groundwater Basin. OCWD’s programs to manage water quality include monitoring, remediation of contaminated groundwater, and recharging high-quality recycled water. OCWD also operates the Prado Wetlands to remove nitrate from Santa Ana River water that is recharged into the groundwater basin. These efforts help provide high-quality groundwater to water users in Orange County. This evaluation provides OCWD with an understanding of the factors affecting TDS and nitrate concentration and provides information to help OCWD manage the groundwater basin. The evaluation also assists with meeting the requirements of an agreement executed by OCWD, entitled ‘Cooperative Agreement to Protect Water Quality and Encourage the Conjunctive Uses of Imported Water in the Santa Ana River Basin’. Parties to the January 18, 2008 agreement include the California Regional Water Quality Control Board, Santa Ana Region (Regional Board) and eight entities with water management roles. This agreement is referred to as the ‘Cooperative Agreement.’ In general terms, the Cooperative Agreement specifies that a ‘Recharging Party’ will collect certain data and perform projections of future TDS and nitrate concentrations. Section 4 of the Cooperative Agreement includes the following language: “The Parties that intentionally recharge imported water within the Santa Ana Region (the “Recharging Parties”) agree voluntarily to collect, compile and analyze the N/TDS water quality data necessary to determine whether the intentional recharge of imported water in the Region may have a significant adverse impact on compliance with the Salinity Objectives

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 1-1 Section 1 Introduction

within the Region. To that end, the Recharging Parties will collect, compile and analyze such N/TDS water quality data and prepare, within eighteen months from the effective date of this Agreement and every three years thereafter, a report containing the following information: a. A summary of the then-current ambient water quality in each groundwater management zone and a comparison of that ambient water quality with the Salinity Objectives. The Recharging Parties shall calculate ambient water quality for each groundwater management zone in a manner that allows for a technically valid comparison with the Salinity Objectives. b. A summary of the amount and quality of imported water recharged in each groundwater management zone during the previous three-year period. c. The initial report and each report prepared at six-year intervals thereafter will include a projection of ambient water quality in each groundwater management zone for the subsequent 20 years. i. The projection of ambient water quality for each groundwater management zone will be based upon professionally accepted modeling techniques, will reasonably account for surface fluxes of salt input, will reflect the effects of all existing and reasonably foreseeable recharge projects for which there is a certified environmental document and will compare baseline ambient water quality with the Salinity Objectives. ii. The projections for different groundwater management zones may be based on different modeling techniques. iii. Each report that includes a 20-year projection of ambient water quality will also present a comparison of then-current water quality in each groundwater management zone with the ambient water quality projection made six years earlier, together with an evaluation of the reason(s) for any differences.” This report fulfills the requirements of Section 4c of the Cooperative Agreement.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 1-2 Section 1 Introduction

1.2 General Description of Orange County Management Zone

The Orange County Groundwater Basin includes the Orange County Management Zone and the Irvine Management Zone, as shown in Figure 1-1. These Management Zones are defined in the Regional Board’s Basin Plan and provide the basis for defining water quality objectives. The Orange County Management Zone covers an area of approximately 300 square miles underlying the north half of Orange County. The aquifers comprising the Orange County Groundwater Basin extend over 2,000 feet deep and form a complex series of interconnected sand and gravel deposits In the inland area, generally northeast of Interstate 5, the clay and silt deposits become thinner and more discontinuous, allowing larger quantities of groundwater to flow between shallow and deeper aquifers. The basin is divided into two primary hydrologic divisions, the Forebay and Pressure areas, as shown in Figure 2-3. The boundary of these areas generally delineates the areas where surface water or shallow groundwater can or cannot move downward to the first producible aquifer in significant quantities. Most of the groundwater recharge occurs in the Forebay. In the Pressure Area, groundwater is generally impeded from percolating into the major producible aquifers. OCWD conducts an extensive groundwater monitoring well network to collect data on aquifers to depths of 2,000 feet in many areas of the basin. Data from these wells were used to delineate the depth of the “principal” aquifer system, within which most of the groundwater production occurs. Shallower aquifers exist above the principal aquifer system. Production from this system, principally for industrial and agricultural uses, is typically about five percent of total basin production. Deeper aquifers exist below the principal aquifer system, but these zones have been found to contain colored water or have been too deep to economically construct production wells; few wells penetrate this system. A vast amount of water is stored within the basin, although only a fraction of this amount can be removed without causing physical damage such as seawater intrusion or the potential for land subsidence. The District estimates that the total amount of fresh groundwater stored in the basin, assuming the basin is completely full, is approximately 66 million acre feet. OCWD developed a hydrologic budget in order to construct a Basin Model and to evaluate basin production capacity and recharge requirements. The hydrologic budget quantifies the amount of basin recharge, groundwater production and subsurface flows along the coast and across the Orange/Los Angeles County line.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 1-3 Section 1 Introduction

Figure 1-1: Boundaries of the Orange County Management Zone

1.3 Types and Sources of Data Used in the Model

The modeling effort described in this technical memorandum uses various types of data and information. These include: • Quantity and quality of water recharged through surface recharge facilities; • Quantity and quality of water recharged through seawater injection barriers; • Quantity and quality of unmeasured recharge, such as percolation of irrigation water into the groundwater basin; • Measurements of groundwater pumping; and

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 1-4 Section 1 Introduction

• Estimates of groundwater outflow from the Orange County Management Zone.

These data come from a variety of sources, including: • OCWD measurements of the quantities of water recharged at surface recharge facilities; • OCWD measurements of the quantities of water recharged at the Talbert Injection Barrier; • OCWD measurements of water quality for water recharged at surface recharge facilities and the Talbert Injection Barrier; • Los Angeles County Department of Public Works measurements of the quantities of water recharged at the Alamitos Injection Barrier; • Water Replenishment District of Southern California measurements of water quality for the Alamitos Injection Barrier; • Metropolitan Water District of Southern California (MWD) measurements of water quality for imported water purchased by OCWD; and • OCWD measurements of water quality for imported water purchased from MWD by OCWD. In general, the quantity and quality of water recharged through surface recharge facilities and seawater injection barriers is well defined using data collected by OCWD. There is less specific information to define the quantity and quality of unmeasured recharge. For example, the amount of percolation of irrigation water into the groundwater basin is not directly measured. The amount is estimated using information described in Section 2 of this report. The amount and quality of imported water recharged in the OC Management Zone during the previous three-year period is summarized in Appendix A. It is important to note that for the purpose of this report, OCWD divides the basin into three layers. Layer 1 is referred to as the Shallow Aquifer. Layer 2 is referred to as the Principal Aquifer where the majority of groundwater is pumped. Layer 3 is referred to as the Deep Aquifer. Calculation of water in storage in the model includes only groundwater in Layers 1 and 2. Layer 3 is not included as this supply is generally not available for production due to depth to water, water quality, and potential negative impacts to other aquifer zones. However, groundwater in the Principal Aquifer is able to flow into the Deep Aquifer. Therefore, in the model the flow into the Deep Aquifer is accounted for as an outflow component.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 1-5 Section 2 Basin Hydrogeology

SECTION 2 BASIN HYDROGEOLOGY

2.1 Description of Basin Hydrogeology

The Orange County Groundwater Basin is located in the area designated by the California Department of Water Resources (DWR) as Basin 8-1, the “Coastal Plain of Orange County Groundwater Basin” in Bulletin 118 (DWR, 2003). Figure 2-1 displays the OCWD boundary in relation to the boundary of Basin 8-1.

Figure 2-1: Coastal Plain of Orange County Groundwater Basin, Basin 8-1

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-1 Section 2 Basin Hydrogeology

The basin underlies north and central Orange County beneath broad lowlands known as the Tustin and Downey plains. The basin covers an area of approximately 350 square miles, bordered by the Coyote and Chino Hills to the north, the Santa Ana Mountains to the northeast, and the Pacific Ocean to the southwest. The basin boundary extends to the Orange County-Los Angeles line to the northwest, where groundwater flow is unrestricted across the county line into the Central Basin of Los Angeles County. The Newport-Inglewood fault zone forms the southwestern boundary of all but the Shallow Aquifer in the basin. The groundwater basin formed in a synclinal, northwest-trending trough that deepens as it continues beyond the Orange-Los Angeles county line. The Newport-Inglewood fault zone, San Joaquin Hills, Coyote Hills, and Santa Ana Mountains form the uplifted margins of the syncline. The total thickness of sedimentary rocks in the basin surpasses 20,000 feet, of which only the upper 2,000 to 4,000 feet contain fresh water. In the southeastern area underlying the city of Irvine and along the basin margins, the thickness of fresh water-bearing sediments is less than 1,000 feet (Herndon and Bonsangue, 2006). Structural folding and faulting along the basin margins, together with down warping and deposition within the basin, have occurred since Oligocene time. The Newport- Inglewood fault zone, comprising the most significant structural feature in the basin from a hydrogeologic standpoint, consists of a series of faulted blocks which are generally up thrown on the southwest side. Folding and faulting along the Newport-Inglewood fault zone have created a natural restriction to seawater intrusion into the groundwater basin (Herndon and Bonsangue, 2006). Pleistocene or younger aquifers within the basin form a complex series of interconnected sand and gravel deposits. In coastal and central portions of the basin, these deposits are extensively separated by lower-permeability clay and silt deposits or aquitards. In the inland areas, the clay and silt deposits become thinner and more discontinuous, allowing larger quantities of groundwater to flow more easily between shallow and deeper aquifers (California Department of Water Resources, 1967). Figure 2-2 presents a geologic cross section through the basin along the Santa Ana River. OCWD subdivided the groundwater basin into three major aquifer systems, based on geological data and vertical potentiometric head differences measured regionally at over 50 multi-depth monitoring wells, shown in Figure 2-8. The three aquifer systems, known as the Shallow, Principal, and Deep, are hydraulically connected, as groundwater is able to flow between them via leakage through the intervening aquitards or discontinuities in the aquitards.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-2 Section 2 Basin Hydrogeology

The Shallow Aquifer system overlies the entire basin and includes the prolific Talbert Aquifer. It generally occurs from the surface to approximately 250 feet below ground surface. The majority of groundwater from the shallow aquifer is pumped by small water systems for industrial and agricultural use, although the cities of Garden Grove and Newport Beach, and the Yorba Linda Water District, operate wells that pump from the shallow aquifer for municipal use. Over 90 percent of groundwater production occurs from wells that are screened within the Principal Aquifer system at depths between 200 and 1,300 feet. A minor amount of groundwater is pumped from the Deep Aquifer, which underlies the Principal Aquifer system and is up to 2,000 feet deep in the center of the basin. Hindering production from the Deep Aquifer system is the depth and the presence of amber colored groundwater in some areas.

Figure 2-2: Geologic Cross-Section, Orange County Groundwater Basin

2.1.1 Forebay and Pressure Areas The Department of Water Resources (DWR, 1934) divided the basin into two primary hydrologic divisions, the Forebay and Pressure areas, as shown in Figure 2-3. The Forebay/Pressure area boundary generally delineates the areas where surface water or shallow groundwater can or cannot move downward to the first producible aquifer in quantities significant from a water supply perspective. From a water quality perspective, the amount of vertical flow to deeper aquifers from surface water or shallow

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-3 Section 2 Basin Hydrogeology groundwater may be significant in terms of impacts of past agricultural or industrial land uses (e.g., fertilizer application and leaky underground storage tanks). The Forebay refers to the area of intake or recharge where most of the groundwater recharge occurs. Highly-permeable sands and gravels with few and discontinuous clay and silt deposits allow direct percolation of Santa Ana River and other surface water. The Forebay area encompasses most of the cities of Anaheim, Fullerton, and Villa Park and portions of the cities of Orange and Yorba Linda. The Pressure Area is generally defined as the area of the basin where large quantities of surface water and near-surface groundwater is impeded from percolating into the major producible aquifers by clay and silt layers at shallow depths (upper 50 feet). The Principal and Deep Aquifers in this area are under “confined” conditions (under hydrostatic pressure); the water levels of wells penetrating these aquifers exhibit large seasonal variations. Most of the central and coastal portions of the basin fall within the Pressure Area.

Figure 2-3: Orange County Groundwater Basin

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-4 Section 2 Basin Hydrogeology

2.1.2 Groundwater Subbasins, Mesas, and Gaps The Orange County Groundwater Basin, as defined by DWR Bulletin 118 Basin 8-1, can be subdivided into subbasins and the coastal region can be distinguished by higher and lower elevation areas, as described in this section and shown in Figure 2-3. Main Basin The Main Basin is the largest sub-basin where the majority of groundwater production occurs. Mesas and Gaps Four relatively flat elevated areas, known as mesas, occur along the coastal boundary of the basin. The mesas were formed by ground surface uplift along the Newport Inglewood Fault Zone. Ancient meandering of the Santa Ana River carved notches through the uplifted area and left behind sand- and gravel-filled deposits beneath the lowland areas between the mesas, known as gaps (Poland et al., 1956). Groundwater in the shallow aquifers within the gaps is susceptible to seawater intrusion. The Talbert and Alamitos seawater intrusion barriers were constructed to address this problem. Locations of mesas and details of seawater barrier operations are shown in Figure 7-1. Irvine Subbasin The Irvine subbasin, bounded by the Santa Ana Mountains and the San Joaquin Hills, forms the southern-most portion of the basin. The Costa Mesa Freeway (State Route 55) and Newport Boulevard form the subbasin’s approximate western boundary with the Main Basin. Here, the aquifers are thinner and contain more clay and silt deposits than aquifers in the main portion of the basin. The aquifer base in the Irvine sub-basin ranges from approximately 1,000 feet deep beneath the former Marine Corps Air Station (MCAS) Tustin to less than 200 feet deep at the eastern boundary of the former MCAS El Toro. East of former MCAS El Toro, the aquifer further thins and transitions into lower-permeability sandstones and other semi- consolidated sediments, which have minor water storage and transmission capacity. Groundwater historically flowed out of the Irvine subbasin westerly into the Main Basin since the amount of natural recharge in the area, predominantly from the Santa Ana Mountains, was typically greater than the amount of pumping (Singer, 1973; Banks, 1984). With the operation of the Irvine Desalter Project commencing in 2007, it is possible that groundwater production in the Irvine subbasin may exceed the natural replenishment from the adjacent hills and mountains, in which case groundwater would be drawn into the Irvine subbasin from the Main Basin.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-5 Section 2 Basin Hydrogeology

Yorba Linda Subbasin The Yorba Linda subbasin is located north of the Forebay recharge area in Anaheim, within the cities of Yorba Linda and Placentia. Due to low transmissivity and high total dissolved solids (TDS) concentrations (Mills, 1987) there is little groundwater pumped from this subbasin. Groundwater from the Yorba Linda subbasin flows southward into the Main Basin since the limited groundwater production is less than the natural replenishment from the adjacent Chino Hills. La Habra Subbasin The La Habra subbasin is located north of the Main Basin within the cities of La Habra and Brea. It comprises a shallow alluvial depression between the Coyote Hills and the Puente Hills. Prior to the 1950s, hundreds of wells produced water for domestic use and irrigation. The majority of these wells were abandoned due to high concentrations of nitrate, total dissolved solids, and metals and taste and odor problems. However, in recent years, the City of La Habra has explored options to increase groundwater production from this subbasin. Hydrogeologic studies have indicated that 2,200 to 5,500 afy of groundwater flows out of the La Habra Basin in two areas: (1) southerly into the Main Basin along the Brea Creek drainage between the East and West Coyote Hills and (2) westerly into the Central Basin in Los Angeles County (James M. Montgomery, 1977; Ramsey, 1980; OCWD, 1994). The areas that lie outside the District boundaries in the northern portion of Basin 8-1, as defined in DWR Bulletin 118, are located in the La Habra subbasin.

2.1.3 Coastal Plain of Orange County: Areas outside OCWD Boundaries

The District boundaries do not encompass the entire area of Basin 8-1 as defined by DWR as shown in Figure 2-4. Areas that are outside of OCWD’s boundary are shown in red highlight. These areas include (1) a northern portion of DWR Basin 8-1 located in the La Habra subbasin, a portion of which is in Los Angeles County, (2) areas along the mountain fronts at the eastern side of the basin and in the southern portion of Basin 8-1 within the Irvine subbasin, and (3) a portion of Basin 8-1 immediately downstream of Prado Dam located in Riverside and San Bernardino counties. OCWD is coordinating with the City of La Habra, the County of Orange, Irvine Ranch Water District, and other stakeholders regarding management of these areas outside the OCWD boundary. OCWD is not aware of any other agency that recharges imported water for groundwater replenishment in DWR Basin 8-1 except for OCWD.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-6 Section 2 Basin Hydrogeology

2.2 Determination of Total Basin Volume

A vast amount of fresh water is stored within the basin, although only a fraction of this water can be removed practically using pumping wells and without causing physical damage such as seawater intrusion or the potential for land subsidence (Alley, 2006). Nonetheless, it is important to note the total volume of groundwater that is within the active flow system, i.e., within the influence of pumping and recharge operations. OCWD used its geographic information system and the aquifer system boundaries described in Section 3.8 to calculate the total volume of each of the three major aquifer systems as well as the intervening aquitards. The total volume was calculated by multiplying the area and thickness of each hydrogeologic unit. Because groundwater fills the pore spaces that represent typically between 20 and 30 percent of the total volume, the total volume was multiplied by this porosity percentage to arrive at a total groundwater volume. Assuming the basin is completely full, based on District estimates, the total amount of fresh groundwater stored in the basin is approximately 66 million acre-feet, as shown in Table 2-1. For comparison, DWR (1967) estimated that about 38 million acre-feet of fresh water is stored in the groundwater basin when full. DWR used a factor known as the specific yield to calculate this volume. The specific yield (typically between 10 and 20 percent) is the amount of water that can be drained by gravity from a certain volume of aquifer and reflects the soil’s ability to retain and hold a significant volume of water due to capillary effects. Thus, DWR’s drainable groundwater volume can be considered consistent with OCWD’s estimate of total groundwater volume in the basin.

Figure 2-4: Basin 8-1 and OCWD Boundaries

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-7 Section 2 Basin Hydrogeology

Table 2-1: Estimated Basin Groundwater Storage by Hydrogeologic Unit (Volumes in Acre-feet)

HYDROGEOLOGIC UNIT PRESSURE AREA FOREBAY TOTAL

Shallow Aquifer System 3,800,000 1,200,000 5,000,000 Aquitard 900,000 200,000 1,100,000 Principal Aquifer System 24,300,000 8,600,000 32,900,000 Aquitard 1,600,000 300,000 1,900,000 Deep Aquifer System 18,800,000 6,300,000 25,100,000 TOTAL 49,400,000 16,600,000 66,000,000

Notes: (1) Volumes calculated using the 2-layer basin model surfaces with ArcInfo Workstation GRID. (2) A porosity of 0.25 was assumed for aquifer systems. (3) A porosity of 0.30 was assumed for aquitards.

2.3 Water Budget

OCWD developed a hydrologic budget (inflows and outflows) for the purpose of constructing the basin-wide groundwater flow model, (“Basin Model”) and for evaluating basin production capacity and recharge requirements. The key components of the budget include measured and unmeasured (estimated) recharge, groundwater production, and subsurface flows along the coast and across the Orange County/Los Angeles County line. Because the basin is not operated on an annual safe-yield basis, the net change in storage in any given year may be positive or negative; however, over a period of several years, the basin must be maintained in an approximate balance as explained in the District’s Groundwater Management Plan (OCWD, 2015). Table 2-2 presents the components of an example balanced basin water budget (no annual change in storage). Note that it does not represent data for any particular year. The annual budget presented is based on the following assumptions: (1) average precipitation, (2) basin storage at 400,000 acre-feet below full, (3) recharge of 275,000 acre-feet in District facilities including surface spreading basins and seawater intrusion barrier wells, and (4) adjusted groundwater production so that total basin inflows and outflows are equal. The sources of recharge water used by the District include Santa Ana River base flow and storm flow, imported water, and GWRS recycled water. The major components of the water budget are described in the following sections.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-8 Section 2 Basin Hydrogeology

Table 2-2: Example Annual Basin Water Budget

FLOW COMPONENT Acre-feet per Year INFLOW Measured Recharge 1 243,000 1. Surface recharge facilities 30,000 2. Talbert Barrier injection 2,000 3. Alamitos Barrier injection, Orange County portion only 275,000 Subtotal: Estimated Unmeasured or Incidental Recharge2 47,000 1. Subsurface Inflow 19,000 2. Areal recharge from rainfall/irrigation 66,000 Subtotal: TOTAL INFLOW: 341,000 OUTFLOW 335,000 1. Groundwater Production 6,000 2. Subsurface Outflow

TOTAL OUTFLOW: 341,000 CHANGE IN STORAGE: 0 1 Evaporation from surface recharge facilities is estimated to be 2,000 afy. 2 Assuming average precipitation (14 inches/year)

2.3.1 Measured Recharge Measured recharge consists of all water artificially recharged at OCWD’s surface water recharge facilities and water injected in the Talbert and Alamitos Barriers. The majority of measured recharge occurs in the District’s surface water system, as shown in Figure 2-5, which receives Santa Ana River base flow and storm flow, imported water and GWRS recycled water. In recent years, GWRS and imported water have become more important as the annual volume of Santa Ana River base flow declines and the drought that began in 2011.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-9 Section 2 Basin Hydrogeology

Figure 2-5: OCWD Recharge Facilities in Anaheim and Orange

Seawater intrusion barriers are shown in Figure 2-6. OCWD’s Talbert Barrier is a series of injection wells that span the 2.5-mile wide Talbert Gap, between the Newport and Huntington Beach mesas. Purified water produced by the GWRS is injected into multiple aquifers; over 95 percent of the injected water flows inland and becomes part of the basin’s groundwater supply. The Alamitos Barrier is a series of wells injecting a blend of imported and recycled water into multiple aquifer zones that span the Alamitos Gap at the Los Angeles/Orange County line. Essentially all of the injected water flows inland, replenishing groundwater basins in the two counties. Inspection of groundwater contour maps indicates that roughly one-third of the Alamitos Barrier injection water remains within or flows into Orange County.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-10 Section 2 Basin Hydrogeology

Figure 2-6: Seawater Intrusion Barriers

2.3.2 Unmeasured Recharge Unmeasured recharge also referred to as “incidental recharge” accounts for a significant amount of the basin’s sustainable yield. This includes recharge from precipitation, irrigation return flows, urban runoff, seawater inflow through the gaps as well as subsurface inflow at the basin margins along the Chino, Coyote, and San Joaquin Hills and the Santa Ana Mountains and beneath the Santa Ana River and Santiago Creek. Subsurface inflow in the Santa Ana River and Santiago Creek refers to groundwater that enters the basin at the mouth of Santa Ana Canyon and in the Santiago Creek drainage below Villa Park Dam. Estimated average subsurface inflow to the basin is shown in Figure 2-7.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-11 Section 2 Basin Hydrogeology

Figure 2-7: Estimated Subsurface Recharge

Total unmeasured recharge ranges between 20,000 to 160,000 afy. This number is the volume left over after all the basin inputs and outputs are accounted for. Net unmeasured or incidental recharge is the amount of incidental recharge remaining in the basin after accounting for losses to Los Angeles County. Under average hydrologic conditions, net incidental recharge averages 66,000 acre-feet per year. This average was substantiated during calibration of the Basin Model and is also consistent with the estimate of 58,000 afy reported by Hardt and Cordes (1971) as part of a U.S. Geological Survey (USGS) modeling study of the basin. Because unmeasured recharge is one of the least understood components of the basin’s water budget, the error margin for any given year is probably in the range of 10,000 to 20,000 acre-feet. Since unmeasured recharge is well distributed throughout the basin, the physical significance

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-12 Section 2 Basin Hydrogeology

(e.g., water level drawdown or mounding in any given area) of over- or underestimating the total recharge volume within this error margin is considered to be minor. 2.3.3 Groundwater Production Active wells pumping water from the basin are shown in Figure 2-8. The approximately 200 large-system wells account for an estimated 97 percent of the total basin production; 200 small wells produce less than 25 afy. Large-capacity wells are all metered, as required by the District Act. Production data was recorded on a semi-annual basin until 1988 when the District began obtaining monthly individual well production measurements.

Simulated outflow to LA County, acre- feet/year

Figure 2-8: Distribution of Groundwater Production, Water Year 2012-14

2.3.4 Subsurface Outflow Groundwater outflow from the basin across the Los Angeles/Orange County line has been estimated to range from approximately 1,000 to 14,000 afy based on groundwater elevation gradients and aquifer transmissivity (DWR, 1967; McGillicuddy, 1989). The Water Replenishment District of Southern California also has estimated underflow from Orange County to Los Angeles County within the aforementioned range. Modeling by OCWD indicates that assuming that groundwater elevations in Los Angeles County remain constant underflow to Los Angeles County increases by approximately 7,500 afy for every 100,000 acre-feet of increased groundwater in storage in Orange County (see Figure 2-9). With the exception of unknown amounts of semi-perched

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-13 Section 2 Basin Hydrogeology

(near-surface) groundwater being intercepted and drained by submerged sewer trunk lines and unlined flood control channels along coastal portions of the basin, no other significant basin outflows are known to occur.

40,000

30,000

June 2014 20,000

342,000 acre- feet below full condition

10,000

Outflow to LA

0

Inflow from LA

-10,000 0 100,000 200,000 300,000 400,000 500,000

Available Storage Space (amount below full condition ), acre-feet

Figure 2-9: Relationship between OCWD Basin Storage and Estimated Outflow to Los Angeles County

2.3.5 Evaporation The total wetted area of the District’s recharge system is over 1,000 acres. OCWD estimates the evaporation from this system on a monthly basis. Generally, total evaporation is on the order of 2,000 acre-feet per year which is approximately one percent of the total volume recharged annually. The relatively minor impact of evaporation reflects high percolation rates (1 to 10 feet per day).

2.4 Calculation of Change in Groundwater Storage

Even though the groundwater basin contains an estimated 66 million acre-feet when full, OCWD operates the basin from a full condition to approximately 500,000 acre-feet below full to protect against irreversible seawater intrusion and land subsidence. On a

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-14 Section 2 Basin Hydrogeology

short-term basis, the basin can be operated at an even lower storage level in an emergency. The District manages storage and water levels in the groundwater basin within a safe operating range as described in OCWD’s Groundwater Management Plan (OCWD, 2015). The safe operating range is defined as the upper and lower levels of groundwater storage in the basin that can be reached without causing negative or adverse impacts. In order to manage the basin within this safe operating range, OCWD calculates the amount of groundwater in storage on an annual basis. The estimated historical minimum storage level of 500,000 to 700,000 acre-feet below full condition occurred in 1956-57 (DWR, 1967; OCWD, 2003). Since this time, the basin storage fluctuated within the safe operating range reaching a full condition in 1969, and 1983. Even though the District calculates and reports accumulated overdraft in its annual Engineers Report, “overdraft” in the traditional sense does not exist in the Orange County Groundwater Basin because the basin is operated to continuously fluctuate within the safe operating range.

The District uses two methods to calculate the storage condition of the basin: (1) water budget method and (2) three-layer storage change method. The water budget method is simply an accounting of the inflows to the basin and outflows. This data is collected and compiled on a monthly basis. Estimates of unmeasured or incidental recharge are used until trued up at the end of the year with the final reports of inflows and outflows. This method produces a monthly estimate of the change in groundwater storage and allows for virtually real-time decision making with respect to managing the basin.

In 2007, OCWD instituted a new three-layer change in storage method for calculating the amount of groundwater in storage. The three-layer method involves creating groundwater elevation contour maps for each of the three aquifer layers (Shallow, Principal, and Deep Aquifers) in the basin, schematically represented in Figure 2-10, for conditions at the end of June of each year. This updated approach includes: • A new full-basin groundwater level based on the following prescribed conditions:

o Observed historical high water levels o Present-day pumping and recharge conditions o Protection from seawater intrusion o Minimal potential for mounding at or near recharge basins

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-15 Section 2 Basin Hydrogeology

• Calculation of the amount of groundwater in storage in each of the three major aquifer systems. A more detailed description of the three-layer methodology is presented in OCWD’s Report on Evaluation of Orange County Groundwater Basin Storage and Operational Strategy (February 2007) and can be found in OCWD’s Groundwater Management Plan (OCWD, 2015).

Figure 2-10: Schematic Cross-Section of the Basin Showing Three Aquifer Layers

Figure 2-11 shows the contoured water levels for the Principal Aquifer in June 2014. The maps are prepared annually and scanned and digitized into the District’s GIS database. The previous year’s water levels are subtracted from the current water levels to calculate change in water levels. Water level change contour maps are prepared for each of the three aquifer layers. Figure 2-12 shows the water level change for the Principal Aquifer from June 2013 to June 2014. For each of the three aquifers, the GIS is used to multiply the water level changes by a grid of aquifer storage coefficients from OCWD’s calibrated groundwater flow model. This results in a storage change volume for each of the three aquifers which are totaled to provide a net annual storage change for the basin, shown in Figure 2-13. In cases where there is a calculation discrepancy between the storage changes estimated by the two methods, the unmeasured recharge value is adjusted to eliminate the difference.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-16 Section 2 Basin Hydrogeology

Figure 2-11: Groundwater Level Contour Map, June 2014

Figure 2-12: Groundwater Level Changes, June 2013-14

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-17 Section 2 Basin Hydrogeology

Available Storage Space (amount below full condition) Acre-feet (x1000)

Figure 2-13: Change in Groundwater Storage, WY 1974-75 to 2013-14

2.5 Elevation Trends

The groundwater elevation profile for the Principal Aquifer following the Santa Ana River from the ocean to the Forebay in Anaheim, for 1969, 2013, and the theoretical full condition are shown in Figure 2-14. A comparison of these profiles shows that groundwater elevations in the Forebay recharge area for all three conditions are similar while in the central and coastal areas of the basin elevations in 2013 are significantly lower. The lowering of coastal area groundwater levels relative to groundwater levels further inland in the Forebay translates into a steeper hydraulic gradient, which drives greater flow from the Forebay to the coastal areas. However, the lowering of coastal water levels also increases the risk of seawater intrusion. Groundwater elevation trends can be examined using five wells with long-term groundwater level data, the locations of which are shown in Figure 2-15. Figures 2-16 and 2-17 show water level hydrographs for wells SA-21 and GG-16, representing historical conditions in the Pressure area and well A-27, representing historical conditions in the Forebay. Water level data for well A-27 near Anaheim Lake dates back to 1932 and indicate that the historic low water level in this area occurred in 1951-52. The subsequent replenishment of Colorado River water essentially refilled the basin by 1965. Water levels in this well reached an historic high in 1994 and have generally remained high as recharge has been nearly continuous at Anaheim Lake since the late 1950s.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-18 Section 2 Basin Hydrogeology

Elevation (feet MSL)

Figure 2-14: Principal Aquifer Groundwater Elevation Profiles, 1969 and 2013

Figure 2-15: Location of Long-Term Groundwater Elevation Hydrograph

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-19 Section 2 Basin Hydrogeology

Figure 2-16: Water Level Hydrographs of Wells SA-21 and GG-16 in Pressure Area

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-20 Section 2 Basin Hydrogeology

Figure 2-17: Water Level Hydrographs of Well A-27 in Forebay

The hydrograph for well SA-21 indicates that water levels in this area have decreased since 1970. Also noteworthy is the large range of water level fluctuations from the early 1990s to early 2000s. The increased water level fluctuations during this period were due to a combination seasonal water demand-driven pumping and participation in the MWD Short-Term Seasonal Storage Program by local Producers (Boyle Engineering and OCWD, 1997), which encouraged increased pumping from the groundwater basin during summer months when MWD was experiencing high demand for imported water. Although this program did not increase the amount of pumping from the basin on an annual basis, it did result in greater water level declines during the summer during the period of 1989 to 2002 when the program was active. Figure 2-18 presents water level hydrographs of two OCWD multi-depth monitoring wells, SAR-1 and OCWD-CTG1, showing the relationship between water level elevations in aquifer zones at different depths. The hydrograph of well SAR-1 in the Forebay exhibits a similarity in water levels between shallow and deep aquifers, which indicates the high degree of hydraulic interconnection between aquifers characteristic of much of the Forebay. The hydrograph of well OCWD-CTG1 is typical of the Pressure Area in that there are large differences in water levels in different aquifers, indicating a reduced level of hydraulic interconnectivity between shallow and deep aquifers caused by fine-grained

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-21 Section 2 Basin Hydrogeology layers that restrict vertical groundwater flow. Water levels in the deepest aquifer zone at well OCWD-CTG1 are higher than overlying aquifers, in part, because few wells directly produce water from these zones. The lack of production from the deepest aquifers is due to the presences of amber-colored water and the depth required to produce water from these zones.

Figure 2-18: Water Level Hydrographs of Wells SAR-1 and OCWD-CTG1

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-22 Section 2 Basin Hydrogeology

2.6 Basin Model

OCWD’s basin model encompasses the entire basin and extends approximately three miles into the Central Basin in Los Angeles County to provide for more accurate model results than if the model boundary stopped at the county line (see Figure 2-19). As noted previously in this chapter, the county line is not a hydrogeologic boundary, i.e., groundwater freely flows through aquifers that have been correlated across the county line.

Figure 2-19: Basin Model Extent

Coverage of the modeled area is accomplished with grid cells having horizontal dimensions of 500 feet by 500 feet (approximately 5.7 acres) and vertical dimensions ranging from approximately 50 to 1,800 feet, depending on the thickness of each model layer at that grid cell location. Basin aquifers and aquitards are grouped into three composite model layers thought sufficient to describe the three distinguishable flow

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-23 Section 2 Basin Hydrogeology

systems corresponding to the Shallow, Principal, and Deep Aquifers. The three model layers comprise a network of over 90,000 grid cells. The widely-accepted computer program, “MODFLOW,” developed by the USGS, was used as the base modeling code for the mathematical model (McDonald and Harbaugh, 1988). Data files for each grid cell in each model layer include the following: • Aquifer top and bottom elevations • Aquifer lateral boundary conditions (ocean, faults, mountains) • Aquifer hydraulic conductivity and storage coefficient/specific yield • Initial groundwater surface elevation • Natural and artificial recharge rates (runoff, precipitation, percolation, injection) • Groundwater production rates for approximately 200 large system and 200 small system wells These data originate from hand-drawn contour maps, spreadsheets, and the Water Resources Management System (WRMS) historical database. The basin model was first calibrated to steady-state conditions to numerically stabilize the simulations, to make rough adjustments to the water budget terms, and to generally match regional groundwater flow patterns. Also, the steady-state calibration helped to determine the sensitivity of simulated groundwater levels to changes in incidental recharge and aquifer parameters such as hydraulic conductivity. Steady-state calibration of the basin model is documented in more detail in the OCWD Master Plan Report (OCWD, 1999). Model construction, calibration, and operation were built upon 12 years of effort by OCWD staff to collect, compile, digitize, and interpret hundreds of borehole geologic and geophysical log, water level hydrographs, and water quality analyses.

2.7.3 Groundwater Model Update and Applications OCWD staff update the basin groundwater model approximately every three to five years, guided by new information warranting the effort (new wells in critical areas) or by needed model evaluations using the most recent years, e.g., estimating the groundwater outflow to Los Angeles County. Major changes and improvements over the past five years include: 1. Model conversion from UNIX to PC using the Groundwater Vistas as the Graphical User Interface. 2. Extension of the model transient calibration through WY 2010-11. The new calibration period is November 1990 to June 2011 which includes a wide range of basin storage conditions as well as a wide range of hydrologic conditions.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-24 Section 2 Basin Hydrogeology

3. Addition of several new Talbert Barrier injection wells and the addition of two new recharge basins, La Jolla and Miraloma Basins. Typical applications of the Basin Model include estimating the effects of potential future pumping and recharge projects on groundwater levels, storage, and the water budget. The storage coefficients determined during the original Basin Model calibration are also used to estimate annual change in groundwater storage. Additional details on OCWD’s basin model can be found in the OCWD Groundwater Management Plan, 2015 Update, Section 3.7.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 2-25 Section 3 Modeling Approach

SECTION 3 MODELING APPROACH

This section reviews the approach used to estimate future TDS and nitrate concentrations in the OC Management Zone.

3.1 Conceptual Model

Section 2 presents a balanced hydrologic budget for the Orange County Management Zone. This balanced water budget is based on average precipitation and average hydrology. Total outflow from the management zone, which primarily consists of groundwater pumping, is equal to the total inflow. This balanced hydrologic budget is used as an approximation of future inflow and outflow from the management zone. For the purposes of developing a mathematical model of future TDS and nitrate concentrations, the following conceptual model is used: • The Orange County Management Zone is represented as a single, lumped unit; • All inflow and outflow into the management zone are assumed to mix completely; • Average hydrology is used, such that inflow and outflow rates are constant through time and are based on the rates in Table 2-2; • The initial concentration is the ambient concentration from the most recent 20- year period (see the Technical Memorandum Recomputation of Ambient Water Quality in the Santa Ana Watershed for the Period 1993 to 2012, Wildermuth Environmental, 2014); for TDS, the initial concentration is 610 milligrams per liter (mg/L); for nitrate-nitrogen, the initial concentration is 2.9 mg/L; • The concentration of Santa Ana River (SAR) baseflow is based on data for the last three years at below Prado Dam; • The concentration of subsurface inflow and foothill recharge is based on concentration data from wells located in areas of subsurface inflow and foothill recharge from the last three years; • The concentration of SAR stormflow is based on estimated data from the sampling location at below Prado Dam; • The Alamitos Injection Barrier supply is calculated as the flow-weighted average for calendar years 2012-2014; • The Groundwater Replenishment System (GWR System) provides 103,000 acre- feet per year (afy) of recharge water with a TDS concentration of 60 mg/L.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-1 Section 3 Modeling Approach

• Irrigation efficiency is assumed to be 75 percent; the TDS of applied water that reaches the groundwater table is four times greater than the TDS of the irrigation water; and • The concentration of applied water and the resultant concentration of applied water that reaches the groundwater table will remain constant.

3.2 Model Methodology

The modeling approach to estimating future TDS and nitrate concentrations is based on a continuous-flow stirred tank reactor (CFSTR) approximation. This approach is the same overall approach as that used in the Chino Basin (see Chino Basin Watermaster, 2002). A similar approach, also called a ‘lumped parameter’ or ‘single-cell’ model has also been used by other studies to assess water quality issues (see Mercado, 1976; Guymon, et al, 1992). The water volume balance for the management zone is:

Inflow – Outflow = Change in Storage The TDS mass balance is also based on this equation (the difference between the mass inflow and mass outflow is equal to the change of mass in storage for the management zone). For TDS, an explicit finite-difference approximation is used. The approximation is:

EQ 1 ∑ [ Ij,t to t+1 * Cj,t ] k,t to ∑ t+1 [O * C t to t+1] = VGWt+1*CGWt+1-VGWt*CGWt Where:

th Ij,t to t+1 is the j inflow during the period t to t+1 th Cj,t is the TDS concentration for the j inflow during the period t to t+1 th Ok,t to t+1 is the k outflow from the groundwater basin during the period t to t+1

VGWt+1 is the volume of groundwater in storage at t+1

Wt+1 is the TDS concentration of groundwater in storage at t+1

C t to t+1 is the TDS concentration of groundwater outflow during the period t to t+1

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-2 Section 3 Modeling Approach

The TDS mass balance is solved for CGWt+1 as follows:

EQ 1 ∑ [ Ij,t to t+1 * Cj,t ]  ∑ [Ok,t to t+1 * C t to t+1] = VGWt+1*CGWt+1-VGWt*CGWt

∑ [ Ij,t to t+1 * Cj,t ]  ∑ [Ok,t to t+1 * [CGWt + CGWt+1 ]/2] = VGWt+1*CGWt+1-VGWt*CGWt

∑ [ Ij,t to t+1 * Cj,t ] + VGWt*CGWt  ∑ [Ok,t to t+1 * CGWt /2] = VGWt+1*CGWt+1 + ∑ [Ok,t to t+1

* CGWt+1 ]/2]

∑ [ Ij,t to t+1 * Cj,t ] + CGWt *[ VGWt* - ∑ [Ok,t to t+1 /2] = CGWt+1 * [VGWt+1* + ∑ [Ok,t to t+1 /2]

CGWt+1 = { ∑ [ Ij,t to t+1 * Cj,t ] + CGWt *[ VGWt* - ∑ [Ok,t to t+1 /2] } / [VGWt+1* + ∑ [Ok,t to t+1 /2]

The calculation of CGWt+1 was done using a computer spreadsheet. A time step of one year was used. This approach was selected because it provides a tool to account for the relative contributions of different types of recharge water and also calculates the balance of salt inflow and outflow. As conditions change in the future, it may be appropriate to evaluate the use of a more detailed model.

3.3 Model Input

The annual volume and concentration of each inflow to the model is specified as input to the model. Table 3-1 summarizes each inflow component, the corresponding TDS concentration, and the tons of salt associated with each inflow. The flow-weighted TDS concentration of the inflows is 479 mg/L.

Table 3-1: Summary of Inflows to Orange County Management Zone Volume TDS Conc. Mass Inflow (acre-feet) (mg/L) (tons) Deep percolation of precipitation 6,500 100 900 Percolation of applied water 9,000 1,900 23,200 Subsurface inflow 37,500 1,177 59,200 SAR baseflow 52,000 700 49,200 SAR stormflow 50,000 200 13,600 Recycled water 103,000 60 8,400

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-3 Section 3 Modeling Approach

Volume TDS Conc. Mass Inflow (acre-feet) (mg/L) (tons) Alamitos Barrier 2,500 350 1,200 MWD imported water 65,000 650 57,300 Total 325,000 479 213,000

DEEP PERCOLATION OF PRECIPITATION The TDS concentration of deep percolation of precipitation was specified at 100 mg/L. This represents the TDS of water that percolates into the groundwater basin in response to precipitation.

PERCOLATION OF APPLIED WATER The TDS concentration of percolated applied water was calculated to be 1,900 mg/L assuming an irrigation efficiency of 75 percent. This calculation was based on a delivered water TDS concentration of 475 mg/L. The delivered water concentration was based on the average TDS of delivered water as calculated in the annual Engineer’s Report prepared by OCWD. Table 3-2 summarizes the delivered water concentration for the last three years. Delivered water consists of a blend of groundwater, imported water from MWD, and Santiago Reservoir water. The delivered water concentration is calculated for each water retailer in each year’s Engineer’s Report. Appendix B provides the calculation of the delivered water concentration for water years 2012-2015.

The TDS concentration for percolated applied water of 1,900 mg/L generally corresponds to the TDS concentration observed in monitoring wells that are completed in the shallow, semi-perched interval of the basin. Table 3-3 lists the most recent TDS concentrations at a series of such wells.

Table 3-2: Delivered Water Quality Summary

TDS Conc. of Delivered Water Water Year (mg/L) 2012-13 461 2013-14 482 2014-15 482 Average 475 Reference: OCWD Engineer’s Report (2014, 2015, 2016)

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-4 Section 3 Modeling Approach

Table 3-3: Recent TDS Concentrations at Monitoring Wells in Shallow Semi-Perched Interval TDS Conc. Well ID Sample Date (mg/L) MSP-10P/1 3/12/2015 1,050 MSP-10P/1 8/17/2015 1,090 OCWD-GA5/1 8/17/2015 2,400 OCWD-GA7/1 8/20/2007 2,080 OCWD-GA7/1 8/17/2015 2,100 OCWD-GA9/1 3/12/2015 1,290 OCWD-GA9/1 8/17/2015 1,720

SANTA ANA RIVER BASEFLOW The TDS of Santa Ana River baseflow was set at 700 mg/L, based on the average TDS for the last three years. Figure 3-1 shows the TDS concentration of the SAR at below Prado Dam.

TDS (mg/L)

900

800

700

600

500

400

300

200

100

Figure 3-1: TDS Concentration in SAR at Below Prado Dam

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-5 Section 3 Modeling Approach

SANTA ANA RIVER STORMFLOW Each year, the Santa Ana River Watermaster prepares a report that estimates the amount of stormflow and baseflow at Prado (SAR Watermaster, 2015). Data in these reports was used to estimate the TDS of Santa Ana River stormflow. Electrical conductivity values are available on a daily basis. These electrical conductivity values are used to estimate TDS on a daily basis. These daily TDS values were used to compare to an estimated TDS concentration that assumed the TDS concentration was a blend of baseflow and stormflow. The estimated TDS concentration of stormflow was varied to achieve a close approximation of the daily TDS values. Figure 3-2 shows this calculation for water year 2004-05. Based on this evaluation, the TDS of SAR stormflow was specified as 200 mg/L.

Estimated TDS from baseflow- stormflow blend (mg/L) 800 TDS baseflow = 620 mg/L 700 TDS stormflow = 200 mg/L

600

500 400

300 c 200

100

0 0 100 200 300 400 500 600 700 800 TDS Estimated from Electrical Conductivity (mg/L)

Figure 3-2: Estimation of Stormflow TDS

RECYCLED WATER The GWR System produces up to 103,000 afy of recycled water. Approximately one- third of this water is recharged through the Talbert Injection Barrier and the remainder is recharged at surface recharge facilities in Anaheim. The average TDS of GWR System product water in 2014 was 54 mg/L. (GWRS 2014 Annual Report, June 17, 2015) The TDS at monitoring well AM-50 is shown in Figure 3-3. This well is located near OCWD’s Miraloma Basin (see Figure 3-4), a new basin that came on line in 2012. This

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-6 Section 3 Modeling Approach

basin is dedicated to recharging only GWRS-produced recycled water. The low-TDS in sampled groundwater indicates the effect of groundwater recharge using GWRS water with an estimated TDS concentration of 60 mg/L on the TDS in the nearby groundwater basin.

Figure 3-3: Monitoring Well AM-50 TDS Concentration

Figure 3-4: Location of Miraloma Basin and Monitoring Well AM-50

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-7 Section 3 Modeling Approach

SUBSURFACE INFLOW As indicated in Table 3-1, a total of 37,500 afy of subsurface inflow was included in the model inflow. The flow-weighted TDS of the subsurface inflow was estimated to be 1,177 mg/L. Subsurface inflow components and the basis for estimating the concentration of the inflows are shown in Table 3-4 and Figure 3-5. For most of the subsurface inflow components, TDS concentration data from wells were used. The locations of the wells used to estimate inflow concentrations are shown in Figure 3-6. TDS data from years 2000-2015 were utilized. For inflow into the Orange County Management Zone from the Irvine Management Zone, the current ambient TDS concentration of 940 mg/L for the Irvine Management Zone was used. (Wildermuth Environmental, 2014) A survey of onsite wastewater disposal systems in Orange County was conducted in 2003 and is included in the County of Orange’s Drainage Area Management Plan (County of Orange, 2003). The survey reported there are over 2,776 onsite disposal systems in the entire county, of which approximately 2,100 are in the OC Management Zone. Appendix C contains a map showing the locations of the onsite disposal systems in Orange County. The Tustin Hills area and the Yorba Linda area are two locations with relatively higher occurrence of onsite waste disposal systems. Recharge along the Tustin Hills is estimated to occur at a TDS concentration of 1,300 mg/L. This concentration is based on wells T-17S4 and T-NEWP. These wells have relatively high TDS concentrations compared to other wells in the management zone. Inflow to the Yorba Linda Sub-basin is also specified with a relatively high TDS, with a TDS concentration of 1,000 mg/L. The high TDS concentrations of inflow from the Tustin Hills and inflow to the Yorba Linda Sub-basin indirectly account for the salt loads from the onsite waste disposal systems in these two areas. For the Alamitos Injection Barrier, the TDS of the injection water was specified at 350 mg/L. This is based on a blend of recycled water and imported water.

Table 3-4: Summary of Subsurface Inflow Components

TDS Volume Mass Inflow Conc. Basis for Conc. Estimate (Acre-feet) (tons) (mg/L) Inflow from La Habra 3,000 1,200 4,884 Well FM-6 Basin Recharge from foothills 6,000 1,300 10,613 Average of wells AM-1 and into Yorba Linda Sub- AM-2 basin Subsurface inflow at 4,000 600 3,265 Well OCWD-LV-1

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-8 Section 3 Modeling Approach

TDS Volume Mass Inflow Conc. Basis for Conc. Estimate (Acre-feet) (tons) (mg/L) Imperial Hwy in Santa Ana Canyon SAR recharge between 4,000 520 2,822 Blend of stormflow and Imperial Hwy and baseflow (75% baseflow, Inflatable Dam 25% stormflow) Subsurface inflow from 10,000 400 5,427 Well SC-1 zone 6 Santiago Canyon Recharge along 4,000 1,100 5,970 Average of wells ANDR-A Peralta Hills and O-21 Recharge along Tustin 2,000 1,300 3,528 Average of wells T-17S4 Hills and T-NEWP Seawater inflow 500 27,000 18,316 Well OCWD-T5/1 (highest through coastal gaps observed TDS in Talbert, Bolsa, Sunset Gaps) Inflow from Irvine 4,000 940 5101 Ambient groundwater Management Zone quality (1993-2012 period) Total 37,500 1,177 59,917

Figure 3-5: Subsurface Inflow into the Orange County Management Zone

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-9 Section 3 Modeling Approach

Figure 3-6: Wells Used To Estimate Subsurface Inflow Concentrations 3.4 Model Verification

Given the nature of the model, a calibration of the model has not been completed. The degree to which the model is a useful predictor of future concentrations can be assessed after a period of time has elapsed and past model projections can be compared to actual conditions. A comparison can be made of the model projection of water quality with the ambient water quality calculated (WEI, 2014). There are however different assumptions used in the ambient water quality calculations and the model, and any comparison needs to consider the different assumptions. Some issues that may be important to assess in the future include: • The ambient water quality calculation uses the previous 20 years of data for each well, compared to the model which uses a year-by-year calculation and assumes all water in the basin mixes each year. • The concentration of delivered water - the actual concentration of delivered water in the future will vary in response to a number of factors, including the TDS of imported water. Operation of the GWR System to provide low TDS water in the groundwater basin will continue to help reduce the TDS of applied water.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-10 Section 3 Modeling Approach

Additionally, if Orange County develops a ocean water desalination facility that provides low-TDS desalted seawater to the area, this will also affect the TDS of delivered water. • The TDS of subsurface inflows - in some cases, it may be beneficial to collect additional data regarding the rate and TDS concentration of subsurface inflows.

3.5 TDS Predictions Using the Model The model was utilized to estimate future TDS concentrations using the approach described in the previous sections. The base case or baseline, referred to as Case 1, assumes that no imported water is used for recharge for the 30-year period. The base case or baseline is utilized to compare with other model runs and determine how changing model inputs affect the predicted concentration. The projected trend for TDS for Case 1 is shown in Figure 3-7. The spreadsheet showing the data used for this projection can be found in Appendix D. Seven additional scenarios were run to model different quantities of recharge source water. These scenarios and the model results are discussed in the following section.

2012 Ambient Water Quality

Water Quality Objective

Figure 3-7: Estimated TDS Concentration in Base Case for 30-year Period

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-11 Section 3 Modeling Approach

3.6 Sensitivity Analysis

The TDS model was used to evaluate the sensitivity to changing selected input values. In each case, pumping is adjusted to balance inflow and outflow. The following model cases or scenarios were analyzed with the model: • Case 2 – Case 2 is the same as Case 1 but with 65,000 afy imported water recharge (this is the amount OCWD has an agreement with MWDOC to purchase); the TDS of the imported water recharged was specified at 650 mg/L

• Case 3 – Case 3 is the same as Case 1 but with 30,000 afy imported water recharge; the TDS of the additional imported water recharged was specified at 650 mg/L

• Case 4 – Case 4 is the same as Case 1 but with 100,000 afy imported water recharge each year; the TDS of the additional imported water recharged was specified at 650 mg/L

• Case 5 – Case 5 is the same as Case 1 but with an additional 30,000 afy recharge water from the GWR System (for a total of 133,000 afy recharge water from the GWR System); the TDS of the additional GWR System recharge water was specified at 60 mg/L

• Case 6 – Case 6 is the same as Case 1 but with the SAR baseflow supply assumed to be 90,000 afy; the TDS is similar to Case 1, specified at 700 mg/L

• Case 7 – Case 7 is the same as Case 1 but with the SAR stormflow supply assumed to be 30,000 afy; the TDS is similar to Case 1, specified at 200 mg/L

• Case 8 – Case 8 is the same as Case 1 but with 65,000 afy imported water recharge at a TDS of 700 mg/L; SAR stormwater supplies were assumed to be 30,000 afy

• Case 9 – Case 9 is the same as Case 1 but with 56,000 afy of desalinated ocean water recharged at a TDS of 350 mg/L; the TDS of the desalinated ocean water is based on the average TDS concentration in the Term Sheet for the Poseidon Huntington Beach Seawater Desalination Project approved by OCWD on May 14, 2015.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-12 Section 3 Modeling Approach

The results are shown in Table 3-5 and Figure 3-8. The TDS concentrations at the end of the 30-year projections ranged from a low of 565 mg/L for Case 5 to a high of 588 mg/L for Case 8. Case 5 includes recharging 133,000 afy of low-TDS recycled water produced by GWRS. The other cases assumed a recharge of 103,000 afy of GWR recycled water. For Case 5, the flow-weighted TDS of inflow of recharge water sources was the lowest at 403 mg/L, another factor that indicates that recharge of GWRS recycled water over the long-term has a significant role in reduction in TDS in the basin. For the first four cases, the volume of the individual recharged water sources remains constant except for the volume of imported water recharged. As expected, as the volume of imported water increases so does the projected TDS concentration in the groundwater basin in the final year (year 30), as shown in Table 3-6. In all cases, the projected TDS concentration trends downward below the initial concentration. For Case 9, which is the same as Case 1 except that it includes recharge of 56,000 afy of desalinated ocean water, the model results show that the TDS concentration in the OC Management Zone improves relative to Case 1 due to the recharge of the desalinated ocean water. As shown in Table 3-5, the flow-weighted TDS of the inflow (recharge) in Case 1 is 443 mg/L and 426 mg/L for Case 9. The better inflow water quality in Case 9 relative to Case 1 causes the final year projected TDS concentration to improve from 577 mg/L in Case 1 to 567 mg/L for Case 9.

Table 3-5: Summary of TDS Estimates for Model Cases Annual Annual Volume of Water Recharged (af) Final Flow- year Pumping weighted Scenario Imported GWRS SAR SAR projected (af) TDS of or ‘Case’ Water Recycled Stormflow Baseflow TDS inflow Water conc. (mg/L) (mg/L) Case 1 238,500 0 103,000 50,000 52,000 443 577 Case 2 303,500 65,000 103,000 50,000 52,000 484 580 Case 3 268,500 30,000 103,000 50,000 52,000 462 579 Case 4 338,500 100,000 103,000 50,000 52,000 500 581 Case 5 268,500 0 133,000 50,000 52,000 403 565 Case 6 276,500 0 103,000 50,000 90,000 476 580 Case 7 248,500 0 103,000 30,000 52,000 463 583 Case 8 283,500 65,000 103,000 30,000 52,000 513 588 Case 9* 294,500 0 103,000 50,000 52,000 426 567 Note: *Case 9 includes recharge of 56,000 afy of desalinated ocean water

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-13 Section 3 Modeling Approach

Table 3-6: Comparison of Amount of Imported Water Recharge and Projected TDS Concentrations for Cases 1-4

Volume of Imported Flow-weighted Final year Projected Case Water Recharged TDS of Inflow TDS concentration (afy) (mg/L) (mg/L) 4 100,000 500 581 2 65,000 484 580 3 30,000 462 579 1 0 443 577

Figure 3-8: TDS Estimates for Model Cases

It is important to note that in all the cases the long-term TDS projection remains below the current ambient concentration of 610 mg/L. The model estimates that TDS concentrations for all model runs will gradually decrease from an initial TDS concentration of 610 mg/L. This is expected considering that the flow-weighted TDS of the water recharged for all the cases is less than the current ambient concentration. In

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-14 Section 3 Modeling Approach

theory, this trend will continue in the future until the projected groundwater basin concentration reaches the inflow TDS concentration. The level of uncertainty for the model results is related to a range of factors. One factor that affects the model results is the uncertainty in the TDS of subsurface inflow. This is due to the limited data available to define the TDS concentration of groundwater inflow into the management zone. The rate of subsurface inflow is also subject to uncertainty. Another factor that affects the model results is uncertainty in the rate and concentration of deep percolation of precipitation and deep percolation of applied water. Calibration of the OCWD MODFLOW groundwater model, the data set regarding annual changes in groundwater storage, and related water budget calculations done on an annual basis over many years provide a good estimate of the total amount of incidental recharge. Incidental recharge includes both deep percolation of precipitation and deep percolation of applied water. However, it is difficult to distinguish these two components using a water budget approach. Since these two components have different TDS concentrations in the model, if the actual rates vary from the model values, this could affect the model predictions. In general terms, the model inputs with the greatest uncertainty are the amount and quality of subsurface inflows, deep percolation of precipitation, and deep percolation of applied water. As indicated in Table 3-7 and the corresponding figures, the model projects that the TDS concentration will decrease in each of the cases. This is because the inflow flow-weighted TDS concentration is below the initial TDS concentration of 610 mg/L. As expected, the case with the lowest TDS concentration projection was Case 5, the model run with the largest volume of recycled water recharged.

3.7 Nitrate Projection for Orange County Management Zone

The approach used to estimate future nitrate concentrations is similar to the approach used for TDS projections. The nitrate (as nitrogen, or nitrate-N) concentration for each inflow component was estimated using available data. Table 3-7 summarizes the inflow terms and their nitrate-N concentrations. Table 3-8 summarizes the components of subsurface inflow. The source of data for the nitrate-N concentration of imported water was from the MWD report, General Mineral and Physical Analysis of Metropolitan’s Water Supplies, Calendar Year Averages, 2015. In this report, the concentration of nitrate was reported as 0.9 mg/L for Lake Mathews (representing Colorado River supplies) and 2.5 mg/L for Silverwood Lake (State Water Project supplies). Using the higher value of 2.5 mg/L provided a more conservative estimate of nitrate concentrations in imported water used

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-15 Section 3 Modeling Approach

for groundwater recharge. For consistency, the nitrate value of 2.5 mg/L was converted to 0.6 mg/L for nitrate-N. The flow-weighted average nitrate-N concentration for all inflows to the management zone is 2.1 mg/L. The initial concentration was set at 2.9 mg/L (based on the current ambient concentration for the most recent 20-year period). Since the inflow concentration is less than the initial concentration, the estimated future nitrate concentration gradually decreases.

For nitrate, the base case or baseline assumed no imported water recharge. The result of the base case was compared to two additional scenarios. The first additional scenario has the same inflows as the base case but with 65,000 afy of imported water recharge. The model results for the base case (Case 1) and the scenario with imported water (Case 2) are shown in Figure 3-9 and the data used for these projections can be found in Appendix E. The concentration of 2.1 mg/L for nitrate-N in inflows to the Orange County Management Zone is below the water quality objective of 3.4 mg/L nitrate-N and the maximum imported water recharge nitrate concentration is also below the water quality objective. Therefore, no additional cases with imported water from the Colorado River or State Water Project were modeled.

Table 3-7: Summary of Inflows to OC Management Zone with Imported Water Volume Nitrate-N Mass Inflow (Acre-Feet) Conc.(mg/L) (tons) Deep Percolation of Precipitation 6,500 1 9 Percolation of applied water 9,000 10 122 SAR baseflow 52,000 4.5 318 SAR stormflow 50,000 0.9 61 Imported water recharge 65,000 0.6 53 Recycled water recharge 103,000 1.7 238 Subsurface inflow 37,500 3.5 178 Alamitos Barrier 2,500 2 7 Total 325,500 2.1 986

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-16 Section 3 Modeling Approach

Table 3-8: Summary of Subsurface Inflow Components Volume Nitrate- Mass Basis for Nitrate Inflow (Acre- N (tons) Estimate feet) (mg/L) Inflow from La Habra Basin 3,000 0.1 0.4 Well FM-6 Recharge from foothills into Average of wells AM- Yorba Linda Sub-basin 6,000 4.4 36 1 and AM-2 Subsurface inflow at Imperial Hwy in Santa Ana Canyon 4,000 2.7 15 Well OCWD-LV-1 SAR recharge, Imperial Hwy Blend of stormflow to Inflatable Dam 4,000 3.6 20 and baseflow Subsurface inflow from Santiago Canyon 10,000 0.2 3 Well SC-1 zone 6 Average of wells Recharge along Peralta Hills 4,000 5.3 29 ANDR-A and O-21 Average of wells T- Recharge along Tustin Hills 2,000 15.1 41 17S4 and T-NEWP Seawater inflow through coastal gaps 500 1.5 1 Well OCWD-T5/1 Inflow from Irvine Ambient groundwater Management Zone 4,000 6.7 36 quality (1993-2012)

Total 37,500 3.5 181

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-17 Section 3 Modeling Approach

Case 1 Case 2

Figure 3-9: Estimated Nitrate (as N) Concentration for 30-year Period

The result of the nitrate concentration model base case was also compared to an additional scenario which is the same as the base case except it includes 56,000 afy of desalinated ocean water. The desalinated ocean water is recharged with an estimated nitrate-nitrogen concentration of 0.5 mg/L. The Term Sheet for the Poseidon Huntington Beach Seawater Desalination Project approved by OCWD on May 14, 2015 does not include a water quality concentration for nitrate. As described in the Technical Memorandum prepared by Trussell Technologies for OCWD dated January 25, 2016, the estimated nitrate concentration of desalinated seawater is near 0.0 mg/L. For the purposes of developing a conservative model assumption, which likely over-estimates the nitrate concentration, the nitrate-nitrogen concentration of desalinated ocean water from the Poseidon Huntington Beach project was assumed to be 0.5 mg/L for this scenario. The data used for this model projection can be found in Appendix E (see Case 3 in Appendix E). The model results show that the nitrate concentration in the OC Management Zone with recharge of 56,000 afy of desalinated ocean water improves relative to the base case. As shown in Appendix E, the flow-weighted TDS of the inflow (recharge) in the base case is 2.6 mg/L and 2.3 mg/L for the scenario with 56,000 afy of desalinated ocean water. The better inflow water quality in the scenario

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-18 Section 3 Modeling Approach with 56,000 afy of desalinated ocean water relative to the model base case causes the final year projected nitrate-nitrogen concentration to improve from 2.85 mg/L in the base case to 2.75 mg/L for the scenario with desalinated ocean water.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 3-19 Section 4 Summary and Conclusion

SECTION 4 SUMMARY AND CONCLUSION

This section provides a summary of the model results and discusses how the results assist in meeting the goals of the cooperative agreement.

In each of the cases, the flow-weighted TDS concentration of inflow to the OC Management Zone is below the current TDS ambient water quality of 610 mg/L and below the water quality objective of 580 mg/L. Overall, when averaging all sources of recharge supplies, the modeling results indicate that recharge of up to 100,000 afy of imported water will not cause an exceedance of the TDS water quality objective for the OC Management Zone and furthermore, the results indicate a gradual decrease in the TDS concentration. For nitrate, the available sources of imported water from MWD have historically had nitrate concentrations below the Orange County Management Zone’s nitrate-nitrogen water quality objective of 3.4 mg/L. Due to the low concentrations of nitrate in recharge source water supplies, as shown in Table 3-5, only the base case and one other case was run in this model. The flow-weighted average nitrate-nitrogen concentration for all inflows was 2.1 mg/L. The initial concentration was 2.9 mg/L, based on the current ambient concentration for the most recent 20-year period. Since the inflow concentration is less than the initial concentration, the estimated future nitrate concentration gradually decreases and, therefore, is not projected to exceed the water quality objective. The modeling results indicate that recharge of up to 100,000 afy of imported water will not cause an exceedance of the nitrate water quality objective for the OC Management Zone and furthermore, the results indicate a gradual decrease in the nitrate concentration. . Comparison of 2016 Model Predictions and Calculated Ambient Water Quality

Model results are based on projections of volumes of different recharge water sources with varying TDS concentrations. In reviewing the 2009 model projections and evaluating the model results with the most recent ambient groundwater calculations, some significant changes to the projected sources of recharge water supplies between the 2009 model and this 2016 model should be noted. The 2009 model runs assumed recharge of Santa Ana River baseflow of 148,000 afy with a TDS concentration of 620 mg/L. Santa Ana River baseflow rates have continued to decline since preparation of the 2009 model. As such, the input for baseflow volumes in the 2016 model report

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 4-1 Section 4 Summary and Conclusion ranged from 52,000 afy to 90,000 afy. The 2016 model assumed an SAR baseflow TDS concentration of 700 mg/L. Another significant difference between the inputs in the 2016 model as compared to the 2009 model is the addition of the new source of recharge water supply. Completion of the Groundwater Replenishment System in 2009 and the expansion of the plant in 2013 have enabled OCWD to significantly increase the volume of low TDS recycled water recharged into the basin. These significant changes to the source of recharge water make it difficult to make meaningful comparisons between the results of the model runs in this report to the predictions in the previous report. Meaningful comparisons are also difficult to make between this model prediction and the calculation of ambient water quality that is conducted by the Basin Monitoring Program Task Force (BMPTF) every three years. The BMPTF model calculates an ambient TDS concentration from the average of each of the previous 20 years using contour maps prepared from available well data The most recent re-computation of TDS for the period 1993 to 2012 calculated a TDS of 610 mg/L for the Orange County Management Zone. The ambient water quality calculation uses the previous 20 years of data for each well, compared to the model which uses a year-by-year calculation and assumes all water in the basin mixes each year. The different time scales used in the ambient water quality calculation compared to the model are a significant difference that limits the utility of comparing results from the two methods.

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 4-2 Section 5 References

SECTION 5 REFERENCES

Chino Basin Watermaster. Letter to Gerard Thibeault, “Chino Basin Watermaster Proposal for New Total Dissolved Solids (TDS) and Total Inorganic Nitrogen Water Quality Objectives for the Chino and Cucamonga Basins Based on Maximum Benefit,” December 2002. County of Orange. Drainage Area Management Plan. 2003. Guymon, G.L., A.C. Bagtzoglou, and M.R. Welch. “A Lumped Stream-Aquifer Model to Assess Reclaimed Water Impacts” Water Resources Bulletin, Vol. 28, No. 2, American Water Resources Association. April 1992. Mercado, Abraham. “Nitrate and Chloride Pollution of Aquifers: A Regional Study with the Aid of a Single-Cell Model” Water Resources Research, Vol 12, No. 4, August 1976. Metropolitan Water District of Southern California. Unpublished water quality data. 2009-15. OCWD. Groundwater Management Plan. July 2015. OCWD. 2012-13 Engineer’s Report on Groundwater Conditions, Water Supply and Basin Utilization in the Orange County Water District. February 2014. OCWD. 2013-14 Engineer’s Report on Groundwater Conditions, Water Supply and Basin Utilization in the Orange County Water District. February 2015. OCWD. 2014-15 Engineer’s Report on Groundwater Conditions, Water Supply and Basin Utilization in the Orange County Water District. February 2016. OCWD. Report on Evaluation of Orange County Groundwater Basin Storage and Operational Strategy. February 2007. OCWD and Poseidon Resources (Surfside LLC). Term Sheet, Water Reliability Agreement, Huntington Beach Seawater Desalination Project. May 2015. Santa Ana River Watermaster. Forth-Fourth Annual Report of the Santa Ana River Watermaster Annual for Water Year October 1, 2013 to September 30, 2014. April 2015. Trussell Technologies. Technical Memorandum “Review of Proposed Water Quality Requirements for the Huntington Beach Desalter”. Prepared for the Orange County Water District. January 25, 2016. Wildermuth Environmental, Inc., Technical Memorandum “Recomputation of Ambient Water Quality in the Santa Ana Watershed for the Period 1993 to 2012,” 2014

Salt and Nitrate Projections for Orange County Management Zone Final Technical Memorandum 5-1

Appendix A

Amount and Quality of imported Water Recharged, Orange County Management Zone Calendar Years 2012-2014

Amount and Quality of Imported Water Recharged Calendar Years 2012 to 1014

The Cooperative Agreement specifies that a summary should be provided of the amount and quality of imported water recharged during the previous three-year period. The quantity of imported water recharged in the previous three water years is summarized in Table A-1.

Table A-1: Summary of Imported Water Recharged in Orange County Management Zone

Volume of Imported Water Recharged (acre-feet/year) Calendar Year Anaheim Lake (OC- San Antonio Talbert Barrier Alamitos Barrier 28 and OC-28A) Creek (OC-59) (OC-44) Imported Water

2012 35,694 280 3.0 1,003 2013 30,885 0 4.7 1,348 2014 62,985 0 7.6 2,494

The quality of the imported water recharged in the Forebay is summarized in Tables A-2 and A-3. Table A-2: Summary of TDS of Imported Water Recharge in Forebay (mg/L)

Calendar Anaheim Lake (OC- San Antonio Talbert Barrier Alamitos Barrier Year 28 and OC-28A) Creek (OC-59) (OC-44) Imported Water

2012 361 296 479 416 2013 372 NA 570 534 2014 591 NA 605 630

Table A-3: Summary of Nitrate-nitrogen of Imported Water Recharge in Forebay (mg/L)

Calendar Anaheim Lake (OC- San Antonio Talbert Barrier Alamitos Barrier Year 28 and OC-28A) Creek (OC-59) (OC-44) Imported Water

2012 0.18 0.70 0.14 0.32 2013 0.25 NA 0.21 0.4 2014 0.18 NA 0.13 0.43

1 Figure A-1 illustrates the flow-weighted TDS of Talbert Injection Barrier water since the 1976. In Figure A-1, the flow-weighted average for each year is plotted. In each year, the TDS has been below 500 mg/L. In 2008, the TDS concentration was below 100 mg/L. This decline in TDS corresponds to when the GWR System began operation. In the previous year (2007), before the GWR System water was available, the TDS concentration was higher as imported water was utilized to a higher degree.

Figure A-1 Flow-Weighted TDS of Talbert Injection Barrier Recharge Water

2 Explanation of Data Used and Method of Calculation of Flow-Weighted Average TDS and Nitrate

OCWD purchases imported water that is used to recharge the Orange County Groundwater Basin. Water from OC-28 and OC-28A is delivered and recharged at Anaheim Lake in the City of Anaheim. OCWD takes samples of water on an approximately monthly basis in months when water is delivered. Water quality samples are analyzed at the District’s Advanced Water Quality Assurance Laboratory in Fountain Valley. The flow-weighted TDS and nitrate averages were calculated on a monthly basis using OCWD’s water quality data. In months where imported water was delivered but water quality samples were not taken, the TDS and nitrate concentrations from the previous month’s sample (or closest month when necessary) were used to calculate the flow-weighted average. In cases where more than one sample was taken in a month, the TDS and nitrate concentrations were averaged.

OCWD received imported water delivered from OC-59 via San Antonio Creek for one month during the three year period. TDS and nitrate data from the MWD General Mineral and Physical Analysis of Metropolitan’s Water Supplies, Table D for November 2012 were used to calculate the flow weighted average of TDS and nitrate, as OCWD did not sample this supply.

Imported water was used as part of the operation of the Talbert Seawater Barrier. OCWD collected water quality samples of this supply on an approximately monthly basis and analyzed the samples at the District lab. For months where water quality samples were not taken the TDS and nitrate concentrations from the previous month were used to calculate the monthly flow-weighted average. In cases where more than one sample was taken in a month, the TDS and nitrate concentrations were averaged.

Imported water is also used to operate the Alamitos Seawater Barrier. This water is supplied by the Long Beach Water Department. The volume of imported water used for the Alamitos Barrier was calculated on an annual basis. TDS and nitrate concentrations used to calculate the annual flow-weighted averages were based on the annual Consumer Confidence Reports issued by the Long Beach Water Department.

3

Appendix B

2013-14 Delivered Water Quality Summary Summary 2013-14 Water Quality

Groundwater1,7 Delivered Blend1,2,7 3 4 3 4 City/Agency TDS NO3-N Hard- TDS NO3-N Hard- ness5 ness5 Anaheim 573 2.9 324 572 2.4 313 Buena Park 375 1.2 219 411 1.0 228 East Orange County Water District 596 3.5 358 590 2.8 338 Fountain Valley 420 1.2 246 458 0.9 252 Fullerton 516 2.8 264 532 2.0 266 Garden Grove 546 4.2 336 549 3.6 326 Golden State Water Company 396 1.6 222 444 1.2 236 Huntington Beach 342 0.4 166 434 0.3 208 Irvine Ranch Water District6 378* 1.8* 153* 378* 1.8* 153* La Palma 296 ND8 148 366 0.1 180 Mesa Water District 355 0.3 111 378 0.2 128 Newport Beach 366 1.6 209 436 1.2 230 Orange 488 2.4 292 512 1.8 286 Santa Ana 414 2.3 238 454 1.8 247 Seal Beach 226 ND8 88 360 0.1 160 Serrano Water District 664 3.1 358 646 2.1 347 Tustin6 504* 4.1* 262* 527* 2.7* 266* Westminster 366 1.4 226 424 1.0 238 Yorba Linda Water District 648 2.7 338 628 2.1 320 Weighted Average7 456 2.2 242 482 1.7 249

1 All groundwater results (alone or blend) are for untreated groundwater (see note 6 below). Units are reported in mg/L. 2 Delivered blend includes untreated groundwater and treated imported MWD water (i.e., blend of Colorado River water and State Project water as measured at the MWD Diemer Plant), except Serrano Water District, which blends with treated Santiago Reservoir water. Units are reported in mg/L. Annual average water qualities for MWD and Santiago Reservoir (Irvine Lake) for 2013-14 are as follows: MWD Water Quality Santiago Reservoir Water Quality TDS = 568 mg/L TDS = 606 mg/L N03-N = 0.2 mg/L N03-N = 0.1 mg/L Hardness (as CaCO3) = 271 mg/L Hardness (as CaCO3) = 325 mg/L 3 Secondary Drinking Water Standards for TDS are as follows: 500 mg/L = recommended limit 1,000 mg/L = upper limit 4 Primary Drinking Water Standard for nitrate NO3-N (i.e., nitrate expressed as nitrogen) is 10 mg/L. 5 Hardness is reported as mg/L of CaCO3. General classifications of hard and soft water are within the following concentration ranges: 0-75 mg/L = soft 150-300 mg/L = hard 75-150 mg/L = moderately hard 300 and up mg/L = very hard 6 Agencies with active groundwater quality improvement projects that treat for one or more of the constituents listed in the table. The results shown herein for “groundwater” and “delivered blend” reflect results from untreated groundwater. Water quality constituents that are marked with an asterisk (*) are reduced prior to delivery to customers. 7All water quality results are flow-weighted averages based on groundwater and imported water delivered to each agency. 8 ND = not detected. Nitrate (as NO3-N) analytical detection limit for OCWD Advanced Water Quality Assurance Laboratory is 0.1 mg/L.

Appendix C

Septic System Locations

Appendix D

TDS Projection Spreadsheets TDS Projection for OC Management Zone Case 1 Average hydrology No MWD replenishment water except at Alamitos Barrier

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total Inflow Subsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 608.8 2017 35,800,000 608.8 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 607.6 2018 35,800,000 607.6 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 606.4 2019 35,800,000 606.4 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 605.2 2020 35,800,000 605.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 604.0 2021 35,800,000 604.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 602.9 2022 35,800,000 602.9 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 601.7 2023 35,800,000 601.7 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 600.5 2024 35,800,000 600.5 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 599.4 2025 35,800,000 599.4 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 598.3 2026 35,800,000 598.3 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 597.1 2027 35,800,000 597.1 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 596.0 2028 35,800,000 596.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 594.9 2029 35,800,000 594.9 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 593.8 2030 35,800,000 593.8 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 592.7 2031 35,800,000 592.7 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 591.6 2032 35,800,000 591.6 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 590.5 2033 35,800,000 590.5 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 589.5 2034 35,800,000 589.5 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 588.4 2035 35,800,000 588.4 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 587.4 2036 35,800,000 587.4 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 586.3 2037 35,800,000 586.3 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 585.3 2038 35,800,000 585.3 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 584.2 2039 35,800,000 584.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 583.2 2040 35,800,000 583.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 582.2 2041 35,800,000 582.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 581.2 2042 35,800,000 581.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 580.2 2043 35,800,000 580.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 579.2 2044 35,800,000 579.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 578.2 2045 35,800,000 578.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 260,500 443 22,000 238,500 260,500 35,800,000 577.2 TDS Projection for OC Management Zone Case 2 - 65,000 afy imported water

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 608.9 2017 35,800,000 608.9 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 607.7 2018 35,800,000 607.7 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 606.6 2019 35,800,000 606.6 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 605.5 2020 35,800,000 605.5 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 604.4 2021 35,800,000 604.4 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 603.3 2022 35,800,000 603.3 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 602.2 2023 35,800,000 602.2 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 601.2 2024 35,800,000 601.2 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 600.1 2025 35,800,000 600.1 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 599.1 2026 35,800,000 599.1 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 598.0 2027 35,800,000 598.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 597.0 2028 35,800,000 597.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 596.0 2029 35,800,000 596.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 595.0 2030 35,800,000 595.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 594.0 2031 35,800,000 594.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 593.0 2032 35,800,000 593.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 592.0 2033 35,800,000 592.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 591.0 2034 35,800,000 591.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 590.0 2035 35,800,000 590.0 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 589.1 2036 35,800,000 589.1 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 588.1 2037 35,800,000 588.1 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 587.2 2038 35,800,000 587.2 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 586.3 2039 35,800,000 586.3 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 585.3 2040 35,800,000 585.3 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 584.4 2041 35,800,000 584.4 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 583.5 2042 35,800,000 583.5 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 582.6 2043 35,800,000 582.6 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 581.7 2044 35,800,000 581.7 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 580.8 2045 35,800,000 580.8 6,500 100 9,000 1,900 52,000 700 50,000 200 65,000 650 103,000 60 37,500 1,177 2,500 350 325,500 484 22,000 303,500 325,500 35,800,000 580.0 TDS Projection for OC Management Zone Case 3 - 30,000 afy imported water

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 608.8 2017 35,800,000 608.8 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 607.7 2018 35,800,000 607.7 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 606.5 2019 35,800,000 606.5 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 605.3 2020 35,800,000 605.3 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 604.2 2021 35,800,000 604.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 603.1 2022 35,800,000 603.1 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 601.9 2023 35,800,000 601.9 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 600.8 2024 35,800,000 600.8 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 599.7 2025 35,800,000 599.7 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 598.6 2026 35,800,000 598.6 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 597.5 2027 35,800,000 597.5 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 596.5 2028 35,800,000 596.5 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 595.4 2029 35,800,000 595.4 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 594.3 2030 35,800,000 594.3 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 593.3 2031 35,800,000 593.3 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 592.2 2032 35,800,000 592.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 591.2 2033 35,800,000 591.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 590.2 2034 35,800,000 590.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 589.2 2035 35,800,000 589.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 588.2 2036 35,800,000 588.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 587.2 2037 35,800,000 587.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 586.2 2038 35,800,000 586.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 585.2 2039 35,800,000 585.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 584.2 2040 35,800,000 584.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 583.2 2041 35,800,000 583.2 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 582.3 2042 35,800,000 582.3 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 581.3 2043 35,800,000 581.3 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 580.4 2044 35,800,000 580.4 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 579.4 2045 35,800,000 579.4 6,500 100 9,000 1,900 52,000 700 50,000 200 30,000 650 103,000 60 37,500 1,177 2,500 350 290,500 464 22,000 268,500 290,500 35,800,000 578.5 TDS Projection for OC Management Zone Case 4 - 100,000 afy imported water

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 608.9 2017 35,800,000 608.9 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 607.8 2018 35,800,000 607.8 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 606.7 2019 35,800,000 606.7 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 605.7 2020 35,800,000 605.7 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 604.6 2021 35,800,000 604.6 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 603.6 2022 35,800,000 603.6 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 602.5 2023 35,800,000 602.5 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 601.5 2024 35,800,000 601.5 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 600.5 2025 35,800,000 600.5 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 599.5 2026 35,800,000 599.5 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 598.5 2027 35,800,000 598.5 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 597.5 2028 35,800,000 597.5 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 596.5 2029 35,800,000 596.5 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 595.6 2030 35,800,000 595.6 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 594.6 2031 35,800,000 594.6 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 593.7 2032 35,800,000 593.7 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 592.7 2033 35,800,000 592.7 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 591.8 2034 35,800,000 591.8 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 590.9 2035 35,800,000 590.9 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 590.0 2036 35,800,000 590.0 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 589.1 2037 35,800,000 589.1 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 588.2 2038 35,800,000 588.2 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 587.3 2039 35,800,000 587.3 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 586.4 2040 35,800,000 586.4 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 585.6 2041 35,800,000 585.6 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 584.7 2042 35,800,000 584.7 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 583.9 2043 35,800,000 583.9 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 583.0 2044 35,800,000 583.0 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 582.2 2045 35,800,000 582.2 6,500 100 9,000 1,900 52,000 700 50,000 200 100,000 650 103,000 60 37,500 1,177 2,500 350 360,500 500 22,000 338,500 360,500 35,800,000 581.4 TDS Projection for OC Management Zone Case 5 - 133,000 afy Recycled Water for Replenishment

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 608.3 2017 35,800,000 608.3 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 606.7 2018 35,800,000 606.7 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 605.0 2019 35,800,000 605.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 603.4 2020 35,800,000 603.4 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 601.8 2021 35,800,000 601.8 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 600.2 2022 35,800,000 600.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 598.6 2023 35,800,000 598.6 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 597.0 2024 35,800,000 597.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 595.4 2025 35,800,000 595.4 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 593.9 2026 35,800,000 593.9 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 592.3 2027 35,800,000 592.3 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 590.8 2028 35,800,000 590.8 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 589.3 2029 35,800,000 589.3 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 587.8 2030 35,800,000 587.8 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 586.3 2031 35,800,000 586.3 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 584.8 2032 35,800,000 584.8 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 583.4 2033 35,800,000 583.4 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 581.9 2034 35,800,000 581.9 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 580.5 2035 35,800,000 580.5 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 579.0 2036 35,800,000 579.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 577.6 2037 35,800,000 577.6 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 576.2 2038 35,800,000 576.2 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 574.8 2039 35,800,000 574.8 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 573.4 2040 35,800,000 573.4 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 572.0 2041 35,800,000 572.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 570.7 2042 35,800,000 570.7 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 569.3 2043 35,800,000 569.3 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 568.0 2044 35,800,000 568.0 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 566.6 2045 35,800,000 566.6 6,500 100 9,000 1,900 52,000 700 50,000 200 0 0 133,000 60 37,500 1,177 2,500 350 290,500 403 22,000 268,500 290,500 35,800,000 565.3 TDS Projection for OC Management Zone Case 6 - 90,000 afy of SAR Baseflow No MWD replenishment water except at Alamitos Barrier

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 608.9 2017 35,800,000 608.9 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 607.8 2018 35,800,000 607.8 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 606.7 2019 35,800,000 606.7 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 605.6 2020 35,800,000 605.6 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 604.5 2021 35,800,000 604.5 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 603.4 2022 35,800,000 603.4 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 602.4 2023 35,800,000 602.4 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 601.3 2024 35,800,000 601.3 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 600.3 2025 35,800,000 600.3 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 599.2 2026 35,800,000 599.2 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 598.2 2027 35,800,000 598.2 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 597.2 2028 35,800,000 597.2 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 596.2 2029 35,800,000 596.2 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 595.2 2030 35,800,000 595.2 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 594.2 2031 35,800,000 594.2 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 593.2 2032 35,800,000 593.2 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 592.2 2033 35,800,000 592.2 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 591.3 2034 35,800,000 591.3 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 590.3 2035 35,800,000 590.3 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 589.3 2036 35,800,000 589.3 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 588.4 2037 35,800,000 588.4 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 587.5 2038 35,800,000 587.5 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 586.5 2039 35,800,000 586.5 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 585.6 2040 35,800,000 585.6 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 584.7 2041 35,800,000 584.7 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 583.8 2042 35,800,000 583.8 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 582.9 2043 35,800,000 582.9 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 582.0 2044 35,800,000 582.0 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 581.1 2045 35,800,000 581.1 6,500 100 9,000 1,900 90,000 700 50,000 200 0 0 103,000 60 37,500 1,177 2,500 350 298,500 476 22,000 276,500 298,500 35,800,000 580.2 TDS Projection for OC Management Zone Case 7 - 30,000 afy of SAR Stormflow No MWD replenishment water except at Alamitos Barrier

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 609.0 2017 35,800,000 609.0 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 608.0 2018 35,800,000 608.0 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 607.1 2019 35,800,000 607.1 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 606.1 2020 35,800,000 606.1 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 605.1 2021 35,800,000 605.1 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 604.2 2022 35,800,000 604.2 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 603.2 2023 35,800,000 603.2 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 602.3 2024 35,800,000 602.3 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 601.4 2025 35,800,000 601.4 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 600.4 2026 35,800,000 600.4 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 599.5 2027 35,800,000 599.5 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 598.6 2028 35,800,000 598.6 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 597.7 2029 35,800,000 597.7 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 596.8 2030 35,800,000 596.8 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 595.9 2031 35,800,000 595.9 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 595.0 2032 35,800,000 595.0 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 594.1 2033 35,800,000 594.1 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 593.3 2034 35,800,000 593.3 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 592.4 2035 35,800,000 592.4 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 591.5 2036 35,800,000 591.5 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 590.7 2037 35,800,000 590.7 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 589.8 2038 35,800,000 589.8 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 588.9 2039 35,800,000 588.9 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 588.1 2040 35,800,000 588.1 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 587.3 2041 35,800,000 587.3 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 586.4 2042 35,800,000 586.4 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 585.6 2043 35,800,000 585.6 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 584.8 2044 35,800,000 584.8 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 584.0 2045 35,800,000 584.0 6,500 100 9,000 1,900 52,000 700 30,000 200 0 0 103,000 60 37,500 1,177 2,500 350 240,500 463 22,000 218,500 240,500 35,800,000 583.2 TDS Projection for OC Management Zone Case 8 - 65,000 afy imported water, 30,000 afy SAR Stormflow

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 609.2 2017 35,800,000 609.2 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 608.4 2018 35,800,000 608.4 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 607.6 2019 35,800,000 607.6 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 606.8 2020 35,800,000 606.8 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 606.0 2021 35,800,000 606.0 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 605.2 2022 35,800,000 605.2 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 604.4 2023 35,800,000 604.4 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 603.6 2024 35,800,000 603.6 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 602.9 2025 35,800,000 602.9 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 602.1 2026 35,800,000 602.1 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 601.3 2027 35,800,000 601.3 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 600.6 2028 35,800,000 600.6 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 599.9 2029 35,800,000 599.9 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 599.1 2030 35,800,000 599.1 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 598.4 2031 35,800,000 598.4 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 597.7 2032 35,800,000 597.7 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 597.0 2033 35,800,000 597.0 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 596.2 2034 35,800,000 596.2 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 595.5 2035 35,800,000 595.5 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 594.8 2036 35,800,000 594.8 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 594.2 2037 35,800,000 594.2 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 593.5 2038 35,800,000 593.5 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 592.8 2039 35,800,000 592.8 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 592.1 2040 35,800,000 592.1 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 591.4 2041 35,800,000 591.4 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 590.8 2042 35,800,000 590.8 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 590.1 2043 35,800,000 590.1 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 589.5 2044 35,800,000 589.5 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 588.8 2045 35,800,000 588.8 6,500 100 9,000 1,900 52,000 700 30,000 200 65,000 700 103,000 60 37,500 1,177 2,500 350 305,500 513 22,000 283,500 305,500 35,800,000 588.2 Table D-9 TDS Projection for OC Management Zone Case 9 - Same as Baseline Case 1 except added desalinated ocean water

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Desalinated Ocean Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending TDS Storage TDS Precipitation Applied Water Recharge Water Replenishment Outflow Outflow Storage Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 610.0 2016 35,800,000 610.0 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 608.4 2017 35,800,000 608.4 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 606.8 2018 35,800,000 606.8 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 605.2 2019 35,800,000 605.2 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 603.6 2020 35,800,000 603.6 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 602.1 2021 35,800,000 602.1 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 600.5 2022 35,800,000 600.5 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 599.0 2023 35,800,000 599.0 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 597.5 2024 35,800,000 597.5 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 596.0 2025 35,800,000 596.0 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 594.5 2026 35,800,000 594.5 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 593.0 2027 35,800,000 593.0 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 591.5 2028 35,800,000 591.5 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 590.1 2029 35,800,000 590.1 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 588.6 2030 35,800,000 588.6 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 587.2 2031 35,800,000 587.2 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 585.8 2032 35,800,000 585.8 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 584.4 2033 35,800,000 584.4 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 583.0 2034 35,800,000 583.0 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 581.6 2035 35,800,000 581.6 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 580.2 2036 35,800,000 580.2 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 578.9 2037 35,800,000 578.9 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 577.5 2038 35,800,000 577.5 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 576.2 2039 35,800,000 576.2 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 574.9 2040 35,800,000 574.9 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 573.6 2041 35,800,000 573.6 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 572.3 2042 35,800,000 572.3 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 571.0 2043 35,800,000 571.0 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 569.7 2044 35,800,000 569.7 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 568.5 2045 35,800,000 568.5 6,500 100 9,000 1,900 52,000 700 50,000 200 56,000 350 103,000 60 37,500 1,177 2,500 350 316,500 426 22,000 294,500 316,500 35,800,000 567.2

Appendix E

Nitrate Projection Spreadsheets Nitrate Projection for OC Management Zone Case 1 Average hydrology No MWD replenishment water except at Alamitos Barrier

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total Inflow Subsurface Pumping Total Ending Ending Nitrate- Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Storage N Outflow Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 2.90 2016 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.90 2017 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.90 2018 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.89 2019 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.89 2020 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.89 2021 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.89 2022 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.89 2023 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.89 2024 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.88 2025 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.88 2026 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.88 2027 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.88 2028 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.88 2029 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.87 2030 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.87 2031 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.87 2032 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.87 2033 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.87 2034 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.87 2035 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.86 2036 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.86 2037 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.86 2038 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.86 2039 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.86 2040 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.86 2041 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.85 2042 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.85 2043 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.85 2044 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.85 2045 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 0 0.6 103,000 2 37,500 4 2,500 2 260,500 2.6 22,000 238,500 260,500 35,800,000 2.85 Nitrate Projection for OC Management Zone Case 2: Average hydrology plus 65,000 afy imported water

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Imported Water Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending Nitrate- Storage TDS Precipitation Applied Water Recharge Replenishment Replenishment Outflow Storage N Outflow Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 2.90 2016 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.89 2017 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.89 2018 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.88 2019 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.88 2020 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.87 2021 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.86 2022 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.86 2023 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.85 2024 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.85 2025 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.84 2026 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.84 2027 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.83 2028 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.83 2029 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.82 2030 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.81 2031 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.81 2032 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.80 2033 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.80 2034 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.79 2035 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.79 2036 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.78 2037 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.78 2038 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.77 2039 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.77 2040 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.76 2041 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.76 2042 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.75 2043 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.75 2044 35,800,000 2.7 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.74 2045 35,800,000 2.7 6,500 1 9,000 10 52,000 5 50,000 1 65,000 0.6 103,000 2 37,500 4 2,500 2 325,500 2.2 22,000 303,500 325,500 35,800,000 2.74 Nitrate Projection for OC Management Zone Case 3: Same as Baseline (Case 1) except added desalinated ocean water

Year Starting Starting Deep Percolation of Deep Percolation of SAR Baseflow Storm Flow Recharge Desalinated Ocean Recycled Water Subsurface Inflow Alamitos Barrier Total InflowSubsurface Pumping Total Ending Ending Nitrate- Storage TDS Precipitation Applied Water Recharge Water Replenishment Outflow Storage N Outflow Concentration (mg/L) (incl Talbert Barrier) (blend imported & recycled) flow conc

(acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (mg/L) (acre-ft) (acre-ft) (acre-ft) (acre-ft) (mg/L) 2015 2.90 2016 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.89 2017 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.89 2018 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.88 2019 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.88 2020 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.87 2021 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.87 2022 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.86 2023 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.86 2024 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.85 2025 35,800,000 2.9 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.85 2026 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.84 2027 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.84 2028 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.83 2029 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.83 2030 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.82 2031 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.82 2032 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.81 2033 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.81 2034 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.80 2035 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.80 2036 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.79 2037 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.79 2038 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.78 2039 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.78 2040 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.77 2041 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.77 2042 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.76 2043 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.76 2044 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.75 2045 35,800,000 2.8 6,500 1 9,000 10 52,000 5 50,000 1 56,000 0.5 103,000 2 37,500 4 2,500 2 316,500 2.3 22,000 294,500 316,500 35,800,000 2.75