What term describes groundwater movement through pores at different rates and varying path lengths?

What term describes groundwater movement through pores at different rates and varying path lengths?

• A. Advection
• B. Diffusion
• C. Dispersion
• D. Capillarity

Answer: (C)

Dispersion describes how groundwater transports and spreads a solute as it moves through a porous medium. Because pore spaces vary in size and connectivity, water doesn’t all travel at the same speed or along the same path. Some channels are faster and shorter, others slower and longer, causing parts of the plume to advance sooner and others to lag. This velocity variation and path-length diversity broaden the plume beyond what would occur from bulk flow alone. The spreading from these differences is called dispersion, with mechanical dispersion from flow heterogeneity and molecular diffusion contributing to the mixing. Advection is the overall bulk movement with average velocity, diffusion is molecular mixing without bulk transport, and capillarity relates to capillary rise in small pores.

Dispersion describes how groundwater transports and spreads a solute as it moves through a porous medium. Because pore spaces vary in size and connectivity, water doesn’t all travel at the same speed or along the same path. Some channels are faster and shorter, others slower and longer, causing parts of the plume to advance sooner and others to lag. This velocity variation and path-length diversity broaden the plume beyond what would occur from bulk flow alone. The spreading from these differences is called dispersion, with mechanical dispersion from flow heterogeneity and molecular diffusion contributing to the mixing. Advection is the overall bulk movement with average velocity, diffusion is molecular mixing without bulk transport, and capillarity relates to capillary rise in small pores.