Aquifers in the United States: Part 3

Arthur & Orum Well Drilling Inc. drills a 600-foot well with 17.4-inch plastic well casing in January 2016 for Nunes Dairy in Tulare County, California, using a GEFCO JED-A reverse circulation rig. The well was designed to pump 2500 gallons per minute and the drilling formations were sand and clay. Tulare is located in the heart of the Central Valley.

Arthur & Orum Well Drilling Inc. drills a 600-foot well with 17.4-inch plastic well casing in January 2016 for Nunes Dairy in Tulare County, California, using a GEFCO JED-A reverse circulation rig. The well was designed to pump 2500 gallons per minute and the drilling formations were sand and clay. Tulare is located in the heart of the Central Valley.

Part three of three: The Turlock Subbasin and San Joaquin Valley

By Mike Price

A small but positive piece of news broke in May regarding California’s 4-year-old drought. Less than 90% of the state is in drought for the first time in three years, reported the U.S. Drought Monitor, a federal website that tracks dry conditions. The drop may not sound like much, but any amount of drought relief is welcomed by the state’s 38 million residents complying with water restrictions.

El Niño is largely the reason for the drop as it typically brings wetter conditions to the West Coast.

Aside from this encouraging news, groundwater levels in many wells in California’s Central Valley were at or below historical low levels in 2015, according to the U.S. Geological Survey. In addition, from 2007 through 2015, land subsidence that correlates to areas with large groundwater-level declines increased significantly in two large agricultural areas near the towns of El Nido and Pixley.

The Turlock Subbasin underlies the San Joaquin River in the San Joaquin Valley of central California, one of the largest aquifers in the western United States. The San Joaquin Valley is one of the most productive agricultural regions in the nation. Over time, overpumping has caused groundwater-level declines and associated aquifer-system compaction and land subsidence—resulting in permanent aquifer-system storage loss in the San Joaquin Valley, according to the USGS.

In this final part of Water Well Journal’s three-part series examining major aquifers in the United States, we look at the Turlock Subbasin and San Joaquin Valley.

The Turlock is a subbasin (542 total square miles) of the San Joaquin Valley groundwater basin which occupies about 13,700 total square miles, making it the largest groundwater basin in California.

Located between the Tuolumne and Merced Rivers, the Turlock is bounded on the west by the San Joaquin River and on the east by crystalline basement rock of the Sierra Nevada foothills. Runoff from snowmelt and rainfall in the Tuolumne River basin plays a significant role in irrigation and domestic water supply for Turlock and Modesto Irrigation Districts, and water supplied to the city of Turlock is solely groundwater from 150-600 feet below the ground.

The primary hydrogeologic units in the Turlock include both consolidated and unconsolidated sedimentary deposits.

The consolidated deposits include the Ione Formation of Miocene age, the Valley Springs Formation of Eocene age, and the Mehrten Formation, which was deposited during the Miocene to Pliocene Epochs. Unconsolidated deposits include continental deposits, older alluvium, younger alluvium, and flood-basin deposits. Lacustrine and marsh deposits, which constitute the Corcoran or E-clay aquitard, underlie the western half of the subbasin.

The San Joaquin Valley represents the southern two-thirds portion of the Central Valley, which is home to the world’s largest swath of ultra-fertile Class 1 soil. The 6.3 million acres of farmland produce more than 350 crops—from fruits and vegetables to nuts and cotton—representing 25% of the food for the United States.

Drilling Challenges

Steve Arthur’s Fresno-based drilling company has stayed busy the last three to four years, driven by the drought conditions and a host of other factors promoting short-term consumption over long-term survival.

But business slowed in May due to farmers determining their upcoming crop plans. It didn’t help prices for such crops like milk, almonds, pistachios, and raisins were down.

Ironically, the main drilling challenge currently resides above ground for Arthur & Orum Well Drilling Inc., which drills from Bakersfield to Merced. The drought has led to an influx of drillers coming into the state, and Steve says “drought chasers” have slashed prices dramatically to stay afloat. Jobs which once paid $50 to $60 a foot are now $30 a foot. Steve drops his prices to compete with the competition, with his overall estimates running a couple of thousand dollars higher than his competition.

Map of the San Joaquin River watershed.
Map of the San Joaquin River watershed.

The market, according to Steve, has been devastated by inexperienced drillers using nontraditional water well drilling equipment and non-water well approved casing. Some are drilling under another state well drilling contractor license number. The goal of these drillers is to drill a well as quick as possible and move on to the next drill site. This shoddy work leads Steve to receive phone calls for wells needing to be redrilled, but the majority of the calls are from well owners who have problems and cannot locate the driller anymore. Steve tries to track down the driller and has mixed results.

“We tell our customers we were in this before the drought and we’re going to be in it after the drought,” he says. “You got a problem, you know where to find us. We’re not going anywhere. That helps the customer if they get a problem.”

Steve’s father, Floyd, started his own business in 1971 under the name of Western Well Drilling. Floyd’s brother-inlaw, Orvel Orum, came on board in 1972 and the name was changed to Arthur & Orum Well Drilling. Orvel retired in 1989, but the name stayed the same.

Today, 79-year-old Floyd is at the office every day at 7 a.m. to go over the day’s activities with Steve. Floyd still serves as president of the company and has moved into more of a consultant position, where Steve is the vice president and runs most of the day-to-day business operations of the company. The company is in the running for the California Business of the Year Award from California State University, Fresno Craig School of Business. The winner was scheduled to be announced on May 25.

Steve prides himself on conducting business honestly and treating his customers and employees like family. He offers his drillers a bonus incentive on drilled footage if the well is constructed correctly. He hopes his competitors who do substandard work will be driven out in the next three to four months.

Meanwhile, the California Contractors State License Board caught 83 people flouting the state’s construction and home repair contracting laws during the CSLB’s annual “Spring Blitz” sting operation in April. Steve only wishes the CSLB would oversee the water well drilling industry more heavily and target phony drillers.

Nearly all of the company’s work is repeat at the moment for his staff of 30 employees and six drill rigs, one of which runs around the clock. The bulk (85%) of drilling is for agriculture and the remaining amount is for domestic drilling.

Arthur & Orum Well Drilling recently hosted an employee appreciation day on May 6.

“We decided to do this because it was such a crazy year,” says Kim Hammond, Steve’s sister and corporate secretary. “Our employees felt the pressure from our farmers because of the drought. We asked a lot from our employees and they rose to the occasion. Our farmers appreciated it.”

Water Quality

The groundwater in the Turlock is predominately of the sodium-calcium bicarbonate type, with sodium bicarbonate and sodium chloride types at the western margin and a small area in the north-central portion, according to the California Department of Water Resources.

There are localized areas of hard groundwater, nitrate, chloride, boron, and dibromochropropane, the major pesticide contaminant of drinking water in California. Some sodium chloride type water of high total dissolved solids is found along the west side of the subbasin.

The city of Turlock reports over time there has been a decline in water quality due to an increase in total dissolved solids and nitrate levels.

In the San Joaquin Valley, arsenic and uranium are found in specific hydrogeological and hydrogeochemical regimes, says Christopher S. Johnson, PG, CHg, president and principal hydrogeologist at Aegis Groundwater Consulting LLC in Fresno, California.

“We have a reasonable understanding of the geographic and vertical occurrences,” Johnson says. “We’ve designed a number of wells to avoid the presence of uranium. The same is true for arsenic. Right now we are preparing to use the same process to address boron.”

Johnson advocates conducting a complete borehole assessment and a smarter approach through design of the well and its components like the screen and gravel pack.

He co-presented on well design reducing concentrations of naturally occurring uranium using subsurface lithologic, radiologic, and geochemical methods in Kerman, California, 15 miles west of Fresno, at the 2005 National Ground Water Association Naturally Occurring Contaminants Conference. The presentation concludes by recommending the need to investigate the subsurface, zone test for confirmation, and design the well based on water quality.

With the San Joaquin Valley an agriculturally-intensive region, nitrates have historically been an issue. Like in the second part of this series on the Ogallala Aquifer, farming practices of fertilizer application in this region could be a consequence of the presence of nitrates. Johnson also says the function of the well design could have been a contributor.

“Nitrates are difficult to specifically solve the problem,” Johnson says. “There is a certain degree of remedial effort to put into this by revising how we build wells. We can build them smarter rather than some archaic, antiquated standard.

“Most counties have a minimum vertical thickness of the sanitary well seal, being 20 feet to 100 feet depending on the county. Most of my wells—when given an option—seal at 700 to 1000 feet. We’re not going to get any water from up there we want, so let’s just seal it off. Generally, we have better results with that.”

Arthur & Orum Well Drilling is family owned and operated. From left to right: Barbara Arthur, Steve Arthur, Kim Hammond (Steve’s sister), Alyssa Lewis (Kim’s daughter), and Floyd Arthur. Photos courtesy Arthur & Orum Well Drilling.
Arthur & Orum Well Drilling is family owned and operated. From left to right: Barbara Arthur, Steve Arthur, Kim Hammond (Steve’s sister), Alyssa Lewis (Kim’s daughter), and Floyd Arthur. Photos courtesy Arthur & Orum Well Drilling.

In the southern area of the San Joaquin Valley near Bakersfield, deep groundwater (more than than 500 feet) is older and can have high levels of arsenic, says Tom Harder, owner of Thomas Harder & Co. Groundwater Consulting in Anaheim, California.

This can present a water quality issue for some of the water banking agencies along the Kern River, according to Harder, particularly during periods when groundwater levels are low, as they are now. Wells used to pump stored water during dry times are typically perforated in both the shallow and deep aquifers. As the groundwater level drops in the shallow aquifer due to pumping, the source of water to the wells is increasingly from the deep aquifer and the arsenic concentration in the pumped water tends to increase.

Agency water is discharged to area canals and the arsenic concentration can’t exceed the maximum contaminant level, which is 10 micrograms per liter. While the water from some individual wells has exceeded the maximum contaminant level, agencies have been able to blend the well water sources to keep the arsenic within acceptable limits. However, further lowering of the groundwater level may limit their ability to do this.

Water Level

Water year 2014 closed as the third driest year since records began in the city of Turlock. In the same year, the city’s 23 active wells pumped a total of 6.6 billion gallons of drinking water (down from 7.4 billion in 2013).

Through its water conservation program, the city’s residents have significantly reduced their water consumption (decreased 13.3% from 2013 to 2014). But due to the drought and other effects within the subbasin, groundwater levels are continuing to decline, according to the city’s water quality annual report. The 2015 report was in the process of being completed at press time.

The California Department of Water Resources estimated spring groundwater levels in 52% of the long-term wells (1934 of 3723) in the Central Valley are at or below the historical spring low levels in 2015. These water-level declines are noticeably evident in the southern two-thirds of the Central Valley known as the San Joaquin Valley, where water-level declines have been connected to land subsidence (more on that later).

The USGS reported the Central Valley has many areas where groundwater levels are more than 100 feet below previous historical lows.

Water-level declines are having a far-reaching impact beyond the wellhead.

For farmers, it takes more energy, thus more money, to pump less groundwater. Making matters worse is the shift away from row crops to essentially perennials needing yearround watering. Tree nut farming has also become more common as of late—particularly for almonds, and creating conversation in the San Joaquin Valley. Almonds are a lucrative crop and need watered year-round.

For water well contractors, it is costing them more time and money to drill these deeper wells.

The increase in time constructing a well has been felt by Arthur & Orum Well Drilling, where what used to take a couple of days is now a week to 10 days depending on the formation for a well averaging 900 to 1000 feet. The deepest wells are in the 1200 to 2000 feet range. In past years the average depth of a well was 600 to 800 feet.

Most of the drilling Arthur & Orum does is either reverse rotary or mud rotary, with air drilling used when closer to the mountains.

Drilling through clay types can be quite gooey, akin to a bucket of grease, Steve says. Therefore, a good mud program with the appropriate mud types, mud additives, and increased mud density is required to prevent problems whenever using reverse or mud drilling.

“You have to mud up ahead of time and know the areas where to put in the right chemical or the formation you’re going to get,” he says. “With the sticky clays and swelling clays, we run a pack in there to keep it from swelling and it makes a big difference if you prep that hole.”

Steve, whose company has not drilled in the Turlock Subbasin in recent years, says many drillers don’t use mud when drilling to save on costs. He warns they risk having washouts. Another reason to use mud is if shale is present. If shale becomes wet, it will begin to crumble off in the hole. A good mud program helps to seal that off.

Safety, the issue focus of this month’s Water Well Journal, isn’t taken lightly by Steve. He tries to get out to the various drill sites at least every other day and scans job sites for proper personal protective equipment being used by his employees.

“I tell guys if you see something you’re not comfortable with, I’ll make a special trip and get the problem solved,” says 56-year-old Steve. “If we have a bad cable, I’ll get a new cable before we go any further. You’re only as good as the people you work with.”

The water-level declines in the Central Valley have garnered local and national media attention in recent years. Steve has been interviewed more times than he can remember and spoken with the likes of 60 Minutes, National Geographic Channel, and HBO.

Concern over the state’s groundwater supply pushed California to pass the landmark Sustainable Groundwater Management Act (SGMA), enacted by Governor Jerry Brown in September 2014. Prior to the passage, California lacked statewide regulation of groundwater pumping or standards for groundwater management.

SGMA, which became effective on January 1, 2015, gives groundwater sustainability agencies local authority to develop and adopt groundwater sustainability plans intended to manage the groundwater to maintain the “safe yield” of the basin.

Basins designated as “critically” overdrafted by the Department of Water Resources in Bulletin 118 must have plans in place by January 31, 2020. Basins “not critically” overdrafted, but designated by the DWR as high or medium priority basins must have plans in place by January 31, 2022.

The Turlock Groundwater Basin Association, formed in 1995, includes members from the majority of local agencies and is providing a basis for moving forward toward SGMA compliance. They include: developing groundwater sustainability agencies; evaluating additional information/data needs; and developing a groundwater sustainability plan for the subbasin.

Land Subsidence

The connection with recent water-level declines have been tied to land subsidence, according to the USGS and its article, “Water Availability and Subsidence in California’s Central Valley.” At some points, up to 11 inches of land subsidence was measured from 2012 to 2015.

However, land subsidence is not new to the Central Valley.

By 1970 half of the Central Valley had dropped more than a foot, according to USGS geologist Joseph Poland who led pioneering research on subsidence. The greatest subsidence tied to groundwater extraction ever recorded in the United States is on the Central Valley’s west side where the water table dropped 400 feet in the early and mid-20th century. The resulting soil compaction led to a drop of more than 28 feet in an area southwest of Mendota.

In the Central Valley, the USGS reports subsidence has caused costly infrastructure damage such as canal buckling and reduced freeboard on canals and bridges.

For Steve, it means building a compression section with steel pipe to help prevent the well from buckling due to subsidence when customers elect not to go with plastic well casing. Compression sections cannot at this time be built with plastic well casing.

When land subsides near a well, the subsurface soils and aquifers create substantial stress to the well casing. A compression section allows the well to withstand forces related to subsidence without experiencing collapsing, breaking, or being damaged to a point where it introduces sand. The compression section allows the casing to telescope inside of it so the pipe can move rather than crumble.

Roscoe Moss Co., a manufacturer of water well casings and screens based in Los Angeles, California, says compression sections are typically installed at the bottom of the blank casing (i.e., pump chamber) above the well screen. The company notes a compression section cannot be retrofitted to an existing well. Therefore, the potential for subsidence must be identified during the design phase of the well.

Steve will talk with the pump installer in the area he is drilling to find out at which depth wells are breaking. Depending on the formation, depth of the well, and other factors, Steve might install multiple (two or three) compression sections.

Compression sections are not the answer but help in fighting subsidence, Steve says.

Harder says between 2007 and 2011 as much as 4 feet of subsidence has occurred in the Tule Subbasin west of Porterville. If the well does buckle, the issue of not being able to get the pump out or down the well can become a possibility.

“Subsidence is mitigated by maintaining groundwater levels at a safe elevation,” Harder says, “and groundwater sustainability agencies need to find out what that elevation is.”

A Look Ahead

California’s 4-year-old drought is wreaking more lifechanging consequences than most realize.

On the frontline of the drought in Firebaugh, 40 miles west of Fresno, struggling farmers have had to lay off workers. Struggling communities are affected when kids drop out of school to move to another area where there is work for their parents. This leads to potential layoffs of teachers due to the lack of students in school. This has occurred over the last two to three years.

President Barack Obama visited Fresno and the droughtstricken town of Firebaugh in February 2014 to deliver a $183 million aid package that included money for ranchers in California who lost livestock, communities running out of water, and farmers needing help conserving their diminishing water resources.

Looking ahead, California is expected to have another cycle of substandard rainfall, snowpack accumulation, and surface water delivery. The bottom line is there are more people in California than the state has water for.

All eyes will be on how the Sustainable Groundwater Management Act enables regulation of groundwater pumping and standards for groundwater management. Harder says the next 20 years will be interesting to see if management agencies are able to work together to devise a common solution.

“If they can’t find common ground, California has a history of adjudication,” Harder says. “Whenever attorneys get involved, it gets long and costly. I know there is motivation to avoid that.”

In the meantime, a heavy workload continues for Harder’s small company of 10 employees. He normally works seven days a week to meet the demand. His current workload consists of three wells in Southern California and three in Bakersfield.

“Water, as you can imagine, in the West is extremely contentious,” Harder says. “It’s economy and life, and when the stakes are high, it’s worth fighting for, so we’ll just have to see.”

Mike Price is the senior editor of Water Well Journal. In addition to his WWJ responsibilities, Price produces NGWA’s newsletter and contributes to the Association’s quarterly scientific publication. He can be reached at Read parts one and two of this series in the April and May issues.