Retaining Walls and Hardbed

Retaining walls are vertical cemented walls built along the banks of Strawberry Creek where bank erosion and flooding pose a threat. They were first built soon after wide-spread destructive flooding in 1962, and the creek has rarely overflown since. In practice, concrete retaining walls have harmful effects on ecosystem health because they remove the natural variation in creek flow, can cause water to be sluggish, and accumulate extra sediment over the creek beds, which buries habitats. Currently, many of these retaining walls are undercut and unstable, which threatens the foundations of buildings nearby. For instance, when a concrete wall was failing at Stephens Hall Bridge, Creeks of UC Berkeley oversaw the installation of a redwood crib wall with native vegetation. The redwood decomposed and the native plant’s roots controlled erosion. Funny how natural systems work well when we return to using them appropriately!