Impact of Infrastructure on Flood Damage

Alexander Luckow

It’s no surprise to anyone that this year’s weather has been crazy: on and off rainstorms have flooded the streets, rock and mudslides have closed roads, and tidal surges have damaged the Capitola wharf. Yet, the design of many places in Santa Cruz may be causing these damaging storms to have a much more potent impact than in previous times.

Take PCS for example: the new amphitheater that was added a few years ago has been closed ever since the rains started. Runoff water from the steps has accumulated in the dirt walkways and have rendered the amphitheater to be overflowing with mud. The previous gravel design was able to absorb water and prevent mud from forming, while the new compact dirt design fails spectacularly. This is only one simple instance of flawed design at PCS, yet flawed design is not just contained to PCS.

The San Lorenzo levy system is another instance of flawed design. Levees were built in the 50s after devastating floods. The city of Santa Cruz was originally supposed to periodically dredge the levy so water would be able to flow smoothly through the channel. However, this became expensive, and instead the city relied on the current to remove the sediment. Unfortunately, “…2.4-5.7 m/s were used in design calculations …[and] the extreme change in velocity detailed in the design manual [do not] occur” (Griggs). Therefore, due to the flawed design of the San Lorenzo levies, sediment buildup is occurring at much higher levels than expected and risks causing floods.

Therefore, flawed design is a major contributing factor in how water runoff damages areas and causes long lasting issues that later generations can’t fix. As such, people must reevaluate the design of these water systems and propose better solutions that help address this important issue. The levee breach near the Pajaro River is just more evidence for us up in Santa Cruz to act now and repair our failing infrastructure.

Griggs, G. B., & Paris, L. (1982). Flood control failure: San Lorenzo River, California. Environmental Management, 6(5), 407–419.