Tuesday, July 18, 2006

The Groundwater Development Process Emery & Garrett Groundwater, Inc.

From Heart of NH Archives
July 2006

The Groundwater Development Process

To call the process that Emery & Garrett Groundwater, Inc. uses High Tech Dowsing is a bit of a tongue in cheek play on words because EGGI’s groundwater search is strictly science, but in point of fact - in many ways it is just as mysterious. After all, most of the work occurs above the ground and the aim is to figure out what is happening below the ground . . . sometimes deep below the ground. “ Even though we have employed hard science to find the water, I can tell you that when we hit water and it gushes out of the ground, there is a whole lot of whooping and excitement.“ says Emery. “You would think we just hit a high yielding oil well.”

The process of finding sufficient groundwater is bound up in a multi-stepped process, that gradually narrows down large study areas to site specific drilling targets. “At any point during that process” says Ken Hardcastle, who has a PhD in Structural Geology from the University of Massachusetts, “we can review the prospects with the client so that they have the choice of whether to move forward. This instills a lot of confidence in the exploration process, because they are always in control.”

The initial phase of a study includes aerial reconnaissance using satellite imagery and aerial photography, geologic mapping, and fracture fabric analysis. A team of scientists from EGGI including hydrologists, geologists, geophysicists and structural geologists then review the hydro-geologic information and narrows the search area to a set of sub-regions that would be most conducive to the development/utilization of underground water resources.

The identified sub-regions are then subjected to on-the-ground geophysical surveys including seismic, electrical resistivity, and/or electromagnetic studies to pinpoint discontinuities in the bedrock or the thickest areas of sand and gravel overlying the bedrock. In addition to these tests EGGI is at the cutting edge of the science having recently purchased the most advanced electrical resistivity equipment out of Sweden. It is the first and only one of its kind to be used in the US. It is at the end of this stage that the team places a series of stakes in the ground indicating the exact location for drilling exploratory test wells.

Additional stages of investigation include the drilling of exploratory wells, installation of production wells, and hydro-geologic testing to assess the overall sustainable yield capacity and water quality of the developed groundwater supply. Evaluating the sustainable yield of a well (or well field) is accomplished by conducting a series of long term groundwater withdrawal tests to determine the “safe” amount of groundwater that can be withdrawn from an aquifer system.

The result of these investigations is the identification and permitting of groundwater supply wells that will provide adequate water to meet clients’ needs while at the same time not adversely affecting neighboring properties and other nearby groundwater users.

“Your reputation is often only as good as your last well,” says Emery. “As a groundwater exploration company, if you conduct groundwater investigations and are unsuccessful, people will hear about it. The word of unsatisfied clients travels fast.” For EGGI, their clients have been very satisfied and remain very loyal … many of them have continued to rehire EGGI for additional services since the early 1990’s.

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