System monitors flood-prone creeks

Creek Level Monitor

When rain is forecast in Palo Alto, Calif., city workers and residents may

turn to a new Web site to learn 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, Matadero 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, police officers and other emergency personnel had to scramble

to bridges to check gauges and radio in the readings about every 20 minutes.

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 is then made available online.

The dynamic creek monitor graphically represents the creek beds at five

bridge locations. 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 the San Francisco Bay to flush the ecosystem to keep it from drying

out.

Many agencies and flood districts have flood prediction Web sites relying

on historical data, but Ballard said he knows of no one 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.