![Colored ink drawing showing drainage areas and sewer inlets in Philaelphia in the early 19th century](https://waterhistoryphl.org/wp-content/uploads/DrainageAreas_20050020521.jpg?w=300)
![Colored ink drawing showing drainage areas and sewer inlets in Philaelphia in the early 19th century](https://waterhistoryphl.org/wp-content/uploads/DrainageAreas_20050020521.jpg?w=300)
Filling valleys and other lowlands, cutting down high ground, piping streams into sewers, filling marshland, dredging and damming streams and rivers, and any other activities or infrastructure designed to alter the original topography of the city to more readily accommodate real estate development.