Soil permeability coefficient (K) determination framework integrating direct and indirect measurement methods for hydraulic conductivity analysis. The diagram branches from the definition of permeability coefficient into two primary pathways: direct methods using constant-head and variable-head permeameters, and indirect methods via grain-size analysis and consolidation testing. Constant-head permeameters suit highly permeable soils while variable-head permeameters serve low-permeability materials like silts and clays. Understanding K is critical for groundwater flow modeling, seepage analysis, and foundation design in civil engineering projects. Fork this diagram on Diagrams.so to customize soil classifications, add site-specific parameters, or integrate with your geotechnical investigation workflows.