System monitors flood-prone creeks

Creek Level Monitor

With rain forecast for the next few days, Palo Alto, Calif., city workers and residents may turn to a new Web site to find out how fast their creeks are rising.

The Creek Level Monitor is a welcome warning tool for people who still vividly remember when the San Francisquito, Matadoro and Adobe creeks overflowed their banks in 1998, said John Ballard, who supervises the storm drain system for the city's Department of Public Works.

At that time, policemen and other emergency personnel had to scramble to bridges to check gauges and radio in the readings every 20 minutes or so.

Now the Web-based system has become an integral part of emergency management operations.

"Local residents watch this very religiously," Ballard said. "We created it so residents can get this information themselves."

After the 1998 flood, Palo Alto Public Works installed ultrasonic devices on bridges and wired them to adjacent storm pump stations to provide remote water-level measurements. The data is transferred by an existing communications system that controls the pumps and made available on the Internet.

The dynamic creek monitor represents the creek beds at five bridge locations graphically. Water levels are shown in blue. An accompanying line graph shows creek, tide and flood basin levels for the preceding 12 hours. Other data includes 24-hour and annual rainfall totals. There's even a Creek Cam at a bridge over West Bayshore Road.

The system also helps park rangers remotely monitor and maintain water levels in the flood basin, which serves as a wildlife and bird sanctuary. Using electric gates on a man-made levy, the rangers periodically allow water from San Francisco Bay to flush the ecosystem to keep it from drying out.

Many agencies and flood districts have flood-prediction Web sites that rely on historical data, but Ballard said, "I don't know of anybody else" that provides current information. The Creek Level Monitor is updated every three minutes.

Future plans call for the system to integrate data from rain gauges in the regional watershed to help predict creek levels before they reach critical levels, Ballard said.