A contractor on a deep excavation near the Ohio River hit groundwater at 18 feet, right where the geotechnical report predicted a silty sand lens. The dewatering system needed a precise hydraulic conductivity value to size the pumps. We mobilized within 48 hours to run a series of Lefranc tests at multiple depths. In Louisville's alluvial terraces, guessing permeability from grain size alone is a gamble. The USACE Louisville District oversees major flood protection works here, and they require field-measured k-values for cutoff wall design. Our team uses the Lugeon method in rock—critical for the limestone and shale contact zones common beneath the city's eastern suburbs. We correlate field data with grain size analysis for a complete hydrogeologic model.
A single Lugeon test in fractured limestone can reveal more about foundation seepage risk than a dozen lab permeameter samples.
Our approach and scope
Local geotechnical context
Louisville's humid subtropical climate delivers 45 inches of annual rainfall, with spring storms saturating the ground and raising perched water tables in colluvial deposits. Contractors who skip field permeability testing before dewatering design end up with undersized systems, flooded excavations, and costly delays. The contact between glacial till and weathered shale acts as a seepage barrier, trapping water and creating unstable conditions on slopes along the Gene Snyder Freeway corridor. In karst terrain, a Lugeon value above 25 Lu signals open conduits that can collapse during pile installation. We saw this on a hospital expansion where grouting was needed after high Lugeon readings. Our field data feeds directly into SEEP/W and MODFLOW models the design team runs.
Applicable standards
ASTM D6391-11 (Field Measurement of Hydraulic Conductivity in Boreholes), USACE EM 1110-2-1901 (Seepage Analysis and Control for Dams), IBC 2021 Section 1803 (Geotechnical Investigations), ASTM D5092/D5092M-16 (Monitoring Wells in Aquifers)
Complementary services
Lefranc Testing in Soils
Variable head tests in boreholes for alluvial, residual, and fill soils. We record falling and rising head responses with digital transducers for k-values down to 10⁻⁷ cm/s.
Lugeon Testing in Rock
Five-stage pressure tests in fractured limestone, shale, and sandstone. Each stage evaluates laminar flow, dilation, and washout behavior, reported in Lugeon units.
Packer Testing for Deep Intervals
Single and double pneumatic packer setups for isolating discrete zones in core holes. Prevents short-circuiting and delivers interval-specific permeability data for dam grouting programs.
Dewatering & Seepage Analysis Support
We provide k-value arrays and pressure-flow plots formatted for direct input into SEEP/W, MODFLOW, or PLAXIS models your engineer uses.
Typical parameters
Common questions
What's the difference between a Lefranc test and a Lugeon test?
The Lefranc test measures hydraulic conductivity in soils using variable head (falling or rising) in a borehole. The Lugeon test is specifically for rock mass; it applies constant pressure in five stages to evaluate fracture flow behavior. Lefranc reports k in cm/s; Lugeon reports in Lugeon units (Lu).
How long does a field permeability test take on site?
A single Lefranc test at one depth interval typically requires 30 to 60 minutes to reach steady-state conditions. A full five-stage Lugeon test in rock takes approximately 90 minutes to two hours per interval. We usually test three to five intervals per boring in a single day.
What does a Lefranc or Lugeon test cost in Louisville?
Field permeability testing in the Louisville area ranges from US$570 to US$900 per test interval, depending on depth, access conditions, and whether we need to set pneumatic packers. A typical program with three intervals in one boring falls in the US$1,700–US$2,700 range.
Do I need a field test or can I use lab permeability from grain size?
Lab tests on disturbed samples miss fractures, macropores, and in-situ density effects. For dewatering design, slope stability, or dam seepage analysis, the USACE and IBC require field-measured k-values. We use lab grain size data as a complement, not a substitute.
How many test intervals do I need for my Louisville site?
It depends on stratigraphy. In the Ohio River alluvium with interbedded sands and silts, we recommend a minimum of three intervals per boring to capture vertical variability. For rock sockets in limestone, one Lugeon test at bearing depth plus another in any fractured zone usually suffices.