imperial forces

Much of West Texas is webbed with concrete-lined dreams of now-abandoned irrigation works that aimed to turn the Pecos River Valley into a Garden of Eden. Unfortunately, whether due to robbing-Peter-to-pump-Paul well drilling, the inherent saltiness of water in these parts, or a river already rustled across the state line, all that is left are crumbling concrete raceways and headgates choked with tumbleweeds. In most cases, this abandoned infrastructure is harmless, a fading reminder of the follies of men. But sometimes this abandoned infrastructure is simply waiting to remind everyone that it’s here.

Named after the well-watered Imperial Valley of California, Benjamin Bush established the town of Imperial, Texas, around 1910 after diverting the Pecos River into the Imperial Reservoir eight miles west of town and running irrigation canals toward, through, and beyond the city limits. Due to salinity and low flows in the Pecos, the project never bore fruit. Perhaps due to the fickleness of the river, some landowners south of town turned oil test boreholes (wells drilled to explore for hydrocarbons) into irrigation wells, a perk of oil exploration where test holes were concreted back to a water-bearing formation. Such wells were considered a bonus for landowners who avoided the substantial cost of drilling. These wells, about 2,800 feet deep, tapped into the San Andres Limestone with water at a salinity of about 7,000 parts per million (under 1,000 is considered fresh; under 3,000 is considered usable for cattle and certain crops; seawater is about 35,000). Unsurprisingly, given the salinity of the water, the farms don’t appear to have lasted long (what do you grow with 7,000 ppm water? pre-salted peanuts?), and they were abandoned along with the wells.

The extraterritorial jurisdiction of Imperial, Texas, outlined in red with Lake Imperial to the west (presently dry) and Lake Boehmer marked by the green waterbody to the southwest of Imperial.

About 20 years ago, something strange began to happen: the wells started flowing. But the water in some wasn’t solely from the San Andres: this water had a salinity approaching 100,000 parts per million, almost three times that of the ocean. And this water was spewing uncontrolled upon the landscape. One well has even created a lake, named Lake Boehmer on Google Maps, that has flooded out the wellsite, some of the irrigation works, and a gravel road that ran through the area.

I recently stopped in to visit Lake Boehmer for the first time, a place that is both gorgeous and terrifying–gorgeous due to the unexpected joy of a large body of water the color of the Caribbean and terrifying because flowing water is dissolving something in the subsurface and all that salt is leaking into shallower groundwater. According to images available on Google Earth Pro, the well started flowing and accumulating water sometime between 1996 and 2003 and the resulting lake has been growing ever since. The image from 2005 suggest water overflowed to the northeast but, despite the lake being larger, has ceased to flow overland in that direction, suggesting land subsidence. The lake’s longest dimension is now about 1,500 feet.

January 1996
January 2003
October 2005
September 2008
January 2011
April 2013
December 2015
December 2019

The Texas Water Development Board’s Groundwater Data Viewer doesn’t have this well in its database, but it does include one (that is also flowing) a short distance to the north. Surveyed for the database in 1957, that well was drilled by the Western Cotton Oil Company to depth of 2,600 feet into the San Andres Limestone and flowed at 900 gallons per minute. A sample collected in 1995 resulted in a salinity of 7,090 parts per million with 2,126 parts per million of chloride. A chemical analysis done in 1999 resulted in a salinity of 7,170 parts per million including 2,260 parts per million of chloride. Sampling notes show that this well was still used for irrigation in 1999 and that the owner shut the well in (turned the flow off) when not in use. More recently, it appears the plug has failed and the well is free-flowing onto the landscape. Another well, about 2,000 feet to the northeast, is also freeflowing. The U.S. Geological Survey sampled this well in 2015 resulting in a salinity of 7,350 parts per million.

the Western Cotton Well

There’s no historical water-quality data for the Lake Boehmer well, but the U.S. Geological Survey rowed a boat out to it in 2015 to sample its flow. They came back with a salinity of 94,700 parts per million with an astounding 53,600 parts per million of chloride. A local hydrogeologist shared with me that the salinity is increasing and that recent electrical conductivity testing suggest a salinity approach 125,000 parts per million. So something is clearly going on at this well that the others aren’t experiencing. One thought is that the well casing, generally steel, has corroded, allowing flow from the San Andres into and then out of the halite-filled Salado Formation. That would explain the radically elevated salinity as well as the apparent subsidence at the site.

As I approached the lake, I passed abandoned farm buildings and empty concrete canals. And then came the smell of the devil: sulfur, which fumed stronger as the lake grew near. The water takes a breath-taking aquamarine color, while waves create contorted sculptures of salt crystals along the shore. I was able to walk most of the old irrigation ditch to the well and get close enough to hear it gurgling (and take the photo at the top of this post).

The lake overlies the Pecos Valley Aquifer, a major aquifer of Texas with the water table about 40 to 50 feet below land surface and the bottom of the aquifer at 180 feet deep. Water quality in the Pecos Valley Aquifer in the area is about 11,000 parts per million, which explains, in part, the preference for the brackish, but fresher, San Andres. Leon Creek runs about 1 mile to the east of the lake, although only ephemerally. The Pecos River is about four to six miles to the north and northeast, respectively, and the last thing it needs is more salinity. My back-of-the-envelope calculation (i = 0.004, K = 10 ft/day, n = 0.15) suggests that groundwater is moving, on average, about 100 feet per year (some of it, due to dispersion, is moving faster). That means it might take 50 years to move a mile and 200 to 300 years to reach (and begin discharging to) the Pecos River. Slightly different assumptions on aquifer properties could halve or third my travel time estimate. The impacts to the river will probably not be immediate, but it’s not a good legacy to leave to future generations.

the abandoned farm at Lake Boehmer
a canal to nowhere…
water as far as the eye can see
the well gurgling at a canal head
salt crystals lining the shore

Ideally, the Lake Boehmer well should have been plugged before it got to this point (I can only imagine the cost of plugging it now; there’s still time for other two wells I mentioned). But about a mile southwest of Lake Boehmer there’s a cautionary tale of what happens when a well plugging goes wrong. This well, referred to as the Holladay Well, registered a salinity of 16,581 parts per million in 1999, suggesting that its casing was starting to fail. Starting in 2004, the land around the well began to sink, formed a water-filled depression that began impacting FM 1053. TxDOT stepped forward to plug the well in 2008 but, while the well ceased flowing at land’s surface, it appears the artesian flow is now fully directed into the Salado Formation, quickening its dissolution. This has resulted in a 1,500-foot wide depression sinking at jaw- (and road-) dropping 0.75 inches a month. At this point, it would be nearly impossible to re-enter the well and fix the plug. Like the best bull at the county fair, we’ll just have to get on and ride this one to where-ever it takes us.

The depression at the Holladay Well. Note the circular faulting, about 1,500 feet in diameter.
The road dip at the Holladay Well (this used to be flat).
The bottom of the Holladay depression.
evidence of faulting in the berm (note the gap).

The use of salty groundwater in the Imperial area is not all disastrous. Just southeast of town along FM 11 is one of Qualitas Health‘s micro-algae farms where they produce water from the Pecos Valley Alluvium with a salinity of about 9,300 parts per million to grow algae. This algae is harvested and then sent to Mexico for processing for pharmaceuticals. The site used to be a shrimp farm before it was converted to algae.

an algae farm southeast of Imperial

A few more miles to the southeast is a relatively new shrimp farm, Crystal Waters Seafood, that also appears to source its water from the Pecos Valley Alluvium. As I drove by, I could see folks with fishing rods and reels as well as a bass boat out on the water. I brought my Yeti and ice because a hydrogeologist cannot resist groundwater shrimp! So I pulled in and called the number. After a few calls, I got an answer and was asked how many pounds of shrimp I wanted. Between calls, I checked out their web page and saw that they also had redfish. When I said I wanted one of those, she asked “How big a one do you want and much time do you have?” which I found perplexing. “What do you mean?” I asked. And she replied “Well, we have to go out on the boat and catch it for you, and it’s hard to predict how long that will take.”

That. Was. Awesome.

Hypersaline flows, sinkholes, and groundwater algae and shrimp, all within a few miles of Imperial, Texas.

Gates along Imperial Canal Number Five.
yessir: that’s a bass boat
FRESH SHRIMP
water well for the shrimp farm
delicioso!

sources:
Handbook of Texas Online
The Texas Tribune
Texas Water Development Board report

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