Color a solution that would cushion the impact of the drought on Manteca residents “purple”.

For more than two decades, Manteca has been burying purple pipe to use recycled wastewater to irrigate parks and other large expanses of landscaping.

The first was a 4-mile plus stretch from Eckert’s Cold Storage on Moffat Boulevard to the wastewater treatment plant.

The latest are segments in new residential development projects from the edge of neighborhood parks to arterial streets where they will eventually connect with more purple pipe that will be buried to connect with the treatment plant.

The “new” water a functioning purple pipe system could ferry to parks, school play fields, and such in the form of wastewater the Manteca — treated to the point a notch or so below being drinkable which is an expensive process to put in place — is significant.

In September, Manteca’s overall  used 477 million gallons of water. At the same time the wastewater treatment plant processed 210 million gallons of wastewater based on 7 million gallons a day flowing into the facility.

Given outdoor water use is still about 50 percent of the city’s water consumption, even if only large turf areas that are allowed to be irrigated using potable water under state restrictions use recycled water instead, it would significantly reduce overall city water consumption.

Previous ‘public works regime’

did 90% of recycled water

plan work and then dropped it

At Tuesday’s Manteca City Council meeting, Mayor Ben Cantu pulled a seemingly innocuous item from the consent agenda.

It was regarding authorizing the placement of a non-potable well that taps into much higher groundwater pockets where the water is unsuitable for drinking in order to irrigate a new park being created at the Trails of Manteca neighborhood near the western end of Woodward Avenue.

The well  — which will cost some where north of $200,000 — is on the developer’s tab. The cost, as with all other infrastructure, will be collapsed into the price of new homes.

It will enable the new park’s landscaping and turf to be watered without using drinking water.

Although there is a ban on watering commercial and business park turf exceptions are carved out for areas that have a public purpose beyond being eye candy of which parks and sports fields top the list.

The well — and those that have been placed at some other municipal parks — are major ways of pumping up water conservation. As such it helps the city get nearer the 20 percent overall potable water use reduction the state hopes will avoid California from having to resort to more draconian measures restricting water use to weather the current drought that is now into its fourth year.

Cantu asked — as he has before numerous times — what the status was of the city’s effort to reclaim wastewater.

The answer likely irked him as well as pleased him.

Staff noted the previous “public works regime” got the state-mandated reclaimed wastewater master plan required before treatment plant water could be used for domestic purposes 90 percent complete before stopping work years ago.

However, the city hall reorganization that created a lot of upheaval more than two years ago coupled with getting the city’s financial accounting in order, is allowing that work to be finished and incorporated into an overall wastewater management plan that is due to be completed in late 2023 or early 2024.

Dealing with wastewater — whether expanding a plant or reclaiming water — is a long laborious process to get a plan in place and the state’s blessing.

That said, Lathrop got theirs in place for River Islands in a matter of years while Manteca since 2001 has had two studies started that were either started or sopped short of completion

Ripon also has a purple pipe line up and running that distributes non-potable water to commercial concerns that connect to the city system.

Great Wolf is only user

of treated wastewater

The other positive information was the fact there is now one reclaimed water user in Manteca — Great Wolf resort.

They use reclaimed water for landscaping. Great Wolf taps into a purple pipe that was installed by the city from the treatment plant and running under the 120 Bypass to Atherton Drive using redevelopment agency funds more than 8 years ago. It was designed to deliver reclaimed wastewater to large turf areas south of the 120 Bypass such as the park in the process of being put in place at Trails of Manteca.

It should be emphasized the recycled water is not used in the 500-room hotel or indoor water park. That said, Great Wolf recycles in excess of 98 percent of the water in the indoor water park through a cleansing process. The low loss rate is due to a temperate controlled indoor setting that allows Great Wolf to eliminate evaporation losses

At the same time, the 99-home Yosemite Greens neighborhood being built along Airport Way has put in place the final purple pipe link from a city installed line running from the treatment plant to Airport Way to extend to the edge of the city golf course.

The golf course is the City of Manteca’s largest water user for turf although they use shallow wells and not treated water.

The plan for the initial study nearly two years ago that was dropped when the city was fashioning requests for proposals. It was set aside after an idea popped up among public works staff that putting in shallow wells at city parks was a much more cost effective way to use non-potable water to irrigate turf.

As a result, a number of existing and new city parks as well — depending on where they were located — as well as the Tidewater Bikeway corridor — are irrigated using non-potable drinking water.

However, there is a long-range concern that by tapping into the higher water table, it will reduce the chance of a large swath of that water eventually percolating down. During its long downward travel, the soils and rock formations help clean many containments from the water.

The city decision to drop the first study was based on nickels and dimes and not whether water per se was a critical resource. It was simply cheaper to use shallow wells than invest in the purple pipe/reclaimed water infrastructure.

That was back at 2001 prices. Now with the return to extended dry periods in the western United States water is becoming a scarce commodity.

The use of purple pipe in

Manteca surfaced first in 2001

Purple pipe has been part of Manteca’s public works lexicon since 2001. That’s when developers paid for a 4-mile plus line to connect Eckert’s Cold Storage with the treatment plant.

Eckert’s is a leading processor of bell peppers that end up on pizza served by a number of national chains.

Heavy nitrates in the processing of bell peppers — especially red bell peppers — was raising havoc with the treatment process and prompting the state  to warn they would have to force Manteca to undergo expensive treatment upgrades.

The solution was to ferry the nitrate laden wash water to the fields surrounding the treatment plant where corn crops were already being grown by farmers leasing the property.

Corn, grown to provide silage fo dairy cattle min the area, grows well with the nutrients in treated wastewater as well as that from washing bell peppers.

In exchange for paying for the Eckert’s purple pipeline, the developers that did so were able to use treatment plant  capacity that Eckert’s was eating up as the plant’s largest users. The developers also paid all applicable sewer connection and plant expansion fees.

If Eckert’s ever went out of business, the city at the time the purple pipe was buried indicated they intended to use the 4-mile pipe that runs along the 120 Bypass to deliver irrigation water to nearby parks and schools and possible even irrigate landscaping along the freeway.

The purple pipe project saved more than 100 jobs as the only short-term solution at the time was for Eckert’s to close down given the firm couldn’t afford the costly pipeline.

The other advantage that a purple pipe system has over shallow wells tapping into non-potable water: It doesn’t require electricity to power pumps to move the water.

The city is also spending money on energy already to treat wastewater to state standards before releasing it into the San Joaquin River.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com