Monterey is located on the Central Coast of California, a few hours south of San Francisco. It is generally a semi-arid area, with rainfall mostly in the winter months, though recent years have exposed the area to greater extremes of both longer droughts (such as the state-wide drought of 2011-2017) and higher amounts of rain during the rainy season, as seen in 2018 and 2019.
The Monterey Peninsula depends on two main water sources that receive the local rainfall: the Carmel River and the Seaside Groundwater Basin
Unlike many areas in California, the Monterey Peninsula has no access to imported water and is completely dependent on local rainfall for its water supply.
Regional Water Issues
- Water Supply Variability: Due to increasingly prolonged and intense periods of rainfall and drought, finding new, more sustainable water sources will be extremely important.
- Water Scarcity and Quality: The overpumping of water from the regional aquifers has led to a depletion of the water supply, and increased salination of groundwater. Addressing this issue would ensure that the aquifers remain healthy and full, pushes out salt, and keeps the Carmel River high.
- Ecological well-being: Currently endangered species such as salmon and steelhead trout are at risk due to the low water levels of the Carmel River. Additionally, coastal wildlife is vulnerable to toxins from wastewater and stormwater being dumped into the Monterey Bay, as well as to future plans to dump brine from the proposed desalination plant in the bay. Thinking of ways to address water issues without desalination, including wastewater and stormwater recycling, would help lead to less habitat damage, and better preservation of the ecological balance of the Monterey Peninsula.
Current Service Providers and Key Infrastructure
The City of Monterey is served by California American Water (CalAm), an investor-owned private water utility provider on the Monterey Peninsula and Monterey One Water (M1W), a publicly owned wastewater agency. In the map below, you can see some of the water infrastructure in place in Monterey, including the boundaries of the CalAm service area, as well as the M1W Regional Treatment Plant, the main sewage treatment plant in Monterey. This plant provides wastewater treatment services to over 250,000 people, processing over 18.5 million gallons of wastewater each day. It discharges the majority of the effluent into the ocean, although approximately 4 billion gallons of water are recycled annually for crop irrigation.
Between 2008 and 2016, the State of California’s Water Resources Control board issued several cease and desist orders to CalAm to stop overdrawing water from the Carmel River, which was adversely affecting both water supply and harming the endangered steelhead trout (CalAm’s diversions from the Carmel River were found to be the largest single adverse effect on fish, wildlife, and riparian habitat in the Carmel River). By December 31, 2021, CalAm is to provide additional sources for drinking water. Two major infrastructure projects have emerged in response to this need for a more sustainable water supply: the Monterey Peninsula Water Supply Project and the Pure Water Monterey Expansion Project.
Current Infrastructure Projects
The Monterey Peninsula Water Supply Project (MPWSP) is a new desalination plant being constructed by CalAm, who will own the facility upon completion. The plant is planned to be located in Marina, CA, just north of the City of Monterey, and is set to process 6.4 million gallons of seawater per day and producing about 6,250 acre feet per year of potable water. This project has been controversial, as CalAm has insisted that this project is necessary to ensure a sustainable water supply for the region, while some communities have argued that this project could affect the groundwater basin, as well as bring harm to the coastal ecosystem. At this current time, construction of the desal plant has temporarily halted, with California Coastal Commission expected to determine whether or not to approve the permit soon (the original vote was scheduled to take place in March 2020, but appears to be delayed due to COVID-19). Regardless, mitigating the salinity in existing groundwater wells will remain a challenge the Peninsula will need to address.
The Pure Water Monterey (PWM) project is an advanced water recycling project, developed in partnership between CalAm, the Monterey Peninsula Water Management District (MPWMD), and M1W, the wastewater and water recycling service provider mentioned earlier. This project aims to provide a sustainable water supply through a multi-stage treatment process that recycles wastewater to state and federal drinking water standards. According to city officials, four types of wastewater are collected – domestic waste water, agricultural produce wash water, agricultural irrigation return flows, and stormwater. The collected wastewater is transported to a treatment plant, where it is treated before being piped to an aquifer recharge area to be injected either into the groundwater upper “vadose zone”, or deeper into the aquifer.
The proposal is designed to add 2,250 acre-feet of recycled potable water production to the existing PWM project, which is designed to provide 3,500 acre-feet per year of recycled potable water to the Monterey Peninsula region. The project is also designed to store water in the aquifer for extraction at a later date, specifically in preparation for future droughts.
Opponents of the MPWSP desalination facility argue that the Pure Water Monterey Project would create enough additional water supply for the region even without the costly desalination project.
Proposed Solution to Regional Water Issues
Monterey is already on the cutting edge of water management: current projects address water supply variability, combat increased salinity in the aquifers, and implement environmentally friendly processes. Our solutions build on those processes and propose further improvements.
We propose:
- CalAm should cease the construction of the desalination plant, and exclusively pursue the wastewater recycling project (Pure Water Monterey).
- Pure Water Monterey should expand the use of stormwater in the water recycling process.
- Pure Water Monterey should become energy positive by incorporating food waste and agricultural byproducts with wastewater to generate energy.
Recycling Over Desal
While both the Monterey Peninsula Water Supply Project and the Pure Water Monterey expansion projects are currently being considered by Monterey, we propose that the Pure Water Monterey project instead of the desalination project is the best step forward. A recent study indicated that either of the projects, on their own, would be able to meet projected future demand, and we believe that Pure Water Monterey would meet this demand at a significantly less financial and ecological risk than the desalination project, while also helping to provide groundwater recharge and mitigate increasing salinity.
Additionally, residents served by CalAm recently voted for the Monterey Peninsula Water Management District to acquire control of the water utility “if and when feasible.” It remains unclear if and when this acquisition will happen, but considering that the Monterey Peninsula Supply Project is funded and owned by CalAm, future steps toward a public takeover over the water utility could have costly and complicated consequences for the region due to the company’s involvement in this plant project.
Expand Stormwater Harvesting
Pure Water Monterey already uses stormwater as one of its four water sources in the water recycling project. However, the region would benefit by expanding their efforts to collect stormwater for recycling and reuse.
We believe that increased focus on capturing, treating, and storing stormwater in aquifers is a great opportunity to the Monterey Peninsula. Monterey would benefit from diverting stormwater to the regional treatment plant as it would keep untreated stormwater from seeping into the local water supply, which has water quality and environmental repercussions. Additionally, bolstering up the collection of stormwater, in addition to the other three sources, increases the diversity of the water recycling portfolio.
This infographic from a project in Adelaide, Australia shows the process of treating stormwater runoff and storing it in an aquifer for use later. The only difference with Pure Water Monterey is that the stormwater being collected would be treated in the water treatment plant before being stored. Expanding the use of stormwater in Monterey would necessitate further development of stormwater infrastructure throughout the region.
Salinas, CA, just east of Monterey, has utilized a $10M California Proposition 1 grant to fund the construction of stormwater capture projects that would collect and send stormwater from Salinas to the Pure Water Monterey facility for recycling. We believe that other communities in this region would benefit by utilizing similar funding to expand their stormwater infrastructure.
Energy Positive Through Biogas Generation
Finally, we propose to make Pure Water Monterey energy positive by incorporating food waste and agricultural byproducts with wastewater to generate biogas energy through the anaerobic digestion process shown in this graphic. Wastewater treatment plants around the country (and globally) are beginning to pursue this option to channel some of their byproducts into an energy generating opportunity.
Currently, Monterey One Water, the main wastewater treatment entity that is also the lead agency for the Pure Water Monterey project, already has on-site anaerobic digesters to treat sewage sludge. However, they are still partly reliant on natural gas to fuel their plant in addition to the captured methane that is generated. Additionally, it is unclear whether the Pure Water Monterey project’s waste byproducts undergo the anaerobic digestion process as well. At the same time the Monterey Bay Community Power (MBCP), the clean energy provider for the area, also has the opportunity to pursue cleaner energy options instead of their current reliance on large hydroelectric dams, which have adverse effects on river ecosystems. We propose that Monterey One Water and MBCP work together with the Monterey Regional Waste Management District to bring in agricultural waste such as livestock waste and crop residue, along with the Waste Management’s current food waste processing, to increase the production of biogas through the anaerobic digestion process, that can then be used to power all three sectors’ processes. Both Monterey One Water and the Waste Management District already have anaerobic digesters on site, but additional infrastructure will need to be put in place to transport ag waste to these digesters.
Implementation
We see this is as a 3-phased approach.
Phase 1 would be choosing water recycling over desalination. We believe this is the quickest and least costly step that will ensure a sustainable water supply at lower environmental cost than desalination. Both projects are already underway, with the water recycling expansion project close to completion. Due to the advanced state of the project, it does not appear that the “ick factor” would be a barrier to further expansion.
Phase 2 and 3 are more long-term goals.
Phase 2 would be the stormwater recycling and storage. This would contribute to a more diverse water portfolio and again at low environmental cost, while ensuring a more sustainable water future in times of drought.
Phase 3 would be incorporating agricultural waste into energy processing. This would enable increased collaboration across the water and energy sectors, and lead to a more energy efficient resource management strategy for the Monterey region.
Potential Barriers to Implementation
Our main concerns with the solutions proposed are the costs of constructing infrastructure to transport stormwater and agricultural waste to the treatment facility. Additionally, any rise in demand would still likely require additional water sourcing, and, as climate change continues, sea level rise leading to saltwater intrusion will likely continue to be an issue. Thus, we propose that our solution be paired with continued conservation and awareness efforts.
Conclusion
Ultimately, we see our solution as contributing to a cheaper, more sustainable and diverse water supply. Our proposed solutions would keep previously overpumped aquifers healthy and mitigate increasing salinity of the groundwater, turn wastewater and stormwater into potable water through an energy efficient treatment process, keep toxic waste and brine out of the Monterey Bay, and allow for more recycled water to be stored for future water-scarce years.