LATE EIGHTEENTH CENTURY HYDROGEOLOGY: A PRE-DARCY PERSPECTIVE

In England, less than a decade before Henry Darcy’s birth in France, Joseph Elkington, a farmer, had developed a national reputation for expertise in land drainage. This expertise was distinctive for its time, in that Elkington had, through field experience and observation of hydrogeologic conditions, developed a remarkably good understanding of the hydrologic cycle at the hillslope scale and fundamental concepts such as the sources of artesian water and the origin of springs. In doing so, he relied upon outcrops to reveal stratigraphy and geologic structure along with the relative degree of permeability of the formations, all this 50 years before pioneering geologic work by William Smith. Elkington carefully investigated the hydrogeology of each property to select the appropriate type of drainage system, including the precise location of drains and pressure relief wells. Through relatively simple methods, the value of vast areas of formerly swampy land was greatly increased for grazing and agriculture purposes. Moreover, Elkington’s projects put the drained water to beneficial use for domestic water supply, irrigation, and milling. When he fell into poor health, the King of England commissioned John Johnstone, a surveyor, to visit Elkington and chronicle his knowledge. The 1797 publication includes detailed cross-sections and plan view perspectives of hydrogeologic conditions and Elkington’s drainage solutions, as well as diagrams of drilling equipment, such as the horizontal auger. The paper will review this work, in order to gain a better understanding of the state of practical hydrogeology at the time of Darcy’s birth.