The variable overburden and karstified limestone beneath the Niagara Escarpment often create a disconnect between lab permeability values and actual mass hydraulic conductivity, something we see repeatedly when reviewing borehole logs from projects near the gorge. A CPT test can map the stratigraphy but tells you nothing about fracture flow, which is why a field permeability test like the Lefranc or Lugeon becomes the only reliable way to size dewatering systems or predict inflows before excavation. We run these tests in soil and rock under the conditions that actually exist—saturated, confined, or with artesian influence—because an underestimation here can flood a foundation pit in under an hour.
A single Lugeon value can redefine your grouting program—what looks like tight rock at NX core scale may swallow cement at 40 L/min under test pressure.
Methodology and scope
Local considerations
NBCC 2015 and CSA A23.3 embed seismic provisions that matter for Niagara Falls Ontario—not because of high seismicity, but because the amplification of ground motion through soft clay over hard dolostone can double the spectral acceleration at the surface compared to bedrock. When a field permeability test is omitted or executed with poor packer seating, the missed high-k zone becomes the preferential flow path during a flood event, eroding fines from the till contact and triggering differential settlement under footings. We have seen open-graded drainage layers blinded by fines migration because the designer used a textbook k value instead of the anisotropic permeability measured in-situ, and that mistake cost the owner a complete subdrain rebuild within two years of occupancy.
Applicable standards
ASTM D4630-19 (Rock Mass Permeability by Lugeon), ASTM D4631-18 (Lefranc Test in Soil), MTO Laboratory Testing Manual (LS-700 series), CSA A23.3-14 (Concrete Structures, groundwater effects)
Associated technical services
Lugeon Packer Test in Rock
Conducted in NQ or HQ boreholes in the Lockport Dolostone and underlying formations. We use a five-stage pressure cycle (low-high-low-medium-high) to derive the P-Q curve, classify flow regime, and calculate the equivalent Lugeon value. This data feeds directly into grouting design, curtain wall specifications, and tunnel inflow predictions for infrastructure near the Niagara River.
Lefranc Test in Overburden Soils
Variable-head or constant-head configuration in glacial till, clay, and granular deposits above the bedrock surface. The test cavity is developed with a slotted casing and sand pack to prevent smearing, and we record recovery rate until the water level stabilizes within 5% of equilibrium. Results are reported as the coefficient of permeability (k in cm/s) with correction for well efficiency where applicable.
Typical parameters
Frequently asked questions
When do you specify a Lugeon test instead of a Lefranc test in Niagara Falls?
The choice depends on the target formation. A Lefranc test is appropriate in soil—glacial till, clay, or granular overburden—typically above the bedrock contact, which in downtown Niagara Falls Ontario sits anywhere from 5 to 25 metres below grade. Once you are into competent Lockport Dolostone or the underlying Rochester Shale, the Lugeon test becomes the correct method because you are measuring fracture flow, not intergranular permeability. The two tests answer fundamentally different questions: Lefranc tells you how fast water moves through soil pores; Lugeon tells you how much grout a fractured rock interval will accept.
What do Lefranc and Lugeon testing cost for a typical project in the Niagara Region?
For a standard investigation with two to three test intervals, field permeability testing in the Niagara Falls area generally runs between CA$830 and CA$1,310 per test interval, which includes packer setup, the five-stage pressure cycle for Lugeon or the variable-head recovery sequence for Lefranc, and the full interpreted report with P-Q curves and transmissivity calculations. Mobilization is priced separately and depends on drill rig availability and site access constraints.
How long does a field permeability test take to run?
A single Lugeon test interval usually requires about 60 to 90 minutes from packer inflation to final pressure step, provided the zone is not taking excessive flow that requires extended pumping to reach steady-state. A Lefranc test in fine-grained soils can take longer—up to 3 hours per interval—because the recovery rate in silty clay is slow and you need the water level to approach equilibrium before you can close the test. We log data continuously so the curve shape tells us when the measurement is valid.