USGS experts on Wednesday surveyed water levels at Coyote Creek which spilled into nighborhoods and streets in San Jose Tuesday, causing historic floods. Experts said "it wasn't so much the velocity, it was the quantity of water that caused the flooding." "We're in unchartered territory," Anthony Guerriero with USGS said. Hydrologists with USGS used all kinds of tools to monitor water flow. They were pleased to see water levels drop as predicted, especially after Tuesday's powerful flooding ripped a measuring stick from its cement base. The job of the USGS is to measure and provide data. NOAA and the Santa Clara Valley Water District make decisions based on that data. The USGS understands how those agencies were caught off guard. "No one really knows how the channel is going to react, especially after multiple years of drought. The channel's chock full of vegetation and debris, just made it even worse," Guerriero said. He says there's little historical data for Coyote Creek, making it very hard to make predictions. Creek waters are lower today, but still flowing at historic highs.