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University of Guam faculty and graduate students study a sinkhole and karst terrain at Tarague Well 4 at Andersen Air Force Base Oct. 8. Navy environmental specialists escorted John Jensen, University of Guam chief hydrogeologist and professor of environmental geology, and Water & Environmental Research Institute Western Pacific director, and his graduate students to the area to study the unique karst at the Air Force Base.

Photo by JoAnna Delfin

UOG Students Study Karst Hydrogeology Features with DoD Environmental Specialists

15 Nov 2021 | Stanley James Marine Corps Base Camp Blaz

Students and faculty from the University of Guam and Water & Environmental Research Institute of the Western Pacific studied karst terrain features on Andersen Air Force Base, Oct. 8. Naval Facilities Engineering Systems Command Marianas environmental specialists assigned to Marine Corps Base Camp Blaz escorted and introduced the group to the two major categories of naturally-formed closed depressions of karst terrain during the tour, solution dolines and cenotes, both of which are sinkholes.

Karst refers to the study of subterranean channels formed through the dissolution of rock. Karst hydrogeology expands upon the field of study to include the groundwater that flows within karst systems.

“These two sinkholes are world-class, textbook-quality features for teaching and studying karst hydrogeology.” John W. Jenson, UOG chief hydrogeologist and professor of environmental geology, WERI

The solution doline at North Ramp is a natural karst drainage feature, capable of handling up to eight inches of stormwater per hour from intense rainfall and tropical cyclones. Solution dolines are created from the top-down dissolution of soluble limestone surface by ponded water, which results in the gentle gradation of terrain with no obvious signs of disturbance on the surface.

Tarague Well 4 is a textbook example of a cenote, a type of sinkhole formed by the collapse of limestone bedrock that exposes groundwater. Cenotes were often used by ancient societies, like the Mayans, as a freshwater source or for ceremonies and rituals.

Jenson described the experience as, “a world-class example of best-practice collaboration in doing and using applied science to solve local practical problems. Incorporating our collaboration into our graduate instruction program is a hugely valuable investment in our local professional workforce.” 

“This trip demonstrated the outstanding working relationship we have between WERI/UOG and our Department of Defense environmental department,” said Brian Antolin, NAVFAC Marianas environmental compliance specialist lead, MCB Camp Blaz. “Camp Blaz Environmental is thankful for Dr. Jensen’s generosity with time on sharing his wealth of knowledge on hydrogeology which is applicable to our ongoing military buildup construction.”

Sink hole Photo by JoAnna Delfin

MCB Camp Blaz conducts environmental assessments before all construction efforts during the buildup process. Jensen’s expertise has improved mitigation efforts by helping Military Construction contractors identify sinkholes and recharge features at project sites. Recommendations and findings from Jensen’s assessments were routed through the Guam Environmental Protection Agency for sinkhole encroachment approval before any earth-moving activity.

Within the past year, MCB Camp Blaz has shared innovative techniques for the removal of invasive species, researched and developed new outplanting and seed propagation techniques for native plants, collaborated with Marianas conservationists, and won the 2021 Secretary of the Navy Environmental Award for Cultural Resources Management Individual or Team.

MCB Camp Blaz works with our partners, by exchanging information and implementing deliberate, cooperative measures to ensure a responsible military buildup process. Additional information and resources can be found on the MCB Camp Blaz website. For the latest news and updates, visit