Owing to the growing conflict in Europe, the U.S. Army established a large base at Bowman Field in 1940. Studies undertaken during its construction led the U.S. Surgeon General's office to contact the City Board of Trustees to complain about the community's sewage. At the time, the houses used separate septic tanks, but their functioning was greatly impaired by the area's exposed and porous limestone. Sewage was draining into the city's streams and ditches and running into Beargrass Creek, affecting the new army base. Preparations for the construction of a unified sewer were suspended by the entrance of the United States into World War II in late 1941, bringing in wartime rationing of men and materiel.