Leckpfade

Leckpfade, literally "leak paths," is a term used primarily in geotechnical engineering, hydrogeology, and environmental engineering to describe preferential pathways through which liquids or gases can migrate through a barrier, liner, or geological formation. These paths may form along microcracks, pore compaction zones, fractures, seams in geomembranes, or in heterogeneous materials where hydraulic conductivity is locally much higher than the surrounding matrix.

Causes include material defects, degradation under chemical attack, thermal cycling, settlement-induced cracking, shear damage, or long-term aging of barriers such as clay liners, concrete structures, or geosynthetic layers. Leckpfade can enable rapid transport of contaminants or process fluids even when the bulk barrier is ostensibly tight.

Assessment involves hydrogeological measurements, tracer tests, borehole logging, electrical resistivity tomography, and monitoring of seepage. Modelling often uses dual-porosity or dual-permeability approaches to represent both matrix flow and fracture flow.

Mitigation strategies emphasize redundancy and integrity of barriers: multiple barriers in series, quality control during construction, robust seam and weld design for geomembranes, grouting or consolidation of fractures, proper backfill compaction, and ongoing monitoring.

Applications include landfills, waste repositories, dams, tunnels, and groundwater remediation systems. The concept is also used in risk assessment to estimate the potential connection between an engineered barrier and the environment via these leak paths. See also leakage, seepage, and preferential flow.