The latest search for a water supply to replace most of the water now taken from the Carmel River aquifer began five years ago. Because there is so much history and confusing information, this report is intended to provide up to date facts and figures.
CalAm’s plan is to produce 6.4 million gallons per day (mgd) or 7,170 acre feet per year (afy) of water by desalinating brackish water pumped from slant wells drilled on the Cemex sand plant in Marina. A test well has indicated that the brackish water will be 8 to 10% fresh water. The future water supply plan also includes 3.1 mgd or 3,500 afy of recycled water that will be produced by advanced technologies that remove all contaminants including most of the dissolved salts and will render it cleaner than almost all of the municipal waters served in the country.
The recycled water project, known as PureWaterMonterey (PWM), is now under construction. It is being produced under an agreement between Monterey One Water (M1W), formally known at the Monterey Regional Water Pollution Control Agency, and the Monterey Peninsula Water Management District. The recycled water will be injected into the ground and withdrawn later for use.
At the hearing for the recycling project’s draft environmental impact report a number of questions were raised about the desal project that are now being reviewed by the lead agency, the California Public Utility Commission (CPUC). A draft final decision on the project is expected next spring with the final go/no-go decision expected next summer.
Here is a quick overview of a few of the major questions and here is the latest Monterey Herald article on the water recycling plan and various scenarios.
WOULD THE DESAL PLANT’S SLANT WELLS HARM THE SALINAS VALLEY AQUIFER? Cal Am says no and says it has studies to backup that position. The slant wells will remove almost 20 mgd of water, which will depress the water table near the wells. Of the well water, 1 to 2 mgd would be fresh water. To avoid the legal ban on exporting Salina Valley groundwater from the basin, Cal Am has agreed to sell an equivalent volume of the costly desalinated water to the Castroville Community Services District at a heavily discounted price.
Marina Coast Water District (Marina Coast) says it will be harmed by the wells and that selling the water to Castroville will not mitigate the damage to its wells. Marina Coast also says that it has studies that back up that position. The slant well extractions might accelerate seawater intrusion and damage other existing public and private well water users.
DOES CAL AM HAVE WATER RIGHTS? Cal Am doesn’t seem to have water rights for this extraction of groundwater. However, the company’s position is that the brackish water is too salty to be usable for municipal or agricultural use, so it is not really groundwater subject to water rights. Critics point out that project will take 1 to 2 mgd per day of fresh water out of the seriously overdrafted Salinas Valley ground water basin to replenish the brackish supply. Does the high level of salinity make a water right unnecessary? How long will it take to get a final decision on this question?
WHAT IF THE CAL AM PROJECT FAILS? The desal questions may take time and costly litigation to resolve. But, there is an alternative water supply that can be considered. The Pure Water Monterey (PWM) recycling project that is already underway can be expanded by taking advantage of currently uncommitted wastewater. By expanding the PWM project, these flows can be added to the supplies processed by the ultra-high-quality treatment system and stored temporarily underground. An additional increment can be added by the lining of ponds that receive storm runoff from Salinas and adding more food processing wash water. The source water allocations for the proposed expansion have already been agreed to in concept by the Monterey County Water Resources Agency. The recycled water uses no groundwater, has no direct ocean intake and the resulting cost will be less than the cost of desalinated sea water.
HOW MUCH WATER IS REALLY NEEDED? As a result of all the conservation efforts, Cal Am’s total production in 2016 was 9,600 acre feet. Pure Water Monterey has defined expansion scenarios based on incremental development of water sources and storage capacities. The ongoing project will produce 3,500 afy, which when added to the baseline supplies without desal will produce 9,044 afy.
If the equipment is run “full throttle” (Scenario A), it will be able to produce about 9,700 afy. But this is not a sound long-term strategy. Building the proposed expansion (Scenario B) will bring the total to 11,300 afy, which should meet the demand for several years. Scenario B is a practical project. The timing will be tight but, if started very soon, it should be operational within the time frame dictated by the state regulators. A reasonable long-term system capacity would be 12,000 to 12,500 afy, which could be met by an additional expansion (Scenario C). This expansion will be dependent on source water that is yet to be secured and will be more expensive and vulnerable to drought cutbacks. If Scenario C is ultimately developed, the recycled water option will have reached a practicable limit and other options will need to be considered for future supplies.
WHERE DO WE GO FROM HERE? The state Public Utilities Commission will be dealing with these issues over the next few months and will reach a final decision on the slant well desal project next summer. If the EIR is accepted and all disputes settled with Salinas Valley interests, Cal Am will probably proceed to obtain the remaining state and other permits and only the Scenario A (the ongoing PWM recycling project, running full out) will be needed. If opponents to the project are not satisfied with the CPUC decision, the final decision may be made in court.
If state regulators reject the CalAm project, or if the project becomes bogged down with lawsuits, or if the regulators required that all available recyclable water must be reused before brackish water can be extracted, the expanded PWM Scenario B can be built and the desalted seawater will not be needed for several years.
Getting past the crisis will allow time to develop options. Desal that depends on pumping ground water in the Salinas valley is a highly risky approach due to water rights, legal challenges and unforeseeable changes to water regulations and water tables, and should be avoided. A supplementary source other than recycled water will be smaller and would provide valuable redundancy. Fortunately, the Monterey Peninsula Water Management District has been investigating other approaches such as increased storage of winter river flows and possible smaller desalination options.
For more on the CalAm project, see: https://www.watersupplyproject.org/faq For PureWaterMonterey, see http://purewatermonterey.org For the DEIR: http://www.cpuc.ca.gov/Environment/info/esa/mpwsp/deir/CalAm_MPWSP_DEIR.pdf
Roger Dolan is a retired water and wastewater engineer and utility manager who lives in Carmel Valley