PARAMELLE, DARCY, AND THEIR APPROACHES TO HYDROGEOLOGY

J.B. Paramelle developed an observation-based method for finding water on karst plateaus in southwestern France in the early 19^th century. Between 1827 and 1853, he used this method to find groundwater at more than 10,000 places in 40 of France’s 86 departments.

Paramelle was more famous than Henry Darcy in 1856, when both men published their major works. In the same section of his book, The Public Fountains of the City of Dijon, where Darcy presents his law, he reviews Paramelle’s methods. Darcy admired Paramelle’s success but did not understand how he found water or estimated its volume, claiming Paramelle’s method to estimate groundwater volume lacked precision.

Paramelle wrote a book entitled The Art of Finding Springs, which was actually about finding groundwater. Paramelle criticizes artesian wells, fashionable in the mid 19^th century, because of high drilling costs and the special geologic conditions they required. Artesian wells often failed to produce water. Darcy had experienced this; early in his career in Dijon, he had worked on an artesian well project whose costs ballooned and whose water rose to 2m below the pavement, requiring a pump to access the water. Darcy chose groundwater from another source to supply the City of Dijon

Just as Darcy turned hydrogeology into a quantitative science, Paramelle bridged the gap from dowsers and “ancient” ways of finding water to a science-based, observational approach that looked for a “thalweg” on and below the land surface. Paramelle’s ideas may seem quaint to us today, but they helped him find water on the dry limestone plateaus. His methods were used well into the 1970s in France. Paramelle set forth general rules for finding groundwater and practical methods of determining its depth and volume. Paramelle readily admitted that hydrogeology is not an exact science, but its laws are valid in most cases. Thus, Paramelle moves into statistics and probability.

Darcy and Paramelle focused on different branches of hydrology. Darcy the engineer, used mathematics to simplify problems, whereas Paramelle focused in the infinitely varied natural conditions where groundwater is found. Modern hydrogeology is founded on both.