San Bernardino sits on a series of Quaternary alluvial fans that slope from the San Bernardino Mountains toward the Santa Ana River. These coarse-grained deposits, mixed with older dissected terraces, create a highly variable subsurface where infiltration rates can shift abruptly across a single parcel. Conducting a field permeability test (Lefranc/Lugeon) in San Bernardino is the only way to obtain reliable hydraulic conductivity values for drainage design, detention basins, or groundwater control. The method adapts to both saturated and unsaturated conditions, which matters given the city's semi-arid climate and seasonal flash-flood events. Before committing to foundation layouts, teams often pair this test with a consolidation test to predict settlement under changing moisture regimes, or a sieve analysis to refine grain-size correlation.
A single field permeability test in San Bernardino can reveal infiltration rates that differ by over two orders of magnitude within 50 meters of alluvial fan.
Approach and scope
The contrast between dry summers and intense winter storms means that infiltration rates measured in June and February can differ by an order of magnitude. In San Bernardino, the field permeability test (Lefranc/Lugeon) replicates worst-case scenarios by maintaining constant head or falling head conditions depending on the material. For gravelly alluvium near the mountain front, the Lefranc variant works best; for fractured granitic bedrock in the foothills, the Lugeon method isolates individual joint sets. Both procedures follow ASTM D6391 for field measurement of hydraulic conductivity. The team records flow rates at three to five pressure stages, then plots the data to detect turbulent flow or joint dilation. This data feeds directly into stormwater management plans required by local municipalities and informs decisions on drainage systems for new subdivisions or roadway extensions.
Technical reference image — San Bernardino
Site-specific factors
Many of San Bernardino's older neighborhoods were built on undocumented fill and reworked alluvium from early 20th-century grading. These heterogeneous soils contain lenses of clay and cobbles that create perched water tables and preferential flow paths. A field permeability test (Lefranc/Lugeon) in San Bernardino identifies these hidden layers before slab-on-grade or basement excavation begins. Without site-specific infiltration data, designers risk undersizing retention basins — a common cause of localized flooding during the El Niño years. The alluvial fans near Kendall Drive and the 210 corridor are particularly sensitive, where a single test hole may show K values of 10⁻³ cm/s while 20 meters away the material behaves like clay at 10⁻⁵ cm/s. This spatial variability demands multiple test locations for any project exceeding 2 acres.
Constant head or falling head tests in boreholes and test pits. Ideal for granular alluvium and silty sands common in the valley floor. Results are reported as K values corrected for water temperature and borehole geometry.
02
Lugeon Packer Testing
Multi-stage pressure injection tests in bedrock using inflatable packers. Designed for fractured granite and metamorphic rock in the mountain front areas. Detects joint dilation, turbulent flow, and permeability changes with pressure.
03
Infiltration Basin Evaluation
Combined field permeability and laboratory grain-size analysis to design detention basins, bioretention cells, and permeable pavement systems. Includes site-specific recommendations for sizing and underdrain placement.
This service complements our laboratory testing work for a complete project analysis.
Relevant standards
ASTM D6391-11 (Field Measurement of Hydraulic Conductivity), ASTM D5092-04 (Design and Installation of Groundwater Monitoring Wells), ASCE/EWRI 12-13 (Standard Guidelines for Urban Stormwater Management), California Building Code (CBC) Chapter 18 – Excavation, Grading, and Foundations
Quick answers
What is the difference between the Lefranc and Lugeon permeability tests?
The Lefranc test uses constant or falling head in an open borehole or test pit and is best for saturated granular soils. The Lugeon test isolates a section of bedrock with inflatable packers and applies increasing pressure stages to measure hydraulic conductivity and detect joint behavior. The choice depends on the formation — alluvial fans favor Lefranc, while fractured bedrock requires Lugeon.
How many test locations do I need for a project in San Bernardino?
For projects under 2 acres, two to three test locations are typically sufficient to capture the alluvial fan variability. Larger subdivisions or commercial sites often require one test per acre or per distinct geologic unit. The city's grading ordinances may specify minimum spacing based on drainage area.
Can field permeability tests be performed in unsaturated soils?
The reference range for this service in San Bernardino is US$620 - US$1.180. The final price depends on the project scope and volume.
How much does a field permeability test cost in San Bernardino?
A single test location typically ranges from $620 to $1,180, depending on depth, access, and whether packers or open borehole is used. The final quote includes mobilization, drilling support, test execution, and a certified report with K values. Volume discounts apply for multiple locations on the same site.
