Existing comment:
Plan for Draining and Grading:
Washington DC's low-lying land has been prone to flooding since the shortly after its inception, as development silted up or blocked the Potomac River's flow. In 1900 the US Army Corps of Engineers commissioned an engineering firm to design new grading and drains, noted in red, to improve the National Mall and the area between Pennsylvania Avenue NW and today's Independence Avenue SW. At right is Capitol Hill.
US Army Corps of Engineers, 1900 |