Dinosaurs + Volcanoes = Geology
B.J. Bonin is a Project Engineer and Geologist who designs municipal water supply wells and assists in designing well houses, lift stations, and treatment plants. He also assists WSB with geological challenges that arise.
As a child, B.J. always liked dinosaurs. But, May 18, 1980 sealed his fate; Mt. St. Helens erupted. Even as an 11-year-old, he knew he wanted to understand volcanoes and the geology involved. Geology is the study of the Earth planetary system, not just rocks. It includes physics, chemistry, material science, hydrology, meteorology, astronomy, biology, economics, and history. B.J. married a fellow a fellow? geologist and, needless to say, they spend their vacations visiting volcanoes.
Having both geology and engineering skill sets allows WSB to use B.J.’s geology skills on an as-needed basis, with the rest of his time spent completing engineering work. This gives WSB the flexibility to apply expertise to a geological problem as it is required without the expense or delay of retaining a consultant. Having both skill sets also permits B.J. to translate engineering to geologists and vice- versa. Including a geologist on the project at the earliest stages can identify potential problems that can be dealt with in the design stage, avoiding potentially costly redesigns and cardinal changes. B.J. recently discovered potential challenge while working on a project for the City of North Branch.
North Branch was having trouble finding water. Part of the problem was that the bedrock was unstable and prone to collapse. To complicate the problem, very little research has been completed on the bedrock geology around North Branch, including both Isanti and Chisago Counties. There have been some state-scale magnetic and gravity surveys, and one seismic study. All surveys and studies identified a fault system around the Chisago-Isanti County line that displaces very old rocks that can be traced north through Pine County, continuing through Wisconsin and up through Lake Superior, but provided little detail. Younger bedrock was thought to have been deposited long after the last movement of the faults and therefore unaffected by the faults. While the investigations are still on-going, I did find a number of interesting things about the bedrock around North Branch. First, I hypothesized that the main fault left a trace on the surface, a depression filled by lakes and creeks, which allows its location to be pinpointed. Second, I hypothesized that the younger bedrock, including the aquifer used by North Branch, was displaced by the fault and contributed to the collapse problems. If this were true, the aquifer on the west side would be less prone to catastrophic collapse and would probably provide a greater volume of water per well. To investigate this, North Branch authorized a test well just east of the County line and west of where I thought the fault was. Drilled this winter, this well had an entirely different sequence of bedrock than at all of the other wells drilled by North Branch, proving: 1) the fault was indeed marked on the surface by a depression, and 2) that the fault displaced bedrock much younger than the prevailing information suggested, and likely contributed to collapse issues. In addition, the test well provided enough information that the displacement of the younger rocks can be measured. Further, the well discovered bedrock not identified previously in this part of Minnesota. Test pumping has yet to be done, so it remains to be seen whether the aquifer west of the fault will yield more water that it does east of the fault. If it does, (I expect it to for a wide variety of reasons) this will save North Branch money by allowing them to build one well west of the fault that produces the same as two (conservatively) east of the fault with a much reduced risk of collapse (there is always some risk). Publication of the results is still pending and will likely be through the Minnesota Geological Society.
North Branch has had problems finding enough drinking water, and has a history of well collapses. To complicate things, no detailed research about the geology of North Branch had been conducted to explain the water supply and collapse issues. By compiling and analyzing geological data from a variety of sources, BJ was able to locate a geologic structure that has major significance to North Branch’s well problems. Furthermore, he hypothesized that this structure had features that were not thought to exist in this part of the state. Based on this new idea, BJ organized what had been a “pin- cushion” approach to water exploration in North Branch to areas that seemed more stable. Drilling confirmed his hypothesis and found areas where North Branch could install wells that were less prone to collapse and have the potential to yield higher volumes of water. BJ plans to publish his findings, which should shed new light on the bedrock geology of Anoka, Isanti, and Chisago Counties in east- central Minnesota, through the Minnesota Geological Survey.
Including a geologist on the project at the earliest stages can identify potential problems that can be dealt with in the design stage, avoiding potentially costly redesigns and cardinal changes. Geology is the common denominator between all infrastructure projects. It plays a part in locating and designing roads, bridges, pipelines, ponds, etc. It goes far beyond soil borings and wells – it’s interpreting what is in between. [ Back ]