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Cleanup of Lingering Rider Well Contamination in East Longmont to Start Next Week

August 11, 2018

Early next week workers will start removing soil near the former site of a Rider Well storage tank in east Longmont that the city last year discovered was contaminated by hydrocarbons.

After the city hired Terracon to investigate 18 well sites in Longmont — one active and 17 that have been plugged and abandoned — the contractor in September and October also found groundwater near the location of the now-removed storage tank had been polluted beyond state regulatory thresholds.

The city in a news release stated TOP Operating, owner of the long-troubled Rider Well near the intersection of County Line and St. Vrain roads, will excavate the tainted soil and haul it to a licensed disposal location.

Lingering contamination

A Terracon report on the city’s website shows the highest level of total petroleum hydrocarbons in soil samples taken between September and October was 1,490 milligrams per kilogram, nearly three times the Colorado Oil and Gas Conservation Commission’s regulatory limit of 500 milligrams per kilogram.

Total petroleum hydrocarbons encompass several hundred chemical compounds that originally come from crude oil.

Soil in an approximate 50-foot radius from the site of the former storage tank — which was between 40 and 50 yards from the formerly problematic Rider Well head — was affected, Longmont civil engineer Jason Elkins said.

Groundwater samples in the area also contained amounts of ethylbenzene, napthalene and xylenes — known as “volatile organic compounds” — as well as sulfates that exceeded Colorado Department of Public Health and Environment standards, which are more stringent than the state oil and gas commission’s limits.

Elkins said the soil contaminated the groundwater.

The tarnished soil is “pitch black,” he said, adding, “you can smell it, you can see it.”

The process of removing the soil will pose no health risk to the public, and is expected to last no longer than several weeks, Longmont Special Projects Manager Brad Schol said.

The city last year assigned Terracon to investigate the 17 plugged and abandoned oil and gas wells and their accompanying facilities, such as storage tanks, and the contractor has completed eight investigations so far, with the Rider site being the only resulting in a red flag.

Elkins said about $90,000 has been spent on the investigations, and he will require more funding to continue the program to complete surveys at the remaining 10 plugged and abandoned drilling sites in the city.

The cleanup is part of a 2012 agreement between the city and TOP to close the well. The closure was delayed by a lawsuit against the city filed by a statewide oil and gas industry group that led to the Colorado Supreme Court overturning Longmont’s voter-approved fracking ban, the city news release stated.

TOP did not respond to multiple requests for comment.

Rider Well history

Contamination at the Rider Well head — which was permanently plugged and abandoned in 2016 — was first documented more than a decade ago.

After the Rider Well was drilled in 1982, TOP Operating bought it 1986, and the construction of Trail Ridge Middle School — about 350 feet away from the site — followed.

Drilling operators commonly used to store wastewater in open pits.

Twelve years ago, housing developer Engle Homes discovered the groundwater was highly contaminated with benzene, a carcinogenic toxin.

TOP Operating was ordered by the state to clean up the site, and the state in 2015 found the area around the well head had been brought into compliance.

The contamination around the former storage tank location was likely caused by a leak from the tank, Terracon wrote in its report.

Terracon’s investigation on behalf of Longmont led the state to this year order a new cleanup, according to Colorado Oil and Gas Conservation Commission online documents.

Affordable housing plan losing steam

Last year, City Council mulled designating the Rider site — which is on city open space — as a future affordable housing development with between 200 and 330 units, but never made a formal decision on the proposal after referring the idea to a citizen advisory board.

The idea seems to have lost steam.

“I think it’s inconceivable to me that we would put any type of development over ground that had been contaminated, even after cleanup,” Ward 1 Councilman Tim Waters said.

Waters was not on the council when the idea was discussed last year, but Mayor Brian Bagley, then the Ward 1 representative, opposed developing the Rider site.

“The contamination needs to be remediated and the area inspected for safety before there can be any discussion of future development. There is a different City Council than there was last year and the landscape for this idea has changed — both literally and figuratively,” city spokesman Rigo Leal said.

The council voted 6-1 to send the idea of building affordable housing on the former drilling site to the Parks and Recreation Advisory Board for more input, but never received any.

″...The board talked around the issue and never discussed it in full. Because there were unresolved health and safety issues at the site, the board decided that any conversation about developing the land was premature,” Leal said.

Sam Lounsberry: 303-473-1322, slounsberry@prairiemountainmedia.com and twitter.com/samlounz .