A proliferation of new life forms such as free-sporing vascular plants began to sprout and spread across the land, forming extensive woodlands, jungle-type environments, and forests that covered the continents. The Devonian Period was also the age when trees evolved; plants thrived and grew into giants. As the flora spread across the Appalachian Basin their root systems broke up the soil and created huge amounts of nutrients, which ran off into the surrounding waters. The topics of shale oil mining, hydraulic fracturing, and produced wastewater are no different. Produced water and flowback from natural gas extraction may be reused in fracking operations, disposed of through underground injection, discharged to surface waters as long as it does not degrade water quality standards. In 1850, Henri Darcy, the city water engineer for Dijon, France, received endless complaints about the filthy water coming from the city mains.