Which material was the most permeable (Gravel, sand, potting soil or mixture sand and gravel)? Which was the least permeable? Which sediment type would be good for aquifers? Are paved parking areas permeable? Porous? How can you tell by sight? Henry Philibert Gaspard Darcy, born in 1803, was assigned to find a water supply for a town in France. Drilling a well didn’t produce enough water, so he used a series of gravity-driven pipes from surface water for water supply. His ongoing research on the rate of flow of groundwater produced this formula:

V = K(G)

V = groundwater velocity;

K = hydraulic conductivity describes how easily groundwater flows through a certain rock or soil;

G = hydraulic gradient, the slope of the water table

• What would Darcy’s Law predict would happen to the rate of flow of groundwater as the hydraulic gradient, (i.e. the slope of the water table) increased?