1893

• The United States Public Health Service reports that "... at certain times of the year the [Potomac] river is so loaded with sediments as to be unfit for bathing as well as for drinking and cooking purposes. It contains fecal bacilli at all times..."

1898

• The first biological survey is conducted on the Potomac River.

1902

• President Theodore Roosevelt focuses national attention on protection of the nation’s water and forest resources in his first State of the Union address.

1905

• United States Geologic Survey reports that the turbidity in the Potomac River is 3000 parts per million (ppm) during floods and 15-20 ppm during a normal low flow.

1911

• Eighty-four species of fish are found in the Potomac River and its tributaries