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Aug-16-2010 15:33printcomments

El Toro's Base Wells, Putting Together the Puzzle

The Navy denies any contamination of the base water supply, despite evidence of contamination in at least two wells.

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(IRVINE, Calif.) - Misplacement of well screens in the shallow contaminated aquifer allowed corrosive salts into the wells and water supply system and increasing the risk of organic solvents like TCE, PCE, vinyl chloride, and benzene entering the base water supply.

The death knell for Marine Corps Air Station El Toro, California, once the premier Marine Corps air station, was sounded in 1985 when trichloroethylene (TCE) was found in three wells during a routine well inspection by the Orange County Water District (OCWD).

El Toro, a former lima bean field, was obtained from the Irvine Company through condemnation proceedings. James Irvine's offer to lease other fields to the Marine Corps for an airfield at the beginning of WW II for only $1 a year was rejected. The Marines wanted the field. Irvine's bean field seem perfect for an airfield, located in a valley at the base of the Saddleback Mountains, fog free for most of the year, close to the Pacific Ocean (short hop for aircraft from Navy carriers), bordering the main line of the Santa Fe Railroad and close to Camp Pendleton. As a result of the court settlement, the government paid the Irvine Company $950,000 in 1944 for the former lima bean field. In 2010 dollars that’s about $11 million.

In 1985, OCWD found two of the contaminated wells were on Irvine Company land and one well on the base. The two Irvine Company well were located 7,000 and 2,000 feet west of the base. TCE at 48 ppb (parts per billion) was found in the well that was 7,000 feet west of the base. This was nearly 10 times the EPA Maximum Contaminate Level of 5 ppb. Not good news for El Toro.

In 1990, El Toro was placed on the National Priority List (EPA Superfund); scheduled for base closure in 1993, closed in 1999, and most of the base sold at a public auction in 2005. In total, the base was in operations for 56 years.

Since the wells were down gradient from El Toro and TCE was a known degreaser for aircraft parts on the base for decades, El Toro was the likely source for the contamination.

In July 1987, the Santa Ana Regional Water Quality Control Board ordered the Marine Corps to investigate the source of the contamination and clean-up the wells.

The reaction of the Marine Corps was to vehemently deny any responsibility for TCE contamination of off-base wells.

Captain S. R. Holm replied to the order, "There does not seem to be any substantiation for the conclusion that the contamination does in fact come this air station." Huh?

Now, in 1987, former MCAS El Toro was surrounded by agricultural fields and Orange groves. Demonstrating an incredible amount of hubris, Captain Holm told the Santa Ana Regional Water Quality Control Board that the Marine Corps would clean up the well on base property but the Irvine Company should bear the costs of "constructing wells to monitor the contamination [off-base] since virtually all of it is underneath the company's land."

The Marines had to know that TCE is an industrial solvent, not used in agriculture, which had been used at El Toro for decades, much of it in the most industrialized portion of the base where the aquifers under the base flow in the direction of the contaminated wells.

According to the same Orange County Register news story, the explanation for resistance by El Toro came from James Reilly, the then director of water quality for the Orange County Water District, "They don't want to do anything until they study the thing to death. This isn't the first time that the water board has struggled with the Marines."

Six years after TCE was found off-base in two irrigation wells, the Navy agreed that the El Toro was the source of the TCE plume. After extensive investigation by the Navy and EPA, the Justice Department in September 2001 finalized a settlement that involved MCAS El Toro, recognizing the base had released volatile organic compounds into shallow groundwater below the surface of the base and ultimately into an adjacent deeper off-base aquifer.

According to a Justice Department report, "the deeper aquifer was also contaminated by nitrates and total dissolved solids from the activities of other entities, and the Water Districts for Orange County and the Irvine Ranch had undertaken a long-term project to pump and treat the water from the deeper aquifer. Through the settlement agreement, the two Water Districts will now be responsible for the long-term cleanup of both the off-base deeper aquifer and the on-base shallow groundwater, at a projected cost of $97 million. In return, the United States will contribute $27.25 million toward the cost of the cleanup. This arrangement results in a significant cost savings both to the United States and to the Water Districts due to the cost efficiency of constructing and operating a total treatment system for both of the contaminated areas."

Was more than one base well contaminated with TCE in 1985? By this date, the only irrigation well on the base was Irvine Company Well #55. Located in the northwest quadrant, just north of Runway 7L, this well was not in the path of the TCE plume. Although not identified in the Orange County Register story, this may be the well where OCWD found .4 ppb of TCE in 1985.

Were Navy wells contaminated with TCE? Yes. Navy sampling of abandoned Well #4 in 1995 found 12 ug/L in the water. Beyond this well, it's difficult to know the extent of TCE contamination of other Navy wells because of missing documentation, including original well construction drawings which show the location of well screen intervals (the point that water enters the well); missing contract files for the purchase of municipal water from two water districts; a unexplained gap of 30 years from 1955 until 1985 in water distribution engineering drawings; and no records of when the on-base wells were abandoned by the Marines.

All of the Navy wells were in the most industrialized portion of the base, in the footprint of the TCE plume, and at risk of contamination from various organic solvents. There's no way to know if well pumping records and original well construction drawings were deliberately purged or inadvertently misplaced.

Our communications with the Naval Facility Engineering Command Southwest (San Diego) were professional and left no doubt where the Navy stood on the issue of the Navy's base well.

The Navy message was clear, almost parroting the lyrics of a 1988 song by Bobby McFerrin, "Don't Worry, be Happy." The Navy dismisses any contamination of the well water, citing the fact that all the Navy wells went deep into the uncontaminated principal aquifer under the base, which was separated by 70 to 140 foot thick clay interval, named the Intermediate Zone. This clay barrier prevented any downward vertical movement of groundwater and organic solvents like TCE, PCE, vinyl chloride, and benzene, all of which contaminated the shallow aquifer under the base. In addition, the Navy noted the early purchase of municipal water from the Metropolitan Water District in 1951 and lack of pumping records after December 1950. The implication was that the base wells were not needed when municipal water was purchased from MWD.

Water in Southern California is both scare and expensive. From the information obtained through FOIAs to the Navy, we were able to piece together a possible scenario of what happened to the Navy wells:

The Navy constructed six wells at El Toro. All of the Navy wells were in the footprint of the TCE plume where TCE in the shallow aquifer range from 50 ug/L to over 500 ug/L or 10 to over 100 times the EPA acceptable level of 5 ug/L.

Only four of the Navy wells were good producers. Navy Well #3 was a dry hole and Navy Well #4 was only in production for 5 months during WW II. The maximum combined flow from four Navy wells was 900 gallons per minute (August 1949).

El Toro wells were not abandoned in 1951 when the Navy purchased softened municipal water from the Metropolitan Water District for both El Toro and the nearby Santa Ana Air Facility. El Toro's water distribution drawings in 1954 show the Navy base wells in the water distribution system. Water distribution engineering drawings are not available for the 30 year period from 1955 to 1985. In 1986, only Irvine Company Well #55 was in the water distribution system; all the Navy wells are apparently abandoned.

The official justification for the purchase of municipal water from MWD is unknown since the government contract file is no longer available, probably destroyed years ago. The information provided by the Navy via several FOIA requests and our calculations indicates that the supply of softened water from MWD was insufficient to meet El Toro's needs for potable water. The MWD contract provided for the delivery of one cubic foot per second of softened municipal water to both El Toro and the Santa Ana Air Facility or about 450 gallons per minute, which was exactly half of the maximum combined flow of the four Navy wells.[1]

The MWD contract for softened water appears to be an attempt to reduce the level of hard water (from the total dissolved solids) by blending municipal water with well water. And, the 450 gallons per minute of municipal water was in itself insufficient to meet the demand requirements of El Toro and Santa Ana and less than the maximum combined flow from El Toro's Navy wells of 900 gallons per minute.

Navy Well #4 was the first well sealed in 1998 and the only well inspected to determine the location of the well screen aquifer. The well screen is the first point that water and contaminants enter a well. The consulting engineering reported that the well screen was a series of vertical slots hand cut by torch from 210 feet below the ground surface (bgs) until the bottom of the well at 494 feet bgs. Since the shallow contaminated aquifer went to 260 feet bgs, this meant that about 50 feet of the well screen was in the contaminated aquifer. In 1995, a sample of the water in the well contained 12 ug/L of TCE. The TCE more than likely entered the well through the well screen in the contaminated shallow aquifer.

It is reasonable to believe that the other Navy wells were constructed in the same manner as Navy Well #4. The original well construction drawings for all of the Navy wells are missing. The Navy had the opportunity to but failed to inspect the other wells to confirm the well screen locations. Once the first well screen was found in the contaminated aquifer, the Navy should have made reasonable efforts to inspect the remaining wells, too. Failure to do so, places a cloud over the Navy's well destruction process, suggesting the possibility of a cover-up. The Navy's engineers did not have the original well construction drawings, the first well sealed was visually inspected, the inspection found 50 feet of the well screen in the contaminated aquifer and TCE was found in a sample of the well water.

Additional support for Navy wells screens in the contaminated shallow aquifer was the need to purchase softened municipal from two water districts. High levels of total dissolved solids ("salts") were only found in the shallow aquifer. The clay barrier (Intermediate Zone) prevented downward migration of water, TDS and organic solvents. The Navy's pumping records only show that Navy Well #4 only pumped for five months during WW II. Where did the hardened water come from? It's reasonable to conclude that the remaining Navy wells had portions of their well screen intervals in the shallow contaminated aquifer, allowing some level of TDS and organic solvents like TCE into the base's water supply.

In 1985, all of the water supply lines into the San Joaquin housing development (300 units) had to be replaced because of corrosion. TDS ("salts") levels in the shallow aquifer were >500 ug/L. According to an informed source, San Joaquin was constructed in the early 1970's. The corrosion to units water supply lines could not have been caused by softened municipal water from the MWD or follow-on contract with the Irvine Ranch Water District but could have easily come from the Navy base wells.

Over time, TDS in the well water would have caused service disruptions and costly repairs to well pumps and other equipment. At some point and as late as the 1970's, the costs of repairs and service disruptions would have forced the base to abandoned the wells.

In July 1969, the Navy negotiated a municipal water services contract with the Irvine Ranch Water District. This contract required IRWD to make available to El Toro 3,500 gallons of water per minute. The Navy was not required to purchase this quantity of water, but this amount of water would supply all of the base's demands for water. This contract remained in effect until the base closed in July 1999. A FOIA request for a copy of the official contract file was denied by the Navy. The contract file could not be located.


[1] The MWD contract provided for the delivery of one cubic foot/second of water for both El Toro and the Santa Ana Air Facility. The United States Geological Survey defines cubic foot per second (cfs) as "the flow rate or discharge equal to one cubic foot of water per second or about 7.5 gallons per second." Converting the MWD's one cubic foot per second into gallons equals about 648,000 gallons/day, (7.5 x 60 x 60 x 24) or about 450 gallons per minute or about 19,440,000 gallons per month for both El Toro and Santa Ana. This amount is exactly half of the maximum combined flow from the Navy's four productive wells.


Bob O’Dowd is a former U.S. Marine with thirty years of experience as an auditor, accountant, and financial manager with the Federal government. Half of that time was spent with the Defense Logistics Agency in Philadelphia. Originally from Pennsylvania, he enlisted in the Marine Corps at age 19, served in the 1st, 3rd, and 4th Marine Aircraft Wings in 52 months of active duty in the 1960s. A graduate of Temple University, Bob has been married to Grace for 33 years. He is the father of two adult children and the grandfather of two boys. Bob has a blog site on former MCAS El Toro at This subject is where Bob intersected with Bob served in the exact same Marine Aviation Squadron that Salem-News founder Tim King served in, twenty years earlier. With their combined on-site knowledge and research ability, Bob and Tim and a handful of other ex-Marines, have put the contamination of MCAS El Toro on the map. The base's soil and groundwater is highly contaminated with trichloroethylene (TCE) and other organic solvents. 

  • . You can email Bob O’Dowd, Environmental and Military Reporter, at this address:

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