The unintended consequences of water conservation
Dr. Kurt Schwabe discusses the impact of water conservation on recycled water; Yorba Linda Water District GM discusses effects of 36% water conservation on his district
During the recent drought, conservation mandates were imposed across the state with some areas mandated to cut their water use by one-third or more. However, reducing water consumption by one-third means a significant reduction in the flow of water through distribution systems, creating challenges for water managers.
What were the unintended consequences of the water conservation mandates? A panel at the Orange County Water Summit discussed the unintended consequences and impacts of the conservation mandates. First, Dr. Kurt Schwabe, adjunct fellow at the Public Policy Institute of Californians Water Policy Center and professor of Environmental Economics and Policy at the UC Riverside, discussed the technical side of the effects of indoor conservation on wastewater recycling; next, Marc Marcantonio, general manager of the Yorba Linda Water District, spoke about the impacts of a 36% conservation mandate on the system and the community.
DR. KURT SCHWABE: Drought, water conservation, and wastewater reuse: Identification of some unintended consequences
Dr. Kurt Schwabe began his presentation by presenting a slide with a quote by Frederick Bastiat about accounting for the full range of impacts of decisions: “There is only one difference between a bad economist and a good one: the bad economist confines himself to the visible effect; the good economist takes into account both the effect that can be seen and those effects that must be foreseen.”
Dr. Schwabe said that the quote expresses the idea that good economics and good cost-benefit analyses account for unintended consequences; Ben Franklin said something similar in a letter he wrote to a friend where he the idea of ‘prudential algebra’, which was sort of a cost-benefit analysis of that time.
“These unintended consequences are not one-time events; they are pervasive,” he said. “It was the genesis of environmental economics, where back in the 60s we realized that market transactions, while good for the market economy, often overlooked unintended consequences and externalities, so we started to bring that into our models. It’s not one-time events. Every consumption and production activity creates an externality or some type of residual which often leads to pollution, so it’s around us, it’s everywhere, and it’s pervasive.”
There are a number of unintended consequences with water conservation, something that Dr. Schwabe and others have been researching. Low flush toilets may lead to more flushing, low flow showerheads may lead to longer showers, front load washers may lead to more rinse cycles, and so on, and Jevon’s Paradox states that increases in irrigation efficiency often lead to more water use, he pointed out. There are also positive unintended consequences in that reducing water use may lead to a reduction in energy use. Dr. Schwabe has noted that these behavioral changes don’t mean that water use increases, but rather water savings from conservation technologies may not be as large as anticipated or as suggested in engineering studies that overlook unintended behavioral changes that often occur when newer technologies are adopted.
That led Dr. Schwabe to the question, are there unintended consequences from water conservation on recycling of wastewater? “This is really important because conservation is a demand side management strategy to address drought and water scarcity, and water recycling is kind of a supply side, augmentation strategy,” he said. “Do they work in concert together or is there sometimes friction between the two and should we be aware of that friction?”
He presented a slide with two graphs. The graph on the left shows the reduction in gallons per capita per day which shows a significant reduction in water use because of the state mandate for conservation. He noted that the nationwide trend has been a reduction in per capita water use nationwide, while wastewater recycling has been increasing as well, as shown in the graph on the right.
To answer the question, what are the impacts of conservation and recycling strategies, Dr. Schwabe gave a simple analysis: If one person in a water district consumes 100 gallons of water, 50% indoor and 50% outdoor, and there is no wastewater recycling, their gallons per day is 100; their use of source water is also 100 gallons. If that water is recycled, assuming 20% of indoor use is consumed and 80% is wastewater, then although the overall gallons per day is still 100, the gallons per day from source water drops to 60 units, or a negative 40% reduction already in terms of the use of imported or source water. If a conservation mandate imposed on society and both groups decide to conserve and reduce their water use indoors by 20%, then the no recycling situation leads to a 10% reduction in imported water use, whereas if the wastewater is recycled, it only leads to a 3% reduction in water use.
“So if recycled water decreases by 20% because of the indoor water conservation, it’s likely going to lead to an increase in TDS and other constituents in our wastewater, and it’s relatively ineffective in reducing imports,” Dr. Schwabe said. “So you could say then that when recycling is present, the degree to which conservation reduces imports or source water use depends on relative fraction of indoor versus outdoor conservation. And therefore if indoor conservation is adopted, then recycling may not be as drought proof as people always claim it is.”
What does the evidence suggest? Dr. Schwabe presented a graph from the Inland Empire Utilities Agency’s regional recycling plant #1 (RP1). The left hand axis shows average inflows in millions of gallon per day showing the trend, which has generally been decreasing over time from 2011 to 2015. He acknowledged that there can be storms which can cause flows to go up, but the general trend is less water going to the recycling plants. The red dots represent wastewater produced in terms of gallons per capita per day; he noted that there is also a trend of flows going down over time which is consistent with the trend in water use.
What about TDS concentrations? “My theoretical model suggests it should be going up and it is, and it’s going up for two reasons,” said Dr. Schwabe. “First of all, as the drought hits, your water supply often becomes a little more saline, and so your source water increases in salinity, but also if people engage in indoor water conservation, then the wastewater becomes more concentrated, and I think that is what explains the differences here over time from 2011 to 2015. The dotted red line on the graph (above, left) is the NPDS permit, and four violations occurred at this plant since 2011. So that is the anecdotal evidence.”
What about systematic evidence? The next step was to gather data from 21 wastewater treatment plants over a 48-month period, including their monthly flow rates and their monthly TDS qualities; that was related to the state mandate and the stress test after the state mandate was rescinded while controlling for other factors that would influence flow and TDS at the plant; they then did a regression analysis.
“The results suggest that the mandate had a negative and statistically significant impact on influent flow; it had a positive and statistically significant impact on effluent TDS, similar to what the theory was predicting and what we know as anecdotally,” he said.
The next stage of the study is to relate that to an effluent-dominated stream and see how flow and quality are affected by changes at the wastewater treatment plant; Dr. Schwabe said some streams will be affected while others aren’t. They are still gathering data for this part of the study, so he isn’t in a position to speak about any results just yet until more data is collected.
At the recycling plant level, if inflow is going down and constituents are going up, how should the plant operator respond? Dr. Schwabe and his colleagues have developed a plant level model that considers the rising levels of constituents; the model looked at blending techniques to cost-effectively address the increase in salinity and other constituents in the wastewater which can be blended into ‘purposed water’ to meet the water quality requirements for the particular type of demand, such as golf courses, turf, or orange groves. “The model illustrates how you can do these blending techniques and identify cost effective blending techniques,” he said.
For dealing with the flow, a much broader model is needed, so Dr. Schwabe and colleagues have also developed a regional model. Currently, they’ve modeled San Bernadino Valley Municipal Water District and the Bunker Hill basin, looking at natural recharge and stochastic recharge over 50 years, as well as changes in demand, changes in prices, and changes in recycling. “We can answer a lot of interesting questions that get at this idea at understanding what the unintended consequences are,” Dr. Schwabe said. “It’s very complex, and without a model like this, it’s hard to understand how changes in the price of agricultural wastewater affects the whole system in terms of recharge and in terms of the water quality going to the stream.”
Dr. Schwabe then gave his conclusions. “So I would summarize then by saying that recycling and conservation are integral parts of California’s portfolio to address water scarcity and drought. The evidence does suggest that the conservation efforts in the drought and the state mandate impacted wastewater treatment influent and quality; these unintended conservation efforts may increase wastewater treatment costs, reduce recycling opportunities, and impair surface water flows and qualities, especially in effluent dominated streams. Basically it suggests that there’s an argument to be made that policymakers need to recognize the potential dependence of recycling, particularly when the conservation is indoors.”
MARC MARCANTONIO: The effect of 36% water conservation mandate on Yorba Linda
Marc Marcantonio is the General Manager of the Yorba Linda Water District. The District provides water and wastewater service to about 80,000 people in the cities of Yorba Linda, Placentia, Anaheim, Brea, and unincorporated Orange County. The area was originally an agricultural community which has transitioned into the sixth richest city of California with large residential lots, hobby farms, and horse and view properties. The community has a large amount of recreational properties; the two largest customers are the city of Yorba Linda and the school district. The district is adjacent to the wildlands of Chino Hills State Park with more than 16,000 homes bordering the state park.
“I bring out these points to illustrate that Yorba Linda Water District has very high irrigation need, especially since rainfall is extremely limited in our area,” he said.
The District has 11 wells, four connections with Metropolitan for imported water, 14 underground reservoirs totaling 54 million gallons, and 12 booster pump stations for 20 different pressure zones, due to the steep terrain present in the area. He noted that the different colors on the service area map represent different elevations throughout the system. “Each one of those is a different pressure zone, which makes managing the system somewhat unique,” he said.
The District has almost completed a project to replace and expand the 40-year old Fairmont booster pump station; completion of the project will mean that the District will now be capable of pumping both groundwater and imported water to their entire service area, giving them two completely redundant sources of supply should any one be lost.
Mr. Marcantonio then reviewed key points from the most recent drought. “When the Governor asked for a voluntary 20% reduction in 2014, our customers exceeded that goal,” he said. “When the emergency was declared in 2015, Yorba Linda Water District was required to reduce our consumption from 2013 levels by 36%, the highest in the state. While nobody thought we could do it, our customers complied and exceeded the 36% requirement. When reason prevailed and the stress test was implemented, Yorba Linda was shown to be drought resilient, and our requirement was reduced to 0.”
He pointed out that their customers have been becoming more efficient, reducing their usage over the past 5 years from 35 million gallons a day down to 20 million gallons per day, despite more population and more water connections.
The District immediately realized many unintended consequences of the emergency drought regulation and water conservation, Mr. Marcantonio said. He noted that the 100% of their wastewater is reused, purifying it for potable use and returned to the aquifer for reuse and the stormwater system routes runoff to settling ponds which recharges groundwater, as does the water used for irrigation.
“The soils in our area our extremely well drained, which is why Orange County Water District locates their settling basins adjacent to us and why our wells are located where they are,” he said. “Virtually all of our water is reused locally, with the exception of that which is lost to evapotranspiration and reused through the hydrologic cycle. I would contend that water is a local issue, unique to every area, so water conservation solutions should follow and also be local. Due to the recent emergency drought declaration, our mandate of 36% of water reduction did not prevent water waste in our district, nor did it provide a single glass of water to East Porterville.”
Public health and public safety is more of a concern than water supply for him, he said, and the District’s terrain along with the community’s experiences have led to their water system having some unique issues.
One of those issues is providing sufficient fire flow for domestic and commercial building fires, as well as the added challenge of being adjacent to the state park and having to deal with wildland fires. He said generally, up to 60 to 70% of any water district’s costs can be for supporting the fire flow requirements of the city or county authority having jurisdiction.
He presented photos of the 2008 Freeway Complex Fire which occurred in their service area, noting that the speed of the fire was overwhelming and the intensity was devastating. “Our average day at peak demand is 20 million gallons a day, but during this fire, it increased to 45 million gallons a day,” he said.
The fire burned over 30,000 acres and 90% of the Chino Hills State Park; 112 homes in Yorba Linda destroyed and 314 residences damaged or destroyed in the cities of Yorba Linda, Brea, and Anaheim. “This resulted in an inverse condemnation judgement of $69 million against Yorba Linda Water District for failure to protect, and continues to instill fear in our community, especially when water is restricted,” he said. “We all know fear is a powerful motivator, which resulted in the public insisting that we invest in infrastructure that is oversized.”
They have several reservoirs that are oversized, including one that serves only 112 homes and should be about a half a million gallons but instead was built to hold 2 million gallons.
This creates a concern for water quality and public health that is magnified during water conservation periods as the key to maintaining water quality in the distribution system is circulation and consumption, Mr. Marcantonio said. With less water flowing through the system, pathogens and unhealthy chemicals may accumulate and be less diluted throughout the distribution system, so if water consumption decreases, flushing of the distribution system must be increased to maintain water quality.
The water quality starts out as being excellent, but long detention times in mains and reservoirs can lead to stagnation. Where distribution systems involve rugged terrain, including hills, ridges, and valleys, there are many places where water does not get circulated or consumed, he explained. One-way water mains, oversized reservoirs, oversized pipes and pumps all contribute to water stagnation, especially during conservation and even with water use efficiency measures.
“Water quality depends on maintaining a good disinfectant residual to these extremities of your distribution system and to prevent nitrification and disinfection byproducts and the only way to ensure this is the flushing of all dead ends,” Mr. Marcantonio said.
Yorba Linda Water District disinfects their groundwater with free chlorine and the import water is disinfected with chloramines; with decreased water use, they must carefully monitor the water quality in the reservoirs, especially to prevent nitrification in reservoirs filled with chloraminated water.
The red dots on the map illustrate over 5000 dead ends, most of which are fire hydrants and mains that are not looped due to terrain issues. “All must be routinely flushed to maintain water quality,” he said. “The less water consumed by customers, the more we must flush.”
There were financial consequences at well. He pointed out that public and private water districts provide a service; their expenses are directly related to the service of water treatment, storage, pumping, and delivery. These expenses include operations, and the repair and replacement of infrastructure.
“We provide fire service, but few districts list the charge on customer bills for fire flow service and most customers simply do not realize that they pay for service,” he said. “As an industry, we don’t help things by charging customers as if we’re selling them water as a commodity, like a retail store might sell products.”
Water providers typically charge a base fee and a consumption charge; because they reused their water prior to the drought emergency, most of the costs were recovered with the consumption charge, thereby keeping the basic service charge artificially low. “This financial model worked well for the district for over 100 years, but it failed when the state took the unprecedented action to mandate a 36% rationing of our water use or face fines up to $10,000 per day,” he said. “The sudden loss of consumption revenue put Yorba Linda Water District upside down on our bond debt covenant ratio, requiring a dramatic increase in the basic service charge. In our case, the unintended consequence was that water bills increased especially for those with low water use, since water sales were reduced 36%.”
The district also lost revenue that was planned for water use efficiency projects. Their distribution system was designed and built over many years, and optimized to provide high volumes of water for fire suppression. Water use efficiency is good, whereas water conservation can strand expensive infrastructure assets, he said.
Perhaps the hardest unintended consequence was the damaging of public trust. “The newspapers in Northern California called Yorba Linda profligate and touted our relatively high water use as being wasteful and entitled, but never once mentioned that we are the model agency for water reuse,” he said. “Locally we went through stages of public denial a drought even existed, then accusations of gouging, harassment, death threats to the staff, and humiliation on public talk shows. We were recipients of a referendum movement to overturn a valid Prop 218 rate increase that the customers approved. We were the recipients of a lawsuit and a recall election and even more.”
“Because public water agencies are critical to life, public trust is imperative,” Mr. Marcantonio said. “Believe me, it’s very easy to lose and very difficult to restore.”
“So in conclusion, we are victims of our own success,” he said. “Our customers wake up every morning, flush their toilets, and the waste disappears magically. They turn the faucet handle and safe drinking water always comes out. This reliability of service has made inconsequential life’s most critical elements. We need to make a paradigm shift and educate the public how difficult and expensive it is to provide safe and reliable drinking water. We need to tell our story. We need to promote our business as a service, instead of a commodity.”
“Confusing conservation with efficiency is like confusing motion with progress. As water providers, our primary mission is public safety and public health. We can’t ignore this for the sake of conservation or efficiency.”
Audience question: Regarding the Freeway Complex Fire, how did they decide that you were responsible, and what about the other communities peripheral to the Chino Hills there, why weren’t they in the same situation you were?
“I’m not an attorney and so my opinions that I will give you on that are from my observations and education,” Mr. Marcantonio said, noting that he wasn’t even here during the Freeway Complex Fire. “Ultimately, if you boil it down to one thing, we were responsible to repay for a small group of homes because in that particular area, the fire hydrants lost water. In all the other areas of our district, even where all the other homes were lost, the system didn’t fail. Water was still available in the fire hydrants. It just overwhelmed the infrastructure’s capability.”
“We all build for fire flow and that why all of our systems are as large as they are; it’s not for drinking water, it’s for our fire fighting mission. It’s designed for domestic fires and commercial fires, not wildfires. Nobody’s system can really handle that type of a fire. But a small group of homes burned because the fire hydrants ran out of water, because the fire burned the pump station down and shorted the pump and the heat deprived the air of oxygen, so the backup gas generator couldn’t operate because of being starved for oxygen – those hydrants didn’t have water, and the court decided that because we’re a public entity, we took the homeowners use of those facilities away and they needed to be compensated for that. In the areas where water continued to flow, we weren’t found liable.”