Engineer s Report on the groundwater conditions, water supply and basin utilization in the. Orange County Water District

Engineer s Report on the groundwater conditions, water supply and basin utilization in the Orange County Water District 2005 2006

2005-2006 ENGINEER S REPORT ON GROUNDWATER CONDITIONS, WATER SUPPLY AND BASIN UTILIZATION IN THE ORANGE COUNTY WATER DISTRICT FEBRUARY 2007 ORANGE COUNTY WATER DISTRICT BOARD OF DIRECTORS Claudia Alvarez Philip L. Anthony Wes Bannister Kathryn L. Barr Denis R. Bilodeau Jan Debay Shawn Nelson Irv Pickler Stephen R. Sheldon Roger C. Yoh Virginia Grebbien, P.E. General Manager

TABLE OF CONTENTS Page EXECUTIVE SUMMARY...1 ACKNOWLEDGMENTS...2 GLOSSARY OF ACRONYMS...3 PART I: GROUNDWATER CONDITIONS...4 2005-06 Summary of Findings...4 Basin Hydrology...5 Groundwater Production...5 Basin Production Percentage...7 Groundwater Levels...7 Coastal Groundwater Conditions...8 Annual Groundwater Basin Overdraft...9 Groundwater Basin Accumulated Overdraft...10 Replenishment Recommendation...13 Recommended Basin Production Percentage...14 Notice of Pubic Hearing...24 PART II: WATER SUPPLY AND BASIN UTILIZATION...17 2005-06 Summary of Findings...17 Supplemental Water...17 Availability of Supplemental Replenishment Water...21 Water Demands and Usage...21 Water Demand Forecast...22 Wastewater Reclamation...23 Water Quality...24 Water Resources Data...25 PART III: WATER PRODUCTION COSTS FOR ENSUING YEAR (2007-08)...26 Summary of Findings...26 Groundwater Production Costs for Non-Irrigation Use...27 Cost of Supplemental Water...28

LIST OF TABLES No. Page 1 Historical Groundwater Production Within Orange County Water District...6 2 2007-08 Budget for Water Purchases...13 3 2005-06 Supplemental Water Usage...19 4 2005-06 In-Lieu Program Water Deliveries...20 5 2005-06 Recycled Water Usage...21 6 Water Demands Within OCWD...22 7 2005-06 Water Quality Summary...25 8 Estimated 2007-08 Groundwater Production Costs...27 9 Estimated 2007-08 Supplemental Water Costs...28 10 Estimated 2007-08 Water Production Cost Comparison...30 LIST OF FIGURES No. Page 1 Groundwater Production...6 2 Groundwater Basin Production Percentage...7 3 Accumulated Basin Overdraft...11 4 Historical Supplemental Water Usage...19 5 Water Demand Projections...23 6 Adopted and Projected Water Rates for Non-Irrigation Use...29

LIST OF PLATES No. Page 1 Groundwater Contour Map, June 2006...31 2 Change in Water Level Between June 2005 and 2006...32 3 Monitoring Well Hydrograph Trends...33 No. APPENDICES Page 1 Water Production Data 2005-06...34 2 2005-06 Groundwater Production Non-Irrigation Use Production Over 25 Acre-feet...35 3 2005-06 Groundwater Production Irrigation Use Production Over 25 Acre-feet...36 4 Typical Groundwater Extraction Facility Characteristics...37 5 2005-06 Water Resources Summary...38 6 Non-Local Water Purchased by OCWD for Water Years 1990-91 through 2005-06...39 7 Values Used in Figure 6 for Water Rates for Non-Irrigation Use...40 8 Executive Summary - Report on Evaluation of Orange County Groundwater Basin Storage and Operational Strategy, February 2007...41

EXECUTIVE SUMMARY Total water demand within Orange County Water District (OCWD) was 474,782 acre-feet (AF) for the 2005-06 water year (beginning July 1, 2005 and ending June 30, 2006). Groundwater production (including In-Lieu Program water, but excluding groundwater production used to supply the Talbert Barrier) for the water year totaled 317,398 AF. For the water year, a total of 14,601 AF of supplemental water was used for the purpose of groundwater replenishment and barrier maintenance. For the water year, which ended June 30, 2006, it is estimated that the annual basin storage decrease without supplemental replenishment water (i.e., also referred to as annual overdraft ) was 42,000 AF when compared to the same time one year earlier. Precipitation within the basin was two-thirds of normal during the water year, totaling 9.1 inches. Based on the groundwater basin conditions for the water year ending June 30, 2006, OCWD may purchase up to 75,000 AF for groundwater basin replenishment during the ensuing water year, beginning July 1, 2007, pursuant to the District Act. 1

ACKNOWLEDGMENTS A number of public and private entities agencies contributed data used in this report including: City of Anaheim City of Buena Park East Orange County Water District City of Fountain Valley City of Fullerton City of Garden Grove Golden State Water Company City of Huntington Beach The Irvine Company Irvine Ranch Water District City of La Palma Mesa Consolidated Water District Metropolitan Water District of Southern California Municipal Water District of Orange County City of Newport Beach City of Orange County of Orange, Resources and Development Management Department Orange County Sanitation District Orange Park Acres Mutual Water Company San Bernardino Valley Municipal Water District City of Santa Ana Santa Ana Watershed Project Authority City of Seal Beach Serrano Water District City of Tustin United States Geological Survey Western Municipal Water District City of Westminster Yorba Linda Water District The cooperation received from all agencies is gratefully acknowledged. This report is based on the 2005-06 Basic Data Report, which is placed on file at the Fountain Valley office of OCWD. 2

GLOSSARY OF ACRONYMS AF Acre-Feet AWPF Advanced Water Purification Facility BEA Basin Equity Assessment BPP Basin Production Percentage CBMWD Central Basin Municipal Water District CPTP Coastal Pumping Transfer Program CR Capacity Reservation CUP Conjunctive Use Program DRWF Dyer Road Well Field EVMWD East Valley Municipal Water District GAP Green Acres Project GWR System Groundwater Replenishment System IRWD Irvine Ranch Water District MCWD Mesa Consolidated Water District mg/l Milligrams per Liter MGD Million Gallons per Day MWD Metropolitan Water District of Southern California MWDOC Municipal Water District of Orange County O&M Operation and Maintenance OCSD Orange County Sanitation District OCWD Orange County Water District RA Replenishment Assessment RTS Readiness to Serve SAR Santa Ana River SBVMWD San Bernardino Valley Municipal Water District SWP State Water Project TDS Total Dissolved Solids WF-21 Water Factory 21 WMWD Western Municipal Water District WRD Water Replenishment District of Southern California WSM Basin Water Supply Management Program 3

PART I: GROUNDWATER CONDITIONS Section 25 of the OCWD District Act requires that OCWD order an annual investigation to report on the groundwater conditions within the District s boundaries. A summary of the groundwater conditions for the water year of July 1, 2005 to June 30, 2006 is as follows. GROUNDWATER CONDITIONS 2005-06 SUMMARY OF FINDINGS 1. Groundwater production (excluding In-Lieu Program water) totaled 228,159 acre-feet (AF) for the 2005-06 water year. 2. Groundwater stored in the basin increased by 66,000 AF for the 2005-06 water year. 3. Accumulated overdraft 1 on June 30 of the 2005-06 water year was 135,000 AF. 2 4. Annual basin storage decrease without supplemental replenishment water 3 was 42,000 for the 2005-06 water year. 5. Average annual basin storage decrease without supplemental replenishment water for the immediate past five water years (2001-02 to 2005-06) was 61,100 AF. 6. Projected annual basin storage decrease without supplemental replenishment water for the current 2006-07 water year is 145,000 AF. 7. Projected annual basin storage decrease without supplemental replenishment water for the ensuing 2007-08 water year is 102,000 AF. 8. Projected accumulated overdraft on June 30 of the current 2006-07 water year is 190,000 AF. 9. Under the provisions of Section 27 of the District Act, a portion of the 2007-08 Replenishment Assessment (RA) could be equal to an amount necessary to purchase up to 75,000 AF of replenishment water. 4 1 Accumulated overdraft was calculated using the OCWD-adopted (February 2007) three-layer storage change methodology and associated new benchmark for full-basin condition. WY2005-06 is the first year this methodology has been used. Refer to other portions within this section for additional explanation. 2 Water from the Metropolitan Water District of Southern California (MWD) Long Term Groundwater Storage Program was included as part of the total stored water in determining the basin s accumulated overdraft. 3 Annual basin storage decrease without supplemental replenishment water is referred to as annual overdraft in the District Act. 4 The limit is determined by adding the five-year annual average basin storage decrease without supplemental replenishment water (61,100 AF) to one-tenth of the dewatered basin storage (135,000 AF), which results in the following: 61,100 AF + [(135,000 AF) x 0.10] = 74,600 AF (or 75,000 AF when rounded). 4

BASIN HYDROLOGY Groundwater conditions in the Orange County groundwater basin are influenced by the natural hydrologic conditions of rainfall, groundwater seepage and stream flow. The basin also is influenced by groundwater extraction and injection through wells, use of imported water for groundwater replenishment, wastewater reclamation and water conservation practices throughout OCWD. The water year beginning July 1, 2005, yielded 9.1 inches of rainfall on average within OCWD s boundaries, which is approximately two-thirds of normal (i.e., 13.4 inches). The previous year (2004-05) had rainfall equaling 30.8 inches, which was 2.3 times the normal. For the most recent 5-year period, rainfall within OCWD averaged 13.2 inches. Stream flow in the Santa Ana River (SAR) for 2005-06 totaled 273,050 AF (as measured downstream of Prado Dam), which was approximately 13 percent above the 30-year flow average of 242,000 AF. GROUNDWATER PRODUCTION Groundwater production from wells within OCWD for the 2005-06 water year totaled 228,159 AF (excludes In-lieu Program water and groundwater used for the Talbert Barrier): 226,265 AF for non-irrigation and 1,893 AF for irrigation uses. The term irrigation used herein refers to irrigation for agricultural, horticultural or floricultural crops and for pasture grown for commercial purposes. OCWD s In-Lieu Program, which replaces quantities of groundwater with imported water to reduce groundwater pumping, was in effect in 2005-06 with an amount totaling 89,239 AF, which includes water from MWD s Long-Term Groundwater Storage Program and Supplemental Storage Program. Groundwater production and in-lieu quantities within OCWD for the period 1960-61 through 2005-06 are presented in Figure 1 and Table 1. Without the In-Lieu Program, groundwater production would have reached 317,397 AF for the 2005-06 water year. Groundwater production and In-Lieu Program quantities for 2005-06 for the major groundwater producers are presented in Appendix 1. The groundwater production for all producers exceeding 25 AF per year for non-irrigation and irrigation purposes are listed in Appendices 2 and 3, respectively. 5

BASIN PRODUCTION PERCENTAGE The Basin Production Percentage (BPP) is defined in the District Act as the ratio that all water to be produced from groundwater supplies within the district bears to all water to be produced by persons and operators within the district from supplemental sources as well as from groundwater within the district. The BPP applies only to water producers that utilize more than 25 AF of groundwater per water year. Water producers that use 25 AF or less from the groundwater basin are excluded from the production percentage limitation. The BPP for the 2005-06 water year was established at 64 percent by the OCWD board of directors in April 2005. The actual 2005-06 BPP achieved by the district s major groundwater producers for non-irrigation use, including In-Lieu Program deliveries and water conservation credits, was 68.5 percent (68.8 percent if conservation credits are excluded). The actual production percentage achieved by each major producer is presented in Appendix 1. Historical assigned and achieved BPPs are presented in Figure 2. FIGURE 2. Groundwater BPP Production Percentage 100% 90% 80% 70% 60% 50% 40% 30% 20% OCWD Assigned Basin Production Percentage In-Lieu Groundwater 10% 0% 1983-84 1985-86 1987-88 1989-90 1991-92 1993-94 1995-96 1997-98 1999-00 2001-02 2003-04 2005-06 Water Year GROUNDWATER LEVELS Groundwater levels in the Orange County groundwater basin are shown on Plate 1. Groundwater level data used to prepare this plate were collected during late June and early July 2006 from approximately 400 production wells and monitoring wells screened within the principal aquifers (approximately 200 to 1,200 feet deep). The groundwater elevation plate shows pumping depressions generally ranging from 30 to 80 feet below sea 7

level in coastal and western areas of the basin. A general indicator of changing basin levels is the zero (0) mean sea level elevation contour line. The zero contour line generally migrated approximately one-half mile seaward when compared to its alignment in the prior year. A review of the Change in Water Levels between June 2005 and 2006 map (refer to Plate 2) reveals the following: In the Anaheim/Fullerton area, water levels rose 10 to 15 feet. Even though water year 2005-06 was slightly drier than normal, water levels rose from imported MWD water (both direct replenishment and In-Lieu). Along the Santa Ana River (SAR) near Warner Basin, water levels were generally unchanged. In most of the Irvine-area, water levels rose 10 to 20 feet because of reduced agricultural well pumping relative to the prior water year (2004-05). However, Principal aquifer levels in north Irvine near the Santa Ana Mountains dropped up to 15 feet, likely due to less rainfall relative to the prior wet year. In the Santiago recharge area, water levels declined 10 to 20 feet, likely due to lower maintained water levels in Santiago Pits relative to the previous wet year along with reduced incidental recharge from the Santiago Creek watershed due to below-average rainfall. However, slightly further south in the Tustin area, water levels rose 10 to 20 feet. In the central and coastal portions of the basin, water levels rose from 0 to 10 feet, except in the Huntington Beach and Seal Beach areas where water levels in the Principal aquifer dropped 5 to 10 feet due to increased pumping from the City of Huntington Beach relative to the previous year. Water level hydrographs for four monitoring wells located in different areas of the basin are shown on Plate 3. The hydrographs span the years between 1970 (shortly after the basin was considered approximately full) and 2006. COASTAL GROUNDWATER CONDITIONS The coastal portion of the groundwater basin, essentially that area within 5 miles of the coast, is sensitive to lower groundwater levels due to seawater intrusion potential and seasonal effects on production well capacity. Coastal groundwater levels are affected by groundwater production, overall groundwater storage in the basin and, to a lesser extent, injection at the Talbert and Alamitos barriers. For the year ending June 30, 2006, groundwater production (excluding agricultural production) from the cities of Fountain Valley, Huntington Beach, Newport Beach, Seal Beach and Westminster as well as IRWD, MCWD and OCWD (excludes groundwater used for injection in the Talbert Barrier) 8

81,000 AF reported for these agencies from the previous year (2004-05). IRWD absorbed The Irvine Company s (TIC) groundwater production (and imported water deliveries) effective July 1, 2005. When combining irrigation pumping for TIC and IRWD for the previous two years and comparing those totals with IRWD s total for 2005-06 a steep reduction is evident for this type of groundwater usage. The totals for 2003-04, 2004-05 and 2005-06 were 4,293 AF, 1,917 AF and 484 AF, respectively. This decrease in pumping is mainly a result of the continued conversion of agricultural lands in the Irvine area to residential and commercial uses. Other areas within OCWD where irrigation pumping occurred showed a more gradual downward trend compared to that of Irvine s groundwater usage for the same period. The Talbert and Alamitos barriers combined injection totaled approximately 12,600 AF (includes all sources of water imported, recycled and groundwater) for the 2005-06 water year, which was a 36 percent decrease from the prior year (2004-05). The decrease in 2005-06 in injection quantity was primarily due to the following factors: 1) injection rates for the Talbert Barrier were reduced starting in December 2005 as groundwater levels reached protective elevations in coastal areas in part as a result of the near-record precipitation experienced in 2004-05, 2) the transmission pipeline (i.e., used for OC-44 deliveries) that conveys water to OCWD s turnout on Adams Avenue in Huntington Beach for use in the Talbert Barrier incurred a significant leak and other matters that required shutdown of the transmission line from mid-february 2006 through late-may 2006, and finally 3) pipeline leaks on the 40-year old Alamitos Barrier pipeline facility required that injection flows be reduced for a number of months and eventually terminated for over two months. It should be noted that recycled water deliveries to the Alamitos Barrier commenced in October 2005, which supplements imported deliveries from the Metropolitan Water District of Southern California (MWD). Coastal groundwater levels in the 2005-06 water year generally reached their lowest point in September 2005 at the end of the summer pumping period. Minimum levels in the Principal aquifer for September 2005 were generally 20 feet higher when compared to the minimum levels for September 2004 in the Costa Mesa and the Dyer Road Well Field areas. Minimum levels in the other coastal areas (Huntington Beach, Fountain Valley and Seal Beach) were approximately 10 to 20 feet higher in September 2005 than for the same comparative period in 2004. ANNUAL GROUNDWATER BASIN OVERDRAFT Annual groundwater basin overdraft (or annual basin storage decrease without supplemental replenishment water as used in this Engineer s Report), as defined in the District Act, is the quantity by which production of groundwater supplies exceeds natural replenishment of groundwater supplies during a water year. This difference between extraction and replenishment can be estimated by determining the change in volume of groundwater in storage that would have occurred had supplemental water not been used 9

for any groundwater recharge purpose, including seawater intrusion protection, water reclamation and the In-Lieu Program. For the 2005-06 water year, it is estimated that the volume of groundwater in storage increased by 66,000 AF. Approximately, a 108,000 AF of water was supplied to the basin as follows: 1) directly from the percolation or injection of imported water from the Colorado River and State Water Project (SWP), 2) indirectly from groundwater producers participation in the In-Lieu Program, and 3) use of recycled water (but excluding deep well water) to supplement imported water in the Talbert and Alamitos seawater intrusion barriers. The annual overdraft (i.e., annual basin storage decrease without supplemental replenishment water) was 42,000 AF for the 2005-06 water year. For the five-year period from July 1, 2001 to June 30, 2006, an annual average of approximately 94,000 AF of supplemental water and recycled water was percolated or injected into the underground basin for replenishment or used directly in lieu of pumping groundwater. The average annual basin storage decrease without supplemental replenishment water during the same 5-year period was approximately 61,000 AF. Average seasonal rainfall in the OCWD service area for this 5-year period was 13.2 inches, which is approximately equal to the historical annual average of 13.4 inches. GROUNDWATER BASIN ACCUMULATED OVERDRAFT The accumulated overdraft, as defined in the District Act, is the quantity of water needed to be replaced at OCWD s intake area to prevent landward movement of ocean water into the fresh groundwater body. Landward movement of ocean water can be prevented if groundwater levels near the coast are several feet above sea level. Groundwater levels along the coast are related to the volume of water stored in the intake area, water pumped from the entire basin and the pattern or location of pumping. Seawater intrusion control projects, however, have been constructed and others are under construction that together will be effective in preventing landward movement of ocean water into the fresh groundwater body. These facilities will allow greater utilization of the basin s storage capacity. OCWD is also dedicated to maximizing its replenishment capabilities by actively negotiating with the U.S. Army Corps of Engineers to increase its water conservation program behind Prado Dam and creating a recharge facility development plan to evaluate cost-effective improvements to its groundwater recharge capabilities. In February 2007, OCWD staff completed a report titled, Report on Evaluation of Orange County Groundwater Basin Storage and Operational Strategy. This report presents a new methodology that had been developed, tested, and documented for calculating accumulated overdraft and storage change based on a three aquifer layer approach. Furthermore, the report provides the basis for calculating accumulated overdraft using a new full-basin benchmark that was developed for each of the three aquifer layers, which in effect replaces the traditional single-layer full benchmark of 1969. Lastly, the report recommends a basin management operational strategy that provides general guidelines 10

Projected accumulated overdrafts for the current water year (2006-07) and the ensuing water year (2007-08) ending June 30 are estimated to be 190,000 AF and 160,000 AF, respectively. Projected annual basin storage decrease without supplemental replenishment water for the current water year (2006-07) is estimated to be 145,000 AF. This quantity is based on the assumption that annual groundwater production for the current water year will be approximately 340,000 AF (including In-Lieu Program water and excluding groundwater used for injection in the Talbert Barrier) and that natural replenishment (captured SAR base and storm flows, and natural incidental recharge) will be approximately 190,000 AF for the Santa Ana River basin under substantially drier than normal conditions for precipitation (as of the end of February 2007). Projected annual basin storage decrease without supplemental replenishment water for the ensuing water year (2007-08) is estimated to be 102,000 AF. This estimate is based on the assumption that annual groundwater production for the ensuing water year will total 362,000 AF, based upon an assumed BPP of 74 percent plus 19,000 AF of production from wellhead water quality improvement projects (discussed further in the subsequent section, Recommended BPP ) and that natural replenishment will total 260,000 AF (in accord with OCWD s groundwater basin management strategy adopted in December 2002). On June 25, 2003 OCWD, the Municipal Water District of Orange County (MWDOC), MWD, and participating producers officially approved the funding agreement for the MWD Long-Term Groundwater Storage Program. This new conjunctive use storage program (also informally referred to as MWD CUP ) provides for MWD to store up to 66,000 AF in the OCWD groundwater basin to be taken later in-lieu of imported supplies during water shortage events. A compensation package from MWD was included in the agreement to build eight new groundwater wells, improvements to the Seawater Barrier, construction of the Diemer Bypass Pipeline and an annual administrative fee. The preferred means to store water in the MWD Storage Account will be through in-lieu storage. Storage also will be available through direct storage using OCWD s spreading grounds. For 2005-06, 15,476 AF of water was placed into the MWD storage account via in-lieu deliveries to participating producers. The annual quantities and cumulative totals of MWD water stored since the program s inception are shown in Appendix 6. On November 16, 2005 OCWD, MWDOC and MWD approved a Letter Agreement to store between 2,000 AF and 40,000AF of imported water in the OCWD groundwater basin for 2005-06. The program is called the 2005-06 Supplemental Storage Program (also referred to as Super In-lieu ) and was established as a one-year program to take advantage of the availability of excess water supplies that resulted from the unusually wet winter experienced during water year 2004-05. For the water year 2005-06, 16,000 AF was stored using the in-lieu program. MWD can call for this stored water starting from water year 2007-08 through water year 2011-12. 12

REPLENISHMENT RECOMMENDATION Section 27(b) of the District Act states the following: The total of the replenishment assessment levied in any year shall not exceed an amount of money found to be necessary to purchase sufficient water to replenish the average annual overdraft for the immediate past five water years plus an additional amount of water sufficient to eliminate over a period of not less than 10 years nor more than 20 years, the accumulated overdraft, plus an amount of money to pay the costs of initiating, carrying on, and completing any of the powers, projects and purposes for which this district is organized. Based upon Section 27(b), that portion of the RA that is used for water purchases for the ensuing water year 2007-08 is limited to the amount needed to purchase 75,000 AF (rounded), as calculated below: Five-year (7/1/2001 through 6/30/2006) Average Annual Basin Storage Decrease without Supplemental Replenishment Water* = 61,000 AF End of Water Year 2005-06 Accumulated Overdraft = 135,000 AF Assumed Time Period to Eliminate Accumulated Overdraft = 10 years Potential Water Purchase Amount: 61,000 AF + (135,000 AF/10 years) = 74,600 AF (use 75,000 AF) *Referred to as the Average Annual Overdraft in Section 27(b) of the District Act. Table 2 presents the proposed 2007-08 budget for water purchases, which shows the proposed quantity of purchased water (76,000 AF) being slightly greater than the prescribed limit (75,000 AF) as allowed for under the provisions of Section 27(b) of the District Act. However, not all water supplies or quantities listed in Table 2 will necessarily be available at the time when OCWD makes a request for given deliveries and OCWD may not necessarily request deliveries at certain times due to operational limitations when a given water supply may be available. TABLE 2. 2007-08 Budget for Water Purchases Water Source AF Rate ($/AF)* Total Cost Alamitos Barrier 2,000 $536 $ 1,072,000 Arlington Desalter 1,000 $248 $ 248,000 MWD Water via OC-44 (for barrier) 8,000 $507 $ 4,056,000 MWD In-Lieu Water 50,000 $375 $18,750,000 MWD Direct Replenishment Water 15,000 $248 $ 3,720,000 WATER PURCHASES SUBTOTAL 76,000 $27,846,000 Applicable Charges Total Cost MWDOC Surcharge (8-year average) $ 364,000 MWD/MWDOC Capacity Charge $ 100,056 MWD/MWDOC RTS Charge $ 68,409 ADDITIONAL CHARGES SUBTOTAL $ 532,465 WATER COST 76,000 $28,378,465 *Rates include required MWDOC surcharge where appropriate. 13

RECOMMENDED BASIN PRODUCTION PERCENTAGE In December 2002, the District approved a new basin management approach for determining the BPP for future water years. The new management approach is based upon developing a base amount of groundwater production the basin can annually sustain utilizing dependable water supplies OCWD expects to receive. For the 2007-08 water year, consideration to set the BPP at or near 74 percent is recommended based upon the following: Following the basin management approach adopted by the District in December 2002. Analysis of the groundwater basin s accumulated overdraft, available supplies to the basin and projected pumping demands indicate that this level of pumping can be sustained without detriment to the basin. The BPP will be set in April 2007. Based on the above assumed water demand, a BPP of 74 percent corresponds to approximately 362,000 AF of groundwater production, which includes 19,000 AF of groundwater production above the BPP to account for groundwater quality enhancement projects, as described below. In order to achieve water quality objectives in the groundwater basin, it is recommended for the ensuing water year 2007-08 that additional production of approximately 19,000 AF (above the BPP) be allowed for the cities of Garden Grove and Tustin, and MCWD and IRWD. These agencies need the additional pumping allowance in order to accommodate groundwater quality improvement projects. As in prior years, production above the BPP from these projects would be partially or fully exempt from the Basin Equity Assessment (BEA) as a result of the basin benefit provided by removing poor-quality groundwater and treating it for beneficial use. In April 2007, staff will apprise the board on the status of the aforementioned conditions. If the estimates of basin supplies in the current or ensuing year are substantially different than those contained in the respective conditions, then a revised BPP may be recommended. NOTICE OF PUBLIC HEARING NOTICE IS HEREBY GIVEN THAT, in accordance to the Orange County Water District (District) Act, the District s Board of Directors ( Board ) will conduct a public hearing to consider levying and imposing a Replenishment Assessment and Additional Replenishment Assessment on all non-exempted groundwater produced form the groundwater underlying the District for the period from July 1, 2007 to June 30, 2008 ( FY 2007-2008 ). The public hearing will be conducted at 5:00 p.m. on April 18, 2007 at the 14

Orange County Water District offices at 10500 Ellis Ave. in Fountain Valley, CA. In connection with the District Board s consideration of the estimated FY 2007-2008 Replenishment Assessment and Additional Replenishment Assessment, the District provides the following information for the benefit of each person or entity upon whose groundwater production the estimated Replenishment Assessment and Additional Replenishment Assessment may be levied and imposed: 1. Amount of Estimated Replenishment Assessment: Uniform rate of $123 per acre-foot of groundwater produced by all persons and entities from the Orange County Groundwater Basin during FY 2007-2008. 2. Amount of Estimated Additional Replenishment Assessment: Uniform rate of $123 per acre-foot of groundwater produced by all persons and entities for all purposes other than irrigation from the Orange County Groundwater Basin during FY 2007-2008. 3. Estimated Fixed Rate in Lieu of Assessments: $246 single payment for FY 2007-2008, that may be paid by the operator of any water producing facility within the District which has a discharge opening not greater than two inches in diameter and which does not provide domestic or irrigation water for an area in excess of one acre. 4. Basis for the Estimated Replenishment Assessment: As authorized by Section 27 of the District Act, the estimated Replenishment Assessment is calculated to represent an amount of money found to be necessary to purchase sufficient water to replenish the average annual overdraft for the immediate past five water years plus an additional amount of water sufficient to eliminate over a period of not less than 10 years nor more than 20 years, the accumulated overdraft, plus an amount of money to pay the costs of initiating, carrying on, and completing any of the powers, projects, and purposes for which this district is organized. 5. Basis for the Estimated Additional Replenishment Assessment: As authorized by Section 27.1 of the District Act, the Estimated Additional Replenishment Assessment is calculated to represent such amounts necessary for the purposes set forth in Section 23 of this act, without regard to the limitations provided by said Section 27. Section 23 of the District Act provides that The proceeds of the replenishment assessment levied, assessed and collected upon the production of water from the groundwater supplies within said district shall be used to acquire water and to pay the costs of initiating, carrying on, and completing any of the powers, projects, and purposes for which this district is organized. 6. Reason for the Estimated Replenishment Assessment and Additional Replenishment Assessment: In accordance with the District Act, the District levies, assesses and imposes the Replenishment Assessment and the Additional Replenishment Assessment to acquire water for the purposes of replenishing groundwater supplies and to pay the costs of 15

initiating, carrying on and completing the powers, projects and purposes authorized by the District Act. District staff have calculated for FY 2007-2008 both (i) the cost of acquiring water to replenish the groundwater supplies, and to pay the costs of initiating, carrying on and completing the powers, projects and purposes authorized by the District Board or to be considered for authorization by the District Board, in the amount of approximately $118.5 million ( Projected Expenses ), and (ii) the total projected revenues of the District, including property taxes, lease revenue, interest revenue and miscellaneous sources of revenue, in the amount of approximately $30.3 million ( Projected Non-RA Revenues ). District staff has estimated, and will recommend that the District Board approve, a FY 2007-2008 Replenishment Assessment and Additional Replenishment Assessment in the area of $246/acre-foot, which is the amount needed to pay that portion of the Projected Expenses that are not otherwise covered by the Projected Non-RA Revenues. Questions regarding the proposed Replenishment Assessment and Additional Replenishment Assessment may be directed to: Shivaji Deshmukh Orange County Water District PO Box 8300 Fountain Valley CA 92728-8300 (714) 378-3216 e-mail: sdeshmukh@ocwd.com 16

PART II: WATER SUPPLY AND BASIN UTILIZATION Section 31.5 of the District Act requires an investigation and annual report setting forth the following information related to water supply and basin utilization within the OCWD service area, together with other information as OCWD may desire: WATER SUPPLY AND BASIN UTILIZATION 2005-06 SUMMARY OF FINDINGS 1. Water usage from all supplemental sources totaled 251,065 AF for the 2005-06 water year, of which 89,239 AF was In-Lieu Program water. 2. Water usage from recycled water produced from within OCWD totaled 14,246 AF for the 2005-06 water year. 3. Water demand within OCWD totaled 474,782 AF for the 2005-06 water year. 4. Estimated demand for groundwater for the ensuing 2007-08 water year is 362,000 AF. 5. Supplemental replenishment water will be available through June 2007. The availability of the water in water year 2007-08 will depend upon precipitation amounts for the remainder of winter 2007 and the following winter. 17

SUPPLEMENTAL WATER Supplemental water is used by water agencies within OCWD s boundary to augment groundwater supplies in satisfying their user demands and by OCWD to recharge the groundwater basin. Supplemental water, as defined in Section 31.5 of the District Act, is any water that originates from outside the Santa Ana River (SAR) watershed (area of 2,081 square miles) with the exception that the portion of the Santiago Creek watershed that lies upstream of Villa Park Dam (note: this watershed lies entirely within the SAR watershed) is also counted as supplemental water. Sources of supplemental water typically include imported deliveries from MWD and diversions from Irvine Lake/Santiago Reservoir (i.e., Santiago Creek) that are conveyed to users within OCWD boundaries. MWD deliveries originate from either the Colorado River or the SWP. In addition, supplemental water would also include deliveries from within the SAR watershed that involve water exchanges (i.e., releasing a quantity of water that originates from within the SAR watershed while importing an equal quantity of supplemental water to replace it). Western Municipal Water District (WMWD) in Riverside County has a water exchange program with OCWD. Non-local waters are defined, for purposes of this report, as waters purchased from agencies outside of the OCWD boundary for use within OCWD. Non-local waters include supplemental water and also water deliveries purchased by OCWD where the water source is located within the SAR watershed. Water deliveries to OCWD from the Arlington Desalter in Riverside and the San Bernardino Valley Municipal Water District s (SBVMWD) High Groundwater Mitigation Project are non-local waters. Both projects involve the pumping (and treatment in Arlington s case) and release of groundwater from SAR upstream groundwater basins to OCWD via the SAR for groundwater replenishment at the OCWD Forebay recharge facilities. For the purpose of being consistent with previous Engineer s Reports and to present information in a concise manner, non-local water deliveries that are purchased and used by OCWD for groundwater replenishment are included in the supplemental water totals in this report. Recycled wastewater that is produced and used within OCWD is considered, for purposes of this report, as neither non-local water nor supplemental water. Therefore, recycled water that originates from within OCWD is reported separately from supplemental water totals. However, recycled water used in the Alamitos Barrier is supplied from Los Angeles County and as such is categorized as supplemental water. Water agencies utilizing supplemental water are listed in Appendix 1. As shown in Table 3, during the 2005-06 water year, use of supplemental water in the OCWD service area totaled 250,372 AF, which resulted from 146,532 AF used directly by water agencies and 103,840 AF (includes In-Lieu Program water) used for groundwater replenishment purposes. Water agencies uses included 138,869 AF for municipal and industrial use and 7,663 AF for agricultural purposes. Historical, supplemental water usage for the 2005-06 water year and 18

For the 2005-06 water year, the OCWD board of directors approved the continuation of the In-Lieu Program, previously sanctioned by MWD. The cost of the In-Lieu Program water to OCWD is the difference between the cost for treated replenishment water (formerly called Long Term Seasonal Storage water) and the cost to produce groundwater (i.e., Replenishment Assessment (RA) plus cost of energy to pump groundwater). OCWD pays this difference to participating agencies. In-Lieu Program water deliveries totaled 89,239 AF for the 2005-06 water year, as shown in Tables 3 and 4. TABLE 4. 2005-06 In-Lieu Program Water Deliveries Agency AF City of Anaheim 5,149.2 City of Buena Park 3,049.6 East Orange County Water District 413.6 City of Fullerton 6,345.1 City of Garden Grove 4,926.0 Golden State Water Company 5,290.6 City of Huntington Beach 6,466.3 Irvine Ranch Water District 12,194.9 Mesa Consolidated Water District 8,893.8 City of Newport Beach 7,682.0 City of Orange 9,120.9 City of Santa Ana 6,019.4 City of Tustin 5,364.7 City of Westminster 1,618.9 Yorba Linda 6,703.9 TOTAL 89,238.9 Groundwater replenishment quantities include direct deliveries to OCWD s Forebay recharge facilities, Alamitos Barrier, Talbert Barrier and indirectly from reduction in pumping through the In-Lieu Program. Replenishment water typically comes from MWD supplies; SAR upstream releases from the Arlington Desalter, WMWD and SBVMWD; and recycled water from OCWD s GWR System Phase 1 and the Water Replenishment District of Southern California (WRD) Alamitos Barrier Recycled Water Project. Recycled water use within OCWD is presented in Table 5 (excluding WRD-supplied recycled water to the Alamitos Barrier, because this water is categorized as supplemental water and is already included in totals reported in Table 3). The major areas of use for recycled water are: 1) groundwater replenishment (specifically a portion of the blended injection water used to supply the Talbert Barrier), and 2) supply water for irrigation and industrial users. 20

TABLE 5. 2005-06 Recycled Water Usage Groundwater Replenishement AF GWR System Phase 1 (Talbert Barrier) 4,087 Irrigation and Industrial IRWD 1 8,798 OCWD (Green Acres Project) 2 1,361 Subtotal 10,159 TOTAL 14,246 1 Recycled water used within the portion of OCWD that lies within IRWD s boundaries (excludes OCWD/IRWD intertie water deliveries to the Green Acres Project). 2 Excludes deliveries to the Orange County Sanitation District and includes IRWD/OCWD Intertie deliveries to the Green Acres Project. AVAILABILITY OF SUPPLEMENTAL REPLENISHMENT WATER MWD water supply conditions are generally good due to above average storage amounts in Northern California reservoirs despite the current dry winter conditions thru mid- February 2007 and Colorado River Aqueduct deliveries that were recently reduced down to 600,000 to 700,000 AF per year. MWD has projected that replenishment water will be available through June 2007. The availability of the water in water year 2007-08 will depend upon precipitation amounts for the reminder of winter 2007 and the following winter. OCWD may purchase up to an additional 30,000 AF of replenishment water by June 30, 2007 while replenishment water is available. The water purchase would structured such that the 30,000 AF purchase would in effect be a pre-purchase of the water year 2007-08 water budget. Although there have been significant cutbacks on MWD s Colorado River supply as a result of the Qualification Settlement Agreement (dictates how California will gradually reduce the state s use of Colorado River water to its annual basic apportionment of 4.4 million AF), it should be noted that due to various factors there have been some increases in the availability of Colorado River supplies during the final months in recent years (i.e., calendar years). WATER DEMANDS AND USAGE During the 2005-06 water year, total water demands within OCWD s service area totaled 474,782 AF. Total demand includes the use of groundwater, imported water, Santiago Creek native water and recycled water. Total demand excludes groundwater, supplemental water and recycled water used by OCWD for groundwater recharge (but includes In-Lieu Program water); and also excludes water credits given for water conservation. 21

Total water usage for the 2005-06 water year was 493,470 AF. Total water usage includes total water demand plus supplemental water purchased for groundwater replenishment and recycled water used for groundwater injection. Water demands for 2005-06 and projected water demands for 2006-07 and 2007-08 are shown in Table 6. 2006-07 (current year) water demands were determined by assessing current year data that is available and projecting that data to develop annual totals for the current year. 2007-08 (ensuing year) water demands are based on projections provided by the District s retail water agencies within OCWD. Long-term projections are shown in Figure 5. TABLE 6. Water Demands Within OCWD Groundwater 1 Imported Water 2,3 Santiago Creek Native Water 3 Recycled Water 4 Total 2005-06 Non-Irrigation 315,504 134,507 5,056 10,159 465,226 Irrigation 1,893 2,238 5,425-9,556 Total 317,397 136,745 10,481 10,159 474,782 2006-07 (Current Year) 5 Non-Irrigation 328,500 137,000 5,000 11,000 481,500 Irrigation 1,500 2,000 5,000-8,500 Total 330,000 139,000 10,000 11,000 490,000 2007-08 (Ensuing Year) 5 Non-Irrigation 361,000 110,500 5,000 11,000 487,500 Irrigation 1,000 1,500 5,000-7,500 Total 362,000 112,000 10,000 11,000 495,000 1 Includes In-Lieu Program water and excludes OCWD s use of groundwater for seawater barrier. 2 Excludes water conservation credits and imported water used for groundwater replenishment. 3 Imported Water and Santiago Creek Native Water are both counted as supplemental water. 4 Excludes recycled water injected into the groundwater basin for seawater intrusion protection. Includes recycled water from IRWD and OCWD s Green Acres Project (excluding OCSD usage). 5 Demands are estimated by OCWD. WATER DEMAND FORECAST OCWD participates with MWDOC and retail groundwater producers to predict future demands in the OCWD service area. Each producer projected its total water demands to the year 2025. These projections include the effect of local water conservation measures. Figure 5 illustrates historical and projected water demands for the OCWD service area to the year 2025. 22

Population within OCWD s service area is expected to increase from 2.3 million currently to 2.55 million people by the year 2025. This population growth is expected to increase water demands from the current approximate 500,000 AF per year to 614,000 AF per year in 2025 as projected in the OCWD Long Term Facilities Plan (Draft Final, dated January 11, 2006). To support increasing water demands, OCWD will look to increase basin production by purchasing imported supplies for groundwater recharge, capturing SAR flows, completing the GWR System, developing other local recycled water supplies for replenishment purposes, expanding recharge facilities and improving the In-Lieu Program. 700,000 600,000 500,000 FIGURE 5. Water Demand Projections Acre-Feet 400,000 300,000 200,000 100,000 0 Historical Demand Projected Demand 1984-85 1989-90 1994-95 1999-00 2004-05 2009-10 2014-15 2019-20 2024-25 Water Year WASTEWATER RECLAMATION Historically, only groundwater, supplemental water and local surface water have been water sources within OCWD. More recently, wastewater reclamation has become an increasingly significant source of additional water. OCWD recycles wastewater at its Green Acres Project (GAP) plant and IRWD at its Michelson plant for non-irrigation and industrial use. Purified recycled wastewater has also been produced by OCWD for use as injection water in the Talbert Barrier. GAP and IRWD serve recycled wastewater for landscape irrigation and industrial use in Fountain Valley, Costa Mesa, Huntington Beach, Newport Beach, Santa Ana and the IRWD service area. For the 2005-06 water year, GAP and IRWD produced 10,159 AF of recycled wastewater. In October 2002, OCWD and the Orange County Sanitation District (OCSD) signed a Joint Exercise of Powers Agreement for the planned $486.9 million GWR System. This project will treat and deliver 72,000 AF per year of wastewater that has been purified to drinking 23

water standards [microfiltration (MF) followed by reverse osmosis (RO) and ultraviolet (UV) light disinfection in combination with hydrogen peroxide treatment] for direct injection into a seawater intrusion barrier and percolation into the OCWD groundwater basin through use of recharge basins. Construction began in early 2003 with completion and start-up scheduled for November 2007. In January 2004, most of the major treatment facilities at Water Factory 21 (WF-21) ceased operation to make way for construction of the Advanced Water Purification Facility (AWPF) of the GWR System. To maintain the Talbert seawater intrusion barrier during construction of the AWPF, OCWD constructed a new MF system, installed new RO membranes at the WF-21 RO facility and constructed a new UV light treatment system to produce 5 million gallons per day (MGD) of injection water. This initial interim facility was called GWR System Phase 1 and operated between June 2004 and August 2006 (planned removal from service). Portions of the facility are being incorporated into the AWPF. The Water Replenishment District of Southern California (WRD) has brought into service the Alamitos Barrier Recycled Water Project. In October 2005, the project began to supply highly treated recycled water to the Alamitos Barrier from the Leo J. Vander Lans 3 MGD advanced wastewater treatment facility [includes MF, RO and UV (with hydrogen peroxide) treatment] located in Long Beach. This project replaces up to 50 percent of the imported water used to supply the barrier. For 2005-06, the project supplied 255 AF of recycled water to the barrier, which constituted approximately 49 percent of the barrier s supply from October 2005 though the end of June 2006. WATER QUALITY When blended together by the major agencies within the OCWD service area, the blended groundwater (without treatment) and treated supplemental water for 2005-06 is determined to have a flow-weighted average of 428 milligrams per liter (mg/l) of total dissolved solids (TDS), which is a decrease from 450 mg/l for average TDS reported for 2004-05. The average groundwater TDS concentration for the basin for 2005-06 is 444 mg/l (versus 441 mg/l reported for 2004-05), ranging from a low of 208 mg/l in the Seal Beach area to greater than 600 mg/l in certain inland areas. Average concentrations of TDS, nitrates and hardness for groundwater and groundwater combined with supplemental water supplied by agencies within OCWD s service area during the 2005-06 water year are shown in Table 7. These concentrations were determined from groundwater and supplemental water analyses and from production reports submitted to and filed with OCWD by each agency. The cities of Garden Grove and Tustin have active groundwater treatment projects that help to reduce certain constituents reported in Table 7 in their groundwater supply prior to it being served to customers (see note 6 in Table 7). 24

TABLE 7. 2005-06 Water Quality Summary TDS 3 NO 3 -N 4 Hard- Groundwater 1,7 Delivered Blend 1,2,7 City/Agency TDS 3 NO 3 -N 4 Hardness 5 ness 5 Anaheim 557 3.3 320 495 2.1 257 Buena Park 321 0.5 182 371 0.5 177 East Orange County Water District 608 4.9 361 461 1.5 219 Fountain Valley 375 1.1 227 387 0.9 210 Fullerton 588 3.3 331 490 1.7 242 Garden Grove 6 471 2.9* 310 441 1.6* 238 Golden State Water Company 499 2.6 271 453 1.4 218 Huntington Beach 336 0.4 210 366 0.4 195 Irvine Ranch Water District 315 0.2 100 369 0.4 139 La Palma 283 ND 8 130 302 0.1 136 Mesa Consolidated Water District 345 0.2 78 384 0.3 132 Newport Beach 369 1.0 173 404 0.6 173 Orange 458 2.1 272 429 1.0 208 Orange Park Acres Mutual Water Co. 680 4.4 433 554 2.5 310 Santa Ana 386 2.4 221 399 1.4 197 Seal Beach 208 ND 8 57 284 0.2 100 Serrano Water District 665 1.5 388 581 1.0 356 Tustin 6 700* 8.1* 397* 549* 4.1* 280* Westminster 326 1.0 199 367 0.7 187 Yorba Linda WD 619 3.3 325 465 1.2 211 Weighted Average 7 444 2.1 242 428 1.2 206 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 2005-06 are as follows: MWD Water Quality Santiago Reservoir Water Quality TDS = 413 mg/l TDS = 458 mg/l N0 3 -N = 0.45 mg/l N0 3 -N = 0.09 mg/l Hardness (as CaCO 3 ) = 173 mg/l Hardness (as CaCO 3 ) = 309 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 NO 3 -N (i.e., nitrate expressed as nitrogen) is 10 mg/l. 5 Hardness is reported as mg/l of CaCO 3. General ranges of hard and soft water are as follows: 0-75 mg/l = soft 150-300 mg/l = hard 75-150 mg/l = moderately hard 300-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. 7 All water quality results are flow-weighted averages based on groundwater and imported water delivered to each entity. 8 ND = non-detect. Nitrate (as NO 3 -N) analytical detection limit = 0.09 mg/l. WATER RESOURCES DATA A summary of water resources data within OCWD for the 2005-06 water year and the previous year (2004-05) is shown in Appendix 5. 25

PART III: WATER PRODUCTION COSTS FOR ENSUING YEAR (2007-08) Section 31.5 of the District Act requires that costs of producing groundwater and obtaining supplemental water be evaluated annually. These costs vary for each producer, depending on many factors. Although these variations in cost are recognized, it is necessary for the purpose of this report to arrive at figures representing the average cost of producing groundwater and purchasing supplemental water. ENSUING YEAR (2007-08) WATER PRODUCTION COSTS SUMMARY OF FINDINGS 1. Cost for producing water from the groundwater basin within OCWD including any replenishment assessment for 2007-08 is estimated to be $413 per acre-foot. 2. Cost of treated, non-interruptible supplemental water for 2007-08 is estimated to be $538 per acre-foot. 4. Cost for untreated, interruptible replenishment water for 2007-08 is estimated to be $255 per acre-foot. 5. Cost for In-lieu Program water for 2007-08 is estimated to be $382 per acre-foot. 26

GROUNDWATER PRODUCTION COSTS FOR NON-IRRIGATION USE Cost for producing an acre-foot of groundwater in the ensuing 2007-08 water year has been estimated for a potable water well for a large groundwater producer (e.g., a city water department, water district) in OCWD. Operations and maintenance (O&M) and energy costs were estimated using cost information provided by several of the large groundwater producers from a survey conducted by OCWD in October 2006. The capital cost component was derived using available project cost data for 8 production wells to be constructed under the MWD Long-Term Groundwater Storage Program. Drilling and development of the 8 wells have been completed. Award of a construction contract for purchase, installation and startup of the groundwater pumping equipment and appurtenances was made on March 15, 2006 (construction work is scheduled for completion in fall 2007). Appendix 4 contains several of the key design characteristics for the 8-well project. The OCWD Replenishment Assessment (RA) used in the cost determination is the proposed RA for 2007-08. The estimated cost for groundwater production for a large groundwater producing entity (e.g., a city water department, water district, etc.) is presented in Table 8. The total cost to produce an acre-foot of groundwater within OCWD in the ensuing 2007-08 water year is estimated at $413 per acre-foot. Based on responses to the aforementioned survey, the flow-weighted average (based upon quantity of water pumped) for energy cost equaled $58 per AF. O&M costs ranged from $20 to $107 per acre-foot with a median cost of approximately $66 per acre-foot. Elements that influence these costs include load factors and variations in groundwater levels. Recently drilled wells are generally deeper than those drilled decades ago. From the aforementioned survey, the average load factor (indicates the percent-of-use of an extraction facility) equaled 37 percent. TABLE 8. Estimated 2007-08 Groundwater Production Costs Item Non-irrigation Annual $ $/AF Energy 150,800 1 58 2 Proposed RA 616,200 1 237 3 Total Production Costs 767,000 295 Capital 135,200 4 52 4 O&M 171,600 1 66 2 Total Other Costs 306,800 118 Total Cost to Producers 1,073,800 413 1 Based upon an annual average production of 2,600 AF per production well. 2 Based on survey of major agencies within OCWD, non-irrigation groundwater users. 3 Proposed for 2007-08. 4 Based on the estimated average cost for design and construction of a production well (excluding land cost) under the MWD Long-Term Groundwater Storage Program (cost amortized over 30 years at 5 percent interest). Design parameters are found in Appendix 4. 27

COST OF SUPPLEMENTAL WATER Supplemental water is supplied to the OCWD service area by MWD. MWD delivers both treated and untreated water as either a non-interruptible supply or an interruptible supply. As a result, there are several categories of water available from MWD. The categories most applicable for purposes of this report are 1) uninterruptible (i.e., firm) treated water, which is referred to as full service water, 2) interruptible treated water, which is referred to as in-lieu water, and 3) interruptible untreated water, which is referred to as replenishment water. Treated water is used directly by the various producers for municipal and industrial purposes, while untreated water is used by OCWD for groundwater replenishment. Table 9 shows the estimated costs for the three aforementioned MWD water categories for the 2007-08 ensuing water year. Figure 6 shows historical supplemental water costs along with historical groundwater production costs. A comparison of estimated costs for groundwater versus supplemental water (non-irrigation use) during the ensuing water year (2007-08) is shown in Table 10 and also in Figure 6. Values used in Figure 6 are presented in tabular form in Appendix 7. TABLE 9. Estimated 2007-08 Supplemental Water Costs 1 Rate and Charge Components Treated Water Rates ($/AF) Firm Deliveries MWD Supply Rate (MWDOC Melded Rate) MWD System Access Rate MWD System Power Rate MWD Water Stewardship Rate MWD Treatment Surcharge MWD RTS and Capacity Charges 2 MWDOC Surcharge Total Rate and Charge Components Full Service Water 77.50 143.00 101.50 25.00 153.00 31.00 7.00 Treated Water Rates ($/AF) 538.00 Untreated Water Rates ($/AF) Interruptible Deliveries In-Lieu Water Replenishment Water MWD Replenishment Water Rate 375.00 248.00 MWDOC Surcharge 7.00 7.00 Total 382.00 255.00 1 MWD rates are final for calendar year 2007 and proposed for calendar year 2008. MWDOC rates are proposed. Supplemental water costs for MWD member agencies (i.e., Anaheim, Fullerton and Santa Ana) are not reported herein due to the variability between the agencies on water supply allocations between MWD s Tier 1 and Tier 2. 2 For purposes of expediency, Readiness-to-Serve (RTS) and Capacity charges have been converted to an approximate cost per acre-foot, but are not normally reported in terms of unit cost. 28

TABLE 10. Estimated 2007-08 Water Production Cost Comparison Non-Irrigation Use Groundwater ($/AF) Supplemental Water ($/AF) Fixed Cost 52 1 538 3 Variable Cost 361 2-3 Total 413 538 1 Capital cost. 2 Cost for energy, O&M plus proposed RA. 3 Delineation of fixed and variable costs is not available. 30

5 72 57 LONG BEACH 22 HAWAIIAN GARDENS 605-40 SEAL BEACH CERRITOS -30 CYPRESS LOS ALAMITOS LA PALMA 405 BUENA PARK WESTMINSTER -60 LA MIRADA -10 39 HUNTINGTON BEACH 0 STANTON 60-60 FULLERTON GARDEN GROVE -30 LA HABRA 22 200 140 FOUNTAIN VALLEY 280 40 240 120 ANAHEIM SANTA ANA RIVER -70 BREA 260 180 100 280 90 SANTA ANA 160 280 PLACENTIA ORANGE -20 80 220 55 300 VILLA PARK 20 100 20 140 TUSTIN 180 160 300 YORBA LINDA 90 91 261 241-80 60 140 100 1 PACIFIC OCEAN -50-40 -30-20 COSTA MESA -50 IRVINE 40 80 120 160 133 180 200 405 NEWPORT BEACH 73 Oregon California Nevada Estimated Groundwater Elevations Within The Principal Aquifer (Feet, MSL) -80 - -10 0 20-300 Freeways / Highways Orange County Water District Water Features PLATE 1 GROUNDWATER CONTOUR MAP JUNE 2006 0 2 4 Miles Reproduced with permission granted by THOMAS BROS. MAPS. Thomas Bros. Maps. All rights reserved 31

5 72 57 LA HABRA BREA LA MIRADA 90 HAWAIIAN GARDENS 605 CERRITOS 0 10 LA PALMA CYPRESS 0 BUENA PARK 10 39-10 FULLERTON 10 ANAHEIM PLACENTIA 10 0 0 20 VILLA PARK YORBA LINDA 90 91 LONG BEACH 22-10 LOS ALAMITOS SEAL BEACH 405 STANTON WESTMINSTER -10-20 HUNTINGTON BEACH 0 GARDEN GROVE 22 10 FOUNTAIN VALLEY SANTA ANA RIVER 10 10-10 SANTA ANA ORANGE 20 30 20 55 10 20 TUSTIN -10-10 0 10 10-10 261 0 241 1 PACIFIC OCEAN COSTA MESA -10 40 10 50 IRVINE 20 133 0 10 30 405 NEWPORT BEACH 73 Oregon California Nevada Estimated Groundwater Elevation Changes Within The Principal Aquifer (Feet) -20 - -10 0 10-50 Freeways / Highways Orange County Water District Water Features PLATE 2 CHANGE IN WATER LEVEL BETWEEN JUNE 2005 AND 2006 0 2 4 Miles Reproduced with permission granted by THOMAS BROS. MAPS. Thomas Bros. Maps. All rights reserved 32

APPENDIX 1. Water Production Data 2005-06 Groundwater (AF) Supplemental Water (AF) (AF) Actual BPP Groundwater Producer Non-Irrigation 1 Irrigation In-Lieu Total Non-Irrigation 1 Irrigation Conservation Total Grand Total Non-Irrigation 1 Program 2 Credit 3 only Anaheim, City of 41,857-5,149 47,006 26,122-449 26,571 73,577 63.9% Buena Park, City of 7,458-3,050 10,508 5,911-45 5,956 16,464 63.8% East Orange County Water District 284-414 698 456-3 459 1,157 60.3% County of Orange 131 - - 131 94 - - 94 225 58.2% Fountain Valley, City of 6,875 - - 6,875 3,858-76 3,934 10,809 63.6% Fullerton, City of 13,956 13 6,345 20,314 11,424 7 95 11,526 31,840 63.8% Garden Grove, City of 4 13,791-4,926 18,717 10,331-198 10,529 29,246 64.0% Golden State Water Company 13,801-5,290 19,091 10,535-174 10,709 29,800 64.1% Huntington Beach, City of 19,549-6,466 26,015 5,902-202 6,104 32,119 81.0% Irvine Ranch Water District 4,5 27,238 484 12,195 39,917 11,166 7,585 102 18,853 58,770 77.8% La Palma, City of 2,042 - - 2,042 368-11 379 2,421 84.4% Mesa Consolidated Water District 4 8,817 54 8,894 17,765 2,739-178 2,917 20,682 85.9% Newport Beach, City of 3,558-7,682 11,240 6,311-42 6,353 17,593 63.9% Orange, City of 5 11,220 123 9,121 20,464 11,546 59 83 11,688 32,152 63.6% Orange County Water District 6 2,365 - - 2,365 - - - - 2,365 100.0% Orange Park Acres Mutual Wtr. Co. 491 - - 491 439 - - 439 930 52.8% Santa Ana, City of 22,398-6,019 28,417 15,988-163 16,151 44,568 63.8% Seal Beach, City of 2,514 - - 2,514 1,487-26 1,513 4,027 62.4% Serrano Water District 5 2,010 - - 2,010 1,378-4 1,382 3,392 59.3% Tustin, City of 4 6,478-5,365 11,843 2,464-49 2,513 14,356 86.7% Westminster, City of 7,136-1,619 8,755 4,808-118 4,926 13,681 64.0% Yorba Linda Water District 4,318 70 6,704 11,092 6,235 12 37 6,284 17,376 63.7% Total Major Groundwater Producers 218,287 744 89,239 308,270 139,562 7,663 2055 149,280 457,550 68.5% Other Producers 7,286 1,149-8,435 - - - - 8,435 - Exempt Well Production 692 - - 692 - - - - 692 - Total Groundwater Production 226,265 1,893 89,239 317,397 139,562 7,663 2,055 149,280 466,677-6 1 2 3 4 5 Water classed as being used for purposes other than commercial agriculture. Imported MWD water purchased for domestic use to offset groundwater pumping. Accounts for only those credits allowed for under the program initiated on Sept. 20, 1995. Agencies that participate in a water quality cleanup project that involves groundwater. Agencies that can receive Santiago Creek native water above Villa Park Dam that are conveyed to users within OCWD. Such water, if delivered, is included within the classification of Supplemental Water as defined in the District Act. Groundwater included herein is that quantity used by OCWD for purposes other than seawater intrusion barrier maintenance. 34

APPENDIX 2. 2005-06 1 Groundwater Production Non-Irrigation Use Production Over 25 AF PRODUCER AF PRODUCER AF A C Products 491.0 Magic Lamp Mobilehome Park 25.1 Alta Vista Country Club 360.2 Melrose Abbey Funeral Center 37.5 Anaheim Cemetery 33.9 Mesa Consolidated Water District 8,816.9 Anaheim, City of 41,857.2 Mesa Verde Country Club 281.2 Angelica Textile Services Plant 10 232.1 Midway City Mutual Water Co. 133.0 Buena Park, City of 7,457.5 Mile Square Golf Course 154.4 Canyon RV Park 119.6 Navy Golf Course 488.7 Catalina St. Pump Owners 44.0 Newport Beach Golf Course 87.7 CCDA Waters, L.L.C. 158.0 Newport Beach, City of 3,558.3 County of Orange 130.5 Niagara Drinking Water 66.4 Cypress GC LLC/Cypress Golf CLU 57.6 North Orange County Community 104.8 Danone Waters of N. America 235.6 Old Ranch Country Club 526.9 Diamond-Newport Ice Corp. 68.5 Orange, City of 11,220.5 Donovan Golf Course Mgmt., Inc. 250.6 Orange County Water District 3,529.6 Eastlake Village HOA 76.7 Orange Park Acres Mutual Water Co. 491.2 East Orange County Water District 284.3 Page Avenue Mutual Water Co. 55.1 Eastside Water Association 252.8 River View Golf 293.6 Fairhaven Memorial Park 203.9 Santa Ana, City of 22,397.7 Forest Lawn Memorial Park 224.1 Santa Ana Country Club 306.9 Fountain Valley, City of 6,875.0 Seal Beach, City of 2,513.7 Fullerton, City of 13,956.4 Serrano Water District 2,009.6 Garden Grove, City of 13,791.5 South Midway City Water Co. 78.5 Golden State Water Company 13,801.3 The Good Shepherd Cemetery 44.2 Hanson Aggregates West, Inc. 58.4 The Lakes Master Association 60.0 Harding Water 48.4 Tustin, City of 6,477.5 Huntington Beach, City of 19,549.5 Villa Capri Mobile Home Park 48.6 Hutton Centre Common Area 29.8 Walt Disney Product Division 69.3 Hynes Estates, Inc. 86.5 Westminster Memorial Park 331.7 Irvine Ranch Water District 27,237.6 Westminster, City of 7,136.3 Knott s Berry Farm 238.3 Yorba Linda Country Club 257.3 La Palma, City of 2,041.8 Yorba Linda Water District 4,318.0 Los Alamitos Race Course 273.2 Total 226,446.0 1 Water year begins July 1. 35

APPENDIX 3. 2005-06 1 Groundwater Production Irrigation Use Production Over 25 AF PRODUCER AF PRODUCER AF A-B Nursery 41.9 Orange County Produce 603.7 F S Nursery 33.6 Orange, City of 123.2 Irvine Ranch Water District 483.6 Pursche, Roy 50.8 Ito-Ozawa Farms 245.2 Village Nurseries 131.2 Mesa Consolidated Water District 54.4 Yorba Linda Water District 69.8 Total 1,837.4 1 Water year begins July 1. 36

APPENDIX 4. Typical Groundwater Extraction Facility Characteristics PARAMETER NON-IRRIGATION Water System Pressure 62 psi Load (Use) Factor 63% Design Flow Rate 2,563 gpm Annual Production 2,600 AF Bowl Efficiency (minimum) 84% Motor Horsepower 325 hp Type Motor Electric Well Casing Diameters 16 20 inches Type of Pump Vertical Turbine Depth of Well 1,052 feet Depth of Bowls 278 feet Total Dynamic Head (TDH) 325 feet Estimated Life 30 years Annual Cost of Facilities 1 $135,200 1 Based on an interest rate of 5 percent amortized over a 30-year period. Cost for land not included. 37

APPENDIX 5. 2005-06 Water Resources Summary 2005-2006 Water Year (AF) 2004-2005 Water Year (AF) Change from last year to this year (AF) SUMMARY OF BASIN CONDITIONS BASIN SUPPLIES Non-local Recharge Water (MWD, In-lieu & other purchases) 81,020 58,974 22,045 MWD Program Stored Water 15,476 15,021 455 Natural Flows (SAR @ Imperial, local inflows & Santiago Creek) 283,991 710,238 (426,247) Incidental Recharge 1 38,672 158,729 (120,057) Seawater Barriers 2 11,429 16,884 (5,455) River Flow Lost to Ocean (47,400) (463,613) 416,213 Evaporation from Basin Surfaces (2,416) (2,390) (26) Change in Recharge Facilities Storage 3 2,624 9,856 (12,480) 3 TOTAL BASIN SUPPLY 383,396 483,987 (100,592) PRODUCTION AND IN-LIEU Groundwater Production 2 228,159 244,370 (16,211) In-Lieu (OCWD Purchases) 73,763 54,596 19,167 In-Lieu (MWD Purchases) 15,476 15,021 455 TOTAL GROUNDWATER PRODUCTION AND IN-LIEU 317,398 313,987 3,411 BASIN STATUS Change in Groundwater Storage 1 66,000 170,000 (104,000) Basin Operation Storage 4 Producible from Storage 465,000 499,000 66,000 Recharge Storage 135,000 201,000 (66,000) Overdraft without MWD Storage 170,439 220,963 (50,524) OTHER KEY INFORMATION 1. Imported Deliveries to Producers 5 236,461 213,555 22,906 2. Producers' Short-term Seasonal Shift Program: 0 4,986 (4,986) 3. BPP (includes OCWD In-Lieu and water conservation credits) 6 68.5% 68.5% 0% 4. Total Water Demand (includes recycled water) 474,782 467,516 7,266 5. Talbert Barrier Supplies: - AWPF/WF-21 (without deep wells) 4,086 4,155 (69) - Fountain Valley water to WF-21 (w/o City wells) 1,080 2,452 (1,372) - OC-44 Water 5,431 8,368 (2,937) - Deep Wells and City Wells 1,165 2,928 (1,763) 6. Green Acres Project (without deep wells, but including OCSD) 4,969 6,506 (1,536) 7. Arlington Desalter Purchases 0 567 (567) 8 SBVMWD High Groundwater Mitigation Project 0 0 0 9. WMWD/EVMWD Exchange Water 0 0 0 10. Year-end Storage behind Prado Dam 6,153 17,735 (11,582) 11. Year-end Storage in Deep Basins 21,006 23,630 (2,624) 12. Total Artificial Recharge (percolation + barriers w/ deep wells) 256,650 258,556 (1,906) 13. Rainfall (average within OCWD boundaries in inches) 9.1 30.6 (21.5) 14. Annual Mean Temperature at Santa Ana Fire Station (F) 66.1 65.8 0.3 1 Estimated. 2 OCWD deep well used for barrier injection is excluded from Seawater Barriers and Groundwater Production. 3 A negative value for Change in Recharge Facilities Storage translates into a positive value (i.e., increase in basin supply) when performing a summation of Total Basin Supply (with the reverse also holding true). 4 Based on water in storage above the 1956 low basin level. 5 Santiago Creek Native and In-Lieu water are included (excluded is imported water used for groundwater replenishment). 6 BPP for major groundwater producers (see Appendix 1). 38

Water Year APPENDIX 7. Values Used in Figure 6 For Water Rates for Non-Irrigation Use RA $/AF Groundwater Production Cost 1,2 MWD Treated Interruptible Rate (In-Lieu Program) 2,3 $/AF MWD Treated Non-Interruptible Rate (Full Service) 2 $/AF $/AF 1985-86 32 85 181 225 1986-87 32 91 187 231 1987-88 32 91 187 231 1988-89 42 105 187 231 1989-90 45 119 136 231 1990-91 48 91 137 232 1991-92 51 100 156 263 1992-93 60 116 206 325 1993-94 67.5 124 257 389 1994-95 88 145 279 416 1995-96 85 140 294 440 1996-97 88 140 303 448 1997-98 91 141 303 455 1998-99 94 143 303 458 1999-00 100 150 303 459 2000-01 107 150 303 459 2001-02 117 162 303 459 2002-03 127 176 299 455 2003-04 149 203 301 460 2004-05 172 229 318 479 2005-06 205 258 337 494 2006-07 223 279 354 510 2007-08 237 4 295 382 538 1 Includes RA plus cost of energy to produce groundwater. 2 Except for RA, all rates are rounded. 3 Starting with calendar year 2002, rates based upon MWD Treated Replenishment Water Rate. 4 Rate is proposed. 40

APPENDIX 8. Executive Summary Report on Evaluation of Orange County Groundwater Basin Storage and Operational Strategy February 2007 41