While there was a scarcity of water on the surface, there was an excess of water underground in all the mines. Floods in the mines were sudden and miners narrowly escaped being drowned by vast underground reservoirs that were unexpectedly tapped. Intrusion of scalding-hot water into the mines was a large problem, and the expense of water removal increased as depths increased. To overcome these troubles, Adolph Sutro conceived the idea of running a drain tunnel under the Comstock Lode from the lowest possible point. A survey was made by Schussler and work commenced in October 1869.