Wastewater recycling is being hailed in many communities as the answer to ongoing drought problems. By cleaning sewage effluent to extract pure water, it’s possible to create a sustainable water supply that is cheaper than seawater desalination or buying a new water supply.
But there’s a little-recognized downside to water recycling: It may damage wildlife habitats already imperiled by water scarcity.
That’s because many rivers in California and the West are already so extensively tapped for human purposes that our sewage effluent – dumped back into streams after treatment – provides an important share of the stream flows that remain.
Even as California’s State Water Resources Control Board encourages water recycling through grants, low-interest loans, and streamlined regulations, other state agencies are raising objections.
In September, the California Department of Fish and Wildlife filed a formal protest against a water recycling proposal by the Sacramento Regional County Sanitation District. The department alleges that by diverting as much as 50,000 acre-feet (62m cubic meters) of water per year from its existing Sacramento River discharge, the district may deprive endangered salmon and other species of important habitat.
The situation puts the Sacramento district in a Catch-22, because its water recycling project is partly motivated by the protection of another species: Delta smelt. A 2014 order by the state water board requires the district to clean up its effluent, which the board determined may be harming the aquatic food chain in the Sacramento-San Joaquin Delta.
The regional sanitation district is the largest single discharger of treated wastewater in the Delta watershed. Most of this effluent is released into the Sacramento River near Freeport.
“The thing that strikes me as interesting is … the state as a whole has determined this is a good idea to recycle water,” said Christoph Dobson, director of policy and planning at the Sacramento regional sanitation district. “So you would hope the state would then be supportive of projects, particularly projects like this, that have multiple benefits to them.”
It certainly says something about the strain on California water supplies when treated human sewage comes to be seen as vital to fishery habitats. But it also may represent a new understanding of the water cycle in the state. After all, that effluent mostly originated as fresh water pumped out of a river somewhere upstream.
The Department of Fish and Wildlife fears that salmon, splittail, sturgeon and other fish could be imperiled if effluent discharges to the Sacramento River are reduced, especially as the drought continues and river flows are low.
Lauren Mulloy, water rights coordinator at Fish and Wildlife, said the recycling project is akin to proposing a new water diversion on the Sacramento River. And water supplies are so tight in the region that a new diversion of equal size would also face a protest, she said.
“When we get discharges into these water courses for many years – sometimes 50 years – it becomes part of the flow regime that the water course and wildlife expect to see on an annual basis,” Mulloy said. “So taking it out is the same as proposing a new diversion.”
A new state water quality permit approved in 2013 requires the regional sanitation district to clean up its discharge effluent. To comply, the district is building what it calls the EchoWater Project. With a price tag of at least $1.5 billion, it will modify existing operations to achieve so-called “tertiary” treatment, a common practice in the industry, but one which the Sacramento district has not yet adopted.
A related project will divert about one-fifth of this effluent, under present conditions, into a new distribution system that will deliver recycled wastewater to 16,000 acres (65 sq km) of farmland in south Sacramento County. Some of the water will also be provided to nearby Stone Lakes National Wildlife Refuge to augment wetland habitat.
The diverted water amounts to about 45 million gallons (205m liters) per day, or about 50,000 acre-feet per year. The project is estimated to cost $200 million.
The district estimates this will reduce total Sacramento River flows by 1 to 2 percent, depending on river conditions.
That doesn’t sound like much. But it could be enough, under some conditions, to produce violations in key water quality standards in the Delta. This would require other agencies to release precious stored water from upstream reservoirs.
But Dobson said this won’t be a permanent concern. Eventually, he said, the irrigation water supplied to farmers will recharge depleted groundwater that they now rely upon. When that happens, the aquifer will again be connected to the Sacramento River, and flows in the river will return to conditions that existed before the recycling project began.
“In the long run, it’s not having a significant reduction in river flows. It ultimately makes its way back to the river in various ways,” he said. “That’s one of the key benefits of the project.”
The state water board has set a goal to increase water recycling by 1 million acre-feet per year, statewide, through 2020, and at least 2 million acre-feet per year by 2030.
Indeed, the ongoing drought has produced so much interest in wastewater recycling that a state fund to support such projects has been temporarily depleted of money.
So it is likely that more water recycling projects will encounter similar protests about declining streamflows.
“While it’s a good idea to use more recycled water, we recognize that it also means reducing stream flows and we need to evaluate if that reduction causes a problem,” said Timothy Moran, a spokesman for the state water board.
If necessary, the board will impose rules on new water recycling projects to protect streamflows, Moran said.
Another example can be found in Ventura County, where the city of Oxnard plans to double its capacity to recycle sewage effluent. This has brought lawsuits by the Wishtoyo Foundation, a nonprofit arm of the Chumash Tribe, against both the state water board and the Los Angeles Regional Water Quality Control Board.
The foundation is concerned about protecting the Santa Clara River. In the lawsuit, it argues the two state agencies should be required to conduct a comprehensive analysis of water needs in the river basin before allowing more water recycling.
Jason Weiner, attorney for the foundation, said Oxnard’s recycling program is intended to prop up unsustainable water uses in the region that already withdraw water from the Santa Clara River, such as strawberry farming and golf course irrigation.
The wastewater recycling itself does not result in any diversion of water from the river. But those who benefit from the recycled water, he said, should be required to stop diverting an equivalent amount of water from the river.
As it stands now, he said, new water recycling projects are being approved without any consideration for the Santa Clara River’s needs. The river is almost completely dry much of the year, yet also home to an endangered population of steelhead trout.
Opening arguments in the case are expected in 2017. If successful, it could require all new wastewater recycling projects in the state to conduct a “reasonable use” analysis to ensure the water they produce benefits the environment and is not wasteful.
“The issue here and across the state is, you can bring all the recycled water in the world online, but that won’t help if you allow it to be used wastefully,” Weiner said. “We’re arguing the boards have a mandatory duty to ensure reasonable use and protection of public trust resources in their allocation of the recycled water.”
In the Sacramento case, the regional sanitation district is expected to begin negotiations with the Department of Fish and Wildlife soon in an effort to resolve its concerns. Mulloy said she hopes to see a rule added that will adjust the volume of water diverted for recycling based on flow conditions in the river.
“I’m expecting we’re going to see more recycled water projects as agencies need to stretch their water for their service areas,” she said. “I like the recycled water projects. I also don’t want to see it harm things. There’s got to be a balance.”