Tides and Floods

Tides and Floods. . , The lower Schuylkill River is tidal, rising and falling an average of 5.5 feet twice a day. Large areas along the river in South and Southwest Philadelphia originally consisted of marshy beaches, which naturally developed to handle the ebb and flow of tidal waters. This large surface area also gave plenty of room for storm water to spread out. The plants and soil of the marshes were well suited to handle periodic flooding., Over the centuries, dams, wharves, bulkheads, and land infill have changed the shape of the Schuylkill. This, in turn, affects how it reacts to tides and floods. The river's now steep and narrow sides leave less room for tide and rain water to spread out and gradually get absorbed. This can lead to dramatic flooding conditions, with high water levels infiltrating the city and causing property damage., Riverfront greenways like Schuylkill Banks play an important role in helping to manage a city's stormwater. Trees, shrubs, and meadows absorb rain so less water enters the river on a regular basis, and the park space creates a buffer to protect homes and businesses along the river from flooding during periods of heavy rainfall or snow melt., [Captions:] , Map showing wetlands south of Philadelphia in the 1680s., Major flooding of the Schuylkill near Race Street following Hurricane Agnes in 1972., Schuylkill River flooding at Walnut Street on May 1, 2014., River traffic on the Schuylkill River by Grays Ferry in the 1850s. The banks were predominately natural marsh.