It’s a Bird! It’s a Plane! No, it’s SCIENCE! Aquifer Mapping Project Begins This Week

Sioux Falls, South Dakota: The City of Sioux Falls and the United States Geological Survey (USGS) are conducting a state-of-the-art groundwater survey this fall. Beginning this week, CGG Canada Services, who is under contract with the City, will begin flying a helicopter over the Big Sioux Aquifer to collect, record, and map its geophysical measurements. The study will determine groundwater, soil, and sand characteristics to help in the future planning of water access points.

Starting on October 6, 2015, and lasting for three to five days, a low-flying helicopter towing a large cylindrical sensor, typically called a “bird,” will fly north of Sioux Falls along the Big Sioux River. The bird will transmit electromagnetic waves deep into the ground. It will measure the below-surface physical properties to determine where the soil and sand are most porous and likely contain the most groundwater.

The helicopter-borne geophysical system, called RESOLVE, will collect measurements near the river and surrounding areas north of the Sioux Falls Regional Airport and continuing up to Dell Rapids. The flight will cover an area approximately five miles wide by 20 miles long, flying low to the ground and back and forth to measure the electrical properties of the earth.

Data collected during this survey will help USGS scientists map the aquifer underneath the Big Sioux River to support a larger scientific effort in understanding the groundwater resources of the area. The USGS and the City of Sioux Falls are working cooperatively to create a groundwater model to better describe the aquifer’s permeability, flow directions, and interaction with the Big Sioux River.

“The Big Sioux River, and in turn the Big Sioux Aquifer, are important water sources for the City of Sioux Falls and this region of South Dakota,” said Mark Cotter, Director of Public Works for the City of Sioux Falls. “Having a better understanding of the specific features of the aquifer will provide the City with important information for our future water planning efforts.”

CGG Canada Services Ltd. is based in Ottawa, Ontario, Canada, and its pilots are highly trained for low-level flying required for geophysical surveys. The company works with the Federal Aviation Administration to ensure flights are in accordance with federal regulations and safety standards. The helicopter will travel approximately 200 feet above the ground at speeds of almost 70 miles per hour.

“This technology allows us to efficiently look into the subsurface of the Big Sioux Aquifer without drilling wells,” said Mark Anderson, the director of the USGS South Dakota Water Science Center. “This information will allow us to map and model the aquifer system and help Sioux Falls manage these critical water supplies far into the future.”

The City of Sioux Falls and USGS will host an open house this evening to provide more information to property owners in the flight path. The open house will take place Monday, October 5, from 5:30 to 6:30 p.m. at the Water Purification Plant, 2000 North Minnesota Avenue. Parking will be provided on the west side of the building. If an ADA accommodation is needed, please contact the Human Relations Office at 605-367-8745 or humanrelations@siouxfalls.org.

For more information and other examples of similar USGS studies, go to pubs.usgs.gov/of/2011/1240/.

Fun Facts

• The City has harvested water from the Big Sioux Aquifer since 1911.
• The City currently pumps water from 55 wells.
• In 2014, approximately 6.8 billion gallons of aquifer water were treated at the Water Purification Plant.
• 99 percent of the total water treated at the plant has been pumped from the aquifer over the past two years.
• The cost to conduct the aerial survey is about $192,000, paid by the City of Sioux Falls.