Directors Officers Philip L. Anthony*

A separate copy of these responses also has been sent to the grand jury under separate cover. On behalf of the entire board of directors, I thank the grand jury for their thorough study of OCWD and the Groundwater Replenishment System, along with their commendation to our staff for their foresight, expertise and dedication. It certainly is well-deserved and their acknowledgement is appreciated. Sincerely, ~ ~ ~ . K. Bilodean Denis R. Bilodeau President Board of Directors FINDINGS 1) Increased urbanization in the upper Santa Ana River basin will increase the amount of Santa Ana River water available for capture in the Anaheim recharge facilities. Orange County Water District (OCWD)'s board of directors agrees that increased urbanization in the Santa Ana River watershed will increase the amount of Santa Ana River water available for capture in the Anaheim recharge facilities. In fact, OCWD has an ongoing program to add additional recharge capabilities and research methods to increase the recharge of Santa Ana River water. OCWD also has an ongoing monitoring program to evaluate the quality of Santa Ana River water and ensure that recharge of Santa Ana River water into the groundwater basin provides a safe source of drinking water. Using Kraemer Basin to recharge purified wastewater will reduce capacity to capture Santa Ana River floodwater and result in the loss of some floodwater during abnormally wet years. Our operational experience indicates that once every ten years, approximately 2,800 acre-feet of flood water will be lost to the ocean. This finding requires the examination of typical storm flows conveyed by the Santa Ana River, the capability to transfer water to Kraemer Basin during storm events and the recharge potential of Kraemer Basin during those same periods. Losses to the ocean are greatly dependent on the accumulated amount of rainfall during the winter season. Approximately one out of 10 years is defined as a "wet" year, in which rainfall significantly exceeds the long- term average for the region. During these wet years, a large volume of water is captured behind Prado Dam and sustained flows in the Santa Ana River range from 500 cubic feet per second (cfs) to 5,000 cfs. Typically, about nine out of 10 years, annual rainfall totals fall within the "dry" to "normal" range and result in very minor losses to the ocean. Although the storms in a typical year can generate substantial short- term runoff, the storms occur so infrequently that large volumes of water are not captured behind Prado Dam, and flows in the river quickly revert to baseflow (around 300 cfs) following the storm events. To understand the impacts of the GWR System on the recharge system, it is important to discuss how water is transferred from the river to Kraemer Basin: The storm flows are diverted and routed sequentially through OCWD's Warner, Anaheim, Miller and Kraemer basins for recharge. Prior to the storm water reaching Kraemer Basin, however, a few operational factors must be considered: Kraemer Basin is located at the terminal end of the previously mentioned basins, so storm flows must exceed the combined holding and recharge capacity of Warner, Anaheim and Miller basins before the flows can enter Kraemer Basin. Transfer capacity to distribute peak storm flows from the Santa Ana River to Kraemer Basin is limited to 180 cfs. The recharge capacity of Miller and Anaheim lakes is as much as • 140 cfs. During typical (dry-to-average) years, the peak flows in the river last less than 48 hours. Due to the pipeline transfer restriction, it is unlikely that flows generated during short-term peak storm periods could be captured and transferred to Kraemer Basin prior to conclusion of the storm event. Because the recharge capacity of Miller and Anaheim lakes is as much as 140 cfs, and the transfer capacity is 180 cfs, only 40 cfs actually will reach Kraemer Basin. This is far less than its recharge capacity of 100 cfs and would still allow 60 cfs of capacity for the GWR System during storm events. Increased losses to the ocean will occur during wet years. As the recharge system percolates silt-laden storm water through the winter and spring, recharge rates will decline. Heavy spring precipitation will likely generate a large pool of water behind Prado Dam. The required releases from the pool will increase flows in the river to 500 cfs, filling the entire recharge system, and forcing the transfer pipeline to Kraemer to be operated at the 180 cfs capacity for months. As the recharge capacity in Anaheim and Miller basins decrease from 140 cfs to 30 cfs over the same period, the pipeline can now send 150 cfs to Kraemer Basin. Because the maximum percolation rate of Kraemer is approximately 100 cfs, there is 50 cfs of surplus water in the system that must be released to the ocean. Under these conditions, there could be losses of up to 2,800 acre- feet to the ocean. This condition is estimated to occur only once every 10 years. To compensate for these potential losses, OCWD has embarked upon several projects designed to improve recharge capacity. Recently completed projects and their recharge capacity include: Santiago Pits Pump Station (25 cfs) Santiago Creek (12 cfs) . Other potential projects include: La Jolla Basin (12 cfs) Fletcher Basin (5 cfs) Santa Ana River desilting facilities Sand wash plant • Multi-lateral injection wells, recharge galleries and trenches The additional recharge capacity resulting from the implementation of these facilities will more than offset the potential losses of Santa Ana River water to the ocean during wet periods. After these improvements are implemented, the utilization of Kraemer Basin to recharge GWR System product water—even during abnormally wet years—is not expected to result in increased losses of Santa Ana River water to the ocean. 3) Increased rates of recharge in the Anaheim recharge facilities will cause local groundwater levels to rise. Groundwater flow modeling evaluations by OCWD predict that rates of recharge significantly above current rates will cause groundwater level increases in the vicinity of OCWD's recharge facilities. While increasing groundwater levels, also known as groundwater mounding, do not significantly impact current recharge operations; they may ultimately reduce recharge rates due to reducing the water table gradient away from the recharge facilities. This potential condition was projected to occur when the groundwater storage in the basin was within 200,000 acre-feet from full (today's storage is 393,000 acre-feet from full). Based on this model projection, OCWD recognizes that future recharge and groundwater production facilities will need to be better distributed around the basin to reduce the potential for shallow groundwater mounding in the localized recharge areas. 4) Depressed groundwater levels near the coast have exacerbated the inland advance of saline water. Through regular groundwater monitoring and investigations, including construction of five multi-depth monitoring wells and isotopic analyses, OCWD has confirmed that saline groundwater has been moving inland in coastal areas—including beneath the Newport and Huntington Beach mesas and portions of the Bolsa and Sunset gaps. OCWD has taken significant steps to halt this encroachment including: Reducing overall basin pumping by 55,000 acre-feet per year.