We keep seeing the same mistake on Grand Rapids projects. The contractor assumes a uniform permeability from a desk study, sizes the dewatering system, and then the excavation floods when they hit a sand lens in the Grand River alluvium. That assumption is expensive. Field permeability testing removes the guesswork. We run the Lefranc test in soil and the Lugeon test in rock, measuring how water actually moves through the formation you are building on. The city’s variable drift thickness—from 50 feet of outwash sand in Walker to shallow bedrock along the Thornapple River—demands site-specific values, not textbook numbers. Our lab in Grand Rapids is AASHTO-accredited and we execute these tests under IBC Chapter 18 and ASCE 7 groundwater investigation protocols. Before you commit to a dewatering strategy, pair this data with a grain-size analysis to calibrate the Hazen correlation against your field results.
One Lugeon test in fractured sandstone can reveal a 10x permeability jump that a single lab sample on intact core completely misses.
How we work
The contrast between downtown Grand Rapids and the Sparta area tells the story. Downtown, you have dense glacial till overlying the Marshall Formation sandstone. A Lugeon test in that sandstone often shows low to moderate transmissivity, but joints and bedding planes can create discrete high-flow zones that a bulk estimate misses. Out in Sparta, the outwash sands and gravels are so clean that a single Lefranc falling-head test can show k-values exceeding 1x10^-3 cm/s. That is a completely different dewatering problem. We use the constant-head Lefranc in fine-grained soils and the falling-head variant in high-permeability formations. Each test records flow rate, applied pressure, and time to equilibrium. Our crew logs the test interval against the boring log so you can correlate permeability with stratigraphy. For rock projects, the Lugeon test runs five pressure stages to detect hydraulic fracturing and turbulent flow behavior. The data package includes the Lugeon value, the P-Q curve, and recommendations on whether the rock mass is laminar, turbulent, or washout-prone.
Frequently asked questions
What is the difference between a Lefranc test and a Lugeon test?
The Lefranc test measures hydraulic conductivity in soil by injecting or extracting water from an isolated section of a borehole, using either constant-head or falling-head methods. The Lugeon test is specific to rock and uses a packer to isolate a test interval, then applies five pressure stages to generate a P-Q curve that reveals the flow regime—laminar, turbulent, dilation, or washout. We use Lefranc in Grand Rapids glacial drift and alluvium, and Lugeon in the Marshall Sandstone and Coldwater Shale bedrock.
How much does a field permeability test cost in Grand Rapids?
A single Lefranc or Lugeon test in Grand Rapids typically runs between US$540 and US$910 per test interval, depending on depth, access conditions, and whether the borehole is already available or needs to be drilled. A full permeability profiling program with multiple tests across a project site is scoped case by case based on the number of intervals and formation conditions.
When does IBC require field permeability testing?
IBC Chapter 18 requires groundwater investigation when the design involves permanent dewatering, cutoff walls, or foundations below the water table where hydrostatic pressure or seepage forces could affect stability. The code expects site-specific permeability data—not just lab correlations—when designing underdrain systems, basement waterproofing, or deep excavations. Our reports are structured to satisfy the groundwater investigation requirements in the IBC and ASCE 7 geotechnical report checklist.
How is the test interval selected in a Lugeon test?
The test interval is selected based on the core log and fracture mapping. We typically isolate 3 to 5 meters of borehole with a pneumatic packer placed above the interval. The interval should target zones of interest—fractured sections, bedding planes, or suspected high-flow horizons. In Grand Rapids’ Marshall Sandstone, we often test intervals where core recovery drops or where RQD indicates open joints, since those are the zones that control bulk permeability.
Can you run permeability tests in an existing monitoring well?
Yes, we can run a Lefranc-type falling-head test in an existing monitoring well if the well screen is in the zone of interest and the filter pack is properly developed. However, the test measures the bulk permeability of the screened interval, not a discrete depth. For design-level data in layered formations—common in Grand Rapids’ glacial stratigraphy—we recommend a new borehole with packer-isolated intervals to get depth-specific k values.
