Surrounded by concrete and brick buildings and asphalt streets, this limestone valley still serves as a collecting basin for Valley Creek. Before the 1870 build-out of downtown, the ground beneath probably supported oak-maple forests. The Valley Creek basin, once covered in trees, was replaced with impervious surface. Rainfall that hits the concrete, cobble, or asphalt streets flows downhill to the nearest storm drain rather than soaking into the soil. Today, the origins of Valley Creek are something of a mystery. Most of it was diverted into underground pipes and paved over many decades ago. The first daylight it sees is at the corner of 7th Street North and 5th Avenue North, near Legion Field. From there, Valley Creek travels to meet the Black Warrior River west of town.
The Railroad Park design offered an alternative to conventional stormwater run-off. The designers created a stormwater circulation system through the park and under the park. On the surface, the rainfall flows through the constructed wetlands, lakes, and streambeds, providing habitat for ducks as well as spectacular vistas and the peaceful sounds of falling water. At the end of the stream on the west side of the park, a hidden piping system draws the water back up to the wetland to start its journey again through the park. A series of reservoirs holds enough water to irrigate the entire park. Needed floodwater storage was created by excavating for this water system, using the spoils to create a series of knolls that bring the view of active trains to eye level.
The 19-acre park collects rainfall each year and recycles all of it onsite. That’s a lot of water that used to make its journey over dusty streets directly into Valley Creek. Where does the water go? Some evaporates into the air, some is used by the park crew to water the plants, and some soaks into the grass and recharges the groundwater like it did before 1870.