By Lacy Carothers

Responsible water management is complex and relies on planning for potential worst-case scenarios to ensure there is enough supply to meet any and all future demand.

Reputable, data-centered water forecasting must look at trends and changes in current customer behavior, new government regulations, growth and new development, changes in commercial activity and climate conditions. To make sure that sufficient water is available in both drought years and wet years, California American Water forecasts demand by looking at state and regional growth projections, commercial and industrial supply and anticipated demand, as well as commercial and residential remodels.

There is no way to oversimplify water demand modeling. There are no shortcuts or workarounds. And Cal Am’s data certainly can’t be arbitrarily underestimated. As the director of our engineering team for Cal Am, when we say that the Monterey Peninsula will likely need 14,480 acre-feet per year of water in 2050, I assure you it’s based on sound data and thoughtful modeling.

Our planning uses realistic inputs based on regional housing needs, changing climate conditions and long-term projections for sustainable water supplies and availability.

Doing otherwise would be irresponsible — putting the entire region’s economic growth and sustainability at risk.

To ensure the Monterey Peninsula’s current and future water supply needs are met, Cal Am is advancing a three-pronged approach to increasing water supply with a new desalination plant as its keystone. Desalination will provide a drought-proof source of water — producing 5,377 acre-feet of treated water per year in the plant’s first phase, enough to serve about 18,300 households.

The other two prongs of increasing water supply include expanding the aquifer storage and recovery program (ASR) in conjunction with the Monterey Peninsula Water Management District to capture excess winter flows from the Carmel River for use during the dry summer months and expansion of Pure Water Monterey’s groundwater replenishment project.

These three sources of water, along with Cal Am’s current water supplies, are expected to provide up to 15,650 acre-feet per year in normal water years and up to 14,910 acre-feet per year in drought years, after full build-out of the desal plant (Phase 2).

Developing this portfolio of reliable water sources is what’s necessary to lift the State Water Resources Control Board (SWRCB) Cease and Desist Order that required Cal Am to significantly reduce pumping from the Carmel River and to develop a new water supply to replace nearly 75% of the Peninsula’s historic water supplies.

The Order continues to prohibit Cal Am from providing water to new service connections until a long-term sustainable water supply is brought online.

Cal Am’s multifaceted approach is better than a single-source solution. Adding desalination to ASR and PWM Expansion supplies — which are highly vulnerable to drought — will bring a reliable, drought-proof water source to the Peninsula.

It will also build redundancy into the system to continue providing water if one component becomes temporarily unavailable.

We are planning for a future where the SWRCB Cease-and-Desist order is lifted, new water hookups are made possible, regional tourism and businesses can grow, the area’s backlog of development projects can begin moving again, and more affordable housing is built.

In order to plan for maximum demand, Cal Am must ensure that all portions of the demand estimates are accounted for. If left unaccounted, Cal Am may experience a supply shortfall which would be irresponsible water planning.

Simply put, to avoid a water supply shortfall, we need all available water solutions, including drought-proof desalination. Diversifying our water sources will reduce the risk of a supply shortage during the next inevitable drought.

Doing anything less would be irresponsible and hinder our future sustainable growth.

Lacy Carothers is the Director of Engineering at California American Water, overseeing the engineering department throughout the state, including management of capital and reoccurring projects, system assessment and regulatory compliance.