On Dec. 5, the directors of Upper Black Squirrel Creek Ground Water Management District met for their monthly board meeting at Farmers State Bank of Calhan. The meeting, led by Upper Black Squirrel President Dave Doran, was open to the public and focused on the final report from the 2023 Airborne Electromagnetic Survey of the district.
The project mapped the subsurface and geology of most of the 270 square-mile aquifer in the 354-square-mile Black Squirrel district.
The AEM data acquisition was performed from June 9 to June 13 out of Meadow Lake Airport in Peyton.
Jared Abraham, a geophysicist from Aqua Geo Frameworks LLC (the company that conducted the study), presented the report.
Those attending the meeting had an opportunity to ask questions related to the study following the presentation.
After acknowledging all the parties that contributed to the project, which spanned from July 2022 to the final report, Abraham presented the individual aspects of the study and the various sources of data that went into creating the 3-D aquifer map. He said the company acquired 800.4 line-miles of data and used several different sources of boreholes from reports as far back as 1995, 2008 and 2016. They also used geophysical well logs. Abraham provided a quick background of the local geology.
Abraham summarized the deliverables and various file packages available to different stakeholders for their respective purposes. Doran said that all the information is publicly available and will be added to the district’s website.
“We put together, the district and others who helped us, a 3D map of the aquifer. Where it is thick, where it is thin, where it is saturated with water, and where it is unsaturated, meaning there is no water, it’s dry,” Abraham said.“That’s what we produced.” He said residents can go to Google Earth and zoom in on their address, “Click on it, and it will tell you how thick the aquifer is.”
“One of the things that we found from this study is that we have very little alluvial water left, alluvial water being the upmost water that sits in the top layer of sands and gravels and above the bedrock aquifers,” Doran said. “That’s the only one we could possibly do any management in.”
One water management technique is recharging, which is “putting water, adding water to replenish what is missing,” Doran said. Abraham added, “Through basins or injection wells.”
“You probably heard about the RIBs — rapid infiltration basins — where they are taking treated municipal water, a form of water that was recycled through a wastewater treatment plant and putting it in these RIBs — infiltration ponds,” Doran said. “That water is theoretically supposed to soak through the constructed ponds into the ground. As it infiltrates into this unsaturated alluvium, the hope is to fill that alluvium back up with more water and go down below that and pump the water up and send it back to the customer.”
He said there are more than 3,000 individual people with domestic wells that rely on the alluvial water for domestic use. And there are a number of big irrigators who farm, and Cherokee, Meridian and Woodman Hills own alluvial wells throughout the entire basin. “So we are not only protecting the domestic well owner, the agricultural user; we are trying to protect what water is left for those big metropolitan districts,” Doran said.
Abraham discussed the key takeaways from the study: “We have a much better idea about the configuration of the alluvial system now. By adding the information from the airborne to the boreholes, we know where the alluvial material exists, and it is slightly different from what was previously thought. I think we have really good confidence in the water table right now. This is a great targeting tool that does not replace good geology and hydrology. It’s to identify opportunities … . Don’t take my maps and put a million-dollar facility here. Take my maps and look at some areas where you might want to put a facility.”