Their Chevrolet Malibu comes to a stop in yet another farm yard and a golden Labrador suddenly emerges.
Bruce Bloomgren cautiously cracks open the car door.
"Let's see if this dog is friendly,'' he said as the dog shoves its snout into the car and onto his lap in answer to the question.
Farm-by-farm and dog-after-dog, Bloomgren and Tyler Reiner are on a quest. Armed with a hand-held Global Positioning System, a clipboard stacked with records and a box full of maps, they aim to record the exact coordinates of more than 850 water wells scattered throughout Renville County by year's end.
There is a well driller's record for every one. Knowing their exact locations will allow Bloomgren to pinpoint their locations on topographic maps of the county, and begin a three- year process of developing maps showing what lies underneath the county's rich farm lands.
Bloomgren, a geologist with the Minnesota Geological Survey, will interpret the logs to create the subterranean maps of Renville County. To the lay person, the logs might as well be military code: A string of words like "silt,'' "clay,'' "sand,'' followed by numbers signifying the depth the material was found.
One log on its own tells little. Start putting the data from many together and a picture emerges, just like assembling a puzzle, said Bloomgren.
The maps will someday offer a good view of where aquifers in the county can best be found, and more.
Hydrologists with the Minnesota Department of Natural Resources will conduct their own field work and drill separate wells in Renville County. They will analyze the chemistry and even determine the age of the water in certain aquifers. Their work will provide information on the recharge rate of the aquifers and how sensitive they are to contamination, said Dale Setterholm, director of the Geological Atlas program.
The information can help tell us where there is sufficient groundwater to meet the needs of the county's livestock industry or for residential and industrial development, and where there isn't.
"If you are going to protect and make wise use of your aquifers, you need to know where they are,'' said Setterholm.
Right now, we know very little.
Ask Steve Peterson, a hog producer north of Olivia. During Bloomgren's stop at his farm, Peterson told him about how anxious he was when well drillers came up with dry holes -- and lots of clay -- before finding the water he needed.
It was no surprise to Bloomgren, who has records showing attempts to find water as deep as 600- and nearly 1,000-feet deep in the county.
The glaciers that pushed all the till to create today's landscape carried lots of clay from the Dakotas.
The glaciers also delivered the sand and gravel deposits that we seek. Setterholm said we know little about the recharge rates of these aquifers located amidst so much impermeable clay.
Nor do we know much about how groundwater and surface water in the region interacts. Groundwater recharge is critical to the flow in waterways such as the Minnesota River, he noted.
Minnesota's Geological Atlas project got its start 30 years ago in Scott County. Officials there found the information so valuable that a couple of years ago they paid the entire costs to have it updated with information from hundreds of new well records.
Statewide, atlas projects have now been completed in 20 counties. Work is under way in 10 others right now, according to Setterholm.
It can cost upwards of $600,000 to $700,000 to complete an atlas project in any given county. The state picks up most of the tab. Renville County is meeting its obligation by hiring Reiner to take on the time-consuming and difficult task of poring through county and well driller records dating to the 1970s. He maps out the approximate locations for the wells, and then he and Bloomgren take to the field with the GPS unit.
It can be challenging, and not just because some farm dogs aren't friendly. Most of the maps pre-date the 911 address system; some logs can be off the mark by miles; and the hand-written notations on where to find a well on any given property can be very confusing or just plain wrong.
Bloomgren and co-workers used to do it all. He said they spent many evenings in motel rooms on the phone, trying to reach landowners to help them locate wells. It's great to have "boots on the ground,'' he said of the help from Reiner and county staff familiar with the turf.
In Renville County, and elsewhere as well, Setterholm said most people have been very accommodating of his requests to find their wells. The weather hasn't always been that way, but he's seen worse: One winter in Roseau County, he carried skis, snowshoes and a sleeping bag in case he got snowed-in.
Instead, he had a hard time getting out of the residents' homes. He had arrived just after county roads were re-opened after a three-day snow storm. Everyone wanted to visit and there were no limits to the coffee and baked treats they used as inducements to keep him put.
Much of their work in Renville County is taking place during the harvest, and Bloomgren and Reiner are finding few people with time to visit.
But they are meeting lots of dogs, friendly and otherwise. "The small ones are the worst, definitely,'' said Bloomgren as he bounded out of the car at yet another farm, this time under the watchful eye of an ankle-high Schnauzer.