Edited sentence: East of Market Street, and along both sides of the Christina River, the land is flat, low-lying and marshy in places.On the western side of Market Street the topography is hilly and rises to a point that marks the watershed between the Brandywine River and the Christina River.The hilly and therefore heathier west side, was more attractive for the original residential areas.The topography and soil conditions affected the residential development pattern within the city.This watershed line runs along Delaware Avenue westward from 10th Street and Market Street