As the Central Coast suffers through its third year of extreme drought, county and city officials are looking for all available new water sources.
A new 38-page interagency report outlines the potential benefits and challenges of significantly increasing the use of recycled water, which currently accounts for only 0.4 percent of the county’s water supply. That percentage should rise to as much as 10 percent or 20,000 acre-feet per year by 2020, the report said.
“The 2014 drought conditions have highlighted the benefits of developing a local, reliable water supply for municipalities as well as agricultural and industrial water users,” the report concluded.
County policy calls for expanding the use of recycled water to make up at least 5 percent of total water use by 2015 and 10 percent of total water use by 2020.
Freshwater in San Luis Obispo County currently comes from two main sources. Groundwater basins account for nearly 90 percent of the water, while surface water, such as lakes and reservoirs, accounts for 10 percent.
Recycled water is the water produced by sewage treatment plants. It is not suitable for human consumption but can be used for a variety of other purposes.
These include crop irrigation, groundwater recharge and stream flow augmentation. The most common means of disposing of recycled water are discharging into creeks and dumping into the ocean.
Creek discharges can replenish groundwater basins and ensure that streams flow year-round, benefitting rare and endangered riparian plants and animals such as steelhead trout and red-legged frogs. Discharging recycled water to the ocean is not considered a beneficial use.
The most common beneficial use of recycled water is landscape irrigation, such as golf courses, parks and playgrounds. For example, the city of San Luis Obispo uses 180 acre-feet a year of recycled water for landscape irrigation and 1,800 acre-feet a year to augment flows in San Luis Obispo Creek.
The biggest impediment to greater use of recycled water is the lack of infrastructure – the pipes and pumps needed to get the water from the treatment plant to the parks and golf courses where it is needed, said Courtney Howard, a water resources engineer with county Public Works.
“The cost of that infrastructure is probably the biggest hurdle in achieving our goal of greater use of recycled water,” she said. “So to the extent that we can get grants to cover some of the cost will speed up implementation.”
The report, titled Regional Recycled Water Strategic Plan, cost $200,000 and was paid for by a state grant. It was prepared for Public Works in conjunction with cities and community services districts in the county.
The report is available at www.slocountywater.org.