Surface Water Treatment

Fresno Surface Water Treatment Facility

Fresno’s first Surface Water Treatment Facility (SWTF) began delivering water June 14, 2004, and is the result of over a decade of planning on a local and regional scale. This facility provides customers with water that is treated to drinking water standards, and also offers a number of other advantages, including increased water pressure and enhanced reliability.

A second surface water treatment facility is planned in southeast Fresno to meet demands anticipated by the redirection of growth implicit in the 2025 General Plan. This ensures a healthy, fresh and safe water supply for years to come.

Supplementing Groundwater

While groundwater has been the sole source of water for Fresno, the SWTF supplements our system with water delivered direct from the Sierra to the facility for treatment. The SWTF supplies thousands of homes in Northeast Fresno, roughly 20+ million gallons of water per day. During the peak demand summer season the facility supplies approximately 15% of Fresno's potable water. During the low demand winter periods the facility supplies over 30% of the community's supply.

The City of Fresno continues to rely on groundwater and recharge as its primary source of water. Groundwater protection and remediation programs remain high on our list of strategic water management objectives. Supply from the SWTF does, however, provide a significant supplement to groundwater. . The benefit is widespread, as our underground aquifer, vital to the City, no longer is the sole source of water. This allows the aquifer to replenish through natural and artificial recharge.

The surface supply along with enhanced groundwater recharge and conservation will balance Fresno's groundwater budget for the first time in over 75 years. A second surface water treatment facility is planned in southeast Fresno to meet demands anticipated by the redirection of growth implicit in the 2025 General Plan.

Source of Supply and Conveyance

Precipitation and snow melt from the Kings and San Joaquin watersheds are provided by the City's federal Central Valley Project contract and Fresno Irrigation District entitlements. The snow melt from the Sierra Nevada Mountains, runs into the Kings and San Joaquin Rivers. Currently, water is supplied via the Enterprise Canal, a 25 mile circuitous, open channel that winds its way through ag and urban settings. The Enterprise Canal can deliver from either of the City’s water supply sources.

In the near future, a five mile pressure pipeline will be constructed directly from the Friant-Kern canal to the Treatment Facility. The pipeline will provide raw water quality enhancements, additional public health protection and adequate hydraulic head to operate the treatment works without supplemental lift. After pipeline completion, the Enterprise Canal will become a secondary supply source.

About the Treatment

The SWTF utilizes a three-step treatment process: clarification, filtration and disinfection.

“ACTIFLO®”

This is a patented term for a unique clarification process. Treatment additives plus microsand are injected into the water and rapidly mixed together to form a “ballasted floc,” resembling a discolored snowflake. This process not only removes suspended material, but also bacteria that may be living within those particles. The process repeats itself in a series of basins as the growing floc settles at the bottom. The cleaner water travels upward through a honeycomb-like set of tubing and is finally sent on to the ozone contact basin. This entire process is commonly called coagulation, flocculation and sedimentation. While it could take nature several years to achieve this clarity of water, this entire process takes about 15 minutes.

The ozone contact basin is where both ozone disinfection and oxidation occur. Water coming from the ACTIFLO® process is injected with thousands of tiny ozone bubbles. A powerful oxidant, ozone destroys many types of microorganisms; color, taste and odor compounds; and some man-made organic compounds. Once the ozone has effectively done its job (within about 10 minutes), it rapidly dissipates. By the time the water leaves this basin, it is ozone-free and travels on to the granular activated carbon filters for additional purification.

Water Testing

More than 128 physical, chemical and microbiological tests are performed every day to ensure that the entire treatment process has achieved its primary public health goal. All data collected in the laboratory is submitted each month to the California State Department of Health Services as part of a monthly regulatory report on the performance of the entire treatment process.

Q & A

Answers to questions often asked about Fresno’s surface water.

What is Surface Water?
Surface water is water from snow melt of the Sierra Nevada Mountains, which runs into the Kings and San Joaquin Rivers.

Why does Fresno need Surface Water Treatment Facilities?
There are many reasons. First and foremost, this facility will allow the City of Fresno to better manage depleting groundwater supplies. As the population in Fresno grows, so do the demands on our groundwater resources. In simplest terms, this new facility will replace a portion of currently delivered groundwater in favor of surface water, relieving high demands on groundwater resources.

How did the City decide this was the best course of action?
Many U.S. cities rely solely on water from rivers and streams for their drinking water. Fresno is fortunate enough to have an underground aquifer from which to draw its drinking water. However, growth and high water usage levels over the years, has resulted in declining groundwater levels. Good environmental stewardship, an increase in demand, and reliability long into the future, the City of Fresno decided to supplement ground water supplies with surface water. This, coupled with on-going conservation measures, sound effective water management and groundwater recharge, we can, over time, begin to balance our water supply throughout the City.

Is surface water safe to drink?
Absolutely. Surface water is treated to exceed drinking water standards. It complies with all Safe Drinking Water Act standards established by the United States Environmental Protection Agency, the California Department of Health Services and the various water quality goals set by the City of Fresno.

Is surface water the same as groundwater?
Not exactly; although it is treated to the same standards. Surface water tends to be much softer than treated groundwater, because of its lower natural mineral content. This results in needing less soap to get your dishes clean and will actually reduce unwanted spotting on glass and tile. Water softeners are unnecessary if you receive this surface water. Turning off your water-softening unit will reduce the impact to your plumbing system, and salts will not be sent down sewer lines and into the wastewater treatment system, reducing the impact to the environment.

What are some other advantages to using treated surface water?
During the summer months, when water usage peaks, you may have experienced low water pressure. The Surface Water Treatment Facility will provide additional water supplies and will help to provide residents with normal pressures, even during peak demand periods.

Why was the location on Chestnut and Behymer chosen?
Some of the largest declines in groundwater resources have been experienced due to the aquifer being less resilient and an increase in demand from growth in this area. This part of town is also the highest elevation in Fresno, offering more efficient delivery and distribution of water throughout North Fresno after treatment. This location was also chosen because of its close proximity to the Friant/Kern Canal and the Enterprise Canal.

How much water does this treatment facility supply?
The SWTF delivers between 15%-30% of Fresno’s water needs, which translates to a rough average of 20 million gallons of water per day.

Who receives water from the SWTF?
The facility’s primary service area encompasses Copper Avenue to the north; Willow Avenue to the east; Friant Road to the west and Shepard Avenue to the south. In the winter months, the delivery area extends up to and beyond Sierra Avenue to the south.

How much did the facility cost?
The $32 million, state-of-the-art facility was funded by existing funds, with no new bond issues or rate increases.

SWTF Construction Information

Location:	10120 North Chestnut, 93720 (near Willow & Behymer)
Permitted Capacity:	30 Millions Gallons of Water Per Day (MGD)
Build out Capacity:	60 MGD
Type of Facility:	Full Conventional with Ballasted Sedimentation and Ozone
Operation:	Base load, 24 hour staffing
Design Engineer:	Montgomery Watson Hazra
Contractor:	Mauldin-Dorfmeier
First water delivered:	June 14, 2004