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Know Your H20

Know Your H20


Do you know where your water comes from?

Know Your H2O is designed to educate people on the link between freshwater management issues and the impact on our ocean, waves, and beaches.

In many places, water travels hundreds of miles through canals and pipelines before reaching homes. Due to persistent drought, growing population and restrictive legislation, less water will be delivered from these sources in the future. Many rivers near the coast have been paved over, and nearly all storm drain pipes empty into our oceans. This dumps animal waste, pesticides, fertilizers, plastics, car oil and more into our watersheds and ultimately into the sea.

Through conservation, using climate-appropriate plants, implementing low impact development, capturing and reusing wastewater, and Indirect Potable Reuse (IPR), we can reduce water pollution in the ocean and improve our drinking water supply. Learn more on Beachapedia.

In San Luis Obispo County, Know Your H2O is actively advocating for managed retreat solutions to move sewage plants from the coastal zone in Morro Bay and Oceano. Also, as a substitute for ocean outfall, we are advocating for wastewater reclamation and the use of constructed wetlands to bury salts while recharging coastal aquifers.

Read about our Accomplishments in SLO County.





The answer is “No”!

The problem: As with PG&E’s plan to conduct seismic testing a few years ago… When the public understands the alternatives to, and impacts of, ocean desalination, they will conclude desalination is not necessary. The BOS and PG&E have cheated the public of an accurate cost / benefit analysis and used a perceived water supply emergency to rush through a bad project.

Environmental effects of ocean intake and discharge (CA State Water Resources Control Board, 2015 policy): “The operation and construction of seawater desalination facilities can result in marine life mortality and harm to aquatic life beneficial uses. During the process of ocean desalination, organisms may be drawn in with the source water and enter the facility’s water processing system. Salt and minerals are removed from salt water to produce fresh water and organisms do not survive the desalination process. The salt, minerals, and other compounds produced as a byproduct of desalination are discharged into the ocean as hypersaline brine. Brine is denser than the receiving ocean water and, depending on discharge methods, may settle on the seafloor and have adverse effect on marine organisms.”

Desalination example: 100 acre feet of intake = 50 acre feet of waste discharged to the bottom of our local ocean environment. Often, “Economy of Scale” arguments are used to decrease the unit cost of production. However, growing this project will proportionally increase the impact on our local ocean environment (see local annual water production statistics below). Also, ocean water desalination is 3-10 times more energy intensive than treating wastewater or other sources.

Diablo desalination is a NEW $$$ PROJECT: Presently, DCPP discharges a billion gallons a day of seawater for its once-through cooling system. That discharge is mixed with brine from existing desalination. When DCPP shuts down in 2025 (or sooner), a new environmental analysis will be needed to assess the impacts of the new project’s intake, the increased brine discharge concentration on local marine life, and whether alternate sources are available that negate the reason for new desalination. Conservation and reclamation represent the future’s new water supply. Providing an honest cost/benefit assessment will save county taxpayers $$$. 

New water supply through continued conservation efforts: The Northern City Management Area (NCMA) includes Arroyo Grande, Grover Beach, Oceano, and Pismo Beach. The NCMA’a 2017 report hasn’t been released yet. Here is information from the NCMA 2016: “8108.3 acre feet is the lowest estimated total water use in the past 30 years”. For urban water user demand only, “Since 2013, when urban water demand was 7,939 a/f, urban demand has declined dramatically to 6,855.37 (2014), 5,942.95 (2015), and 5,476.6 (2016).”

In 2016, urban water users in the NCMA conserved 2500 acre feet of water compared to 2013. Can you imagine the impact of 2500 acre feet per year of brine discharge to our local marine environment? Comparatively, the cost of this conservation has been very low while being very beneficial to the environment. Conservation has allowed continued releases to streams from Lopez Lake and it has decreased the potential of seawater intrusion to our aquifers.

The question is: How much more can we conserve? Our community can sustain this conservation trend by continuing to decrease outdoor water irrigation (typically 30-40% of residential water use). Also, during rainy years, the State Water Project deliveries to Oceano and Pismo Beach represent imported water supplies which offset stresses on groundwater and Lopez Lake and provide new water to reclaim after our water reclamation plants are built.

New water supply through new water reclamation efforts: Pismo Beach, Arroyo Grande, Grover Beach, and Oceano share an ocean outfall. Collectively, they discharge over 4000 acre feet of treated effluent per year (roughly ⅔ of urban water use). This recoverable resource has already been captured and treated (partially, but not to “recycled water” standards), and Pismo Beach and South SLO County Sanitation District await funds to move toward Indirect Potable Reuse by either building onto existing infrastructure or building a new $200 million plant to serve the Five Cities region. Recycled water represents the drought-proof cushion we need to sustain Lopez Lake, maintain adequate creek levels for wildlife, and keep our groundwater aquifers charged for residential and agricultural use.