Lake Capote Dam has defied traditional engineering principles, leaking water for over 80 years despite extensive modifications. The earth-fill dam is a small, spring-fed, off-stream, man-made lake located in the northeastern San Juan Basin of the Southern Rocky Mountains in Colorado.
In 2023, Dr. Mohamed Khalil, a geoscientist at the University of Nebraska-Lincoln, and colleagues tackled the problem. He has pioneered innovative, non-invasive geophysical survey methods that identify seepage and settlement in hydraulic structures far more accurately and efficiently than traditional approaches. The team used Electrical Resistivity Tomography (ERT), Induced Polarization (IP), and Spontaneous Potential (SP) surveys to study the seepage conditions of Lake Capote’s dam.
The initial engineering teams were relying on one-dimensional geotechnical borehole data in a complex 3-dimensional world. Khalil and his colleagues found a hidden, faulted, and fractured sandstone bed acting as a pressurized, cracked pipe and proved that other parts of the dam show evidence for high seepage pathways through the dam embankment.
The researchers noted that no detailed geologic map was available for this specific area of Lake Capote. None showed underground faults. Until this study was published, the cracks were completely invisible to the historical record. In fact, Lake Capote Dam had a geological fault, quietly waiting for water to find its way into the fragmented sediments.
Khalil wrote a paper on the work they did at Lake Capote Dam, titled “Differentiation of Structurally Controlled Seepage in a Dam and Dike Complex by Integrated Geophysical Surveys,” which identified and analyzed previously undiscovered geologic features that affect the lake’s seepage conditions. He submitted it to “Environmental & Engineering Geoscience,” the official journal of the Association of Environmental & Engineering Geologists.
The paper was awarded the 2026 Best Paper Award during the 69th Annual Meeting of the Association of Environmental & Engineering Geologists held Sept. 13-19 in Chattanooga, Tennessee.
The paper’s findings, Khalil wrote, “demonstrate the value added to forensic investigations of dams by the integration of different geophysical methods, and they also portend the crucial importance and cost-saving potential of pre-construction geological and geophysical site characterization of dam sites.”
Khalil is an assistant geoscientist with UNL’s Conservation and Survey Division and the Panhandle Research, Extension, and Education Center.
