The atmospheric river that swept through the Bay Area Sunday through Monday was a mixed blessing, filling reservoirs and creeks again but flooding low-lying areas like Witter Field and knocking over trees and power lines. The National Weather Service reported on Tuesday that the Oakland Hills received over 4″ of rain in 72 hours.
After years without torrential downpours, many residents were dismayed to find water in their basements when sump pumps failed.
A tree down on Winsor took power lines with it. (Photo courtesy of Tanya Vawter) 
Water seeped into a central Piedmont home when a sump pump failed
Witter Field, which hasn’t flooded recently due to the drought, looked like a placid lake when the rain stopped. The last replacement of turf and track was in 2007; winter rain has presented a challenge for the field’s underground drainage system. In 2019 estimates to repair the field were around $3 million. (See “Witter must wait”, Feb. 2019)
Bushy Dell Creek in Piedmont Park roared back to life, creating cascades of water and sending a stream of debris to the bottom of the park by the PHS softball field.
A veritable waterfall spilling down from the top of the park 
Halfway down the creek almost overflows its banks 
Storm debris clogs the drainage system at the bottom of the park 
A maintenance worker clears debris from a blocked storm drain
Intense downpours are definitely predicted to occur with climate change. The city is currently mapping the storm system and that will help scale the need and costs of repair. If it’s a private drainage system connecting to the public system thats failing them that’s accost for the property owner.
I’m not sure about the storm drain system being in such good shape; I had Old Faithful in my backyard caused by a break in the line. A huge hole remains. When I called Public Works, their response was that this was happening in several parts of town and that our storm drain system simply cannot handle such downpours. So if atmospheric rivers are the way our future storms will arrive, we will have to upgrade the storm system to handle this byproduct of climate change.
A silver lining of these recent storm events is that they show the city’s storm water system is in pretty good shape. No major overflows, slides, or flooding after above average storm events. Once the sewer system is repaired, probably within 10 years, the city will want use the sewer tax revenue for storm water system repair. But if that infrastructure is fine why not repurpose the tax for facility maintenance? Fix what is broken, not what isn’t.