Wastewater Disposal Options in Sonoma County

The Federal government considers tertiary treated wastewater too contaminated to put in the ocean, and the State Water Quality Control Board wants the pollutants out of the river – so why is Sonoma County proposing to dispose of wastewater in its own drinking water supply?

At a time when other California counties are spending billions to clean up their water supplies, a more sensible solution is to treat the tertiary wastewater to groundwater recharge standards. Sonoma County can choose a different path - one that protects, not degrades, its clean water supply

Sonoma County needs to stop – rethink – and revise its future water supply strategies. The current set of projects are in direct conflict with the Clean Water Act and the Biologic Opinion designed to protect our water resources and endangered fish populations.

Sonoma County Water Agency (SCWA) proposals include the:

· Water Project – an additional 26,000 acre-feet water allocation from Lake Sonoma and the infrastructure for delivery to its urban customers. This project includes the Dry Creek by-pass pipeline designed to reduce summer in-stream flows in Dry Creek from 100 cfs to 40 cfs, with a minimum of 25 cfs at the intersection of Dry Creek and the Russian River.

· North Sonoma County Agricultural Reuse Project (NSCARP) – dispose of tertiary wastewater over 21,000 acres of land directly above the drinking water aquifer supplying SCWA’s 600,000 water customers. In other words, a project where the agricultural land owners in Alexander, Dry Creek and Russian River valleys exchange fresh groundwater irrigation with urban wastewater irrigation.

These two heavy construction projects are at once enormously expensive – about $885 million dollars – and ill-considered. They are 20^th century solutions to 21^st century challenges.

Frequently-Asked Questions – That are unanswered in the NSCARP EIR

Doesn’t wastewater reuse make good environmental sense? Isn’t it being used elsewhere in Sonoma County? Why not use it in our alluvial valleys?

Wastewater reuse is an important goal in water-constrained California. And, current regulations treat all tertiary- treated wastewater as equal, when, in fact, the concentrations of organic chemicals, metals, salts, and nutrients vary significantly from source to source and the potential for impact varying based on the reuse site conditions. Decisions on wastewater reuse should be appropriate to the soils, hydrology and geology of the disposal site.

Irrigation with wastewater is not appropriate to our alluvial valleys because of our highly permeable alluvial soils and shallow groundwater tables. Our gravelly, alluvial soils allow the wastewater to rapidly percolate to the drinking water aquifer with little to no adsorption of chemical contaminants.

There are four key players in the “exchange your freshwater for wastewater” drama: 1) clean and abundant rainwater; 2) the soil zone; 3) premium grapes and 4) the underlying groundwater aquifer. The potential for impacts to our drinking water supply – lies in the answers to questions about “what,” “how much,” and “where”.

What chemical compounds are in the wastewater? What monitoring and controls will be placed on farming practices to ensure these compounds do not degrade groundwater or surface water?
How much clean water will be available to recharge and dilute the chemical load?
Where are the soils effective at removing chemicals and nutrients? And, where are the down gradient wells or “hot spots” where chemical concentrations will be well above the averages modeled?

The NSCARP environmental studies do not provide answers to these questions.

Potable water is a matter of concern to everyone in Sonoma and Northern Marin counties – shouldn’t we have the answers to these questions before the environmental impact reports are certified?

In addition to supplying domestic and irrigation water to 21,000 people with private wells in Alexander, Dry Creek and Russian River valleys, the groundwater aquifers below our agricultural valleys are also the source of pure, naturally filtered drinking water for 600,000 Sonoma County Water Agency customers.

The NSCARP Final EIR did not address new scientific information available in the public record. The City of Santa Rosa hired expert consultants to determine the level of treatment or attenuation of nutrients and certain California Toxic Rule constituents (such as lead, copper and cyanide) when wastewater was discharged through in the soil and groundwater south of Healdsburg. Field studies in the Middle Reach of the Russian River documented the fact that the aquifer is shallow, has high transmission rates, and that our valley soils are highly porous and do not readily attenuate metals. Thus, indirect discharge could not assure treatment goals for California Toxic Rule constituents, and Santa Rosa dropped the alternative from further consideration.

How does the NSCARP wastewater reuse project increase the likelihood of groundwater contamination?

The crux of the problem is three-fold:

First, our precious valley soils are highly permeable – basically, our valley floors are just a thin layer of soil, silt and sand over a deep base of gravel. Due to these factors and the high porosity of alluvial soils, our valley soils may not treat or take out metals and chemical compounds to the same extent that other soil types attenuate contaminants. Thus, wastewater disposal in the alluvial valleys may result in higher levels of contaminants being flushed into the groundwater. In some cases, it may be similar to a direct discharge to groundwater.

Second, the urban wastewater just isn’t clean enough. What is known to be present in Santa Rosa’s wastewater alone raises concerns. While treated to “tertiary” levels, Santa Rosa’s wastewater still contains high levels of total salts and nutrients as well as significant levels of metals and cyanide. Santa Rosa’s wastewater has also been shown to contain:

· Selenium close to levels toxic to fish;

· Mercury close to levels toxic to humans, and

· Boron close to levels toxic to grapevines.

Given that the groundwater recharges the Russian River, the Santa Rosa indirect discharge study focused on the lateral distance required by transport through soils and groundwater to treat California Toxic Rule constituents sufficiently to meet surface water regulations. The study found that these constituents (lead, copper, etc) require 150-300 feet of subsurface travel, and even then treatment goals could not be assured. Of course, an indirect discharge project would ensure there were no domestic wells along the transport path. Large scale agricultural reuse, however, allows wastewater discharge within 50 feet of your well.

Although certain metals and nutrients may be regulated and measured – hundreds of untested organic compounds or emerging contaminants are also present. Many of these emerging compounds are not completely removed through conventional wastewater treatment processes, and may not be effectively removed through microbial action in the soil or adsorption onto soils.

The EPA, FDA and USGS are just beginning to study pharmaceuticals and endocrine disrupting contaminants in wastewater. Even when these emerging contaminants are present in low concentrations, combining or synergistic effects between compounds are raising concerns. To infer that just because a certain chemical or compound is not regulated it therefore has no impact defies logic – especially when your drinking water is at stake.

Also, many of these organic compounds are pharmaceuticals that are known to cause mutations among amphibians and fish. USGS researchers state that the mutations are likely caused by exposure to “endocrine disruptors” – chemical compounds that mimic the body’s natural hormones. And, that fish may be an indicator species. USGS fish pathologist Vicki Blazer stated, “The endocrine system of fish is very similar to the endocrine system of humans.”

Third, to compensate for nutrients and other compounds in wastewater, our farming practices may require monitoring and regulation.

Vineyard managers currently use fertilizers, and they apply these nutrients at the time and at rates as needed by the vines. Since the treated wastewater also contains nutrients, such as nitrates, application of wastewater can introduce more nutrients at rates and times in excess of the plant’s needs. When using wastewater irrigation, such excess nutrients, salts, metals and organic compounds concentrate in the soil zone.

With irrigation from pumped groundwater, the chemical load from fertilizers and other farming practices is diluted. However, with wastewater there is a compounding effect – an increase in chemical and nutrient concentrations in the soil.

Then, when our heavy rains come, these accumulated metals, salts, nutrients and unknown organic compounds “flush” directly into our drinking water aquifer, which in our alluvial valleys can seasonally range from only 15-50 feet below the surface.

To limit this degradation of our groundwater, new unspecified regulations on farming practices may be required to control application of chemicals and nutrients.

What happens if one farmer accepts NSCARP wastewater and another neighbor doesn’t?

We’re all in this together – let’s not pit neighbor against neighbor. The impacts will be greatest on the wells down-gradient from lands applying wastewater irrigation. The impacts of groundwater contamination will not be uniform across the aquifer. The groundwater drawn by your well could have contaminants at much higher concentrations than the “averages” predicted in the expert analyses.

What if you decide not to take wastewater, but your neighbor applies wastewater to his property? And wonder if your neighbor disregards safeguards or regulations on chemical use or controls on application of wastewater?

Who is responsible – the entity that sold the wastewater or the farmer who applied it? These questions must be answered before the NSCARP final environmental report is certified.

What about the fish? How will NSCARP potentially affect the Endangered Fish?

Currently, during the summer, water seeps from the creek or river, recharging the groundwater. When groundwater pumping is reduced, the water balance changes. With the imported wastewater from NSCARP replacing groundwater pumping for irrigation during the summer months, Dry Creek and the Russian River will become a “gaining” stream – this means that groundwater will now seep into the surface water.

In addition to the findings from DCVA’s hydrologists, the NSCARP EIR response to comments revealed that the City of Santa Rosa’s environmental studies also contained analyses of the interaction between groundwater and surface water. Santa Rosa’s studies concluded that, “Reduced groundwater pumping can result in discharge of groundwater to surface water sources. The groundwater/surface water interaction is the net difference between the total pumping demands and the total recharge for the localized hydrologic budget near the well.” So, groundwater recharges surface water, and the indirect discharge studies found a potential impact on surface waters from California Toxic’s Rule constituents.

If our groundwater becomes contaminated with pharmaceuticals and other emerging contaminants known to affect aquatic species, then NSCARP also poses a significant risk to the survival of the coho salmon and steelhead fisheries because the contaminants will work their way into Dry Creek and the Russian River. This impact is in direct violation of the Biological Opinion requiring restoration to protect fish species.

What are other California counties doing with their treated wastewater?

San Francisco County’s Westside Basin project faced a similar decision point. Just like Sonoma County’s agricultural valleys, irrigation of Golden Gate Park is on highly porous soils overlying a drinking water aquifer. San Francisco made the prudent decision to upgrade to advanced treatment, and not risk pollution of the aquifer from irrigating with tertiary treated water.

Why not follow Southern California water supply and wastewater districts that are proving the viability of advanced treatment processes to create additional sources of potable water. The Orange County Groundwater Replenishment System project involves an advanced wastewater treatment plant that through microfiltration, reverse osmosis and ultraviolet light, renders their wastewater suitable for aquifer injection. This project cost $490 million, producing potable water at less than $500/acre foot.

Why is the County’s Water Agency not more focused on protecting its clean water supplies? Once the groundwater is contaminated, it will cost much more to clean the aquifer, not to mention the cost of a water treatment facility. This is where the two projects cited at the beginning of this article come together:

The water contractors want 26,000 AF of additional water: SCWA’s Water Project is a proposed $500 million dollar infrastructure project, including a Dry Creek bypass pipeline and a potential water treatment plant. The objective is additional potable water for the urban core.
NSCARP is a $385 million heavy construction/ energy intensive disposal option. This project risks the contamination of the very drinking water aquifer relied on by the local residents and the 600,000 SCWA water customers.
And, these two projects together could potentially raise the cost of water from SCWA to over $1000/acre foot – twice that of the Orange County project – an advanced treatment project which is much more effective at solving the water supply problem.

Do these economics add up? Sonoma County can follow a wiser path – we can invest now to treat the wastewater to groundwater recharge standards. Using new technologies, the Sonoma County Water Agency can create a new water supply available to produce the greatest public benefit.

This can be done without damaging our agri-tourism industry through a massive decade-long construction project and without impacting to our precious drinking water supply.

Submitted by Judith Olney, Director

Dry Creek Valley Association

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