What if it floods again?

<p>The numbers are significant — $56 million in flood damage, preceded by 13 days of rain, leading to evacuation orders for four mobile home parks.</p><p>For the victims, the 2005 New Year’s Eve flood was significant, too — they told their stories of ruined cars, soggy homes and nervous nights to city officials in the aftermath, sometimes with harsh words.</p><p>But the following winter, the difference was like night and day — little rain, no major flooding and perhaps some calmer nerves.</p><p>With the two-year anniversary of Petaluma’s last big flood coming up, those in charge of managing the Petaluma River watershed are hoping for the best, but making preparations for the worst.</p><p>And they’ve got some more significant numbers — two dozen stretches of local creeks cleared of mud and debris over two years, 40,000 cubic yards of built-up river silt removed and one old railroad bridge taken down, bringing the flood-control project to full strength.</p><p>Making room for water</p><p>Perhaps the most important piece of flood-prevention work completed in Petaluma was the removal of the railroad trestle.</p><p>After numerous delays due to canceled funding and even a visit by Sen. Barbara Boxer and Congresswoman Lynn Woolsey to the bridge near Lakeville Street last year, the U.S. Army Corps of Engineers completed the $3.2 million removal last week.</p><p>The bridge, part of a railroad spur line that crossed the Petaluma River from Hunt & Behrens to Dairymen’s Feed, acted as a bottleneck in the river during heavy flows.</p><p>Debris would get caught around its pilings and start slowing down the flow of water, causing the river level to rise.</p><p>Indeed, with its removal, the $43 million Payran flood control project upstream now operates at 100 percent capacity, city officials said. With the bridge in place, the flood project — more than 20 years in the making — was only 65 percent effective.</p><p>Some minor work — filling a gap in the flood wall and excavating some silt — remains to be done before the Payran flood fix is officially complete, but those projects don’t impact the flow of water like the bridge did.</p><p>Another positive flood-protection step this year was the completion of river dredging, officials said. The river had not been dredged since 2003, and the heavy storms of 2005-2006 dumped a lot of unexpected silt into the waterway — leaving less room to accommodate winter water flows within the banks.</p><p>The $1.6 million dredging work — from the Turning Basin south to the tip of the McNear Peninsula and in the marina — was mainly funded by the Federal Emergency Management Agency, with the city paying $385,000 of the cost.</p><p>In addition, the city and the Sonoma County Water Agency again collaborated on creek maintenance, particularly those waterways that run near areas that flooded in 2005.</p><p>Last year, 10 segments of local creeks were cleared of vegetation, debris and mud that slow down the flow of water from the hills above the Petaluma valley into the river.</p><p>This year, the two bodies are tackling 14 stream segments in work currently under way.</p><p>Segments of Capri Creek and East Washington Creek were the worst, said Ron Benkert, the water agency’s head of stream maintenance.</p><p>Where Capri Creek flows under Maria Drive, “the box culvert under the road crossing was pretty full,” he said. On East Washington Creek, near Garfield Drive, the culvert under Garfield was “completely full of sediment.”</p><p>Dean Eckerson, a water department engineer for the city, said Petaluma crews have also done significant creek maintenance work, in addition to routine steps like clearing catchment basins of leaves before winter.</p><p>A drainage ditch along Corona Road in front of the post office, leading to the intersection with North McDowell Boulevard, “was silted in and full of tules,” Eckerson said. “That’s been a problem area for some time.”</p><p>Crews dug out the ditch, which acts as a tributary to Corona Creek, he said.</p><p>And after Benkert’s crews did their work on East Washington Creek, the city was able to dig out storm drain outfall pipes that had been buried under sediment, Eckerson said.</p><p>Both men said the dry spring, while bad for Sonoma County’s supply of drinking water, benefited flood protection and runoff drainage by not washing debris and mud into creek channels.</p><p>“We’ve not seen the extensive erosion and sedimentation, so that’s a plus side,” Eckerson said.</p><p>They also said maintenance in the Petaluma watershed has increased in the past few years, but will need to continue to stay effective.</p><p>“The last couple of years, we’ve been pretty successful in addressing the priority areas,” Eckerson said.</p><p>“I think we’re starting to catch up,” Benkert said. “The cattails keeps coming back every year and the sediment builds up every year, so it is a continual maintenance effort for us.”</p><p>If Petalumans see a maintenance problem in a local creek, Benkert said they can call his office at the water agency at 521-1845.</p><p>Planning for problems</p><p>This fall, city officials (with the help of local Boy Scouts) hand-delivered five-page packets of information on flood protection to north Petaluma mobile home parks, the auto mall and businesses along Industrial Avenue.</p><p>The information — also available on the city’s Web site, www.cityofpetaluma.net, explains what residents and business owners should do to prepare for flooding.</p><p>“The public has some responsibility for their own safety,” Fire Chief Chris Albertson said. “Be aware of your surroundings, monitor the creeks and monitor the weather reports.”</p><p>Petaluma emergency workers will be doing the same, he said.</p><p>“We watch the tides, we watch the weather reports, we watch our urban creek electronic monitoring devices and we make decisions on what is prudent,” Albertson said.</p><p>The Petaluma River watershed is like a bowl, he said, that slowly fills with water delivered by urban creeks during heavy rain.</p><p>Typically, if flooding occurs, it happens first at Penngrove Park along Lichau Creek, he said.</p><p>When that happens, the fire department stations an ambulance and fire engine in Leisure Lake mobile home park on Stony Point Road.</p><p>“If we have to evacuate, we will,” Albertson said.</p><p>If Stony Point floods, the mobile home park becomes an island, so firefighters and police evacuate residents to the community center so they are not cut off from help.</p><p>But residents and business owners along the river can help prepare for that possibility ahead of time, the city said, advising the following steps:</p><p>n If flooding is possible, valuable items in a home or office should be moved off the floor.</p><p>n Outdoor objects should be brought inside so they don’t float away and cause damage.</p><p>n Important papers, medications and other necessary items should be gathered together in case of evacuation.</p><p>n Store clean drinking water and turn off utilities.</p><p>n Don’t walk or drive through flooded areas and stay away from downed power lines.</p><p>Again this year, the city will be updating a telephone hotline with weather information at 781-1283.</p><p>(Contact Corey Young at corey.young@arguscourier.com)</p>