City Flood Control System Under Siege
By Mike Lee
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When a sinkhole bigger than a commuter bus opened up on a University City road earlier this month, it created a headache for people who work nearby. The cause was traced to a corrugated metal storm water pipe, which today is known for chronic failures. Most residents only think about such things when heavy rains roll across the region and expose weaknesses in the storm water system. But just out of sight, water continually erodes San Diego’s sprawling flood-control network and sediment continually reduces its capacity.
“The potential exists for problems like this — maybe not with the same level of impact, but the same underlying cause — to occur in places throughout the city,” said Bill Harris, a spokesman for the city’s Storm Water Division. The maze of pipes and drains needs a city-estimated $246 million for patching spots with known and suspected problems, including areas where buckling pavement suggests the potential for more sinkholes. The other major issue facing the city’s stormwater system is that San Diego lacks critical environmental signoffs for maintaining open channels and creeks that residents depend on for protection from seasonal flooding. At 2 p.m. Monday, the Storm Water Division will seek approval from the City Council to clear out many of the waterways that have become clogged with dirt, rocks, garbage and plants. Councilmembers signaled sympathy for such efforts on Tuesday when they approved more work in the flood-prone Tijuana River Valley despite concerns about ecological impacts.
That work could cost $3 million a year, including disposal costs for up to 30,000 cubic yards a year of contaminated trash and sediment removed from the channels. “We need the channel clean before somebody does get killed,” said Dan Winne president of Happy Trails Horse Rentals, who has witnessed catastrophic flooding in recent years. “At least it will drain the water away from the ranches, away from the people and will protect them in some way.”
San Diegans for Open Government, a nonprofit advocacy group, challenged the city’s plan on several fronts, saying that it will damage wetlands and did not undergo adequate public review. The council unanimously upheld the staff’s plan, which means sand dredging could start by late November if rain doesn’t make the site impassable. “I appreciate the statements about protecting the environment, but we have to protect business and homes and lives, too,” said council member Marti Emerald. “In many ways, this kind of … ongoing maintenance is probably healthier for the environment than doing nothing.” San Diego’s challenges with money and environmental permits are mirrored across the country, where key pieces of water infrastructure are falling apart due to lack of investment and environmentalists advocated for rethinking management of creeks and channels that drain urban areas to the ocean.
The city and other local governments have struggled for years to find a balance between flood control and protection of rare wetland habitat, much of which has been lost to development. The stakes are particularly high this fall given the acrimony that erupted last winter when San Diego and environmentalists battled over flood control projects while the region was under a deluge. City crews ended up removing debris from some bottlenecks, but green groups were able to thwart work at other spots with lawsuits that said the city was improperly using emergency exemptions in places where problems have been known for years.
On Monday, the debate at City Hall will center on a 20-year blueprint for improving the flow of water through 32 miles of channels that city officials and environmentalists have debated over the past two years. City officials estimated the overall cost at $60 million, including extensive environmental restoration to make up for damage done by the work. San Diego is seeking the overarching permits in hopes of streamling the permitting process for each stretch of channel, what can be a costly and time-consuming process. The city’s goal is to start work under the master permit in September.
Environmentalists have opposed the need for some of the city’s proposals, which they say are unnecessary for flood control and damaging to streamside habitat. They also said the city hasn’t done enough cumulative review of the projects and they want the Storm Water Division to be more accountable to the public as detailed work plans take shape. “The biggest issue … is accountability,” said Gabriel Solmer, advocacy director for San Diego Coastkeeper. She said the city hasn’t gone far enough to invite public comment on site-specific plans. “I don’t think that is the message the city should be sending to residents who want to be involved,” she said.
At the Storm Water Division, Harris said the city made major revisions to appease conservationists, including a pledge not to clear vegetation in about one-third of the flood channels and providing detailed descriptions of staging spots and access routes where work is planned. “We will be performing surgical maintenance,” Harris said. “It’s a huge commitment, but a commitment that is born out of the understanding of the priority our community places on these areas.” Whatever the council decides about the open waterways, San Diego still will have a long list of failing pipes that typically are costly to replace but not controversial. The most problematic ones are made of corrugated metal, which came into vogue during the 1950s and remained popular for decades because it’s lighter than other options and easier to use for corners and other tight spots. Today, the city prefers reinforced concrete pipe. But storm water managers still count about 38 miles of corrugated metal pipe — which the city banned in 1992 — and acknowledge that there could be other stretches that may only be found when they fail.
Even though the $246 million bill for deferred maintenance seems huge, Harris said San Diego has been making solid progress given the citywide budget cuts. Over the past year, for example, the storm water agency has spent about $10 million from a bond to make upgrades such as pump station retrofits in flood-prone Pacific Beach. Corrugated pipe replacement is the top priority for roughly $30 million the Storm Water Division is seeking in the next city infrastructure bond issue expected in the spring.
Crews from the San Diego Urban Corps have been working the past two months to remove the nonnative water primrose from the San Diego River in Santee. The Urban Corps’ Habitat Management Services will continue to be along the Mission Creek/Mast Park section of the river, working through the early part of December to get rid of the invasive plant with yellow flowers and green leaves. The plant, native to South America, grows in thick mats that slow the river’s flow, reduce the water’s dissolved oxygen level and raise the water temperature. The vine-like plant is also a habitat for mosquito larvae.
Of course, the inspiration for one of the first vertical gardens in the region is bigger than salsa. The idea is to cultivate urban residents’ interest in homegrown food, explore new ways of adding plants to the landscape and introduce a practice that is popular in Europe but is just starting to take root in the United States. “My vision was to have these cornstalks so high that they can be seen from the freeway,” Sam Duran, CEO of the Urban Corps, said as cars whizzed past on Interstate 5.